Merge pull request 'MyFSIO v0.1.6 Release' (#7) from next into main

Reviewed-on: #7

README.md

@@ -86,7 +86,7 @@ Presigned URLs follow the AWS CLI playbook:
 | `AWS_REGION` | `us-east-1` | Region used in Signature V4 scope |
 | `AWS_SERVICE` | `s3` | Service used in Signature V4 scope |
 
-> Buckets now live directly under `data/` while system metadata (versions, IAM, bucket policies, multipart uploads, etc.) lives in `data/.myfsio.sys`. Existing installs can keep their environment variables, but the defaults now match MinIO's `data/.system` pattern for easier bind-mounting.
+> Buckets now live directly under `data/` while system metadata (versions, IAM, bucket policies, multipart uploads, etc.) lives in `data/.myfsio.sys`.
 
 ## API Cheatsheet (IAM headers required)
 

app/__init__.py

@@ -2,13 +2,14 @@
 from __future__ import annotations
 
 import logging
+import shutil
 import sys
 import time
 import uuid
 from logging.handlers import RotatingFileHandler
 from pathlib import Path
 from datetime import timedelta
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
 
 from flask import Flask, g, has_request_context, redirect, render_template, request, url_for
 from flask_cors import CORS
@@ -18,14 +19,43 @@ from werkzeug.middleware.proxy_fix import ProxyFix
 from .bucket_policies import BucketPolicyStore
 from .config import AppConfig
 from .connections import ConnectionStore
+from .encryption import EncryptionManager
 from .extensions import limiter, csrf
 from .iam import IamService
+from .kms import KMSManager
 from .replication import ReplicationManager
 from .secret_store import EphemeralSecretStore
 from .storage import ObjectStorage
 from .version import get_version
 
 
+def _migrate_config_file(active_path: Path, legacy_paths: List[Path]) -> Path:
+    """Migrate config file from legacy locations to the active path.
+    
+    Checks each legacy path in order and moves the first one found to the active path.
+    This ensures backward compatibility for users upgrading from older versions.
+    """
+    active_path.parent.mkdir(parents=True, exist_ok=True)
+    
+    if active_path.exists():
+        return active_path
+    
+    for legacy_path in legacy_paths:
+        if legacy_path.exists():
+            try:
+                shutil.move(str(legacy_path), str(active_path))
+            except OSError:
+                # Fall back to copy + delete if move fails (e.g., cross-device)
+                shutil.copy2(legacy_path, active_path)
+                try:
+                    legacy_path.unlink(missing_ok=True)
+                except OSError:
+                    pass
+            break
+    
+    return active_path
+
+
 def create_app(
     test_config: Optional[Dict[str, Any]] = None,
     *,
@@ -72,12 +102,50 @@ def create_app(
     secret_store = EphemeralSecretStore(default_ttl=app.config.get("SECRET_TTL_SECONDS", 300))
     
     # Initialize Replication components
-    connections_path = Path(app.config["STORAGE_ROOT"]) / ".connections.json"
+    # Store config files in the system config directory for consistency
-    replication_rules_path = Path(app.config["STORAGE_ROOT"]) / ".replication_rules.json"
+    storage_root = Path(app.config["STORAGE_ROOT"])
+    config_dir = storage_root / ".myfsio.sys" / "config"
+    config_dir.mkdir(parents=True, exist_ok=True)
+    
+    # Define paths with migration from legacy locations
+    connections_path = _migrate_config_file(
+        active_path=config_dir / "connections.json",
+        legacy_paths=[
+            storage_root / ".myfsio.sys" / "connections.json",  # Previous location
+            storage_root / ".connections.json",  # Original legacy location
+        ],
+    )
+    replication_rules_path = _migrate_config_file(
+        active_path=config_dir / "replication_rules.json",
+        legacy_paths=[
+            storage_root / ".myfsio.sys" / "replication_rules.json",  # Previous location
+            storage_root / ".replication_rules.json",  # Original legacy location
+        ],
+    )
     
     connections = ConnectionStore(connections_path)
     replication = ReplicationManager(storage, connections, replication_rules_path)
     
+    # Initialize encryption and KMS
+    encryption_config = {
+        "encryption_enabled": app.config.get("ENCRYPTION_ENABLED", False),
+        "encryption_master_key_path": app.config.get("ENCRYPTION_MASTER_KEY_PATH"),
+        "default_encryption_algorithm": app.config.get("DEFAULT_ENCRYPTION_ALGORITHM", "AES256"),
+    }
+    encryption_manager = EncryptionManager(encryption_config)
+    
+    kms_manager = None
+    if app.config.get("KMS_ENABLED", False):
+        kms_keys_path = Path(app.config.get("KMS_KEYS_PATH", ""))
+        kms_master_key_path = Path(app.config.get("ENCRYPTION_MASTER_KEY_PATH", ""))
+        kms_manager = KMSManager(kms_keys_path, kms_master_key_path)
+        encryption_manager.set_kms_provider(kms_manager)
+
+    # Wrap storage with encryption layer if encryption is enabled
+    if app.config.get("ENCRYPTION_ENABLED", False):
+        from .encrypted_storage import EncryptedObjectStorage
+        storage = EncryptedObjectStorage(storage, encryption_manager)
+
     app.extensions["object_storage"] = storage
     app.extensions["iam"] = iam
     app.extensions["bucket_policies"] = bucket_policies
@@ -85,6 +153,8 @@ def create_app(
     app.extensions["limiter"] = limiter
     app.extensions["connections"] = connections
     app.extensions["replication"] = replication
+    app.extensions["encryption"] = encryption_manager
+    app.extensions["kms"] = kms_manager
 
     @app.errorhandler(500)
     def internal_error(error):
@@ -119,9 +189,12 @@ def create_app(
 
     if include_api:
         from .s3_api import s3_api_bp
+        from .kms_api import kms_api_bp
 
         app.register_blueprint(s3_api_bp)
+        app.register_blueprint(kms_api_bp)
         csrf.exempt(s3_api_bp)
+        csrf.exempt(kms_api_bp)
 
     if include_ui:
         from .ui import ui_bp
@@ -158,14 +231,12 @@ def create_ui_app(test_config: Optional[Dict[str, Any]] = None) -> Flask:
 
 def _configure_cors(app: Flask) -> None:
     origins = app.config.get("CORS_ORIGINS", ["*"])
-    methods = app.config.get("CORS_METHODS", ["GET", "PUT", "POST", "DELETE", "OPTIONS"])
+    methods = app.config.get("CORS_METHODS", ["GET", "PUT", "POST", "DELETE", "OPTIONS", "HEAD"])
-    allow_headers = app.config.get(
+    allow_headers = app.config.get("CORS_ALLOW_HEADERS", ["*"])
-        "CORS_ALLOW_HEADERS",
+    expose_headers = app.config.get("CORS_EXPOSE_HEADERS", ["*"])
-        ["Content-Type", "X-Access-Key", "X-Secret-Key", "X-Amz-Date", "X-Amz-SignedHeaders"],
-    )
     CORS(
         app,
-        resources={r"/*": {"origins": origins, "methods": methods, "allow_headers": allow_headers}},
+        resources={r"/*": {"origins": origins, "methods": methods, "allow_headers": allow_headers, "expose_headers": expose_headers}},
         supports_credentials=True,
     )
 

app/bucket_policies.py

@@ -11,17 +11,51 @@ from typing import Any, Dict, Iterable, List, Optional, Sequence
 RESOURCE_PREFIX = "arn:aws:s3:::"
 
 ACTION_ALIASES = {
-    "s3:getobject": "read",
+    # List actions
-    "s3:getobjectversion": "read",
     "s3:listbucket": "list",
     "s3:listallmybuckets": "list",
+    "s3:listbucketversions": "list",
+    "s3:listmultipartuploads": "list",
+    "s3:listparts": "list",
+    # Read actions
+    "s3:getobject": "read",
+    "s3:getobjectversion": "read",
+    "s3:getobjecttagging": "read",
+    "s3:getobjectversiontagging": "read",
+    "s3:getobjectacl": "read",
+    "s3:getbucketversioning": "read",
+    "s3:headobject": "read",
+    "s3:headbucket": "read",
+    # Write actions
     "s3:putobject": "write",
     "s3:createbucket": "write",
+    "s3:putobjecttagging": "write",
+    "s3:putbucketversioning": "write",
+    "s3:createmultipartupload": "write",
+    "s3:uploadpart": "write",
+    "s3:completemultipartupload": "write",
+    "s3:abortmultipartupload": "write",
+    "s3:copyobject": "write",
+    # Delete actions
     "s3:deleteobject": "delete",
     "s3:deleteobjectversion": "delete",
     "s3:deletebucket": "delete",
+    "s3:deleteobjecttagging": "delete",
+    # Share actions (ACL)
     "s3:putobjectacl": "share",
+    "s3:putbucketacl": "share",
+    "s3:getbucketacl": "share",
+    # Policy actions
     "s3:putbucketpolicy": "policy",
+    "s3:getbucketpolicy": "policy",
+    "s3:deletebucketpolicy": "policy",
+    # Replication actions
+    "s3:getreplicationconfiguration": "replication",
+    "s3:putreplicationconfiguration": "replication",
+    "s3:deletereplicationconfiguration": "replication",
+    "s3:replicateobject": "replication",
+    "s3:replicatetags": "replication",
+    "s3:replicatedelete": "replication",
 }
 
 

app/config.py

@@ -50,6 +50,7 @@ class AppConfig:
     aws_service: str
     ui_enforce_bucket_policies: bool
     log_level: str
+    log_to_file: bool
     log_path: Path
     log_max_bytes: int
     log_backup_count: int
@@ -58,6 +59,7 @@ class AppConfig:
     cors_origins: list[str]
     cors_methods: list[str]
     cors_allow_headers: list[str]
+    cors_expose_headers: list[str]
     session_lifetime_days: int
     auth_max_attempts: int
     auth_lockout_minutes: int
@@ -66,6 +68,11 @@ class AppConfig:
     stream_chunk_size: int
     multipart_min_part_size: int
     bucket_stats_cache_ttl: int
+    encryption_enabled: bool
+    encryption_master_key_path: Path
+    kms_enabled: bool
+    kms_keys_path: Path
+    default_encryption_algorithm: str
 
     @classmethod
     def from_env(cls, overrides: Optional[Dict[str, Any]] = None) -> "AppConfig":
@@ -104,19 +111,19 @@ class AppConfig:
         iam_env_override = "IAM_CONFIG" in overrides or "IAM_CONFIG" in os.environ
         bucket_policy_override = "BUCKET_POLICY_PATH" in overrides or "BUCKET_POLICY_PATH" in os.environ
 
-        default_iam_path = PROJECT_ROOT / "data" / ".myfsio.sys" / "config" / "iam.json"
+        default_iam_path = storage_root / ".myfsio.sys" / "config" / "iam.json"
-        default_bucket_policy_path = PROJECT_ROOT / "data" / ".myfsio.sys" / "config" / "bucket_policies.json"
+        default_bucket_policy_path = storage_root / ".myfsio.sys" / "config" / "bucket_policies.json"
 
         iam_config_path = Path(_get("IAM_CONFIG", default_iam_path)).resolve()
         bucket_policy_path = Path(_get("BUCKET_POLICY_PATH", default_bucket_policy_path)).resolve()
 
         iam_config_path = _prepare_config_file(
             iam_config_path,
-            legacy_path=None if iam_env_override else PROJECT_ROOT / "data" / "iam.json",
+            legacy_path=None if iam_env_override else storage_root / "iam.json",
         )
         bucket_policy_path = _prepare_config_file(
             bucket_policy_path,
-            legacy_path=None if bucket_policy_override else PROJECT_ROOT / "data" / "bucket_policies.json",
+            legacy_path=None if bucket_policy_override else storage_root / "bucket_policies.json",
         )
         api_base_url = _get("API_BASE_URL", None)
         if api_base_url:
@@ -126,7 +133,8 @@ class AppConfig:
         aws_service = str(_get("AWS_SERVICE", "s3"))
         enforce_ui_policies = str(_get("UI_ENFORCE_BUCKET_POLICIES", "0")).lower() in {"1", "true", "yes", "on"}
         log_level = str(_get("LOG_LEVEL", "INFO")).upper()
-        log_dir = Path(_get("LOG_DIR", PROJECT_ROOT / "logs")).resolve()
+        log_to_file = str(_get("LOG_TO_FILE", "1")).lower() in {"1", "true", "yes", "on"}
+        log_dir = Path(_get("LOG_DIR", storage_root.parent / "logs")).resolve()
         log_dir.mkdir(parents=True, exist_ok=True)
         log_path = log_dir / str(_get("LOG_FILE", "app.log"))
         log_max_bytes = int(_get("LOG_MAX_BYTES", 5 * 1024 * 1024))
@@ -141,21 +149,20 @@ class AppConfig:
             return parts or default
 
         cors_origins = _csv(str(_get("CORS_ORIGINS", "*")), ["*"])
-        cors_methods = _csv(str(_get("CORS_METHODS", "GET,PUT,POST,DELETE,OPTIONS")), ["GET", "PUT", "POST", "DELETE", "OPTIONS"])
+        cors_methods = _csv(str(_get("CORS_METHODS", "GET,PUT,POST,DELETE,OPTIONS,HEAD")), ["GET", "PUT", "POST", "DELETE", "OPTIONS", "HEAD"])
-        cors_allow_headers = _csv(str(_get("CORS_ALLOW_HEADERS", "Content-Type,X-Access-Key,X-Secret-Key,X-Amz-Algorithm,X-Amz-Credential,X-Amz-Date,X-Amz-Expires,X-Amz-SignedHeaders,X-Amz-Signature")), [
+        cors_allow_headers = _csv(str(_get("CORS_ALLOW_HEADERS", "*")), ["*"])
-            "Content-Type",
+        cors_expose_headers = _csv(str(_get("CORS_EXPOSE_HEADERS", "*")), ["*"])
-            "X-Access-Key",
-            "X-Secret-Key",
-            "X-Amz-Algorithm",
-            "X-Amz-Credential",
-            "X-Amz-Date",
-            "X-Amz-Expires",
-            "X-Amz-SignedHeaders",
-            "X-Amz-Signature",
-        ])
         session_lifetime_days = int(_get("SESSION_LIFETIME_DAYS", 30))
         bucket_stats_cache_ttl = int(_get("BUCKET_STATS_CACHE_TTL", 60))  # Default 60 seconds
         
+        # Encryption settings
+        encryption_enabled = str(_get("ENCRYPTION_ENABLED", "0")).lower() in {"1", "true", "yes", "on"}
+        encryption_keys_dir = storage_root / ".myfsio.sys" / "keys"
+        encryption_master_key_path = Path(_get("ENCRYPTION_MASTER_KEY_PATH", encryption_keys_dir / "master.key")).resolve()
+        kms_enabled = str(_get("KMS_ENABLED", "0")).lower() in {"1", "true", "yes", "on"}
+        kms_keys_path = Path(_get("KMS_KEYS_PATH", encryption_keys_dir / "kms_keys.json")).resolve()
+        default_encryption_algorithm = str(_get("DEFAULT_ENCRYPTION_ALGORITHM", "AES256"))
+
         return cls(storage_root=storage_root,
                    max_upload_size=max_upload_size,
                    ui_page_size=ui_page_size,
@@ -167,6 +174,7 @@ class AppConfig:
                    aws_service=aws_service,
                    ui_enforce_bucket_policies=enforce_ui_policies,
                    log_level=log_level,
+                   log_to_file=log_to_file,
                    log_path=log_path,
                    log_max_bytes=log_max_bytes,
                    log_backup_count=log_backup_count,
@@ -175,6 +183,7 @@ class AppConfig:
                    cors_origins=cors_origins,
                    cors_methods=cors_methods,
                    cors_allow_headers=cors_allow_headers,
+                   cors_expose_headers=cors_expose_headers,
                    session_lifetime_days=session_lifetime_days,
                    auth_max_attempts=auth_max_attempts,
                    auth_lockout_minutes=auth_lockout_minutes,
@@ -182,7 +191,108 @@ class AppConfig:
                    secret_ttl_seconds=secret_ttl_seconds,
                    stream_chunk_size=stream_chunk_size,
                    multipart_min_part_size=multipart_min_part_size,
-                   bucket_stats_cache_ttl=bucket_stats_cache_ttl)
+                   bucket_stats_cache_ttl=bucket_stats_cache_ttl,
+                   encryption_enabled=encryption_enabled,
+                   encryption_master_key_path=encryption_master_key_path,
+                   kms_enabled=kms_enabled,
+                   kms_keys_path=kms_keys_path,
+                   default_encryption_algorithm=default_encryption_algorithm)
+
+    def validate_and_report(self) -> list[str]:
+        """Validate configuration and return a list of warnings/issues.
+        
+        Call this at startup to detect potential misconfigurations before
+        the application fully commits to running.
+        """
+        issues = []
+        
+        # Check if storage_root is writable
+        try:
+            test_file = self.storage_root / ".write_test"
+            test_file.touch()
+            test_file.unlink()
+        except (OSError, PermissionError) as e:
+            issues.append(f"CRITICAL: STORAGE_ROOT '{self.storage_root}' is not writable: {e}")
+        
+        # Check if storage_root looks like a temp directory
+        storage_str = str(self.storage_root).lower()
+        if "/tmp" in storage_str or "\\temp" in storage_str or "appdata\\local\\temp" in storage_str:
+            issues.append(f"WARNING: STORAGE_ROOT '{self.storage_root}' appears to be a temporary directory. Data may be lost on reboot!")
+        
+        # Check if IAM config path is under storage_root
+        try:
+            self.iam_config_path.relative_to(self.storage_root)
+        except ValueError:
+            issues.append(f"WARNING: IAM_CONFIG '{self.iam_config_path}' is outside STORAGE_ROOT '{self.storage_root}'. Consider setting IAM_CONFIG explicitly or ensuring paths are aligned.")
+        
+        # Check if bucket policy path is under storage_root
+        try:
+            self.bucket_policy_path.relative_to(self.storage_root)
+        except ValueError:
+            issues.append(f"WARNING: BUCKET_POLICY_PATH '{self.bucket_policy_path}' is outside STORAGE_ROOT '{self.storage_root}'. Consider setting BUCKET_POLICY_PATH explicitly.")
+        
+        # Check if log path is writable
+        try:
+            self.log_path.parent.mkdir(parents=True, exist_ok=True)
+            test_log = self.log_path.parent / ".write_test"
+            test_log.touch()
+            test_log.unlink()
+        except (OSError, PermissionError) as e:
+            issues.append(f"WARNING: Log directory '{self.log_path.parent}' is not writable: {e}")
+        
+        # Check log path location
+        log_str = str(self.log_path).lower()
+        if "/tmp" in log_str or "\\temp" in log_str or "appdata\\local\\temp" in log_str:
+            issues.append(f"WARNING: LOG_DIR '{self.log_path.parent}' appears to be a temporary directory. Logs may be lost on reboot!")
+        
+        # Check if encryption keys path is under storage_root (when encryption is enabled)
+        if self.encryption_enabled:
+            try:
+                self.encryption_master_key_path.relative_to(self.storage_root)
+            except ValueError:
+                issues.append(f"WARNING: ENCRYPTION_MASTER_KEY_PATH '{self.encryption_master_key_path}' is outside STORAGE_ROOT. Ensure proper backup procedures.")
+        
+        # Check if KMS keys path is under storage_root (when KMS is enabled)
+        if self.kms_enabled:
+            try:
+                self.kms_keys_path.relative_to(self.storage_root)
+            except ValueError:
+                issues.append(f"WARNING: KMS_KEYS_PATH '{self.kms_keys_path}' is outside STORAGE_ROOT. Ensure proper backup procedures.")
+        
+        # Warn about production settings
+        if self.secret_key == "dev-secret-key":
+            issues.append("WARNING: Using default SECRET_KEY. Set SECRET_KEY environment variable for production.")
+        
+        if "*" in self.cors_origins:
+            issues.append("INFO: CORS_ORIGINS is set to '*'. Consider restricting to specific domains in production.")
+        
+        return issues
+
+    def print_startup_summary(self) -> None:
+        """Print a summary of the configuration at startup."""
+        print("\n" + "=" * 60)
+        print("MyFSIO Configuration Summary")
+        print("=" * 60)
+        print(f"  STORAGE_ROOT:     {self.storage_root}")
+        print(f"  IAM_CONFIG:       {self.iam_config_path}")
+        print(f"  BUCKET_POLICY:    {self.bucket_policy_path}")
+        print(f"  LOG_PATH:         {self.log_path}")
+        if self.api_base_url:
+            print(f"  API_BASE_URL:     {self.api_base_url}")
+        if self.encryption_enabled:
+            print(f"  ENCRYPTION:       Enabled (Master key: {self.encryption_master_key_path})")
+        if self.kms_enabled:
+            print(f"  KMS:              Enabled (Keys: {self.kms_keys_path})")
+        print("=" * 60)
+        
+        issues = self.validate_and_report()
+        if issues:
+            print("\nConfiguration Issues Detected:")
+            for issue in issues:
+                print(f"  • {issue}")
+            print()
+        else:
+            print("  ✓ Configuration validated successfully\n")
 
     def to_flask_config(self) -> Dict[str, Any]:
         return {
@@ -204,6 +314,7 @@ class AppConfig:
             "MULTIPART_MIN_PART_SIZE": self.multipart_min_part_size,
             "BUCKET_STATS_CACHE_TTL": self.bucket_stats_cache_ttl,
             "LOG_LEVEL": self.log_level,
+            "LOG_TO_FILE": self.log_to_file,
             "LOG_FILE": str(self.log_path),
             "LOG_MAX_BYTES": self.log_max_bytes,
             "LOG_BACKUP_COUNT": self.log_backup_count,
@@ -212,5 +323,11 @@ class AppConfig:
             "CORS_ORIGINS": self.cors_origins,
             "CORS_METHODS": self.cors_methods,
             "CORS_ALLOW_HEADERS": self.cors_allow_headers,
+            "CORS_EXPOSE_HEADERS": self.cors_expose_headers,
             "SESSION_LIFETIME_DAYS": self.session_lifetime_days,
+            "ENCRYPTION_ENABLED": self.encryption_enabled,
+            "ENCRYPTION_MASTER_KEY_PATH": str(self.encryption_master_key_path),
+            "KMS_ENABLED": self.kms_enabled,
+            "KMS_KEYS_PATH": str(self.kms_keys_path),
+            "DEFAULT_ENCRYPTION_ALGORITHM": self.default_encryption_algorithm,
         }

app/encrypted_storage.py

@@ -0,0 +1,276 @@
+"""Encrypted storage layer that wraps ObjectStorage with encryption support."""
+from __future__ import annotations
+
+import io
+from pathlib import Path
+from typing import Any, BinaryIO, Dict, Optional
+
+from .encryption import EncryptionManager, EncryptionMetadata, EncryptionError
+from .storage import ObjectStorage, ObjectMeta, StorageError
+
+
+class EncryptedObjectStorage:
+    """Object storage with transparent server-side encryption.
+    
+    This class wraps ObjectStorage and provides transparent encryption/decryption
+    of objects based on bucket encryption configuration.
+    
+    Encryption is applied when:
+    1. Bucket has default encryption configured (SSE-S3 or SSE-KMS)
+    2. Client explicitly requests encryption via headers
+    
+    The encryption metadata is stored alongside object metadata.
+    """
+    
+    STREAMING_THRESHOLD = 64 * 1024
+    
+    def __init__(self, storage: ObjectStorage, encryption_manager: EncryptionManager):
+        self.storage = storage
+        self.encryption = encryption_manager
+    
+    @property
+    def root(self) -> Path:
+        return self.storage.root
+    
+    def _should_encrypt(self, bucket_name: str, 
+                        server_side_encryption: str | None = None) -> tuple[bool, str, str | None]:
+        """Determine if object should be encrypted.
+        
+        Returns:
+            Tuple of (should_encrypt, algorithm, kms_key_id)
+        """
+        if not self.encryption.enabled:
+            return False, "", None
+        
+        if server_side_encryption:
+            if server_side_encryption == "AES256":
+                return True, "AES256", None
+            elif server_side_encryption.startswith("aws:kms"):
+                parts = server_side_encryption.split(":")
+                kms_key_id = parts[2] if len(parts) > 2 else None
+                return True, "aws:kms", kms_key_id
+        
+        try:
+            encryption_config = self.storage.get_bucket_encryption(bucket_name)
+            if encryption_config and encryption_config.get("Rules"):
+                rule = encryption_config["Rules"][0]
+                # AWS format: Rules[].ApplyServerSideEncryptionByDefault.SSEAlgorithm
+                sse_default = rule.get("ApplyServerSideEncryptionByDefault", {})
+                algorithm = sse_default.get("SSEAlgorithm", "AES256")
+                kms_key_id = sse_default.get("KMSMasterKeyID")
+                return True, algorithm, kms_key_id
+        except StorageError:
+            pass
+        
+        return False, "", None
+    
+    def _is_encrypted(self, metadata: Dict[str, str]) -> bool:
+        """Check if object is encrypted based on its metadata."""
+        return "x-amz-server-side-encryption" in metadata
+    
+    def put_object(
+        self,
+        bucket_name: str,
+        object_key: str,
+        stream: BinaryIO,
+        *,
+        metadata: Optional[Dict[str, str]] = None,
+        server_side_encryption: Optional[str] = None,
+        kms_key_id: Optional[str] = None,
+    ) -> ObjectMeta:
+        """Store an object, optionally with encryption.
+        
+        Args:
+            bucket_name: Name of the bucket
+            object_key: Key for the object
+            stream: Binary stream of object data
+            metadata: Optional user metadata
+            server_side_encryption: Encryption algorithm ("AES256" or "aws:kms")
+            kms_key_id: KMS key ID (for aws:kms encryption)
+        
+        Returns:
+            ObjectMeta with object information
+        """
+        should_encrypt, algorithm, detected_kms_key = self._should_encrypt(
+            bucket_name, server_side_encryption
+        )
+        
+        if kms_key_id is None:
+            kms_key_id = detected_kms_key
+        
+        if should_encrypt:
+            data = stream.read()
+            
+            try:
+                ciphertext, enc_metadata = self.encryption.encrypt_object(
+                    data, 
+                    algorithm=algorithm,
+                    kms_key_id=kms_key_id,
+                    context={"bucket": bucket_name, "key": object_key},
+                )
+                
+                combined_metadata = metadata.copy() if metadata else {}
+                combined_metadata.update(enc_metadata.to_dict())
+                
+                encrypted_stream = io.BytesIO(ciphertext)
+                result = self.storage.put_object(
+                    bucket_name,
+                    object_key,
+                    encrypted_stream,
+                    metadata=combined_metadata,
+                )
+                
+                result.metadata = combined_metadata
+                return result
+                
+            except EncryptionError as exc:
+                raise StorageError(f"Encryption failed: {exc}") from exc
+        else:
+            return self.storage.put_object(
+                bucket_name,
+                object_key,
+                stream,
+                metadata=metadata,
+            )
+    
+    def get_object_data(self, bucket_name: str, object_key: str) -> tuple[bytes, Dict[str, str]]:
+        """Get object data, decrypting if necessary.
+        
+        Returns:
+            Tuple of (data, metadata)
+        """
+        path = self.storage.get_object_path(bucket_name, object_key)
+        metadata = self.storage.get_object_metadata(bucket_name, object_key)
+        
+        with path.open("rb") as f:
+            data = f.read()
+        
+        enc_metadata = EncryptionMetadata.from_dict(metadata)
+        if enc_metadata:
+            try:
+                data = self.encryption.decrypt_object(
+                    data,
+                    enc_metadata,
+                    context={"bucket": bucket_name, "key": object_key},
+                )
+            except EncryptionError as exc:
+                raise StorageError(f"Decryption failed: {exc}") from exc
+        
+        clean_metadata = {
+            k: v for k, v in metadata.items()
+            if not k.startswith("x-amz-encryption") 
+            and k != "x-amz-encrypted-data-key"
+        }
+        
+        return data, clean_metadata
+    
+    def get_object_stream(self, bucket_name: str, object_key: str) -> tuple[BinaryIO, Dict[str, str], int]:
+        """Get object as a stream, decrypting if necessary.
+        
+        Returns:
+            Tuple of (stream, metadata, original_size)
+        """
+        data, metadata = self.get_object_data(bucket_name, object_key)
+        return io.BytesIO(data), metadata, len(data)
+    
+    def list_buckets(self):
+        return self.storage.list_buckets()
+    
+    def bucket_exists(self, bucket_name: str) -> bool:
+        return self.storage.bucket_exists(bucket_name)
+    
+    def create_bucket(self, bucket_name: str) -> None:
+        return self.storage.create_bucket(bucket_name)
+    
+    def delete_bucket(self, bucket_name: str) -> None:
+        return self.storage.delete_bucket(bucket_name)
+    
+    def bucket_stats(self, bucket_name: str, cache_ttl: int = 60):
+        return self.storage.bucket_stats(bucket_name, cache_ttl)
+    
+    def list_objects(self, bucket_name: str):
+        return self.storage.list_objects(bucket_name)
+    
+    def get_object_path(self, bucket_name: str, object_key: str):
+        return self.storage.get_object_path(bucket_name, object_key)
+    
+    def get_object_metadata(self, bucket_name: str, object_key: str):
+        return self.storage.get_object_metadata(bucket_name, object_key)
+    
+    def delete_object(self, bucket_name: str, object_key: str) -> None:
+        return self.storage.delete_object(bucket_name, object_key)
+    
+    def purge_object(self, bucket_name: str, object_key: str) -> None:
+        return self.storage.purge_object(bucket_name, object_key)
+    
+    def is_versioning_enabled(self, bucket_name: str) -> bool:
+        return self.storage.is_versioning_enabled(bucket_name)
+    
+    def set_bucket_versioning(self, bucket_name: str, enabled: bool) -> None:
+        return self.storage.set_bucket_versioning(bucket_name, enabled)
+    
+    def get_bucket_tags(self, bucket_name: str):
+        return self.storage.get_bucket_tags(bucket_name)
+    
+    def set_bucket_tags(self, bucket_name: str, tags):
+        return self.storage.set_bucket_tags(bucket_name, tags)
+    
+    def get_bucket_cors(self, bucket_name: str):
+        return self.storage.get_bucket_cors(bucket_name)
+    
+    def set_bucket_cors(self, bucket_name: str, rules):
+        return self.storage.set_bucket_cors(bucket_name, rules)
+    
+    def get_bucket_encryption(self, bucket_name: str):
+        return self.storage.get_bucket_encryption(bucket_name)
+    
+    def set_bucket_encryption(self, bucket_name: str, config_payload):
+        return self.storage.set_bucket_encryption(bucket_name, config_payload)
+    
+    def get_bucket_lifecycle(self, bucket_name: str):
+        return self.storage.get_bucket_lifecycle(bucket_name)
+    
+    def set_bucket_lifecycle(self, bucket_name: str, rules):
+        return self.storage.set_bucket_lifecycle(bucket_name, rules)
+    
+    def get_object_tags(self, bucket_name: str, object_key: str):
+        return self.storage.get_object_tags(bucket_name, object_key)
+    
+    def set_object_tags(self, bucket_name: str, object_key: str, tags):
+        return self.storage.set_object_tags(bucket_name, object_key, tags)
+    
+    def delete_object_tags(self, bucket_name: str, object_key: str):
+        return self.storage.delete_object_tags(bucket_name, object_key)
+    
+    def list_object_versions(self, bucket_name: str, object_key: str):
+        return self.storage.list_object_versions(bucket_name, object_key)
+    
+    def restore_object_version(self, bucket_name: str, object_key: str, version_id: str):
+        return self.storage.restore_object_version(bucket_name, object_key, version_id)
+    
+    def list_orphaned_objects(self, bucket_name: str):
+        return self.storage.list_orphaned_objects(bucket_name)
+    
+    def initiate_multipart_upload(self, bucket_name: str, object_key: str, *, metadata=None) -> str:
+        return self.storage.initiate_multipart_upload(bucket_name, object_key, metadata=metadata)
+    
+    def upload_multipart_part(self, bucket_name: str, upload_id: str, part_number: int, stream: BinaryIO) -> str:
+        return self.storage.upload_multipart_part(bucket_name, upload_id, part_number, stream)
+    
+    def complete_multipart_upload(self, bucket_name: str, upload_id: str, ordered_parts):
+        return self.storage.complete_multipart_upload(bucket_name, upload_id, ordered_parts)
+    
+    def abort_multipart_upload(self, bucket_name: str, upload_id: str) -> None:
+        return self.storage.abort_multipart_upload(bucket_name, upload_id)
+    
+    def list_multipart_parts(self, bucket_name: str, upload_id: str):
+        return self.storage.list_multipart_parts(bucket_name, upload_id)
+    
+    def get_bucket_quota(self, bucket_name: str):
+        return self.storage.get_bucket_quota(bucket_name)
+    
+    def set_bucket_quota(self, bucket_name: str, *, max_bytes=None, max_objects=None):
+        return self.storage.set_bucket_quota(bucket_name, max_bytes=max_bytes, max_objects=max_objects)
+    
+    def _compute_etag(self, path: Path) -> str:
+        return self.storage._compute_etag(path)

app/encryption.py

@@ -0,0 +1,395 @@
+"""Encryption providers for server-side and client-side encryption."""
+from __future__ import annotations
+
+import base64
+import io
+import json
+import secrets
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, BinaryIO, Dict, Generator, Optional
+
+from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+
+
+class EncryptionError(Exception):
+    """Raised when encryption/decryption fails."""
+
+
+@dataclass
+class EncryptionResult:
+    """Result of encrypting data."""
+    ciphertext: bytes
+    nonce: bytes
+    key_id: str
+    encrypted_data_key: bytes
+
+
+@dataclass
+class EncryptionMetadata:
+    """Metadata stored with encrypted objects."""
+    algorithm: str
+    key_id: str
+    nonce: bytes
+    encrypted_data_key: bytes
+    
+    def to_dict(self) -> Dict[str, str]:
+        return {
+            "x-amz-server-side-encryption": self.algorithm,
+            "x-amz-encryption-key-id": self.key_id,
+            "x-amz-encryption-nonce": base64.b64encode(self.nonce).decode(),
+            "x-amz-encrypted-data-key": base64.b64encode(self.encrypted_data_key).decode(),
+        }
+    
+    @classmethod
+    def from_dict(cls, data: Dict[str, str]) -> Optional["EncryptionMetadata"]:
+        algorithm = data.get("x-amz-server-side-encryption")
+        if not algorithm:
+            return None
+        try:
+            return cls(
+                algorithm=algorithm,
+                key_id=data.get("x-amz-encryption-key-id", "local"),
+                nonce=base64.b64decode(data.get("x-amz-encryption-nonce", "")),
+                encrypted_data_key=base64.b64decode(data.get("x-amz-encrypted-data-key", "")),
+            )
+        except Exception:
+            return None
+
+
+class EncryptionProvider:
+    """Base class for encryption providers."""
+    
+    def encrypt(self, plaintext: bytes, context: Dict[str, str] | None = None) -> EncryptionResult:
+        raise NotImplementedError
+    
+    def decrypt(self, ciphertext: bytes, nonce: bytes, encrypted_data_key: bytes,
+                key_id: str, context: Dict[str, str] | None = None) -> bytes:
+        raise NotImplementedError
+    
+    def generate_data_key(self) -> tuple[bytes, bytes]:
+        """Generate a data key and its encrypted form.
+        
+        Returns:
+            Tuple of (plaintext_key, encrypted_key)
+        """
+        raise NotImplementedError
+
+
+class LocalKeyEncryption(EncryptionProvider):
+    """SSE-S3 style encryption using a local master key.
+    
+    Uses envelope encryption:
+    1. Generate a unique data key for each object
+    2. Encrypt the data with the data key (AES-256-GCM)
+    3. Encrypt the data key with the master key
+    4. Store the encrypted data key alongside the ciphertext
+    """
+    
+    KEY_ID = "local"
+    
+    def __init__(self, master_key_path: Path):
+        self.master_key_path = master_key_path
+        self._master_key: bytes | None = None
+    
+    @property
+    def master_key(self) -> bytes:
+        if self._master_key is None:
+            self._master_key = self._load_or_create_master_key()
+        return self._master_key
+    
+    def _load_or_create_master_key(self) -> bytes:
+        """Load master key from file or generate a new one."""
+        if self.master_key_path.exists():
+            try:
+                return base64.b64decode(self.master_key_path.read_text().strip())
+            except Exception as exc:
+                raise EncryptionError(f"Failed to load master key: {exc}") from exc
+        
+        key = secrets.token_bytes(32)
+        try:
+            self.master_key_path.parent.mkdir(parents=True, exist_ok=True)
+            self.master_key_path.write_text(base64.b64encode(key).decode())
+        except OSError as exc:
+            raise EncryptionError(f"Failed to save master key: {exc}") from exc
+        return key
+    
+    def _encrypt_data_key(self, data_key: bytes) -> bytes:
+        """Encrypt the data key with the master key."""
+        aesgcm = AESGCM(self.master_key)
+        nonce = secrets.token_bytes(12)
+        encrypted = aesgcm.encrypt(nonce, data_key, None)
+        return nonce + encrypted
+    
+    def _decrypt_data_key(self, encrypted_data_key: bytes) -> bytes:
+        """Decrypt the data key using the master key."""
+        if len(encrypted_data_key) < 12 + 32 + 16:  # nonce + key + tag
+            raise EncryptionError("Invalid encrypted data key")
+        aesgcm = AESGCM(self.master_key)
+        nonce = encrypted_data_key[:12]
+        ciphertext = encrypted_data_key[12:]
+        try:
+            return aesgcm.decrypt(nonce, ciphertext, None)
+        except Exception as exc:
+            raise EncryptionError(f"Failed to decrypt data key: {exc}") from exc
+    
+    def generate_data_key(self) -> tuple[bytes, bytes]:
+        """Generate a data key and its encrypted form."""
+        plaintext_key = secrets.token_bytes(32)
+        encrypted_key = self._encrypt_data_key(plaintext_key)
+        return plaintext_key, encrypted_key
+    
+    def encrypt(self, plaintext: bytes, context: Dict[str, str] | None = None) -> EncryptionResult:
+        """Encrypt data using envelope encryption."""
+        data_key, encrypted_data_key = self.generate_data_key()
+        
+        aesgcm = AESGCM(data_key)
+        nonce = secrets.token_bytes(12)
+        ciphertext = aesgcm.encrypt(nonce, plaintext, None)
+        
+        return EncryptionResult(
+            ciphertext=ciphertext,
+            nonce=nonce,
+            key_id=self.KEY_ID,
+            encrypted_data_key=encrypted_data_key,
+        )
+    
+    def decrypt(self, ciphertext: bytes, nonce: bytes, encrypted_data_key: bytes,
+                key_id: str, context: Dict[str, str] | None = None) -> bytes:
+        """Decrypt data using envelope encryption."""
+        # Decrypt the data key
+        data_key = self._decrypt_data_key(encrypted_data_key)
+        
+        # Decrypt the data
+        aesgcm = AESGCM(data_key)
+        try:
+            return aesgcm.decrypt(nonce, ciphertext, None)
+        except Exception as exc:
+            raise EncryptionError(f"Failed to decrypt data: {exc}") from exc
+
+
+class StreamingEncryptor:
+    """Encrypts/decrypts data in streaming fashion for large files.
+    
+    For large files, we encrypt in chunks. Each chunk is encrypted with the
+    same data key but a unique nonce derived from the base nonce + chunk index.
+    """
+    
+    CHUNK_SIZE = 64 * 1024  
+    HEADER_SIZE = 4  
+    
+    def __init__(self, provider: EncryptionProvider, chunk_size: int = CHUNK_SIZE):
+        self.provider = provider
+        self.chunk_size = chunk_size
+    
+    def _derive_chunk_nonce(self, base_nonce: bytes, chunk_index: int) -> bytes:
+        """Derive a unique nonce for each chunk."""
+        # XOR the base nonce with the chunk index
+        nonce_int = int.from_bytes(base_nonce, "big")
+        derived = nonce_int ^ chunk_index
+        return derived.to_bytes(12, "big")
+    
+    def encrypt_stream(self, stream: BinaryIO, 
+                       context: Dict[str, str] | None = None) -> tuple[BinaryIO, EncryptionMetadata]:
+        """Encrypt a stream and return encrypted stream + metadata."""
+
+        data_key, encrypted_data_key = self.provider.generate_data_key()
+        base_nonce = secrets.token_bytes(12)
+        
+        aesgcm = AESGCM(data_key)
+        encrypted_chunks = []
+        chunk_index = 0
+        
+        while True:
+            chunk = stream.read(self.chunk_size)
+            if not chunk:
+                break
+            
+            chunk_nonce = self._derive_chunk_nonce(base_nonce, chunk_index)
+            encrypted_chunk = aesgcm.encrypt(chunk_nonce, chunk, None)
+            
+            size_prefix = len(encrypted_chunk).to_bytes(self.HEADER_SIZE, "big")
+            encrypted_chunks.append(size_prefix + encrypted_chunk)
+            chunk_index += 1
+        
+        header = chunk_index.to_bytes(4, "big")
+        encrypted_data = header + b"".join(encrypted_chunks)
+        
+        metadata = EncryptionMetadata(
+            algorithm="AES256",
+            key_id=self.provider.KEY_ID if hasattr(self.provider, "KEY_ID") else "local",
+            nonce=base_nonce,
+            encrypted_data_key=encrypted_data_key,
+        )
+        
+        return io.BytesIO(encrypted_data), metadata
+    
+    def decrypt_stream(self, stream: BinaryIO, metadata: EncryptionMetadata) -> BinaryIO:
+        """Decrypt a stream using the provided metadata."""
+        if isinstance(self.provider, LocalKeyEncryption):
+            data_key = self.provider._decrypt_data_key(metadata.encrypted_data_key)
+        else:
+            raise EncryptionError("Unsupported provider for streaming decryption")
+        
+        aesgcm = AESGCM(data_key)
+        base_nonce = metadata.nonce
+        
+        chunk_count_bytes = stream.read(4)
+        if len(chunk_count_bytes) < 4:
+            raise EncryptionError("Invalid encrypted stream: missing header")
+        chunk_count = int.from_bytes(chunk_count_bytes, "big")
+        
+        decrypted_chunks = []
+        for chunk_index in range(chunk_count):
+            size_bytes = stream.read(self.HEADER_SIZE)
+            if len(size_bytes) < self.HEADER_SIZE:
+                raise EncryptionError(f"Invalid encrypted stream: truncated at chunk {chunk_index}")
+            chunk_size = int.from_bytes(size_bytes, "big")
+            
+            encrypted_chunk = stream.read(chunk_size)
+            if len(encrypted_chunk) < chunk_size:
+                raise EncryptionError(f"Invalid encrypted stream: incomplete chunk {chunk_index}")
+            
+            chunk_nonce = self._derive_chunk_nonce(base_nonce, chunk_index)
+            try:
+                decrypted_chunk = aesgcm.decrypt(chunk_nonce, encrypted_chunk, None)
+                decrypted_chunks.append(decrypted_chunk)
+            except Exception as exc:
+                raise EncryptionError(f"Failed to decrypt chunk {chunk_index}: {exc}") from exc
+        
+        return io.BytesIO(b"".join(decrypted_chunks))
+
+
+class EncryptionManager:
+    """Manages encryption providers and operations."""
+    
+    def __init__(self, config: Dict[str, Any]):
+        self.config = config
+        self._local_provider: LocalKeyEncryption | None = None
+        self._kms_provider: Any = None  # Set by KMS module
+        self._streaming_encryptor: StreamingEncryptor | None = None
+    
+    @property
+    def enabled(self) -> bool:
+        return self.config.get("encryption_enabled", False)
+    
+    @property
+    def default_algorithm(self) -> str:
+        return self.config.get("default_encryption_algorithm", "AES256")
+    
+    def get_local_provider(self) -> LocalKeyEncryption:
+        if self._local_provider is None:
+            key_path = Path(self.config.get("encryption_master_key_path", "data/.myfsio.sys/keys/master.key"))
+            self._local_provider = LocalKeyEncryption(key_path)
+        return self._local_provider
+    
+    def set_kms_provider(self, kms_provider: Any) -> None:
+        """Set the KMS provider (injected from kms module)."""
+        self._kms_provider = kms_provider
+    
+    def get_provider(self, algorithm: str, kms_key_id: str | None = None) -> EncryptionProvider:
+        """Get the appropriate encryption provider for the algorithm."""
+        if algorithm == "AES256":
+            return self.get_local_provider()
+        elif algorithm == "aws:kms":
+            if self._kms_provider is None:
+                raise EncryptionError("KMS is not configured")
+            return self._kms_provider.get_provider(kms_key_id)
+        else:
+            raise EncryptionError(f"Unsupported encryption algorithm: {algorithm}")
+    
+    def get_streaming_encryptor(self) -> StreamingEncryptor:
+        if self._streaming_encryptor is None:
+            self._streaming_encryptor = StreamingEncryptor(self.get_local_provider())
+        return self._streaming_encryptor
+    
+    def encrypt_object(self, data: bytes, algorithm: str = "AES256",
+                       kms_key_id: str | None = None,
+                       context: Dict[str, str] | None = None) -> tuple[bytes, EncryptionMetadata]:
+        """Encrypt object data."""
+        provider = self.get_provider(algorithm, kms_key_id)
+        result = provider.encrypt(data, context)
+        
+        metadata = EncryptionMetadata(
+            algorithm=algorithm,
+            key_id=result.key_id,
+            nonce=result.nonce,
+            encrypted_data_key=result.encrypted_data_key,
+        )
+        
+        return result.ciphertext, metadata
+    
+    def decrypt_object(self, ciphertext: bytes, metadata: EncryptionMetadata,
+                       context: Dict[str, str] | None = None) -> bytes:
+        """Decrypt object data."""
+        provider = self.get_provider(metadata.algorithm, metadata.key_id)
+        return provider.decrypt(
+            ciphertext,
+            metadata.nonce,
+            metadata.encrypted_data_key,
+            metadata.key_id,
+            context,
+        )
+    
+    def encrypt_stream(self, stream: BinaryIO, algorithm: str = "AES256",
+                       context: Dict[str, str] | None = None) -> tuple[BinaryIO, EncryptionMetadata]:
+        """Encrypt a stream for large files."""
+        encryptor = self.get_streaming_encryptor()
+        return encryptor.encrypt_stream(stream, context)
+    
+    def decrypt_stream(self, stream: BinaryIO, metadata: EncryptionMetadata) -> BinaryIO:
+        """Decrypt a stream."""
+        encryptor = self.get_streaming_encryptor()
+        return encryptor.decrypt_stream(stream, metadata)
+
+
+class ClientEncryptionHelper:
+    """Helpers for client-side encryption.
+    
+    Client-side encryption is performed by the client, but this helper
+    provides key generation and materials for clients that need them.
+    """
+    
+    @staticmethod
+    def generate_client_key() -> Dict[str, str]:
+        """Generate a new client encryption key."""
+        from datetime import datetime, timezone
+        key = secrets.token_bytes(32)
+        return {
+            "key": base64.b64encode(key).decode(),
+            "algorithm": "AES-256-GCM",
+            "created_at": datetime.now(timezone.utc).isoformat(),
+        }
+    
+    @staticmethod
+    def encrypt_with_key(plaintext: bytes, key_b64: str) -> Dict[str, str]:
+        """Encrypt data with a client-provided key."""
+        key = base64.b64decode(key_b64)
+        if len(key) != 32:
+            raise EncryptionError("Key must be 256 bits (32 bytes)")
+        
+        aesgcm = AESGCM(key)
+        nonce = secrets.token_bytes(12)
+        ciphertext = aesgcm.encrypt(nonce, plaintext, None)
+        
+        return {
+            "ciphertext": base64.b64encode(ciphertext).decode(),
+            "nonce": base64.b64encode(nonce).decode(),
+            "algorithm": "AES-256-GCM",
+        }
+    
+    @staticmethod
+    def decrypt_with_key(ciphertext_b64: str, nonce_b64: str, key_b64: str) -> bytes:
+        """Decrypt data with a client-provided key."""
+        key = base64.b64decode(key_b64)
+        nonce = base64.b64decode(nonce_b64)
+        ciphertext = base64.b64decode(ciphertext_b64)
+        
+        if len(key) != 32:
+            raise EncryptionError("Key must be 256 bits (32 bytes)")
+        
+        aesgcm = AESGCM(key)
+        try:
+            return aesgcm.decrypt(nonce, ciphertext, None)
+        except Exception as exc:
+            raise EncryptionError(f"Decryption failed: {exc}") from exc

app/errors.py

@@ -129,6 +129,25 @@ class EntityTooLargeError(AppError):
     status_code: int = 413
 
 
+@dataclass
+class QuotaExceededAppError(AppError):
+    """Bucket quota exceeded."""
+    code: str = "QuotaExceeded"
+    message: str = "The bucket quota has been exceeded"
+    status_code: int = 403
+    quota: Optional[Dict[str, Any]] = None
+    usage: Optional[Dict[str, int]] = None
+    
+    def __post_init__(self):
+        if self.quota or self.usage:
+            self.details = {}
+            if self.quota:
+                self.details["quota"] = self.quota
+            if self.usage:
+                self.details["usage"] = self.usage
+        super().__post_init__()
+
+
 def handle_app_error(error: AppError) -> Response:
     """Handle application errors with appropriate response format."""
     log_extra = {"error_code": error.code}
@@ -163,5 +182,6 @@ def register_error_handlers(app):
         ObjectNotFoundError, InvalidObjectKeyError,
         AccessDeniedError, InvalidCredentialsError,
         MalformedRequestError, InvalidArgumentError, EntityTooLargeError,
+        QuotaExceededAppError,
     ]:
         app.register_error_handler(error_class, handle_app_error)

app/iam.py

@@ -15,7 +15,7 @@ class IamError(RuntimeError):
     """Raised when authentication or authorization fails."""
 
 
-S3_ACTIONS = {"list", "read", "write", "delete", "share", "policy"}
+S3_ACTIONS = {"list", "read", "write", "delete", "share", "policy", "replication"}
 IAM_ACTIONS = {
     "iam:list_users",
     "iam:create_user",
@@ -26,22 +26,59 @@ IAM_ACTIONS = {
 ALLOWED_ACTIONS = (S3_ACTIONS | IAM_ACTIONS) | {"iam:*"}
 
 ACTION_ALIASES = {
+    # List actions
     "list": "list",
     "s3:listbucket": "list",
     "s3:listallmybuckets": "list",
+    "s3:listbucketversions": "list",
+    "s3:listmultipartuploads": "list",
+    "s3:listparts": "list",
+    # Read actions
     "read": "read",
     "s3:getobject": "read",
     "s3:getobjectversion": "read",
+    "s3:getobjecttagging": "read",
+    "s3:getobjectversiontagging": "read",
+    "s3:getobjectacl": "read",
+    "s3:getbucketversioning": "read",
+    "s3:headobject": "read",
+    "s3:headbucket": "read",
+    # Write actions
     "write": "write",
     "s3:putobject": "write",
     "s3:createbucket": "write",
+    "s3:putobjecttagging": "write",
+    "s3:putbucketversioning": "write",
+    "s3:createmultipartupload": "write",
+    "s3:uploadpart": "write",
+    "s3:completemultipartupload": "write",
+    "s3:abortmultipartupload": "write",
+    "s3:copyobject": "write",
+    # Delete actions
     "delete": "delete",
     "s3:deleteobject": "delete",
+    "s3:deleteobjectversion": "delete",
     "s3:deletebucket": "delete",
+    "s3:deleteobjecttagging": "delete",
+    # Share actions (ACL)
     "share": "share",
     "s3:putobjectacl": "share",
+    "s3:putbucketacl": "share",
+    "s3:getbucketacl": "share",
+    # Policy actions
     "policy": "policy",
     "s3:putbucketpolicy": "policy",
+    "s3:getbucketpolicy": "policy",
+    "s3:deletebucketpolicy": "policy",
+    # Replication actions
+    "replication": "replication",
+    "s3:getreplicationconfiguration": "replication",
+    "s3:putreplicationconfiguration": "replication",
+    "s3:deletereplicationconfiguration": "replication",
+    "s3:replicateobject": "replication",
+    "s3:replicatetags": "replication",
+    "s3:replicatedelete": "replication",
+    # IAM actions
     "iam:listusers": "iam:list_users",
     "iam:createuser": "iam:create_user",
     "iam:deleteuser": "iam:delete_user",

app/kms.py

@@ -0,0 +1,344 @@
+"""Key Management Service (KMS) for encryption key management."""
+from __future__ import annotations
+
+import base64
+import json
+import secrets
+import uuid
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+
+from .encryption import EncryptionError, EncryptionProvider, EncryptionResult
+
+
+@dataclass
+class KMSKey:
+    """Represents a KMS encryption key."""
+    key_id: str
+    description: str
+    created_at: str
+    enabled: bool = True
+    key_material: bytes = field(default_factory=lambda: b"", repr=False)
+    
+    @property
+    def arn(self) -> str:
+        return f"arn:aws:kms:local:000000000000:key/{self.key_id}"
+    
+    def to_dict(self, include_key: bool = False) -> Dict[str, Any]:
+        data = {
+            "KeyId": self.key_id,
+            "Arn": self.arn,
+            "Description": self.description,
+            "CreationDate": self.created_at,
+            "Enabled": self.enabled,
+            "KeyState": "Enabled" if self.enabled else "Disabled",
+            "KeyUsage": "ENCRYPT_DECRYPT",
+            "KeySpec": "SYMMETRIC_DEFAULT",
+        }
+        if include_key:
+            data["KeyMaterial"] = base64.b64encode(self.key_material).decode()
+        return data
+    
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "KMSKey":
+        key_material = b""
+        if "KeyMaterial" in data:
+            key_material = base64.b64decode(data["KeyMaterial"])
+        return cls(
+            key_id=data["KeyId"],
+            description=data.get("Description", ""),
+            created_at=data.get("CreationDate", datetime.now(timezone.utc).isoformat()),
+            enabled=data.get("Enabled", True),
+            key_material=key_material,
+        )
+
+
+class KMSEncryptionProvider(EncryptionProvider):
+    """Encryption provider using a specific KMS key."""
+    
+    def __init__(self, kms: "KMSManager", key_id: str):
+        self.kms = kms
+        self.key_id = key_id
+    
+    @property
+    def KEY_ID(self) -> str:
+        return self.key_id
+    
+    def generate_data_key(self) -> tuple[bytes, bytes]:
+        """Generate a data key encrypted with the KMS key."""
+        return self.kms.generate_data_key(self.key_id)
+    
+    def encrypt(self, plaintext: bytes, context: Dict[str, str] | None = None) -> EncryptionResult:
+        """Encrypt data using envelope encryption with KMS."""
+        data_key, encrypted_data_key = self.generate_data_key()
+        
+        aesgcm = AESGCM(data_key)
+        nonce = secrets.token_bytes(12)
+        ciphertext = aesgcm.encrypt(nonce, plaintext, 
+                                     json.dumps(context).encode() if context else None)
+        
+        return EncryptionResult(
+            ciphertext=ciphertext,
+            nonce=nonce,
+            key_id=self.key_id,
+            encrypted_data_key=encrypted_data_key,
+        )
+    
+    def decrypt(self, ciphertext: bytes, nonce: bytes, encrypted_data_key: bytes,
+                key_id: str, context: Dict[str, str] | None = None) -> bytes:
+        """Decrypt data using envelope encryption with KMS."""
+        # Note: Data key is encrypted without context (AAD), so we decrypt without context
+        data_key = self.kms.decrypt_data_key(key_id, encrypted_data_key, context=None)
+        
+        aesgcm = AESGCM(data_key)
+        try:
+            return aesgcm.decrypt(nonce, ciphertext,
+                                  json.dumps(context).encode() if context else None)
+        except Exception as exc:
+            raise EncryptionError(f"Failed to decrypt data: {exc}") from exc
+
+
+class KMSManager:
+    """Manages KMS keys and operations.
+    
+    This is a local implementation that mimics AWS KMS functionality.
+    Keys are stored encrypted on disk.
+    """
+    
+    def __init__(self, keys_path: Path, master_key_path: Path):
+        self.keys_path = keys_path
+        self.master_key_path = master_key_path
+        self._keys: Dict[str, KMSKey] = {}
+        self._master_key: bytes | None = None
+        self._loaded = False
+    
+    @property
+    def master_key(self) -> bytes:
+        """Load or create the master key for encrypting KMS keys."""
+        if self._master_key is None:
+            if self.master_key_path.exists():
+                self._master_key = base64.b64decode(
+                    self.master_key_path.read_text().strip()
+                )
+            else:
+                self._master_key = secrets.token_bytes(32)
+                self.master_key_path.parent.mkdir(parents=True, exist_ok=True)
+                self.master_key_path.write_text(
+                    base64.b64encode(self._master_key).decode()
+                )
+        return self._master_key
+    
+    def _load_keys(self) -> None:
+        """Load keys from disk."""
+        if self._loaded:
+            return
+        
+        if self.keys_path.exists():
+            try:
+                data = json.loads(self.keys_path.read_text(encoding="utf-8"))
+                for key_data in data.get("keys", []):
+                    key = KMSKey.from_dict(key_data)
+                    if key_data.get("EncryptedKeyMaterial"):
+                        encrypted = base64.b64decode(key_data["EncryptedKeyMaterial"])
+                        key.key_material = self._decrypt_key_material(encrypted)
+                    self._keys[key.key_id] = key
+            except Exception:
+                pass
+        
+        self._loaded = True
+    
+    def _save_keys(self) -> None:
+        """Save keys to disk (with encrypted key material)."""
+        keys_data = []
+        for key in self._keys.values():
+            data = key.to_dict(include_key=False)
+            encrypted = self._encrypt_key_material(key.key_material)
+            data["EncryptedKeyMaterial"] = base64.b64encode(encrypted).decode()
+            keys_data.append(data)
+        
+        self.keys_path.parent.mkdir(parents=True, exist_ok=True)
+        self.keys_path.write_text(
+            json.dumps({"keys": keys_data}, indent=2),
+            encoding="utf-8"
+        )
+    
+    def _encrypt_key_material(self, key_material: bytes) -> bytes:
+        """Encrypt key material with the master key."""
+        aesgcm = AESGCM(self.master_key)
+        nonce = secrets.token_bytes(12)
+        ciphertext = aesgcm.encrypt(nonce, key_material, None)
+        return nonce + ciphertext
+    
+    def _decrypt_key_material(self, encrypted: bytes) -> bytes:
+        """Decrypt key material with the master key."""
+        aesgcm = AESGCM(self.master_key)
+        nonce = encrypted[:12]
+        ciphertext = encrypted[12:]
+        return aesgcm.decrypt(nonce, ciphertext, None)
+    
+    def create_key(self, description: str = "", key_id: str | None = None) -> KMSKey:
+        """Create a new KMS key."""
+        self._load_keys()
+        
+        if key_id is None:
+            key_id = str(uuid.uuid4())
+        
+        if key_id in self._keys:
+            raise EncryptionError(f"Key already exists: {key_id}")
+        
+        key = KMSKey(
+            key_id=key_id,
+            description=description,
+            created_at=datetime.now(timezone.utc).isoformat(),
+            enabled=True,
+            key_material=secrets.token_bytes(32),
+        )
+        
+        self._keys[key_id] = key
+        self._save_keys()
+        return key
+    
+    def get_key(self, key_id: str) -> KMSKey | None:
+        """Get a key by ID."""
+        self._load_keys()
+        return self._keys.get(key_id)
+    
+    def list_keys(self) -> List[KMSKey]:
+        """List all keys."""
+        self._load_keys()
+        return list(self._keys.values())
+    
+    def enable_key(self, key_id: str) -> None:
+        """Enable a key."""
+        self._load_keys()
+        key = self._keys.get(key_id)
+        if not key:
+            raise EncryptionError(f"Key not found: {key_id}")
+        key.enabled = True
+        self._save_keys()
+    
+    def disable_key(self, key_id: str) -> None:
+        """Disable a key."""
+        self._load_keys()
+        key = self._keys.get(key_id)
+        if not key:
+            raise EncryptionError(f"Key not found: {key_id}")
+        key.enabled = False
+        self._save_keys()
+    
+    def delete_key(self, key_id: str) -> None:
+        """Delete a key (schedule for deletion in real KMS)."""
+        self._load_keys()
+        if key_id not in self._keys:
+            raise EncryptionError(f"Key not found: {key_id}")
+        del self._keys[key_id]
+        self._save_keys()
+    
+    def encrypt(self, key_id: str, plaintext: bytes,
+                context: Dict[str, str] | None = None) -> bytes:
+        """Encrypt data directly with a KMS key."""
+        self._load_keys()
+        key = self._keys.get(key_id)
+        if not key:
+            raise EncryptionError(f"Key not found: {key_id}")
+        if not key.enabled:
+            raise EncryptionError(f"Key is disabled: {key_id}")
+        
+        aesgcm = AESGCM(key.key_material)
+        nonce = secrets.token_bytes(12)
+        aad = json.dumps(context).encode() if context else None
+        ciphertext = aesgcm.encrypt(nonce, plaintext, aad)
+        
+        key_id_bytes = key_id.encode("utf-8")
+        return len(key_id_bytes).to_bytes(2, "big") + key_id_bytes + nonce + ciphertext
+    
+    def decrypt(self, ciphertext: bytes,
+                context: Dict[str, str] | None = None) -> tuple[bytes, str]:
+        """Decrypt data directly with a KMS key.
+        
+        Returns:
+            Tuple of (plaintext, key_id)
+        """
+        self._load_keys()
+        
+        key_id_len = int.from_bytes(ciphertext[:2], "big")
+        key_id = ciphertext[2:2 + key_id_len].decode("utf-8")
+        rest = ciphertext[2 + key_id_len:]
+        
+        key = self._keys.get(key_id)
+        if not key:
+            raise EncryptionError(f"Key not found: {key_id}")
+        if not key.enabled:
+            raise EncryptionError(f"Key is disabled: {key_id}")
+        
+        nonce = rest[:12]
+        encrypted = rest[12:]
+        
+        aesgcm = AESGCM(key.key_material)
+        aad = json.dumps(context).encode() if context else None
+        try:
+            plaintext = aesgcm.decrypt(nonce, encrypted, aad)
+            return plaintext, key_id
+        except Exception as exc:
+            raise EncryptionError(f"Decryption failed: {exc}") from exc
+    
+    def generate_data_key(self, key_id: str,
+                          context: Dict[str, str] | None = None) -> tuple[bytes, bytes]:
+        """Generate a data key and return both plaintext and encrypted versions.
+        
+        Returns:
+            Tuple of (plaintext_key, encrypted_key)
+        """
+        self._load_keys()
+        key = self._keys.get(key_id)
+        if not key:
+            raise EncryptionError(f"Key not found: {key_id}")
+        if not key.enabled:
+            raise EncryptionError(f"Key is disabled: {key_id}")
+        
+        plaintext_key = secrets.token_bytes(32)
+
+        encrypted_key = self.encrypt(key_id, plaintext_key, context)
+        
+        return plaintext_key, encrypted_key
+    
+    def decrypt_data_key(self, key_id: str, encrypted_key: bytes,
+                         context: Dict[str, str] | None = None) -> bytes:
+        """Decrypt a data key."""
+        plaintext, _ = self.decrypt(encrypted_key, context)
+        return plaintext
+    
+    def get_provider(self, key_id: str | None = None) -> KMSEncryptionProvider:
+        """Get an encryption provider for a specific key."""
+        self._load_keys()
+        
+        if key_id is None:
+            if not self._keys:
+                key = self.create_key("Default KMS Key")
+                key_id = key.key_id
+            else:
+                key_id = next(iter(self._keys.keys()))
+        
+        if key_id not in self._keys:
+            raise EncryptionError(f"Key not found: {key_id}")
+        
+        return KMSEncryptionProvider(self, key_id)
+    
+    def re_encrypt(self, ciphertext: bytes, destination_key_id: str,
+                   source_context: Dict[str, str] | None = None,
+                   destination_context: Dict[str, str] | None = None) -> bytes:
+        """Re-encrypt data with a different key."""
+
+        plaintext, source_key_id = self.decrypt(ciphertext, source_context)
+        
+        return self.encrypt(destination_key_id, plaintext, destination_context)
+    
+    def generate_random(self, num_bytes: int = 32) -> bytes:
+        """Generate cryptographically secure random bytes."""
+        if num_bytes < 1 or num_bytes > 1024:
+            raise EncryptionError("Number of bytes must be between 1 and 1024")
+        return secrets.token_bytes(num_bytes)

app/kms_api.py

@@ -0,0 +1,463 @@
+"""KMS and encryption API endpoints."""
+from __future__ import annotations
+
+import base64
+import uuid
+from typing import Any, Dict
+
+from flask import Blueprint, Response, current_app, jsonify, request
+
+from .encryption import ClientEncryptionHelper, EncryptionError
+from .extensions import limiter
+from .iam import IamError
+
+kms_api_bp = Blueprint("kms_api", __name__, url_prefix="/kms")
+
+
+def _require_principal():
+    """Require authentication for KMS operations."""
+    from .s3_api import _require_principal as s3_require_principal
+    return s3_require_principal()
+
+
+def _kms():
+    """Get KMS manager from app extensions."""
+    return current_app.extensions.get("kms")
+
+
+def _encryption():
+    """Get encryption manager from app extensions."""
+    return current_app.extensions.get("encryption")
+
+
+def _error_response(code: str, message: str, status: int) -> tuple[Dict[str, Any], int]:
+    return {"__type": code, "message": message}, status
+
+
+# ---------------------- Key Management ----------------------
+
+@kms_api_bp.route("/keys", methods=["GET", "POST"])
+@limiter.limit("30 per minute")
+def list_or_create_keys():
+    """List all KMS keys or create a new key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    if request.method == "POST":
+        payload = request.get_json(silent=True) or {}
+        key_id = payload.get("KeyId") or payload.get("key_id")
+        description = payload.get("Description") or payload.get("description", "")
+        
+        try:
+            key = kms.create_key(description=description, key_id=key_id)
+            current_app.logger.info(
+                "KMS key created",
+                extra={"key_id": key.key_id, "principal": principal.access_key},
+            )
+            return jsonify({
+                "KeyMetadata": key.to_dict(),
+            })
+        except EncryptionError as exc:
+            return _error_response("KMSInternalException", str(exc), 400)
+    
+    # GET - List keys
+    keys = kms.list_keys()
+    return jsonify({
+        "Keys": [{"KeyId": k.key_id, "KeyArn": k.arn} for k in keys],
+        "Truncated": False,
+    })
+
+
+@kms_api_bp.route("/keys/<key_id>", methods=["GET", "DELETE"])
+@limiter.limit("30 per minute")
+def get_or_delete_key(key_id: str):
+    """Get or delete a specific KMS key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    if request.method == "DELETE":
+        try:
+            kms.delete_key(key_id)
+            current_app.logger.info(
+                "KMS key deleted",
+                extra={"key_id": key_id, "principal": principal.access_key},
+            )
+            return Response(status=204)
+        except EncryptionError as exc:
+            return _error_response("NotFoundException", str(exc), 404)
+    
+    # GET
+    key = kms.get_key(key_id)
+    if not key:
+        return _error_response("NotFoundException", f"Key not found: {key_id}", 404)
+    
+    return jsonify({"KeyMetadata": key.to_dict()})
+
+
+@kms_api_bp.route("/keys/<key_id>/enable", methods=["POST"])
+@limiter.limit("30 per minute")
+def enable_key(key_id: str):
+    """Enable a KMS key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    try:
+        kms.enable_key(key_id)
+        current_app.logger.info(
+            "KMS key enabled",
+            extra={"key_id": key_id, "principal": principal.access_key},
+        )
+        return Response(status=200)
+    except EncryptionError as exc:
+        return _error_response("NotFoundException", str(exc), 404)
+
+
+@kms_api_bp.route("/keys/<key_id>/disable", methods=["POST"])
+@limiter.limit("30 per minute")
+def disable_key(key_id: str):
+    """Disable a KMS key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    try:
+        kms.disable_key(key_id)
+        current_app.logger.info(
+            "KMS key disabled",
+            extra={"key_id": key_id, "principal": principal.access_key},
+        )
+        return Response(status=200)
+    except EncryptionError as exc:
+        return _error_response("NotFoundException", str(exc), 404)
+
+
+# ---------------------- Encryption Operations ----------------------
+
+@kms_api_bp.route("/encrypt", methods=["POST"])
+@limiter.limit("60 per minute")
+def encrypt_data():
+    """Encrypt data using a KMS key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    key_id = payload.get("KeyId")
+    plaintext_b64 = payload.get("Plaintext")
+    context = payload.get("EncryptionContext")
+    
+    if not key_id:
+        return _error_response("ValidationException", "KeyId is required", 400)
+    if not plaintext_b64:
+        return _error_response("ValidationException", "Plaintext is required", 400)
+    
+    try:
+        plaintext = base64.b64decode(plaintext_b64)
+    except Exception:
+        return _error_response("ValidationException", "Plaintext must be base64 encoded", 400)
+    
+    try:
+        ciphertext = kms.encrypt(key_id, plaintext, context)
+        return jsonify({
+            "CiphertextBlob": base64.b64encode(ciphertext).decode(),
+            "KeyId": key_id,
+            "EncryptionAlgorithm": "SYMMETRIC_DEFAULT",
+        })
+    except EncryptionError as exc:
+        return _error_response("KMSInternalException", str(exc), 400)
+
+
+@kms_api_bp.route("/decrypt", methods=["POST"])
+@limiter.limit("60 per minute")
+def decrypt_data():
+    """Decrypt data using a KMS key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    ciphertext_b64 = payload.get("CiphertextBlob")
+    context = payload.get("EncryptionContext")
+    
+    if not ciphertext_b64:
+        return _error_response("ValidationException", "CiphertextBlob is required", 400)
+    
+    try:
+        ciphertext = base64.b64decode(ciphertext_b64)
+    except Exception:
+        return _error_response("ValidationException", "CiphertextBlob must be base64 encoded", 400)
+    
+    try:
+        plaintext, key_id = kms.decrypt(ciphertext, context)
+        return jsonify({
+            "Plaintext": base64.b64encode(plaintext).decode(),
+            "KeyId": key_id,
+            "EncryptionAlgorithm": "SYMMETRIC_DEFAULT",
+        })
+    except EncryptionError as exc:
+        return _error_response("InvalidCiphertextException", str(exc), 400)
+
+
+@kms_api_bp.route("/generate-data-key", methods=["POST"])
+@limiter.limit("60 per minute")
+def generate_data_key():
+    """Generate a data encryption key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    key_id = payload.get("KeyId")
+    context = payload.get("EncryptionContext")
+    key_spec = payload.get("KeySpec", "AES_256")
+    
+    if not key_id:
+        return _error_response("ValidationException", "KeyId is required", 400)
+    
+    if key_spec not in {"AES_256", "AES_128"}:
+        return _error_response("ValidationException", "KeySpec must be AES_256 or AES_128", 400)
+    
+    try:
+        plaintext_key, encrypted_key = kms.generate_data_key(key_id, context)
+        
+        # Trim key if AES_128 requested
+        if key_spec == "AES_128":
+            plaintext_key = plaintext_key[:16]
+        
+        return jsonify({
+            "Plaintext": base64.b64encode(plaintext_key).decode(),
+            "CiphertextBlob": base64.b64encode(encrypted_key).decode(),
+            "KeyId": key_id,
+        })
+    except EncryptionError as exc:
+        return _error_response("KMSInternalException", str(exc), 400)
+
+
+@kms_api_bp.route("/generate-data-key-without-plaintext", methods=["POST"])
+@limiter.limit("60 per minute")
+def generate_data_key_without_plaintext():
+    """Generate a data encryption key without returning the plaintext."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    key_id = payload.get("KeyId")
+    context = payload.get("EncryptionContext")
+    
+    if not key_id:
+        return _error_response("ValidationException", "KeyId is required", 400)
+    
+    try:
+        _, encrypted_key = kms.generate_data_key(key_id, context)
+        return jsonify({
+            "CiphertextBlob": base64.b64encode(encrypted_key).decode(),
+            "KeyId": key_id,
+        })
+    except EncryptionError as exc:
+        return _error_response("KMSInternalException", str(exc), 400)
+
+
+@kms_api_bp.route("/re-encrypt", methods=["POST"])
+@limiter.limit("30 per minute")
+def re_encrypt():
+    """Re-encrypt data with a different key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    ciphertext_b64 = payload.get("CiphertextBlob")
+    destination_key_id = payload.get("DestinationKeyId")
+    source_context = payload.get("SourceEncryptionContext")
+    destination_context = payload.get("DestinationEncryptionContext")
+    
+    if not ciphertext_b64:
+        return _error_response("ValidationException", "CiphertextBlob is required", 400)
+    if not destination_key_id:
+        return _error_response("ValidationException", "DestinationKeyId is required", 400)
+    
+    try:
+        ciphertext = base64.b64decode(ciphertext_b64)
+    except Exception:
+        return _error_response("ValidationException", "CiphertextBlob must be base64 encoded", 400)
+    
+    try:
+        # First decrypt, get source key id
+        plaintext, source_key_id = kms.decrypt(ciphertext, source_context)
+        
+        # Re-encrypt with destination key
+        new_ciphertext = kms.encrypt(destination_key_id, plaintext, destination_context)
+        
+        return jsonify({
+            "CiphertextBlob": base64.b64encode(new_ciphertext).decode(),
+            "SourceKeyId": source_key_id,
+            "KeyId": destination_key_id,
+        })
+    except EncryptionError as exc:
+        return _error_response("KMSInternalException", str(exc), 400)
+
+
+@kms_api_bp.route("/generate-random", methods=["POST"])
+@limiter.limit("60 per minute")
+def generate_random():
+    """Generate random bytes."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    num_bytes = payload.get("NumberOfBytes", 32)
+    
+    try:
+        num_bytes = int(num_bytes)
+    except (TypeError, ValueError):
+        return _error_response("ValidationException", "NumberOfBytes must be an integer", 400)
+    
+    try:
+        random_bytes = kms.generate_random(num_bytes)
+        return jsonify({
+            "Plaintext": base64.b64encode(random_bytes).decode(),
+        })
+    except EncryptionError as exc:
+        return _error_response("ValidationException", str(exc), 400)
+
+
+# ---------------------- Client-Side Encryption Helpers ----------------------
+
+@kms_api_bp.route("/client/generate-key", methods=["POST"])
+@limiter.limit("30 per minute")
+def generate_client_key():
+    """Generate a client-side encryption key."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    key_info = ClientEncryptionHelper.generate_client_key()
+    return jsonify(key_info)
+
+
+@kms_api_bp.route("/client/encrypt", methods=["POST"])
+@limiter.limit("60 per minute")
+def client_encrypt():
+    """Encrypt data using client-side encryption."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    payload = request.get_json(silent=True) or {}
+    plaintext_b64 = payload.get("Plaintext")
+    key_b64 = payload.get("Key")
+    
+    if not plaintext_b64 or not key_b64:
+        return _error_response("ValidationException", "Plaintext and Key are required", 400)
+    
+    try:
+        plaintext = base64.b64decode(plaintext_b64)
+        result = ClientEncryptionHelper.encrypt_with_key(plaintext, key_b64)
+        return jsonify(result)
+    except Exception as exc:
+        return _error_response("EncryptionError", str(exc), 400)
+
+
+@kms_api_bp.route("/client/decrypt", methods=["POST"])
+@limiter.limit("60 per minute")
+def client_decrypt():
+    """Decrypt data using client-side encryption."""
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    payload = request.get_json(silent=True) or {}
+    ciphertext_b64 = payload.get("Ciphertext") or payload.get("ciphertext")
+    nonce_b64 = payload.get("Nonce") or payload.get("nonce")
+    key_b64 = payload.get("Key") or payload.get("key")
+    
+    if not ciphertext_b64 or not nonce_b64 or not key_b64:
+        return _error_response("ValidationException", "Ciphertext, Nonce, and Key are required", 400)
+    
+    try:
+        plaintext = ClientEncryptionHelper.decrypt_with_key(ciphertext_b64, nonce_b64, key_b64)
+        return jsonify({
+            "Plaintext": base64.b64encode(plaintext).decode(),
+        })
+    except Exception as exc:
+        return _error_response("DecryptionError", str(exc), 400)
+
+
+# ---------------------- Encryption Materials for S3 Client-Side Encryption ----------------------
+
+@kms_api_bp.route("/materials/<key_id>", methods=["POST"])
+@limiter.limit("60 per minute")
+def get_encryption_materials(key_id: str):
+    """Get encryption materials for client-side S3 encryption.
+    
+    This is used by S3 encryption clients that want to use KMS for
+    key management but perform encryption client-side.
+    """
+    principal, error = _require_principal()
+    if error:
+        return error
+    
+    kms = _kms()
+    if not kms:
+        return _error_response("KMSNotEnabled", "KMS is not configured", 400)
+    
+    payload = request.get_json(silent=True) or {}
+    context = payload.get("EncryptionContext")
+    
+    try:
+        plaintext_key, encrypted_key = kms.generate_data_key(key_id, context)
+        
+        return jsonify({
+            "PlaintextKey": base64.b64encode(plaintext_key).decode(),
+            "EncryptedKey": base64.b64encode(encrypted_key).decode(),
+            "KeyId": key_id,
+            "Algorithm": "AES-256-GCM",
+            "KeyWrapAlgorithm": "kms",
+        })
+    except EncryptionError as exc:
+        return _error_response("KMSInternalException", str(exc), 400)

app/s3_api.py

@@ -18,7 +18,7 @@ from .bucket_policies import BucketPolicyStore
 from .extensions import limiter
 from .iam import IamError, Principal
 from .replication import ReplicationManager
-from .storage import ObjectStorage, StorageError
+from .storage import ObjectStorage, StorageError, QuotaExceededError
 
 s3_api_bp = Blueprint("s3_api", __name__)
 
@@ -784,8 +784,9 @@ def _apply_object_headers(
     metadata: Dict[str, str] | None,
     etag: str,
 ) -> None:
-    response.headers["Content-Length"] = str(file_stat.st_size)
+    if file_stat is not None:
-    response.headers["Last-Modified"] = http_date(file_stat.st_mtime)
+        response.headers["Content-Length"] = str(file_stat.st_size)
+        response.headers["Last-Modified"] = http_date(file_stat.st_mtime)
     response.headers["ETag"] = f'"{etag}"'
     response.headers["Accept-Ranges"] = "bytes"
     for key, value in (metadata or {}).items():
@@ -802,6 +803,7 @@ def _maybe_handle_bucket_subresource(bucket_name: str) -> Response | None:
         "acl": _bucket_acl_handler,
         "versions": _bucket_list_versions_handler,
         "lifecycle": _bucket_lifecycle_handler,
+        "quota": _bucket_quota_handler,
     }
     requested = [key for key in handlers if key in request.args]
     if not requested:
@@ -1399,6 +1401,87 @@ def _parse_lifecycle_config(payload: bytes) -> list:
     return rules
 
 
+def _bucket_quota_handler(bucket_name: str) -> Response:
+    """Handle bucket quota configuration (GET/PUT/DELETE /<bucket>?quota)."""
+    if request.method not in {"GET", "PUT", "DELETE"}:
+        return _method_not_allowed(["GET", "PUT", "DELETE"])
+    
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "policy")
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+    
+    storage = _storage()
+    
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+    
+    if request.method == "GET":
+        quota = storage.get_bucket_quota(bucket_name)
+        if not quota:
+            return _error_response("NoSuchQuotaConfiguration", "No quota configuration found", 404)
+        
+        # Return as JSON for simplicity (not a standard S3 API)
+        stats = storage.bucket_stats(bucket_name)
+        return jsonify({
+            "quota": quota,
+            "usage": {
+                "bytes": stats.get("bytes", 0),
+                "objects": stats.get("objects", 0),
+            }
+        })
+    
+    if request.method == "DELETE":
+        try:
+            storage.set_bucket_quota(bucket_name, max_size_bytes=None, max_objects=None)
+        except StorageError as exc:
+            return _error_response("NoSuchBucket", str(exc), 404)
+        current_app.logger.info("Bucket quota deleted", extra={"bucket": bucket_name})
+        return Response(status=204)
+    
+    # PUT
+    payload = request.get_json(silent=True)
+    if not payload:
+        return _error_response("MalformedRequest", "Request body must be JSON with quota limits", 400)
+    
+    max_size_bytes = payload.get("max_size_bytes")
+    max_objects = payload.get("max_objects")
+    
+    if max_size_bytes is None and max_objects is None:
+        return _error_response("InvalidArgument", "At least one of max_size_bytes or max_objects is required", 400)
+    
+    # Validate types
+    if max_size_bytes is not None:
+        try:
+            max_size_bytes = int(max_size_bytes)
+            if max_size_bytes < 0:
+                raise ValueError("must be non-negative")
+        except (TypeError, ValueError) as exc:
+            return _error_response("InvalidArgument", f"max_size_bytes {exc}", 400)
+    
+    if max_objects is not None:
+        try:
+            max_objects = int(max_objects)
+            if max_objects < 0:
+                raise ValueError("must be non-negative")
+        except (TypeError, ValueError) as exc:
+            return _error_response("InvalidArgument", f"max_objects {exc}", 400)
+    
+    try:
+        storage.set_bucket_quota(bucket_name, max_size_bytes=max_size_bytes, max_objects=max_objects)
+    except StorageError as exc:
+        return _error_response("NoSuchBucket", str(exc), 404)
+    
+    current_app.logger.info(
+        "Bucket quota updated",
+        extra={"bucket": bucket_name, "max_size_bytes": max_size_bytes, "max_objects": max_objects}
+    )
+    return Response(status=204)
+
+
 def _bulk_delete_handler(bucket_name: str) -> Response:
     principal, error = _require_principal()
     if error:
@@ -1748,6 +1831,8 @@ def object_handler(bucket_name: str, object_key: str):
                 stream,
                 metadata=metadata or None,
             )
+        except QuotaExceededError as exc:
+            return _error_response("QuotaExceeded", str(exc), 403)
         except StorageError as exc:
             message = str(exc)
             if "Bucket" in message:
@@ -1779,19 +1864,48 @@ def object_handler(bucket_name: str, object_key: str):
         except StorageError as exc:
             return _error_response("NoSuchKey", str(exc), 404)
         metadata = storage.get_object_metadata(bucket_name, object_key)
-        stat = path.stat()
+        mimetype = mimetypes.guess_type(object_key)[0] or "application/octet-stream"
-        mimetype = mimetypes.guess_type(path.name)[0] or "application/octet-stream"
+        
-        etag = storage._compute_etag(path)
+        # Check if object is encrypted and needs decryption
+        is_encrypted = "x-amz-server-side-encryption" in metadata
         
         if request.method == "GET":
-            response = Response(_stream_file(path), mimetype=mimetype, direct_passthrough=True)
+            if is_encrypted and hasattr(storage, 'get_object_data'):
-            logged_bytes = stat.st_size
+                # Use encrypted storage to decrypt
+                try:
+                    data, clean_metadata = storage.get_object_data(bucket_name, object_key)
+                    response = Response(data, mimetype=mimetype)
+                    logged_bytes = len(data)
+                    # Use decrypted size for Content-Length
+                    response.headers["Content-Length"] = len(data)
+                    etag = hashlib.md5(data).hexdigest()
+                except StorageError as exc:
+                    return _error_response("InternalError", str(exc), 500)
+            else:
+                # Stream unencrypted file directly
+                stat = path.stat()
+                response = Response(_stream_file(path), mimetype=mimetype, direct_passthrough=True)
+                logged_bytes = stat.st_size
+                etag = storage._compute_etag(path)
         else:
-            response = Response(status=200)
+            # HEAD request
+            if is_encrypted and hasattr(storage, 'get_object_data'):
+                # For encrypted objects, we need to report decrypted size
+                try:
+                    data, _ = storage.get_object_data(bucket_name, object_key)
+                    response = Response(status=200)
+                    response.headers["Content-Length"] = len(data)
+                    etag = hashlib.md5(data).hexdigest()
+                except StorageError as exc:
+                    return _error_response("InternalError", str(exc), 500)
+            else:
+                stat = path.stat()
+                response = Response(status=200)
+                etag = storage._compute_etag(path)
             response.headers["Content-Type"] = mimetype
             logged_bytes = 0
 
-        _apply_object_headers(response, file_stat=stat, metadata=metadata, etag=etag)
+        _apply_object_headers(response, file_stat=path.stat() if not is_encrypted else None, metadata=metadata, etag=etag)
         action = "Object read" if request.method == "GET" else "Object head"
         current_app.logger.info(action, extra={"bucket": bucket_name, "key": object_key, "bytes": logged_bytes})
         return response
@@ -2226,6 +2340,8 @@ def _complete_multipart_upload(bucket_name: str, object_key: str) -> Response:
 
     try:
         meta = _storage().complete_multipart_upload(bucket_name, upload_id, parts)
+    except QuotaExceededError as exc:
+        return _error_response("QuotaExceeded", str(exc), 403)
     except StorageError as exc:
         if "NoSuchBucket" in str(exc):
             return _error_response("NoSuchBucket", str(exc), 404)

app/storage.py

@@ -75,6 +75,15 @@ class StorageError(RuntimeError):
     """Raised when the storage layer encounters an unrecoverable problem."""
 
 
+class QuotaExceededError(StorageError):
+    """Raised when an operation would exceed bucket quota limits."""
+    
+    def __init__(self, message: str, quota: Dict[str, Any], usage: Dict[str, int]):
+        super().__init__(message)
+        self.quota = quota
+        self.usage = usage
+
+
 @dataclass
 class ObjectMeta:
     key: str
@@ -169,16 +178,38 @@ class ObjectStorage:
 
         object_count = 0
         total_bytes = 0
+        version_count = 0
+        version_bytes = 0
+        
+        # Count current objects in the bucket folder
         for path in bucket_path.rglob("*"):
             if path.is_file():
                 rel = path.relative_to(bucket_path)
-                if rel.parts and rel.parts[0] in self.INTERNAL_FOLDERS:
+                if not rel.parts:
                     continue
-                stat = path.stat()
+                top_folder = rel.parts[0]
-                object_count += 1
+                if top_folder not in self.INTERNAL_FOLDERS:
-                total_bytes += stat.st_size
+                    stat = path.stat()
+                    object_count += 1
+                    total_bytes += stat.st_size
         
-        stats = {"objects": object_count, "bytes": total_bytes}
+        # Count archived versions in the system folder
+        versions_root = self._bucket_versions_root(bucket_name)
+        if versions_root.exists():
+            for path in versions_root.rglob("*.bin"):
+                if path.is_file():
+                    stat = path.stat()
+                    version_count += 1
+                    version_bytes += stat.st_size
+        
+        stats = {
+            "objects": object_count,
+            "bytes": total_bytes,
+            "version_count": version_count,
+            "version_bytes": version_bytes,
+            "total_objects": object_count + version_count,  # All objects including versions
+            "total_bytes": total_bytes + version_bytes,  # All storage including versions
+        }
         
         try:
             cache_path.parent.mkdir(parents=True, exist_ok=True)
@@ -243,6 +274,7 @@ class ObjectStorage:
         stream: BinaryIO,
         *,
         metadata: Optional[Dict[str, str]] = None,
+        enforce_quota: bool = True,
     ) -> ObjectMeta:
         bucket_path = self._bucket_path(bucket_name)
         if not bucket_path.exists():
@@ -253,12 +285,52 @@ class ObjectStorage:
         destination = bucket_path / safe_key
         destination.parent.mkdir(parents=True, exist_ok=True)
 
-        if self._is_versioning_enabled(bucket_path) and destination.exists():
+        # Check if this is an overwrite (won't add to object count)
+        is_overwrite = destination.exists()
+        existing_size = destination.stat().st_size if is_overwrite else 0
+
+        if self._is_versioning_enabled(bucket_path) and is_overwrite:
             self._archive_current_version(bucket_id, safe_key, reason="overwrite")
 
-        checksum = hashlib.md5()
+        # Write to temp file first to get actual size
-        with destination.open("wb") as target:
+        tmp_dir = self._system_root_path() / self.SYSTEM_TMP_DIR
-            shutil.copyfileobj(_HashingReader(stream, checksum), target)
+        tmp_dir.mkdir(parents=True, exist_ok=True)
+        tmp_path = tmp_dir / f"{uuid.uuid4().hex}.tmp"
+        
+        try:
+            checksum = hashlib.md5()
+            with tmp_path.open("wb") as target:
+                shutil.copyfileobj(_HashingReader(stream, checksum), target)
+            
+            new_size = tmp_path.stat().st_size
+            
+            # Check quota before finalizing
+            if enforce_quota:
+                # Calculate net change (new size minus size being replaced)
+                size_delta = new_size - existing_size
+                object_delta = 0 if is_overwrite else 1
+                
+                quota_check = self.check_quota(
+                    bucket_name,
+                    additional_bytes=max(0, size_delta),
+                    additional_objects=object_delta,
+                )
+                if not quota_check["allowed"]:
+                    raise QuotaExceededError(
+                        quota_check["message"] or "Quota exceeded",
+                        quota_check["quota"],
+                        quota_check["usage"],
+                    )
+            
+            # Move to final destination
+            shutil.move(str(tmp_path), str(destination))
+            
+        finally:
+            # Clean up temp file if it still exists
+            try:
+                tmp_path.unlink(missing_ok=True)
+            except OSError:
+                pass
 
         stat = destination.stat()
         if metadata:
@@ -289,6 +361,27 @@ class ObjectStorage:
         safe_key = self._sanitize_object_key(object_key)
         return self._read_metadata(bucket_path.name, safe_key) or {}
 
+    def _cleanup_empty_parents(self, path: Path, stop_at: Path) -> None:
+        """Remove empty parent directories up to (but not including) stop_at.
+        
+        On Windows/OneDrive, directories may be locked briefly after file deletion.
+        This method retries with a small delay to handle that case.
+        """
+        for parent in path.parents:
+            if parent == stop_at:
+                break
+            # Retry a few times with small delays for Windows/OneDrive
+            for attempt in range(3):
+                try:
+                    if parent.exists() and not any(parent.iterdir()):
+                        parent.rmdir()
+                        break  # Success, move to next parent
+                except OSError:
+                    if attempt < 2:
+                        time.sleep(0.1)  # Brief delay before retry
+                    # Final attempt failed - continue to next parent
+                    break
+
     def delete_object(self, bucket_name: str, object_key: str) -> None:
         bucket_path = self._bucket_path(bucket_name)
         path = self._object_path(bucket_name, object_key)
@@ -303,12 +396,7 @@ class ObjectStorage:
         self._delete_metadata(bucket_id, rel)
         
         self._invalidate_bucket_stats_cache(bucket_id)
-        
+        self._cleanup_empty_parents(path, bucket_path)
-        for parent in path.parents:
-            if parent == bucket_path:
-                break
-            if parent.exists() and not any(parent.iterdir()):
-                parent.rmdir()
 
     def purge_object(self, bucket_name: str, object_key: str) -> None:
         bucket_path = self._bucket_path(bucket_name)
@@ -330,12 +418,7 @@ class ObjectStorage:
         
         # Invalidate bucket stats cache
         self._invalidate_bucket_stats_cache(bucket_id)
-        
+        self._cleanup_empty_parents(target, bucket_path)
-        for parent in target.parents:
-            if parent == bucket_path:
-                break
-            if parent.exists() and not any(parent.iterdir()):
-                parent.rmdir()
 
     def is_versioning_enabled(self, bucket_name: str) -> bool:
         bucket_path = self._bucket_path(bucket_name)
@@ -413,6 +496,124 @@ class ObjectStorage:
         bucket_path = self._require_bucket_path(bucket_name)
         self._set_bucket_config_entry(bucket_path.name, "lifecycle", rules)
 
+    def get_bucket_quota(self, bucket_name: str) -> Dict[str, Any]:
+        """Get quota configuration for bucket.
+        
+        Returns:
+            Dict with 'max_bytes' and 'max_objects' (None if unlimited).
+        """
+        bucket_path = self._require_bucket_path(bucket_name)
+        config = self._read_bucket_config(bucket_path.name)
+        quota = config.get("quota")
+        if isinstance(quota, dict):
+            return {
+                "max_bytes": quota.get("max_bytes"),
+                "max_objects": quota.get("max_objects"),
+            }
+        return {"max_bytes": None, "max_objects": None}
+
+    def set_bucket_quota(
+        self,
+        bucket_name: str,
+        *,
+        max_bytes: Optional[int] = None,
+        max_objects: Optional[int] = None,
+    ) -> None:
+        """Set quota limits for a bucket.
+        
+        Args:
+            bucket_name: Name of the bucket
+            max_bytes: Maximum total size in bytes (None to remove limit)
+            max_objects: Maximum number of objects (None to remove limit)
+        """
+        bucket_path = self._require_bucket_path(bucket_name)
+        
+        if max_bytes is None and max_objects is None:
+            # Remove quota entirely
+            self._set_bucket_config_entry(bucket_path.name, "quota", None)
+            return
+        
+        quota: Dict[str, Any] = {}
+        if max_bytes is not None:
+            if max_bytes < 0:
+                raise StorageError("max_bytes must be non-negative")
+            quota["max_bytes"] = max_bytes
+        if max_objects is not None:
+            if max_objects < 0:
+                raise StorageError("max_objects must be non-negative")
+            quota["max_objects"] = max_objects
+        
+        self._set_bucket_config_entry(bucket_path.name, "quota", quota)
+
+    def check_quota(
+        self,
+        bucket_name: str,
+        additional_bytes: int = 0,
+        additional_objects: int = 0,
+    ) -> Dict[str, Any]:
+        """Check if an operation would exceed bucket quota.
+        
+        Args:
+            bucket_name: Name of the bucket
+            additional_bytes: Bytes that would be added
+            additional_objects: Objects that would be added
+            
+        Returns:
+            Dict with 'allowed' (bool), 'quota' (current limits),
+            'usage' (current usage), and 'message' (if not allowed).
+        """
+        quota = self.get_bucket_quota(bucket_name)
+        if not quota:
+            return {
+                "allowed": True,
+                "quota": None,
+                "usage": None,
+                "message": None,
+            }
+        
+        # Get current stats (uses cache when available)
+        stats = self.bucket_stats(bucket_name)
+        # Use totals which include versions for quota enforcement
+        current_bytes = stats.get("total_bytes", stats.get("bytes", 0))
+        current_objects = stats.get("total_objects", stats.get("objects", 0))
+        
+        result = {
+            "allowed": True,
+            "quota": quota,
+            "usage": {
+                "bytes": current_bytes,
+                "objects": current_objects,
+                "version_count": stats.get("version_count", 0),
+                "version_bytes": stats.get("version_bytes", 0),
+            },
+            "message": None,
+        }
+        
+        max_bytes_limit = quota.get("max_bytes")
+        max_objects = quota.get("max_objects")
+        
+        if max_bytes_limit is not None:
+            projected_bytes = current_bytes + additional_bytes
+            if projected_bytes > max_bytes_limit:
+                result["allowed"] = False
+                result["message"] = (
+                    f"Quota exceeded: adding {additional_bytes} bytes would result in "
+                    f"{projected_bytes} bytes, exceeding limit of {max_bytes_limit} bytes"
+                )
+                return result
+        
+        if max_objects is not None:
+            projected_objects = current_objects + additional_objects
+            if projected_objects > max_objects:
+                result["allowed"] = False
+                result["message"] = (
+                    f"Quota exceeded: adding {additional_objects} objects would result in "
+                    f"{projected_objects} objects, exceeding limit of {max_objects} objects"
+                )
+                return result
+        
+        return result
+
     def get_object_tags(self, bucket_name: str, object_key: str) -> List[Dict[str, str]]:
         """Get tags for an object."""
         bucket_path = self._bucket_path(bucket_name)
@@ -529,6 +730,7 @@ class ObjectStorage:
         else:
             self._delete_metadata(bucket_id, safe_key)
         stat = destination.stat()
+        self._invalidate_bucket_stats_cache(bucket_id)
         return ObjectMeta(
             key=safe_key.as_posix(),
             size=stat.st_size,
@@ -677,6 +879,7 @@ class ObjectStorage:
         bucket_name: str,
         upload_id: str,
         ordered_parts: List[Dict[str, Any]],
+        enforce_quota: bool = True,
     ) -> ObjectMeta:
         if not ordered_parts:
             raise StorageError("parts list required")
@@ -687,6 +890,7 @@ class ObjectStorage:
         if not parts_map:
             raise StorageError("No uploaded parts found")
         validated: List[tuple[int, Dict[str, Any]]] = []
+        total_size = 0
         for part in ordered_parts:
             raw_number = part.get("part_number")
             if raw_number is None:
@@ -706,10 +910,33 @@ class ObjectStorage:
             if supplied_etag and record.get("etag") and supplied_etag.strip('"') != record["etag"]:
                 raise StorageError(f"ETag mismatch for part {number}")
             validated.append((number, record))
+            total_size += record.get("size", 0)
         validated.sort(key=lambda entry: entry[0])
 
         safe_key = self._sanitize_object_key(manifest["object_key"])
         destination = bucket_path / safe_key
+        
+        # Check if this is an overwrite
+        is_overwrite = destination.exists()
+        existing_size = destination.stat().st_size if is_overwrite else 0
+        
+        # Check quota before writing
+        if enforce_quota:
+            size_delta = total_size - existing_size
+            object_delta = 0 if is_overwrite else 1
+            
+            quota_check = self.check_quota(
+                bucket_name,
+                additional_bytes=max(0, size_delta),
+                additional_objects=object_delta,
+            )
+            if not quota_check["allowed"]:
+                raise QuotaExceededError(
+                    quota_check["message"] or "Quota exceeded",
+                    quota_check["quota"],
+                    quota_check["usage"],
+                )
+        
         destination.parent.mkdir(parents=True, exist_ok=True)
         
         lock_file_path = self._system_bucket_root(bucket_id) / "locks" / f"{safe_key.as_posix().replace('/', '_')}.lock"

app/ui.py

@@ -6,7 +6,7 @@ import uuid
 import psutil
 import shutil
 from typing import Any
-from urllib.parse import urlparse
+from urllib.parse import quote, urlparse
 
 import boto3
 import requests
@@ -30,6 +30,7 @@ from .bucket_policies import BucketPolicyStore
 from .connections import ConnectionStore, RemoteConnection
 from .extensions import limiter
 from .iam import IamError
+from .kms import KMSManager
 from .replication import ReplicationManager, ReplicationRule
 from .secret_store import EphemeralSecretStore
 from .storage import ObjectStorage, StorageError
@@ -50,6 +51,9 @@ def _iam():
     return current_app.extensions["iam"]
 
 
+def _kms() -> KMSManager | None:
+    return current_app.extensions.get("kms")
+
 
 def _bucket_policies() -> BucketPolicyStore:
     store: BucketPolicyStore = current_app.extensions["bucket_policies"]
@@ -185,6 +189,7 @@ def inject_nav_state() -> dict[str, Any]:
     return {
         "principal": principal,
         "can_manage_iam": can_manage,
+        "can_view_metrics": can_manage,  # Only admins can view metrics
         "csrf_token": generate_csrf,
     }
 
@@ -255,9 +260,9 @@ def buckets_overview():
         visible_buckets.append({
             "meta": bucket,
             "summary": {
-                "objects": stats["objects"],
+                "objects": stats["total_objects"],
-                "total_bytes": stats["bytes"],
+                "total_bytes": stats["total_bytes"],
-                "human_size": _format_bytes(stats["bytes"]),
+                "human_size": _format_bytes(stats["total_bytes"]),
             },
             "access_label": access_label,
             "access_badge": access_badge,
@@ -336,9 +341,46 @@ def bucket_detail(bucket_name: str):
         except IamError:
             can_manage_versioning = False
 
+    # Check replication permission
+    can_manage_replication = False
+    if principal:
+        try:
+            _iam().authorize(principal, bucket_name, "replication")
+            can_manage_replication = True
+        except IamError:
+            can_manage_replication = False
+
+    # Check if user is admin (can configure replication settings, not just toggle)
+    is_replication_admin = False
+    if principal:
+        try:
+            _iam().authorize(principal, None, "iam:list_users")
+            is_replication_admin = True
+        except IamError:
+            is_replication_admin = False
+
     # Replication info - don't compute sync status here (it's slow), let JS fetch it async
     replication_rule = _replication().get_rule(bucket_name)
-    connections = _connections().list()
+    # Load connections for admin, or for non-admin if there's an existing rule (to show target name)
+    connections = _connections().list() if (is_replication_admin or replication_rule) else []
+
+    # Encryption settings
+    encryption_config = storage.get_bucket_encryption(bucket_name)
+    kms_manager = _kms()
+    kms_keys = kms_manager.list_keys() if kms_manager else []
+    kms_enabled = current_app.config.get("KMS_ENABLED", False)
+    encryption_enabled = current_app.config.get("ENCRYPTION_ENABLED", False)
+    can_manage_encryption = can_manage_versioning  # Same as other bucket properties
+
+    # Quota settings (admin only)
+    bucket_quota = storage.get_bucket_quota(bucket_name)
+    bucket_stats = storage.bucket_stats(bucket_name)
+    can_manage_quota = False
+    try:
+        _iam().authorize(principal, None, "iam:list_users")
+        can_manage_quota = True
+    except IamError:
+        pass
 
     return render_template(
         "bucket_detail.html",
@@ -349,10 +391,20 @@ def bucket_detail(bucket_name: str):
         bucket_policy=bucket_policy,
         can_edit_policy=can_edit_policy,
         can_manage_versioning=can_manage_versioning,
+        can_manage_replication=can_manage_replication,
+        can_manage_encryption=can_manage_encryption,
+        is_replication_admin=is_replication_admin,
         default_policy=default_policy,
         versioning_enabled=versioning_enabled,
         replication_rule=replication_rule,
         connections=connections,
+        encryption_config=encryption_config,
+        kms_keys=kms_keys,
+        kms_enabled=kms_enabled,
+        encryption_enabled=encryption_enabled,
+        bucket_quota=bucket_quota,
+        bucket_stats=bucket_stats,
+        can_manage_quota=can_manage_quota,
     )
 
 
@@ -647,9 +699,18 @@ def bulk_download_objects(bucket_name: str):
                 # But strictly we should check. Let's check.
                 _authorize_ui(principal, bucket_name, "read", object_key=key)
                 
-                path = storage.get_object_path(bucket_name, key)
+                # Check if object is encrypted
-                # Use the key as the filename in the zip
+                metadata = storage.get_object_metadata(bucket_name, key)
-                zf.write(path, arcname=key)
+                is_encrypted = "x-amz-server-side-encryption" in metadata
+                
+                if is_encrypted and hasattr(storage, 'get_object_data'):
+                    # Decrypt and add to zip
+                    data, _ = storage.get_object_data(bucket_name, key)
+                    zf.writestr(key, data)
+                else:
+                    # Add unencrypted file directly
+                    path = storage.get_object_path(bucket_name, key)
+                    zf.write(path, arcname=key)
             except (StorageError, IamError):
                 # Skip files we can't read or don't exist
                 continue
@@ -691,13 +752,34 @@ def purge_object_versions(bucket_name: str, object_key: str):
 @ui_bp.get("/buckets/<bucket_name>/objects/<path:object_key>/preview")
 def object_preview(bucket_name: str, object_key: str) -> Response:
     principal = _current_principal()
+    storage = _storage()
     try:
         _authorize_ui(principal, bucket_name, "read", object_key=object_key)
-        path = _storage().get_object_path(bucket_name, object_key)
+        path = storage.get_object_path(bucket_name, object_key)
+        metadata = storage.get_object_metadata(bucket_name, object_key)
     except (StorageError, IamError) as exc:
         status = 403 if isinstance(exc, IamError) else 404
         return Response(str(exc), status=status)
+    
     download = request.args.get("download") == "1"
+    
+    # Check if object is encrypted and needs decryption
+    is_encrypted = "x-amz-server-side-encryption" in metadata
+    if is_encrypted and hasattr(storage, 'get_object_data'):
+        try:
+            data, _ = storage.get_object_data(bucket_name, object_key)
+            import io
+            import mimetypes
+            mimetype = mimetypes.guess_type(object_key)[0] or "application/octet-stream"
+            return send_file(
+                io.BytesIO(data),
+                mimetype=mimetype,
+                as_attachment=download,
+                download_name=path.name
+            )
+        except StorageError as exc:
+            return Response(f"Decryption failed: {exc}", status=500)
+    
     return send_file(path, as_attachment=download, download_name=path.name)
 
 
@@ -712,12 +794,16 @@ def object_presign(bucket_name: str, object_key: str):
     except IamError as exc:
         return jsonify({"error": str(exc)}), 403
     
-    connection_url = "http://127.0.0.1:5000"
+    api_base = current_app.config.get("API_BASE_URL") or "http://127.0.0.1:5000"
-    url = f"{connection_url}/presign/{bucket_name}/{object_key}"
+    api_base = api_base.rstrip("/")
+    encoded_key = quote(object_key, safe="/")
+    url = f"{api_base}/presign/{bucket_name}/{encoded_key}"
     
+    # Use API base URL for forwarded headers so presigned URLs point to API, not UI
+    parsed_api = urlparse(api_base)
     headers = _api_headers()
-    headers["X-Forwarded-Host"] = request.host
+    headers["X-Forwarded-Host"] = parsed_api.netloc or "127.0.0.1:5000"
-    headers["X-Forwarded-Proto"] = request.scheme
+    headers["X-Forwarded-Proto"] = parsed_api.scheme or "http"
     headers["X-Forwarded-For"] = request.remote_addr or "127.0.0.1"
     
     try:
@@ -853,6 +939,127 @@ def update_bucket_versioning(bucket_name: str):
     return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
 
 
+@ui_bp.post("/buckets/<bucket_name>/quota")
+def update_bucket_quota(bucket_name: str):
+    """Update bucket quota configuration (admin only)."""
+    principal = _current_principal()
+    
+    # Quota management is admin-only
+    is_admin = False
+    try:
+        _iam().authorize(principal, None, "iam:list_users")
+        is_admin = True
+    except IamError:
+        pass
+    
+    if not is_admin:
+        flash("Only administrators can manage bucket quotas", "danger")
+        return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    action = request.form.get("action", "set")
+    
+    if action == "remove":
+        try:
+            _storage().set_bucket_quota(bucket_name, max_bytes=None, max_objects=None)
+            flash("Bucket quota removed", "info")
+        except StorageError as exc:
+            flash(_friendly_error_message(exc), "danger")
+        return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    # Parse quota values
+    max_mb_str = request.form.get("max_mb", "").strip()
+    max_objects_str = request.form.get("max_objects", "").strip()
+    
+    max_bytes = None
+    max_objects = None
+    
+    if max_mb_str:
+        try:
+            max_mb = int(max_mb_str)
+            if max_mb < 1:
+                raise ValueError("Size must be at least 1 MB")
+            max_bytes = max_mb * 1024 * 1024  # Convert MB to bytes
+        except ValueError as exc:
+            flash(f"Invalid size value: {exc}", "danger")
+            return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    if max_objects_str:
+        try:
+            max_objects = int(max_objects_str)
+            if max_objects < 0:
+                raise ValueError("Object count must be non-negative")
+        except ValueError as exc:
+            flash(f"Invalid object count: {exc}", "danger")
+            return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    try:
+        _storage().set_bucket_quota(bucket_name, max_bytes=max_bytes, max_objects=max_objects)
+        if max_bytes is None and max_objects is None:
+            flash("Bucket quota removed", "info")
+        else:
+            flash("Bucket quota updated", "success")
+    except StorageError as exc:
+        flash(_friendly_error_message(exc), "danger")
+    
+    return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+
+
+@ui_bp.post("/buckets/<bucket_name>/encryption")
+def update_bucket_encryption(bucket_name: str):
+    """Update bucket default encryption configuration."""
+    principal = _current_principal()
+    try:
+        _authorize_ui(principal, bucket_name, "write")
+    except IamError as exc:
+        flash(_friendly_error_message(exc), "danger")
+        return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    action = request.form.get("action", "enable")
+    
+    if action == "disable":
+        # Disable encryption
+        try:
+            _storage().set_bucket_encryption(bucket_name, None)
+            flash("Default encryption disabled", "info")
+        except StorageError as exc:
+            flash(_friendly_error_message(exc), "danger")
+        return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    # Enable or update encryption
+    algorithm = request.form.get("algorithm", "AES256")
+    kms_key_id = request.form.get("kms_key_id", "").strip() or None
+    
+    # Validate algorithm
+    if algorithm not in ("AES256", "aws:kms"):
+        flash("Invalid encryption algorithm", "danger")
+        return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+    
+    # Build encryption config following AWS format
+    encryption_config: dict[str, Any] = {
+        "Rules": [
+            {
+                "ApplyServerSideEncryptionByDefault": {
+                    "SSEAlgorithm": algorithm,
+                }
+            }
+        ]
+    }
+    
+    if algorithm == "aws:kms" and kms_key_id:
+        encryption_config["Rules"][0]["ApplyServerSideEncryptionByDefault"]["KMSMasterKeyID"] = kms_key_id
+    
+    try:
+        _storage().set_bucket_encryption(bucket_name, encryption_config)
+        if algorithm == "aws:kms":
+            flash("Default KMS encryption enabled", "success")
+        else:
+            flash("Default AES-256 encryption enabled", "success")
+    except StorageError as exc:
+        flash(_friendly_error_message(exc), "danger")
+    
+    return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="properties"))
+
+
 @ui_bp.get("/iam")
 def iam_dashboard():
     principal = _current_principal()
@@ -1168,17 +1375,52 @@ def delete_connection(connection_id: str):
 def update_bucket_replication(bucket_name: str):
     principal = _current_principal()
     try:
-        _authorize_ui(principal, bucket_name, "write")
+        _authorize_ui(principal, bucket_name, "replication")
     except IamError as exc:
         flash(str(exc), "danger")
         return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="replication"))
     
+    # Check if user is admin (required for create/delete operations)
+    is_admin = False
+    try:
+        _iam().authorize(principal, None, "iam:list_users")
+        is_admin = True
+    except IamError:
+        is_admin = False
+        
     action = request.form.get("action")
     
     if action == "delete":
+        # Admin only - remove configuration entirely
+        if not is_admin:
+            flash("Only administrators can remove replication configuration", "danger")
+            return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="replication"))
         _replication().delete_rule(bucket_name)
-        flash("Replication disabled", "info")
+        flash("Replication configuration removed", "info")
-    else:
+    elif action == "pause":
+        # Users can pause - just set enabled=False
+        rule = _replication().get_rule(bucket_name)
+        if rule:
+            rule.enabled = False
+            _replication().set_rule(rule)
+            flash("Replication paused", "info")
+        else:
+            flash("No replication configuration to pause", "warning")
+    elif action == "resume":
+        # Users can resume - just set enabled=True
+        rule = _replication().get_rule(bucket_name)
+        if rule:
+            rule.enabled = True
+            _replication().set_rule(rule)
+            flash("Replication resumed", "success")
+        else:
+            flash("No replication configuration to resume", "warning")
+    elif action == "create":
+        # Admin only - create new configuration
+        if not is_admin:
+            flash("Only administrators can configure replication settings", "danger")
+            return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="replication"))
+            
         from .replication import REPLICATION_MODE_NEW_ONLY, REPLICATION_MODE_ALL
         import time
         
@@ -1205,6 +1447,8 @@ def update_bucket_replication(bucket_name: str):
                 flash("Replication configured. Existing objects are being replicated in the background.", "success")
             else:
                 flash("Replication configured. Only new uploads will be replicated.", "success")
+    else:
+        flash("Invalid action", "danger")
             
     return redirect(url_for("ui.bucket_detail", bucket_name=bucket_name, tab="replication"))
 
@@ -1214,7 +1458,7 @@ def get_replication_status(bucket_name: str):
     """Async endpoint to fetch replication sync status without blocking page load."""
     principal = _current_principal()
     try:
-        _authorize_ui(principal, bucket_name, "read")
+        _authorize_ui(principal, bucket_name, "replication")
     except IamError:
         return jsonify({"error": "Access denied"}), 403
     
@@ -1254,6 +1498,16 @@ def connections_dashboard():
 def metrics_dashboard():
     principal = _current_principal()
     
+    # Metrics are restricted to admin users
+    try:
+        _iam().authorize(principal, None, "iam:list_users")
+    except IamError:
+        flash("Access denied: Metrics require admin permissions", "danger")
+        return redirect(url_for("ui.buckets_overview"))
+    
+    from app.version import APP_VERSION
+    import time
+    
     cpu_percent = psutil.cpu_percent(interval=0.1)
     memory = psutil.virtual_memory()
     
@@ -1266,13 +1520,21 @@ def metrics_dashboard():
     
     total_objects = 0
     total_bytes_used = 0
+    total_versions = 0
     
     # Note: Uses cached stats from storage layer to improve performance
     cache_ttl = current_app.config.get("BUCKET_STATS_CACHE_TTL", 60)
     for bucket in buckets:
         stats = storage.bucket_stats(bucket.name, cache_ttl=cache_ttl)
-        total_objects += stats["objects"]
+        # Use totals which include archived versions
-        total_bytes_used += stats["bytes"]
+        total_objects += stats.get("total_objects", stats.get("objects", 0))
+        total_bytes_used += stats.get("total_bytes", stats.get("bytes", 0))
+        total_versions += stats.get("version_count", 0)
+    
+    # Calculate system uptime
+    boot_time = psutil.boot_time()
+    uptime_seconds = time.time() - boot_time
+    uptime_days = int(uptime_seconds / 86400)
         
     return render_template(
         "metrics.html",
@@ -1293,8 +1555,11 @@ def metrics_dashboard():
         app={
             "buckets": total_buckets,
             "objects": total_objects,
+            "versions": total_versions,
             "storage_used": _format_bytes(total_bytes_used),
             "storage_raw": total_bytes_used,
+            "version": APP_VERSION,
+            "uptime_days": uptime_days,
         }
     )
 

app/version.py

@@ -1,7 +1,7 @@
 """Central location for the application version string."""
 from __future__ import annotations
 
-APP_VERSION = "0.1.2"
+APP_VERSION = "0.1.6"
 
 
 def get_version() -> str:

docs.md

@@ -33,6 +33,63 @@ python run.py --mode api   # API only (port 5000)
 python run.py --mode ui    # UI only (port 5100)
 ```
 
+### Configuration validation
+
+Validate your configuration before deploying:
+
+```bash
+# Show configuration summary
+python run.py --show-config
+./myfsio --show-config
+
+# Validate and check for issues (exits with code 1 if critical issues found)
+python run.py --check-config
+./myfsio --check-config
+```
+
+### Linux Installation (Recommended for Production)
+
+For production deployments on Linux, use the provided installation script:
+
+```bash
+# Download the binary and install script
+# Then run the installer with sudo:
+sudo ./scripts/install.sh --binary ./myfsio
+
+# Or with custom paths:
+sudo ./scripts/install.sh \
+  --binary ./myfsio \
+  --install-dir /opt/myfsio \
+  --data-dir /mnt/storage/myfsio \
+  --log-dir /var/log/myfsio \
+  --api-url https://s3.example.com \
+  --user myfsio
+
+# Non-interactive mode (for automation):
+sudo ./scripts/install.sh --binary ./myfsio -y
+```
+
+The installer will:
+1. Create a dedicated system user
+2. Set up directories with proper permissions
+3. Generate a secure `SECRET_KEY`
+4. Create an environment file at `/opt/myfsio/myfsio.env`
+5. Install and configure a systemd service
+
+After installation:
+```bash
+sudo systemctl start myfsio    # Start the service
+sudo systemctl enable myfsio   # Enable on boot
+sudo systemctl status myfsio   # Check status
+sudo journalctl -u myfsio -f   # View logs
+```
+
+To uninstall:
+```bash
+sudo ./scripts/uninstall.sh              # Full removal
+sudo ./scripts/uninstall.sh --keep-data  # Keep data directory
+```
+
 ### Docker quickstart
 
 The repo now ships a `Dockerfile` so you can run both services in one container:
@@ -69,19 +126,97 @@ The repo now tracks a human-friendly release string inside `app/version.py` (see
 
 ## 3. Configuration Reference
 
+All configuration is done via environment variables. The table below lists every supported variable.
+
+### Core Settings
+
 | Variable | Default | Notes |
 | --- | --- | --- |
 | `STORAGE_ROOT` | `<repo>/data` | Filesystem home for all buckets/objects. |
-| `MAX_UPLOAD_SIZE` | `1073741824` | Bytes. Caps incoming uploads in both API + UI. |
+| `MAX_UPLOAD_SIZE` | `1073741824` (1 GiB) | Bytes. Caps incoming uploads in both API + UI. |
 | `UI_PAGE_SIZE` | `100` | `MaxKeys` hint shown in listings. |
-| `SECRET_KEY` | `dev-secret-key` | Flask session key for UI auth. |
+| `SECRET_KEY` | Auto-generated | Flask session key. Auto-generates and persists if not set. **Set explicitly in production.** |
-| `IAM_CONFIG` | `<repo>/data/.myfsio.sys/config/iam.json` | Stores users, secrets, and inline policies. |
+| `API_BASE_URL` | `None` | Public URL for presigned URLs. Required behind proxies. |
-| `BUCKET_POLICY_PATH` | `<repo>/data/.myfsio.sys/config/bucket_policies.json` | Bucket policy store (auto hot-reload). |
-| `API_BASE_URL` | `None` | Used by the UI to hit API endpoints (presign/policy). If unset, the UI will auto-detect the host or use `X-Forwarded-*` headers. |
 | `AWS_REGION` | `us-east-1` | Region embedded in SigV4 credential scope. |
 | `AWS_SERVICE` | `s3` | Service string for SigV4. |
 
-Set env vars (or pass overrides to `create_app`) to point the servers at custom paths.
+### IAM & Security
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `IAM_CONFIG` | `data/.myfsio.sys/config/iam.json` | Stores users, secrets, and inline policies. |
+| `BUCKET_POLICY_PATH` | `data/.myfsio.sys/config/bucket_policies.json` | Bucket policy store (auto hot-reload). |
+| `AUTH_MAX_ATTEMPTS` | `5` | Failed login attempts before lockout. |
+| `AUTH_LOCKOUT_MINUTES` | `15` | Lockout duration after max failed attempts. |
+| `SESSION_LIFETIME_DAYS` | `30` | How long UI sessions remain valid. |
+| `SECRET_TTL_SECONDS` | `300` | TTL for ephemeral secrets (presigned URLs). |
+| `UI_ENFORCE_BUCKET_POLICIES` | `false` | Whether the UI should enforce bucket policies. |
+
+### CORS (Cross-Origin Resource Sharing)
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `CORS_ORIGINS` | `*` | Comma-separated allowed origins. Use specific domains in production. |
+| `CORS_METHODS` | `GET,PUT,POST,DELETE,OPTIONS,HEAD` | Allowed HTTP methods. |
+| `CORS_ALLOW_HEADERS` | `*` | Allowed request headers. |
+| `CORS_EXPOSE_HEADERS` | `*` | Response headers visible to browsers (e.g., `ETag`). |
+
+### Rate Limiting
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `RATE_LIMIT_DEFAULT` | `200 per minute` | Default rate limit for API endpoints. |
+| `RATE_LIMIT_STORAGE_URI` | `memory://` | Storage backend for rate limits. Use `redis://host:port` for distributed setups. |
+
+### Logging
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `LOG_LEVEL` | `INFO` | Log verbosity: `DEBUG`, `INFO`, `WARNING`, `ERROR`. |
+| `LOG_TO_FILE` | `true` | Enable file logging. |
+| `LOG_DIR` | `<repo>/logs` | Directory for log files. |
+| `LOG_FILE` | `app.log` | Log filename. |
+| `LOG_MAX_BYTES` | `5242880` (5 MB) | Max log file size before rotation. |
+| `LOG_BACKUP_COUNT` | `3` | Number of rotated log files to keep. |
+
+### Encryption
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `ENCRYPTION_ENABLED` | `false` | Enable server-side encryption support. |
+| `ENCRYPTION_MASTER_KEY_PATH` | `data/.myfsio.sys/keys/master.key` | Path to the master encryption key file. |
+| `DEFAULT_ENCRYPTION_ALGORITHM` | `AES256` | Default algorithm for new encrypted objects. |
+| `KMS_ENABLED` | `false` | Enable KMS key management for encryption. |
+| `KMS_KEYS_PATH` | `data/.myfsio.sys/keys/kms_keys.json` | Path to store KMS key metadata. |
+
+### Performance Tuning
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `STREAM_CHUNK_SIZE` | `65536` (64 KB) | Chunk size for streaming large files. |
+| `MULTIPART_MIN_PART_SIZE` | `5242880` (5 MB) | Minimum part size for multipart uploads. |
+| `BUCKET_STATS_CACHE_TTL` | `60` | Seconds to cache bucket statistics. |
+| `BULK_DELETE_MAX_KEYS` | `500` | Maximum keys per bulk delete request. |
+
+### Server Settings
+
+| Variable | Default | Notes |
+| --- | --- | --- |
+| `APP_HOST` | `0.0.0.0` | Network interface to bind to. |
+| `APP_PORT` | `5000` | API server port (UI uses 5100). |
+| `FLASK_DEBUG` | `0` | Enable Flask debug mode. **Never enable in production.** |
+
+### Production Checklist
+
+Before deploying to production, ensure you:
+
+1. **Set `SECRET_KEY`** - Use a strong, unique value (e.g., `openssl rand -base64 32`)
+2. **Restrict CORS** - Set `CORS_ORIGINS` to your specific domains instead of `*`
+3. **Configure `API_BASE_URL`** - Required for correct presigned URLs behind proxies
+4. **Enable HTTPS** - Use a reverse proxy (nginx, Cloudflare) with TLS termination
+5. **Review rate limits** - Adjust `RATE_LIMIT_DEFAULT` based on your needs
+6. **Secure master keys** - Back up `ENCRYPTION_MASTER_KEY_PATH` if using encryption
+7. **Use `--prod` flag** - Runs with Waitress instead of Flask dev server
 
 ### Proxy Configuration
 
@@ -91,6 +226,333 @@ If running behind a reverse proxy (e.g., Nginx, Cloudflare, or a tunnel), ensure
 
 The application automatically trusts these headers to generate correct presigned URLs (e.g., `https://s3.example.com/...` instead of `http://127.0.0.1:5000/...`). Alternatively, you can explicitly set `API_BASE_URL` to your public endpoint.
 
+## 4. Upgrading and Updates
+
+### Version Checking
+
+The application version is tracked in `app/version.py` and exposed via:
+- **Health endpoint:** `GET /healthz` returns JSON with `version` field
+- **Metrics dashboard:** Navigate to `/ui/metrics` to see the running version in the System Status card
+
+To check your current version:
+
+```bash
+# API health endpoint
+curl http://localhost:5000/healthz
+
+# Or inspect version.py directly
+cat app/version.py | grep APP_VERSION
+```
+
+### Pre-Update Backup Procedures
+
+**Always backup before upgrading to prevent data loss:**
+
+```bash
+# 1. Stop the application
+# Ctrl+C if running in terminal, or:
+docker stop myfsio  # if using Docker
+
+# 2. Backup configuration files (CRITICAL)
+mkdir -p backups/$(date +%Y%m%d_%H%M%S)
+cp -r data/.myfsio.sys/config backups/$(date +%Y%m%d_%H%M%S)/
+
+# 3. Backup all data (optional but recommended)
+tar -czf backups/data_$(date +%Y%m%d_%H%M%S).tar.gz data/
+
+# 4. Backup logs for audit trail
+cp -r logs backups/$(date +%Y%m%d_%H%M%S)/
+```
+
+**Windows PowerShell:**
+
+```powershell
+# Create timestamped backup
+$timestamp = Get-Date -Format "yyyyMMdd_HHmmss"
+New-Item -ItemType Directory -Path "backups\$timestamp" -Force
+
+# Backup configs
+Copy-Item -Recurse "data\.myfsio.sys\config" "backups\$timestamp\"
+
+# Backup entire data directory
+Compress-Archive -Path "data\" -DestinationPath "backups\data_$timestamp.zip"
+```
+
+**Critical files to backup:**
+- `data/.myfsio.sys/config/iam.json` – User accounts and access keys
+- `data/.myfsio.sys/config/bucket_policies.json` – Bucket access policies
+- `data/.myfsio.sys/config/kms_keys.json` – Encryption keys (if using KMS)
+- `data/.myfsio.sys/config/secret_store.json` – Application secrets
+
+### Update Procedures
+
+#### Source Installation Updates
+
+```bash
+# 1. Backup (see above)
+# 2. Pull latest code
+git fetch origin
+git checkout main  # or your target branch/tag
+git pull
+
+# 3. Check for dependency changes
+pip install -r requirements.txt
+
+# 4. Review CHANGELOG/release notes for breaking changes
+cat CHANGELOG.md  # if available
+
+# 5. Run migration scripts (if any)
+# python scripts/migrate_vX_to_vY.py  # example
+
+# 6. Restart application
+python run.py
+```
+
+#### Docker Updates
+
+```bash
+# 1. Backup (see above)
+# 2. Pull/rebuild image
+docker pull yourregistry/myfsio:latest
+# OR rebuild from source:
+docker build -t myfsio:latest .
+
+# 3. Stop and remove old container
+docker stop myfsio
+docker rm myfsio
+
+# 4. Start new container with same volumes
+docker run -d \
+  --name myfsio \
+  -p 5000:5000 -p 5100:5100 \
+  -v "$(pwd)/data:/app/data" \
+  -v "$(pwd)/logs:/app/logs" \
+  -e SECRET_KEY="your-secret" \
+  myfsio:latest
+
+# 5. Verify health
+curl http://localhost:5000/healthz
+```
+
+### Version Compatibility Checks
+
+Before upgrading across major versions, verify compatibility:
+
+| From Version | To Version | Breaking Changes | Migration Required |
+|--------------|------------|------------------|-------------------|
+| 0.1.x | 0.2.x | None expected | No |
+| < 0.1.0 | >= 0.1.0 | New IAM config format | Yes - run migration script |
+
+**Automatic compatibility detection:**
+
+The application will log warnings on startup if config files need migration:
+
+```
+WARNING: IAM config format is outdated (v1). Please run: python scripts/migrate_iam.py
+```
+
+**Manual compatibility check:**
+
+```bash
+# Compare version schemas
+python -c "from app.version import APP_VERSION; print(f'Running: {APP_VERSION}')"
+python scripts/check_compatibility.py data/.myfsio.sys/config/
+```
+
+### Migration Steps for Breaking Changes
+
+When release notes indicate breaking changes, follow these steps:
+
+#### Config Format Migrations
+
+```bash
+# 1. Backup first (critical!)
+cp data/.myfsio.sys/config/iam.json data/.myfsio.sys/config/iam.json.backup
+
+# 2. Run provided migration script
+python scripts/migrate_iam_v1_to_v2.py
+
+# 3. Validate migration
+python scripts/validate_config.py
+
+# 4. Test with read-only mode first (if available)
+# python run.py --read-only
+
+# 5. Restart normally
+python run.py
+```
+
+#### Database/Storage Schema Changes
+
+If object metadata format changes:
+
+```bash
+# 1. Run storage migration script
+python scripts/migrate_storage.py --dry-run  # preview changes
+
+# 2. Apply migration
+python scripts/migrate_storage.py --apply
+
+# 3. Verify integrity
+python scripts/verify_storage.py
+```
+
+#### IAM Policy Updates
+
+If IAM action names change (e.g., `s3:Get` → `s3:GetObject`):
+
+```bash
+# Migration script will update all policies
+python scripts/migrate_policies.py \
+  --input data/.myfsio.sys/config/iam.json \
+  --backup data/.myfsio.sys/config/iam.json.v1
+
+# Review changes before committing
+python scripts/diff_policies.py \
+  data/.myfsio.sys/config/iam.json.v1 \
+  data/.myfsio.sys/config/iam.json
+```
+
+### Rollback Procedures
+
+If an update causes issues, rollback to the previous version:
+
+#### Quick Rollback (Source)
+
+```bash
+# 1. Stop application
+# Ctrl+C or kill process
+
+# 2. Revert code
+git checkout <previous-version-tag>
+# OR
+git reset --hard HEAD~1
+
+# 3. Restore configs from backup
+cp backups/20241213_103000/config/* data/.myfsio.sys/config/
+
+# 4. Downgrade dependencies if needed
+pip install -r requirements.txt
+
+# 5. Restart
+python run.py
+```
+
+#### Docker Rollback
+
+```bash
+# 1. Stop current container
+docker stop myfsio
+docker rm myfsio
+
+# 2. Start previous version
+docker run -d \
+  --name myfsio \
+  -p 5000:5000 -p 5100:5100 \
+  -v "$(pwd)/data:/app/data" \
+  -v "$(pwd)/logs:/app/logs" \
+  -e SECRET_KEY="your-secret" \
+  myfsio:0.1.3  # specify previous version tag
+
+# 3. Verify
+curl http://localhost:5000/healthz
+```
+
+#### Emergency Config Restore
+
+If only config is corrupted but code is fine:
+
+```bash
+# Stop app
+# Restore from latest backup
+cp backups/20241213_103000/config/iam.json data/.myfsio.sys/config/
+cp backups/20241213_103000/config/bucket_policies.json data/.myfsio.sys/config/
+
+# Restart app
+python run.py
+```
+
+### Blue-Green Deployment (Zero Downtime)
+
+For production environments requiring zero downtime:
+
+```bash
+# 1. Run new version on different port (e.g., 5001/5101)
+APP_PORT=5001 UI_PORT=5101 python run.py &
+
+# 2. Health check new instance
+curl http://localhost:5001/healthz
+
+# 3. Update load balancer to route to new ports
+
+# 4. Monitor for issues
+
+# 5. Gracefully stop old instance
+kill -SIGTERM <old-pid>
+```
+
+### Post-Update Verification
+
+After any update, verify functionality:
+
+```bash
+# 1. Health check
+curl http://localhost:5000/healthz
+
+# 2. Login to UI
+open http://localhost:5100/ui
+
+# 3. Test IAM authentication
+curl -H "X-Amz-Security-Token: <your-access-key>:<your-secret>" \
+  http://localhost:5000/
+
+# 4. Test presigned URL generation
+# Via UI or API
+
+# 5. Check logs for errors
+tail -n 100 logs/myfsio.log
+```
+
+### Automated Update Scripts
+
+Create a custom update script for your environment:
+
+```bash
+#!/bin/bash
+# update.sh - Automated update with rollback capability
+
+set -e  # Exit on error
+
+VERSION_NEW="$1"
+BACKUP_DIR="backups/$(date +%Y%m%d_%H%M%S)"
+
+echo "Creating backup..."
+mkdir -p "$BACKUP_DIR"
+cp -r data/.myfsio.sys/config "$BACKUP_DIR/"
+
+echo "Updating to version $VERSION_NEW..."
+git fetch origin
+git checkout "v$VERSION_NEW"
+pip install -r requirements.txt
+
+echo "Starting application..."
+python run.py &
+APP_PID=$!
+
+# Wait and health check
+sleep 5
+if curl -f http://localhost:5000/healthz; then
+  echo "Update successful!"
+else
+  echo "Health check failed, rolling back..."
+  kill $APP_PID
+  git checkout -
+  cp -r "$BACKUP_DIR/config/*" data/.myfsio.sys/config/
+  python run.py &
+  exit 1
+fi
+```
+
 ## 4. Authentication & IAM
 
 1. On first boot, `data/.myfsio.sys/config/iam.json` is seeded with `localadmin / localadmin` that has wildcard access.
@@ -102,6 +564,46 @@ The application automatically trusts these headers to generate correct presigned
 
 The API expects every request to include `X-Access-Key` and `X-Secret-Key` headers. The UI persists them in the Flask session after login.
 
+### Available IAM Actions
+
+| Action | Description | AWS Aliases |
+| --- | --- | --- |
+| `list` | List buckets and objects | `s3:ListBucket`, `s3:ListAllMyBuckets`, `s3:ListBucketVersions`, `s3:ListMultipartUploads`, `s3:ListParts` |
+| `read` | Download objects | `s3:GetObject`, `s3:GetObjectVersion`, `s3:GetObjectTagging`, `s3:HeadObject`, `s3:HeadBucket` |
+| `write` | Upload objects, create buckets | `s3:PutObject`, `s3:CreateBucket`, `s3:CreateMultipartUpload`, `s3:UploadPart`, `s3:CompleteMultipartUpload`, `s3:AbortMultipartUpload`, `s3:CopyObject` |
+| `delete` | Remove objects and buckets | `s3:DeleteObject`, `s3:DeleteObjectVersion`, `s3:DeleteBucket` |
+| `share` | Manage ACLs | `s3:PutObjectAcl`, `s3:PutBucketAcl`, `s3:GetBucketAcl` |
+| `policy` | Manage bucket policies | `s3:PutBucketPolicy`, `s3:GetBucketPolicy`, `s3:DeleteBucketPolicy` |
+| `replication` | Configure and manage replication | `s3:GetReplicationConfiguration`, `s3:PutReplicationConfiguration`, `s3:ReplicateObject`, `s3:ReplicateTags`, `s3:ReplicateDelete` |
+| `iam:list_users` | View IAM users | `iam:ListUsers` |
+| `iam:create_user` | Create IAM users | `iam:CreateUser` |
+| `iam:delete_user` | Delete IAM users | `iam:DeleteUser` |
+| `iam:rotate_key` | Rotate user secrets | `iam:RotateAccessKey` |
+| `iam:update_policy` | Modify user policies | `iam:PutUserPolicy` |
+| `iam:*` | All IAM actions (admin wildcard) | — |
+
+### Example Policies
+
+**Full Control (admin):**
+```json
+[{"bucket": "*", "actions": ["list", "read", "write", "delete", "share", "policy", "replication", "iam:*"]}]
+```
+
+**Read-Only:**
+```json
+[{"bucket": "*", "actions": ["list", "read"]}]
+```
+
+**Single Bucket Access (no listing other buckets):**
+```json
+[{"bucket": "user-bucket", "actions": ["read", "write", "delete"]}]
+```
+
+**Bucket Access with Replication:**
+```json
+[{"bucket": "my-bucket", "actions": ["list", "read", "write", "delete", "replication"]}]
+```
+
 ## 5. Bucket Policies & Presets
 
 - **Storage**: Policies are persisted in `data/.myfsio.sys/config/bucket_policies.json` under `{"policies": {"bucket": {...}}}`.
@@ -173,9 +675,207 @@ s3.complete_multipart_upload(
 )
 ```
 
-## 6. Site Replication
+## 7. Encryption
 
-MyFSIO supports **Site Replication**, allowing you to automatically copy new objects from one MyFSIO instance (Source) to another (Target). This is useful for disaster recovery, data locality, or backups.
+MyFSIO supports **server-side encryption at rest** to protect your data. When enabled, objects are encrypted using AES-256-GCM before being written to disk.
+
+### Encryption Types
+
+| Type | Description |
+|------|-------------|
+| **AES-256 (SSE-S3)** | Server-managed encryption using a local master key |
+| **KMS (SSE-KMS)** | Encryption using customer-managed keys via the built-in KMS |
+
+### Enabling Encryption
+
+#### 1. Set Environment Variables
+
+```powershell
+# PowerShell
+$env:ENCRYPTION_ENABLED = "true"
+$env:KMS_ENABLED = "true"  # Optional, for KMS key management
+python run.py
+```
+
+```bash
+# Bash
+export ENCRYPTION_ENABLED=true
+export KMS_ENABLED=true
+python run.py
+```
+
+#### 2. Configure Bucket Default Encryption (UI)
+
+1. Navigate to your bucket in the UI
+2. Click the **Properties** tab
+3. Find the **Default Encryption** card
+4. Click **Enable Encryption**
+5. Choose algorithm:
+   - **AES-256**: Uses the server's master key
+   - **aws:kms**: Uses a KMS-managed key (select from dropdown)
+6. Save changes
+
+Once enabled, all **new objects** uploaded to the bucket will be automatically encrypted.
+
+### KMS Key Management
+
+When `KMS_ENABLED=true`, you can manage encryption keys via the KMS API:
+
+```bash
+# Create a new KMS key
+curl -X POST http://localhost:5000/kms/keys \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..." \
+  -d '{"alias": "my-key", "description": "Production encryption key"}'
+
+# List all keys
+curl http://localhost:5000/kms/keys \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+# Get key details
+curl http://localhost:5000/kms/keys/{key-id} \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+# Rotate a key (creates new key material)
+curl -X POST http://localhost:5000/kms/keys/{key-id}/rotate \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+# Disable/Enable a key
+curl -X POST http://localhost:5000/kms/keys/{key-id}/disable \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+curl -X POST http://localhost:5000/kms/keys/{key-id}/enable \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+# Schedule key deletion (30-day waiting period)
+curl -X DELETE http://localhost:5000/kms/keys/{key-id}?waiting_period_days=30 \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+```
+
+### How It Works
+
+1. **Envelope Encryption**: Each object is encrypted with a unique Data Encryption Key (DEK)
+2. **Key Wrapping**: The DEK is encrypted (wrapped) by the master key or KMS key
+3. **Storage**: The encrypted DEK is stored alongside the encrypted object
+4. **Decryption**: On read, the DEK is unwrapped and used to decrypt the object
+
+### Client-Side Encryption
+
+For additional security, you can use client-side encryption. The `ClientEncryptionHelper` class provides utilities:
+
+```python
+from app.encryption import ClientEncryptionHelper
+
+# Generate a client-side key
+key = ClientEncryptionHelper.generate_key()
+key_b64 = ClientEncryptionHelper.key_to_base64(key)
+
+# Encrypt before upload
+plaintext = b"sensitive data"
+encrypted, metadata = ClientEncryptionHelper.encrypt_for_upload(plaintext, key)
+
+# Upload with metadata headers
+# x-amz-meta-x-amz-key: <wrapped-key>
+# x-amz-meta-x-amz-iv: <iv>
+# x-amz-meta-x-amz-matdesc: <material-description>
+
+# Decrypt after download
+decrypted = ClientEncryptionHelper.decrypt_from_download(encrypted, metadata, key)
+```
+
+### Important Notes
+
+- **Existing objects are NOT encrypted** - Only new uploads after enabling encryption are encrypted
+- **Master key security** - The master key file (`master.key`) should be backed up securely and protected
+- **Key rotation** - Rotating a KMS key creates new key material; existing objects remain encrypted with the old material
+- **Disabled keys** - Objects encrypted with a disabled key cannot be decrypted until the key is re-enabled
+- **Deleted keys** - Once a key is deleted (after the waiting period), objects encrypted with it are permanently inaccessible
+
+### Verifying Encryption
+
+To verify an object is encrypted:
+1. Check the raw file in `data/<bucket>/` - it should be unreadable binary
+2. Look for `.meta` files containing encryption metadata
+3. Download via the API/UI - the object should be automatically decrypted
+
+## 8. Bucket Quotas
+
+MyFSIO supports **storage quotas** to limit how much data a bucket can hold. Quotas are enforced on uploads and multipart completions.
+
+### Quota Types
+
+| Limit | Description |
+|-------|-------------|
+| **Max Size (MB)** | Maximum total storage in megabytes (includes current objects + archived versions) |
+| **Max Objects** | Maximum number of objects (includes current objects + archived versions) |
+
+### Managing Quotas (Admin Only)
+
+Quota management is restricted to administrators (users with `iam:*` or `iam:list_users` permissions).
+
+#### Via UI
+
+1. Navigate to your bucket in the UI
+2. Click the **Properties** tab
+3. Find the **Storage Quota** card
+4. Enter limits:
+   - **Max Size (MB)**: Leave empty for unlimited
+   - **Max Objects**: Leave empty for unlimited
+5. Click **Update Quota**
+
+To remove a quota, click **Remove Quota**.
+
+#### Via API
+
+```bash
+# Set quota (max 100MB, max 1000 objects)
+curl -X PUT "http://localhost:5000/bucket/<bucket>?quota" \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..." \
+  -d '{"max_bytes": 104857600, "max_objects": 1000}'
+
+# Get current quota
+curl "http://localhost:5000/bucket/<bucket>?quota" \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..."
+
+# Remove quota
+curl -X PUT "http://localhost:5000/bucket/<bucket>?quota" \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: ..." -H "X-Secret-Key: ..." \
+  -d '{"max_bytes": null, "max_objects": null}'
+```
+
+### Quota Behavior
+
+- **Version Counting**: When versioning is enabled, archived versions count toward the quota
+- **Enforcement Points**: Quotas are checked during `PUT` object and `CompleteMultipartUpload` operations
+- **Error Response**: When quota is exceeded, the API returns `HTTP 400` with error code `QuotaExceeded`
+- **Visibility**: All users can view quota usage in the bucket detail page, but only admins can modify quotas
+
+### Example Error
+
+```xml
+<Error>
+  <Code>QuotaExceeded</Code>
+  <Message>Bucket quota exceeded: storage limit reached</Message>
+  <BucketName>my-bucket</BucketName>
+</Error>
+```
+
+## 9. Site Replication
+
+### Permission Model
+
+Replication uses a two-tier permission system:
+
+| Role | Capabilities |
+|------|--------------|
+| **Admin** (users with `iam:*` permissions) | Create/delete replication rules, configure connections and target buckets |
+| **Users** (with `replication` permission) | Enable/disable (pause/resume) existing replication rules |
+
+> **Note:** The Replication tab is hidden for users without the `replication` permission on the bucket.
+
+This separation allows administrators to pre-configure where data should replicate, while allowing authorized users to toggle replication on/off without accessing connection credentials.
 
 ### Architecture
 
@@ -253,13 +953,15 @@ Now, configure the primary instance to replicate to the target.
     - **Secret Key**: The secret you generated on the Target.
     - Click **Add Connection**.
 
-3.  **Enable Replication**:
+3.  **Enable Replication** (Admin):
     - Navigate to **Buckets** and select the source bucket.
     - Switch to the **Replication** tab.
     - Select the `Secondary Site` connection.
     - Enter the target bucket name (`backup-bucket`).
     - Click **Enable Replication**.
 
+    Once configured, users with `replication` permission on this bucket can pause/resume replication without needing access to connection details.
+
 ### Verification
 
 1.  Upload a file to the source bucket.
@@ -270,6 +972,18 @@ Now, configure the primary instance to replicate to the target.
 aws --endpoint-url http://target-server:5002 s3 ls s3://backup-bucket
 ```
 
+### Pausing and Resuming Replication
+
+Users with the `replication` permission (but not admin rights) can pause and resume existing replication rules:
+
+1. Navigate to the bucket's **Replication** tab.
+2. If replication is **Active**, click **Pause Replication** to temporarily stop syncing.
+3. If replication is **Paused**, click **Resume Replication** to continue syncing.
+
+When paused, new objects uploaded to the source will not replicate until replication is resumed. Objects uploaded while paused will be replicated once resumed.
+
+> **Note:** Only admins can create new replication rules, change the target connection/bucket, or delete rules entirely.
+
 ### Bidirectional Replication (Active-Active)
 
 To set up two-way replication (Server A ↔ Server B):
@@ -285,7 +999,7 @@ To set up two-way replication (Server A ↔ Server B):
 
 **Note**: Deleting a bucket will automatically remove its associated replication configuration.
 
-## 7. Running Tests
+## 11. Running Tests
 
 ```bash
 pytest -q
@@ -295,7 +1009,7 @@ The suite now includes a boto3 integration test that spins up a live HTTP server
 
 The suite covers bucket CRUD, presigned downloads, bucket policy enforcement, and regression tests for anonymous reads when a Public policy is attached.
 
-## 8. Troubleshooting
+## 12. Troubleshooting
 
 | Symptom | Likely Cause | Fix |
 | --- | --- | --- |
@@ -304,7 +1018,7 @@ The suite covers bucket CRUD, presigned downloads, bucket policy enforcement, an
 | Presign modal errors with 403 | IAM user lacks `read/write/delete` for target bucket or bucket policy denies | Update IAM inline policies or remove conflicting deny statements. |
 | Large upload rejected immediately | File exceeds `MAX_UPLOAD_SIZE` | Increase env var or shrink object. |
 
-## 9. API Matrix
+## 13. API Matrix
 
 ```
 GET    /                               # List buckets
@@ -318,10 +1032,6 @@ POST   /presign/<bucket>/<key>          # Generate SigV4 URL
 GET    /bucket-policy/<bucket>          # Fetch policy
 PUT    /bucket-policy/<bucket>          # Upsert policy
 DELETE /bucket-policy/<bucket>          # Delete policy
+GET    /<bucket>?quota                  # Get bucket quota
+PUT    /<bucket>?quota                  # Set bucket quota (admin only)
 ```
-
-## 10. Next Steps
-
-- Tailor IAM + policy JSON files for team-ready presets.
-- Wrap `run_api.py` with gunicorn or another WSGI server for long-running workloads.
-- Extend `bucket_policies.json` to cover Deny statements that simulate production security controls.

requirements.txt

@@ -1,9 +1,10 @@
-Flask>=3.0.2
+Flask>=3.1.2
-Flask-Limiter>=3.5.0
+Flask-Limiter>=4.1.0
-Flask-Cors>=4.0.0
+Flask-Cors>=6.0.1
-Flask-WTF>=1.2.1
+Flask-WTF>=1.2.2
-pytest>=7.4
+pytest>=9.0.1
-requests>=2.31
+requests>=2.32.5
-boto3>=1.34
+boto3>=1.42.1
-waitress>=2.1.2
+waitress>=3.0.2
-psutil>=5.9.0
+psutil>=7.1.3
+cryptography>=46.0.3

run.py

@@ -8,6 +8,7 @@ import warnings
 from multiprocessing import Process
 
 from app import create_api_app, create_ui_app
+from app.config import AppConfig
 
 
 def _server_host() -> str:
@@ -55,12 +56,48 @@ if __name__ == "__main__":
     parser.add_argument("--ui-port", type=int, default=5100)
     parser.add_argument("--prod", action="store_true", help="Run in production mode using Waitress")
     parser.add_argument("--dev", action="store_true", help="Force development mode (Flask dev server)")
+    parser.add_argument("--check-config", action="store_true", help="Validate configuration and exit")
+    parser.add_argument("--show-config", action="store_true", help="Show configuration summary and exit")
     args = parser.parse_args()
 
+    # Handle config check/show modes
+    if args.check_config or args.show_config:
+        config = AppConfig.from_env()
+        config.print_startup_summary()
+        if args.check_config:
+            issues = config.validate_and_report()
+            critical = [i for i in issues if i.startswith("CRITICAL:")]
+            sys.exit(1 if critical else 0)
+        sys.exit(0)
+
     # Default to production mode when running as compiled binary
     # unless --dev is explicitly passed
     prod_mode = args.prod or (_is_frozen() and not args.dev)
     
+    # Validate configuration before starting
+    config = AppConfig.from_env()
+    
+    # Show startup summary only on first run (when marker file doesn't exist)
+    first_run_marker = config.storage_root / ".myfsio.sys" / ".initialized"
+    is_first_run = not first_run_marker.exists()
+    
+    if is_first_run:
+        config.print_startup_summary()
+        
+        # Check for critical issues that should prevent startup
+        issues = config.validate_and_report()
+        critical_issues = [i for i in issues if i.startswith("CRITICAL:")]
+        if critical_issues:
+            print("ABORTING: Critical configuration issues detected. Fix them before starting.")
+            sys.exit(1)
+        
+        # Create the marker file to indicate successful first run
+        try:
+            first_run_marker.parent.mkdir(parents=True, exist_ok=True)
+            first_run_marker.write_text(f"Initialized on {__import__('datetime').datetime.now().isoformat()}\n")
+        except OSError:
+            pass  # Non-critical, just skip marker creation
+    
     if prod_mode:
         print("Running in production mode (Waitress)")
     else:

scripts/install.sh

@@ -0,0 +1,370 @@
+#!/bin/bash
+#
+# MyFSIO Installation Script
+# This script sets up MyFSIO for production use on Linux systems.
+#
+# Usage:
+#   ./install.sh [OPTIONS]
+#
+# Options:
+#   --install-dir DIR    Installation directory (default: /opt/myfsio)
+#   --data-dir DIR       Data directory (default: /var/lib/myfsio)
+#   --log-dir DIR        Log directory (default: /var/log/myfsio)
+#   --user USER          System user to run as (default: myfsio)
+#   --port PORT          API port (default: 5000)
+#   --ui-port PORT       UI port (default: 5100)
+#   --api-url URL        Public API URL (for presigned URLs behind proxy)
+#   --no-systemd         Skip systemd service creation
+#   --binary PATH        Path to myfsio binary (will download if not provided)
+#   -y, --yes            Skip confirmation prompts
+#
+
+set -e
+
+INSTALL_DIR="/opt/myfsio"
+DATA_DIR="/var/lib/myfsio"
+LOG_DIR="/var/log/myfsio"
+SERVICE_USER="myfsio"
+API_PORT="5000"
+UI_PORT="5100"
+API_URL=""
+SKIP_SYSTEMD=false
+BINARY_PATH=""
+AUTO_YES=false
+
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        --install-dir)
+            INSTALL_DIR="$2"
+            shift 2
+            ;;
+        --data-dir)
+            DATA_DIR="$2"
+            shift 2
+            ;;
+        --log-dir)
+            LOG_DIR="$2"
+            shift 2
+            ;;
+        --user)
+            SERVICE_USER="$2"
+            shift 2
+            ;;
+        --port)
+            API_PORT="$2"
+            shift 2
+            ;;
+        --ui-port)
+            UI_PORT="$2"
+            shift 2
+            ;;
+        --api-url)
+            API_URL="$2"
+            shift 2
+            ;;
+        --no-systemd)
+            SKIP_SYSTEMD=true
+            shift
+            ;;
+        --binary)
+            BINARY_PATH="$2"
+            shift 2
+            ;;
+        -y|--yes)
+            AUTO_YES=true
+            shift
+            ;;
+        -h|--help)
+            head -30 "$0" | tail -25
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+echo ""
+echo "============================================================"
+echo "               MyFSIO Installation Script"
+echo "            S3-Compatible Object Storage"
+echo "============================================================"
+echo ""
+echo "Documentation: https://go.jzwsite.com/myfsio"
+echo ""
+
+if [[ $EUID -ne 0 ]]; then
+    echo "Error: This script must be run as root (use sudo)"
+    exit 1
+fi
+
+echo "------------------------------------------------------------"
+echo "STEP 1: Review Installation Configuration"
+echo "------------------------------------------------------------"
+echo ""
+echo "  Install directory:  $INSTALL_DIR"
+echo "  Data directory:     $DATA_DIR"
+echo "  Log directory:      $LOG_DIR"
+echo "  Service user:       $SERVICE_USER"
+echo "  API port:           $API_PORT"
+echo "  UI port:            $UI_PORT"
+if [[ -n "$API_URL" ]]; then
+    echo "  Public API URL:     $API_URL"
+fi
+if [[ -n "$BINARY_PATH" ]]; then
+    echo "  Binary path:        $BINARY_PATH"
+fi
+echo ""
+
+if [[ "$AUTO_YES" != true ]]; then
+    read -p "Do you want to proceed with these settings? [y/N] " -n 1 -r
+    echo
+    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+        echo "Installation cancelled."
+        exit 0
+    fi
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 2: Creating System User"
+echo "------------------------------------------------------------"
+echo ""
+if id "$SERVICE_USER" &>/dev/null; then
+    echo "  [OK] User '$SERVICE_USER' already exists"
+else
+    useradd --system --no-create-home --shell /usr/sbin/nologin "$SERVICE_USER"
+    echo "  [OK] Created user '$SERVICE_USER'"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 3: Creating Directories"
+echo "------------------------------------------------------------"
+echo ""
+mkdir -p "$INSTALL_DIR"
+echo "  [OK] Created $INSTALL_DIR"
+mkdir -p "$DATA_DIR"
+echo "  [OK] Created $DATA_DIR"
+mkdir -p "$LOG_DIR"
+echo "  [OK] Created $LOG_DIR"
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 4: Installing Binary"
+echo "------------------------------------------------------------"
+echo ""
+if [[ -n "$BINARY_PATH" ]]; then
+    if [[ -f "$BINARY_PATH" ]]; then
+        cp "$BINARY_PATH" "$INSTALL_DIR/myfsio"
+        echo "  [OK] Copied binary from $BINARY_PATH"
+    else
+        echo "  [ERROR] Binary not found at $BINARY_PATH"
+        exit 1
+    fi
+elif [[ -f "./myfsio" ]]; then
+    cp "./myfsio" "$INSTALL_DIR/myfsio"
+    echo "  [OK] Copied binary from ./myfsio"
+else
+    echo "  [ERROR] No binary provided."
+    echo "          Use --binary PATH or place 'myfsio' in current directory"
+    exit 1
+fi
+chmod +x "$INSTALL_DIR/myfsio"
+echo "  [OK] Set executable permissions"
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 5: Generating Secret Key"
+echo "------------------------------------------------------------"
+echo ""
+SECRET_KEY=$(openssl rand -base64 32)
+echo "  [OK] Generated secure SECRET_KEY"
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 6: Creating Configuration File"
+echo "------------------------------------------------------------"
+echo ""
+cat > "$INSTALL_DIR/myfsio.env" << EOF
+# MyFSIO Configuration
+# Generated by install.sh on $(date)
+# Documentation: https://go.jzwsite.com/myfsio
+
+# Storage paths
+STORAGE_ROOT=$DATA_DIR
+LOG_DIR=$LOG_DIR
+
+# Network
+APP_HOST=0.0.0.0
+APP_PORT=$API_PORT
+
+# Security - CHANGE IN PRODUCTION
+SECRET_KEY=$SECRET_KEY
+CORS_ORIGINS=*
+
+# Public URL (set this if behind a reverse proxy)
+$(if [[ -n "$API_URL" ]]; then echo "API_BASE_URL=$API_URL"; else echo "# API_BASE_URL=https://s3.example.com"; fi)
+
+# Logging
+LOG_LEVEL=INFO
+LOG_TO_FILE=true
+
+# Rate limiting
+RATE_LIMIT_DEFAULT=200 per minute
+
+# Optional: Encryption (uncomment to enable)
+# ENCRYPTION_ENABLED=true
+# KMS_ENABLED=true
+EOF
+chmod 600 "$INSTALL_DIR/myfsio.env"
+echo "  [OK] Created $INSTALL_DIR/myfsio.env"
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 7: Setting Permissions"
+echo "------------------------------------------------------------"
+echo ""
+chown -R "$SERVICE_USER:$SERVICE_USER" "$INSTALL_DIR"
+echo "  [OK] Set ownership for $INSTALL_DIR"
+chown -R "$SERVICE_USER:$SERVICE_USER" "$DATA_DIR"
+echo "  [OK] Set ownership for $DATA_DIR"
+chown -R "$SERVICE_USER:$SERVICE_USER" "$LOG_DIR"
+echo "  [OK] Set ownership for $LOG_DIR"
+
+if [[ "$SKIP_SYSTEMD" != true ]]; then
+    echo ""
+    echo "------------------------------------------------------------"
+    echo "STEP 8: Creating Systemd Service"
+    echo "------------------------------------------------------------"
+    echo ""
+    cat > /etc/systemd/system/myfsio.service << EOF
+[Unit]
+Description=MyFSIO S3-Compatible Storage
+Documentation=https://go.jzwsite.com/myfsio
+After=network.target
+
+[Service]
+Type=simple
+User=$SERVICE_USER
+Group=$SERVICE_USER
+WorkingDirectory=$INSTALL_DIR
+EnvironmentFile=$INSTALL_DIR/myfsio.env
+ExecStart=$INSTALL_DIR/myfsio
+Restart=on-failure
+RestartSec=5
+
+# Security hardening
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=$DATA_DIR $LOG_DIR
+PrivateTmp=true
+
+# Resource limits (adjust as needed)
+# LimitNOFILE=65535
+# MemoryMax=2G
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+    systemctl daemon-reload
+    echo "  [OK] Created /etc/systemd/system/myfsio.service"
+    echo "  [OK] Reloaded systemd daemon"
+else
+    echo ""
+    echo "------------------------------------------------------------"
+    echo "STEP 8: Skipping Systemd Service (--no-systemd flag used)"
+    echo "------------------------------------------------------------"
+fi
+
+echo ""
+echo "============================================================"
+echo "               Installation Complete!"
+echo "============================================================"
+echo ""
+
+if [[ "$SKIP_SYSTEMD" != true ]]; then
+    echo "------------------------------------------------------------"
+    echo "STEP 9: Start the Service"
+    echo "------------------------------------------------------------"
+    echo ""
+    
+    if [[ "$AUTO_YES" != true ]]; then
+        read -p "Would you like to start MyFSIO now? [Y/n] " -n 1 -r
+        echo
+        START_SERVICE=true
+        if [[ $REPLY =~ ^[Nn]$ ]]; then
+            START_SERVICE=false
+        fi
+    else
+        START_SERVICE=true
+    fi
+    
+    if [[ "$START_SERVICE" == true ]]; then
+        echo "  Starting MyFSIO service..."
+        systemctl start myfsio
+        echo "  [OK] Service started"
+        echo ""
+        
+        read -p "Would you like to enable MyFSIO to start on boot? [Y/n] " -n 1 -r
+        echo
+        if [[ ! $REPLY =~ ^[Nn]$ ]]; then
+            systemctl enable myfsio
+            echo "  [OK] Service enabled on boot"
+        fi
+        echo ""
+        
+        sleep 2
+        echo "  Service Status:"
+        echo "  ---------------"
+        if systemctl is-active --quiet myfsio; then
+            echo "  [OK] MyFSIO is running"
+        else
+            echo "  [WARNING] MyFSIO may not have started correctly"
+            echo "            Check logs with: journalctl -u myfsio -f"
+        fi
+    else
+        echo "  [SKIPPED] Service not started"
+        echo ""
+        echo "  To start manually, run:"
+        echo "    sudo systemctl start myfsio"
+        echo ""
+        echo "  To enable on boot, run:"
+        echo "    sudo systemctl enable myfsio"
+    fi
+fi
+
+echo ""
+echo "============================================================"
+echo "                      Summary"
+echo "============================================================"
+echo ""
+echo "Access Points:"
+echo "  API:  http://$(hostname -I 2>/dev/null | awk '{print $1}' || echo "localhost"):$API_PORT"
+echo "  UI:   http://$(hostname -I 2>/dev/null | awk '{print $1}' || echo "localhost"):$UI_PORT/ui"
+echo ""
+echo "Default Credentials:"
+echo "  Username: localadmin"
+echo "  Password: localadmin"
+echo "  [!] WARNING: Change these immediately after first login!"
+echo ""
+echo "Configuration Files:"
+echo "  Environment:     $INSTALL_DIR/myfsio.env"
+echo "  IAM Users:       $DATA_DIR/.myfsio.sys/config/iam.json"
+echo "  Bucket Policies: $DATA_DIR/.myfsio.sys/config/bucket_policies.json"
+echo ""
+echo "Useful Commands:"
+echo "  Check status:    sudo systemctl status myfsio"
+echo "  View logs:       sudo journalctl -u myfsio -f"
+echo "  Restart:         sudo systemctl restart myfsio"
+echo "  Stop:            sudo systemctl stop myfsio"
+echo ""
+echo "Documentation: https://go.jzwsite.com/myfsio"
+echo ""
+echo "============================================================"
+echo "          Thank you for installing MyFSIO!"
+echo "============================================================"
+echo ""

scripts/uninstall.sh

@@ -0,0 +1,244 @@
+#!/bin/bash
+#
+# MyFSIO Uninstall Script
+# This script removes MyFSIO from your system.
+#
+# Usage:
+#   ./uninstall.sh [OPTIONS]
+#
+# Options:
+#   --keep-data         Don't remove data directory
+#   --keep-logs         Don't remove log directory
+#   --install-dir DIR   Installation directory (default: /opt/myfsio)
+#   --data-dir DIR      Data directory (default: /var/lib/myfsio)
+#   --log-dir DIR       Log directory (default: /var/log/myfsio)
+#   --user USER         System user (default: myfsio)
+#   -y, --yes           Skip confirmation prompts
+#
+
+set -e
+
+INSTALL_DIR="/opt/myfsio"
+DATA_DIR="/var/lib/myfsio"
+LOG_DIR="/var/log/myfsio"
+SERVICE_USER="myfsio"
+KEEP_DATA=false
+KEEP_LOGS=false
+AUTO_YES=false
+
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        --keep-data)
+            KEEP_DATA=true
+            shift
+            ;;
+        --keep-logs)
+            KEEP_LOGS=true
+            shift
+            ;;
+        --install-dir)
+            INSTALL_DIR="$2"
+            shift 2
+            ;;
+        --data-dir)
+            DATA_DIR="$2"
+            shift 2
+            ;;
+        --log-dir)
+            LOG_DIR="$2"
+            shift 2
+            ;;
+        --user)
+            SERVICE_USER="$2"
+            shift 2
+            ;;
+        -y|--yes)
+            AUTO_YES=true
+            shift
+            ;;
+        -h|--help)
+            head -20 "$0" | tail -15
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+echo ""
+echo "============================================================"
+echo "               MyFSIO Uninstallation Script"
+echo "============================================================"
+echo ""
+echo "Documentation: https://go.jzwsite.com/myfsio"
+echo ""
+
+if [[ $EUID -ne 0 ]]; then
+    echo "Error: This script must be run as root (use sudo)"
+    exit 1
+fi
+
+echo "------------------------------------------------------------"
+echo "STEP 1: Review What Will Be Removed"
+echo "------------------------------------------------------------"
+echo ""
+echo "The following items will be removed:"
+echo ""
+echo "  Install directory: $INSTALL_DIR"
+if [[ "$KEEP_DATA" != true ]]; then
+    echo "  Data directory:    $DATA_DIR (ALL YOUR DATA WILL BE DELETED!)"
+else
+    echo "  Data directory:    $DATA_DIR (WILL BE KEPT)"
+fi
+if [[ "$KEEP_LOGS" != true ]]; then
+    echo "  Log directory:     $LOG_DIR"
+else
+    echo "  Log directory:     $LOG_DIR (WILL BE KEPT)"
+fi
+echo "  Systemd service:   /etc/systemd/system/myfsio.service"
+echo "  System user:       $SERVICE_USER"
+echo ""
+
+if [[ "$AUTO_YES" != true ]]; then
+    echo "WARNING: This action cannot be undone!"
+    echo ""
+    read -p "Are you sure you want to uninstall MyFSIO? [y/N] " -n 1 -r
+    echo
+    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+        echo ""
+        echo "Uninstallation cancelled."
+        exit 0
+    fi
+    
+    if [[ "$KEEP_DATA" != true ]]; then
+        echo ""
+        read -p "This will DELETE ALL YOUR DATA. Type 'DELETE' to confirm: " CONFIRM
+        if [[ "$CONFIRM" != "DELETE" ]]; then
+            echo ""
+            echo "Uninstallation cancelled."
+            echo "Tip: Use --keep-data to preserve your data directory"
+            exit 0
+        fi
+    fi
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 2: Stopping Service"
+echo "------------------------------------------------------------"
+echo ""
+if systemctl is-active --quiet myfsio 2>/dev/null; then
+    systemctl stop myfsio
+    echo "  [OK] Stopped myfsio service"
+else
+    echo "  [SKIP] Service not running"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 3: Disabling Service"
+echo "------------------------------------------------------------"
+echo ""
+if systemctl is-enabled --quiet myfsio 2>/dev/null; then
+    systemctl disable myfsio
+    echo "  [OK] Disabled myfsio service"
+else
+    echo "  [SKIP] Service not enabled"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 4: Removing Systemd Service File"
+echo "------------------------------------------------------------"
+echo ""
+if [[ -f /etc/systemd/system/myfsio.service ]]; then
+    rm -f /etc/systemd/system/myfsio.service
+    systemctl daemon-reload
+    echo "  [OK] Removed /etc/systemd/system/myfsio.service"
+    echo "  [OK] Reloaded systemd daemon"
+else
+    echo "  [SKIP] Service file not found"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 5: Removing Installation Directory"
+echo "------------------------------------------------------------"
+echo ""
+if [[ -d "$INSTALL_DIR" ]]; then
+    rm -rf "$INSTALL_DIR"
+    echo "  [OK] Removed $INSTALL_DIR"
+else
+    echo "  [SKIP] Directory not found: $INSTALL_DIR"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 6: Removing Data Directory"
+echo "------------------------------------------------------------"
+echo ""
+if [[ "$KEEP_DATA" != true ]]; then
+    if [[ -d "$DATA_DIR" ]]; then
+        rm -rf "$DATA_DIR"
+        echo "  [OK] Removed $DATA_DIR"
+    else
+        echo "  [SKIP] Directory not found: $DATA_DIR"
+    fi
+else
+    echo "  [KEPT] Data preserved at: $DATA_DIR"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 7: Removing Log Directory"
+echo "------------------------------------------------------------"
+echo ""
+if [[ "$KEEP_LOGS" != true ]]; then
+    if [[ -d "$LOG_DIR" ]]; then
+        rm -rf "$LOG_DIR"
+        echo "  [OK] Removed $LOG_DIR"
+    else
+        echo "  [SKIP] Directory not found: $LOG_DIR"
+    fi
+else
+    echo "  [KEPT] Logs preserved at: $LOG_DIR"
+fi
+
+echo ""
+echo "------------------------------------------------------------"
+echo "STEP 8: Removing System User"
+echo "------------------------------------------------------------"
+echo ""
+if id "$SERVICE_USER" &>/dev/null; then
+    userdel "$SERVICE_USER" 2>/dev/null || true
+    echo "  [OK] Removed user '$SERVICE_USER'"
+else
+    echo "  [SKIP] User not found: $SERVICE_USER"
+fi
+
+echo ""
+echo "============================================================"
+echo "            Uninstallation Complete!"
+echo "============================================================"
+echo ""
+
+if [[ "$KEEP_DATA" == true ]]; then
+    echo "Your data has been preserved at: $DATA_DIR"
+    echo ""
+    echo "To reinstall MyFSIO with existing data, run:"
+    echo "  curl -fsSL https://go.jzwsite.com/myfsio-install | sudo bash"
+    echo ""
+fi
+
+if [[ "$KEEP_LOGS" == true ]]; then
+    echo "Your logs have been preserved at: $LOG_DIR"
+    echo ""
+fi
+
+echo "Thank you for using MyFSIO."
+echo "Documentation: https://go.jzwsite.com/myfsio"
+echo ""
+echo "============================================================"
+echo ""

static/css/main.css

@@ -396,12 +396,25 @@ code {
 .preview-card { top: 1rem; }
 
 .preview-stage {
-	min-height: 260px;
 	background-color: var(--myfsio-preview-bg);
 	overflow: hidden;
 	border-color: var(--myfsio-card-border) !important;
 }
 
+.preview-stage:has(#preview-placeholder:not(.d-none)) {
+	min-height: 0;
+}
+
+.preview-stage:has(#preview-image:not(.d-none)),
+.preview-stage:has(#preview-video:not(.d-none)),
+.preview-stage:has(#preview-iframe:not(.d-none)) {
+	min-height: 200px;
+}
+
+#preview-placeholder {
+	padding: 2rem 1rem;
+}
+
 .upload-progress-stack {
 	display: flex;
 	flex-direction: column;
@@ -928,6 +941,19 @@ pre code {
 	background-color: var(--myfsio-hover-bg) !important;
 }
 
+.folder-row {
+	background-color: var(--myfsio-section-bg);
+	transition: background-color 0.15s ease;
+}
+
+.folder-row:hover {
+	background-color: var(--myfsio-hover-bg) !important;
+}
+
+.folder-row td:first-child {
+	padding-left: 0.5rem;
+}
+
 .btn-group-sm .btn {
 	padding: 0.25rem 0.6rem;
 	font-size: 0.875rem;

templates/base.html

@@ -51,22 +51,18 @@
             <li class="nav-item">
               <a class="nav-link" href="{{ url_for('ui.buckets_overview') }}">Buckets</a>
             </li>
+            {% if can_manage_iam %}
             <li class="nav-item">
-              <a class="nav-link {% if not can_manage_iam %}nav-link-muted{% endif %}" href="{{ url_for('ui.iam_dashboard') }}">
+              <a class="nav-link" href="{{ url_for('ui.iam_dashboard') }}">IAM</a>
-                IAM
-                {% if not can_manage_iam %}<span class="badge ms-2 text-bg-warning">Restricted</span>{% endif %}
-              </a>
             </li>
             <li class="nav-item">
-              <a class="nav-link {% if not can_manage_iam %}nav-link-muted{% endif %}" href="{{ url_for('ui.connections_dashboard') }}">
+              <a class="nav-link" href="{{ url_for('ui.connections_dashboard') }}">Connections</a>
-                Connections
-                {% if not can_manage_iam %}<span class="badge ms-2 text-bg-warning">Restricted</span>{% endif %}
-              </a>
             </li>
             <li class="nav-item">
               <a class="nav-link" href="{{ url_for('ui.metrics_dashboard') }}">Metrics</a>
             </li>
             {% endif %}
+            {% endif %}
             {% if principal %}
             <li class="nav-item">
               <a class="nav-link" href="{{ url_for('ui.docs_page') }}">Docs</a>

templates/docs.html

@@ -55,8 +55,8 @@ python run.py --mode ui
             <tbody>
               <tr>
                 <td><code>API_BASE_URL</code></td>
-                <td><code>http://127.0.0.1:5000</code></td>
+                <td><code>None</code></td>
-                <td>The public URL of the API. <strong>Required</strong> if running behind a proxy or if the UI and API are on different domains. Ensures presigned URLs are generated correctly.</td>
+                <td>The public URL of the API. <strong>Required</strong> if running behind a proxy. Ensures presigned URLs are generated correctly.</td>
               </tr>
               <tr>
                 <td><code>STORAGE_ROOT</code></td>
@@ -65,13 +65,13 @@ python run.py --mode ui
               </tr>
               <tr>
                 <td><code>MAX_UPLOAD_SIZE</code></td>
-                <td><code>5 GB</code></td>
+                <td><code>1 GB</code></td>
-                <td>Max request body size.</td>
+                <td>Max request body size in bytes.</td>
               </tr>
               <tr>
                 <td><code>SECRET_KEY</code></td>
-                <td>(Random)</td>
+                <td>(Auto-generated)</td>
-                <td>Flask session key. Set this in production.</td>
+                <td>Flask session key. Auto-generates if not set. <strong>Set explicitly in production.</strong></td>
               </tr>
               <tr>
                 <td><code>APP_HOST</code></td>
@@ -81,11 +81,81 @@ python run.py --mode ui
               <tr>
                 <td><code>APP_PORT</code></td>
                 <td><code>5000</code></td>
-                <td>Listen port.</td>
+                <td>Listen port (UI uses 5100).</td>
+              </tr>
+              <tr class="table-secondary">
+                <td colspan="3" class="fw-semibold">CORS Settings</td>
+              </tr>
+              <tr>
+                <td><code>CORS_ORIGINS</code></td>
+                <td><code>*</code></td>
+                <td>Allowed origins. <strong>Restrict in production.</strong></td>
+              </tr>
+              <tr>
+                <td><code>CORS_METHODS</code></td>
+                <td><code>GET,PUT,POST,DELETE,OPTIONS,HEAD</code></td>
+                <td>Allowed HTTP methods.</td>
+              </tr>
+              <tr>
+                <td><code>CORS_ALLOW_HEADERS</code></td>
+                <td><code>*</code></td>
+                <td>Allowed request headers.</td>
+              </tr>
+              <tr>
+                <td><code>CORS_EXPOSE_HEADERS</code></td>
+                <td><code>*</code></td>
+                <td>Response headers visible to browsers (e.g., <code>ETag</code>).</td>
+              </tr>
+              <tr class="table-secondary">
+                <td colspan="3" class="fw-semibold">Security Settings</td>
+              </tr>
+              <tr>
+                <td><code>AUTH_MAX_ATTEMPTS</code></td>
+                <td><code>5</code></td>
+                <td>Failed login attempts before lockout.</td>
+              </tr>
+              <tr>
+                <td><code>AUTH_LOCKOUT_MINUTES</code></td>
+                <td><code>15</code></td>
+                <td>Lockout duration after max failed attempts.</td>
+              </tr>
+              <tr>
+                <td><code>RATE_LIMIT_DEFAULT</code></td>
+                <td><code>200 per minute</code></td>
+                <td>Default API rate limit.</td>
+              </tr>
+              <tr class="table-secondary">
+                <td colspan="3" class="fw-semibold">Encryption Settings</td>
+              </tr>
+              <tr>
+                <td><code>ENCRYPTION_ENABLED</code></td>
+                <td><code>false</code></td>
+                <td>Enable server-side encryption support.</td>
+              </tr>
+              <tr>
+                <td><code>KMS_ENABLED</code></td>
+                <td><code>false</code></td>
+                <td>Enable KMS key management for encryption.</td>
+              </tr>
+              <tr class="table-secondary">
+                <td colspan="3" class="fw-semibold">Logging Settings</td>
+              </tr>
+              <tr>
+                <td><code>LOG_LEVEL</code></td>
+                <td><code>INFO</code></td>
+                <td>Log verbosity: DEBUG, INFO, WARNING, ERROR.</td>
+              </tr>
+              <tr>
+                <td><code>LOG_TO_FILE</code></td>
+                <td><code>true</code></td>
+                <td>Enable file logging.</td>
               </tr>
             </tbody>
           </table>
         </div>
+        <div class="alert alert-warning mt-3 mb-0 small">
+          <strong>Production Checklist:</strong> Set <code>SECRET_KEY</code>, restrict <code>CORS_ORIGINS</code>, configure <code>API_BASE_URL</code>, enable HTTPS via reverse proxy, and use <code>--prod</code> flag.
+        </div>
       </div>
     </article>
     <article id="background" class="card shadow-sm docs-section">
@@ -130,7 +200,7 @@ WorkingDirectory=/opt/myfsio
 ExecStart=/opt/myfsio/myfsio
 Restart=on-failure
 RestartSec=5
-Environment=MYFSIO_DATA_DIR=/var/lib/myfsio
+Environment=STORAGE_ROOT=/var/lib/myfsio
 Environment=API_BASE_URL=https://s3.example.com
 
 [Install]
@@ -408,10 +478,172 @@ s3.complete_multipart_upload(
         </p>
       </div>
     </article>
+    <article id="quotas" class="card shadow-sm docs-section">
+      <div class="card-body">
+        <div class="d-flex align-items-center gap-2 mb-3">
+          <span class="docs-section-kicker">10</span>
+          <h2 class="h4 mb-0">Bucket Quotas</h2>
+        </div>
+        <p class="text-muted">Limit how much data a bucket can hold using storage quotas. Quotas are enforced on uploads and multipart completions.</p>
+        
+        <h3 class="h6 text-uppercase text-muted mt-4">Quota Types</h3>
+        <div class="table-responsive mb-3">
+          <table class="table table-sm table-bordered small">
+            <thead class="table-light">
+              <tr>
+                <th>Limit</th>
+                <th>Description</th>
+              </tr>
+            </thead>
+            <tbody>
+              <tr>
+                <td><strong>Max Size (MB)</strong></td>
+                <td>Maximum total storage in megabytes (includes current objects + archived versions)</td>
+              </tr>
+              <tr>
+                <td><strong>Max Objects</strong></td>
+                <td>Maximum number of objects (includes current objects + archived versions)</td>
+              </tr>
+            </tbody>
+          </table>
+        </div>
+
+        <h3 class="h6 text-uppercase text-muted mt-4">Managing Quotas (Admin Only)</h3>
+        <p class="small text-muted">Quota management is restricted to administrators (users with <code>iam:*</code> permissions).</p>
+        <ol class="docs-steps mb-3">
+          <li>Navigate to your bucket → <strong>Properties</strong> tab → <strong>Storage Quota</strong> card.</li>
+          <li>Enter limits: <strong>Max Size (MB)</strong> and/or <strong>Max Objects</strong>. Leave empty for unlimited.</li>
+          <li>Click <strong>Update Quota</strong> to save, or <strong>Remove Quota</strong> to clear limits.</li>
+        </ol>
+
+        <h3 class="h6 text-uppercase text-muted mt-4">API Usage</h3>
+<pre class="mb-3"><code class="language-bash"># Set quota (max 100MB, max 1000 objects)
+curl -X PUT "{{ api_base }}/bucket/&lt;bucket&gt;?quota" \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;" \
+  -d '{"max_bytes": 104857600, "max_objects": 1000}'
+
+# Get current quota
+curl "{{ api_base }}/bucket/&lt;bucket&gt;?quota" \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;"
+
+# Remove quota
+curl -X PUT "{{ api_base }}/bucket/&lt;bucket&gt;?quota" \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;" \
+  -d '{"max_bytes": null, "max_objects": null}'</code></pre>
+
+        <div class="alert alert-light border mb-0">
+          <div class="d-flex gap-2">
+            <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-info-circle text-muted mt-1" viewBox="0 0 16 16">
+              <path d="M8 15A7 7 0 1 1 8 1a7 7 0 0 1 0 14zm0 1A8 8 0 1 0 8 0a8 8 0 0 0 0 16z"/>
+              <path d="m8.93 6.588-2.29.287-.082.38.45.083c.294.07.352.176.288.469l-.738 3.468c-.194.897.105 1.319.808 1.319.545 0 1.178-.252 1.465-.598l.088-.416c-.2.176-.492.246-.686.246-.275 0-.375-.193-.304-.533L8.93 6.588zM9 4.5a1 1 0 1 1-2 0 1 1 0 0 1 2 0z"/>
+            </svg>
+            <div>
+              <strong>Version Counting:</strong> When versioning is enabled, archived versions count toward the quota. The quota is checked against total storage, not just current objects.
+            </div>
+          </div>
+        </div>
+      </div>
+    </article>
+    <article id="encryption" class="card shadow-sm docs-section">
+      <div class="card-body">
+        <div class="d-flex align-items-center gap-2 mb-3">
+          <span class="docs-section-kicker">11</span>
+          <h2 class="h4 mb-0">Encryption</h2>
+        </div>
+        <p class="text-muted">Protect data at rest with server-side encryption using AES-256-GCM. Objects are encrypted before being written to disk and decrypted transparently on read.</p>
+        
+        <h3 class="h6 text-uppercase text-muted mt-4">Encryption Types</h3>
+        <div class="table-responsive mb-3">
+          <table class="table table-sm table-bordered small">
+            <thead class="table-light">
+              <tr>
+                <th>Type</th>
+                <th>Description</th>
+              </tr>
+            </thead>
+            <tbody>
+              <tr>
+                <td><strong>AES-256 (SSE-S3)</strong></td>
+                <td>Server-managed encryption using a local master key</td>
+              </tr>
+              <tr>
+                <td><strong>KMS (SSE-KMS)</strong></td>
+                <td>Encryption using customer-managed keys via the built-in KMS</td>
+              </tr>
+            </tbody>
+          </table>
+        </div>
+
+        <h3 class="h6 text-uppercase text-muted mt-4">Enabling Encryption</h3>
+        <ol class="docs-steps mb-3">
+          <li>
+            <strong>Set environment variables:</strong>
+<pre class="mb-2"><code class="language-bash"># PowerShell
+$env:ENCRYPTION_ENABLED = "true"
+$env:KMS_ENABLED = "true"  # Optional
+python run.py
+
+# Bash
+export ENCRYPTION_ENABLED=true
+export KMS_ENABLED=true
+python run.py</code></pre>
+          </li>
+          <li>
+            <strong>Configure bucket encryption:</strong> Navigate to your bucket → <strong>Properties</strong> tab → <strong>Default Encryption</strong> card → Click <strong>Enable Encryption</strong>.
+          </li>
+          <li>
+            <strong>Choose algorithm:</strong> Select <strong>AES-256</strong> for server-managed keys or <strong>aws:kms</strong> to use a KMS-managed key.
+          </li>
+        </ol>
+
+        <div class="alert alert-warning border-warning bg-warning-subtle mb-3">
+          <div class="d-flex gap-2">
+            <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-exclamation-triangle mt-1" viewBox="0 0 16 16">
+              <path d="M7.938 2.016A.13.13 0 0 1 8.002 2a.13.13 0 0 1 .063.016.146.146 0 0 1 .054.057l6.857 11.667c.036.06.035.124.002.183a.163.163 0 0 1-.054.06.116.116 0 0 1-.066.017H1.146a.115.115 0 0 1-.066-.017.163.163 0 0 1-.054-.06.176.176 0 0 1 .002-.183L7.884 2.073a.147.147 0 0 1 .054-.057zm1.044-.45a1.13 1.13 0 0 0-1.96 0L.165 13.233c-.457.778.091 1.767.98 1.767h13.713c.889 0 1.438-.99.98-1.767L8.982 1.566z"/>
+              <path d="M7.002 12a1 1 0 1 1 2 0 1 1 0 0 1-2 0zM7.1 5.995a.905.905 0 1 1 1.8 0l-.35 3.507a.552.552 0 0 1-1.1 0L7.1 5.995z"/>
+            </svg>
+            <div>
+              <strong>Important:</strong> Only <em>new uploads</em> after enabling encryption will be encrypted. Existing objects remain unencrypted.
+            </div>
+          </div>
+        </div>
+
+        <h3 class="h6 text-uppercase text-muted mt-4">KMS Key Management</h3>
+        <p class="small text-muted">When <code>KMS_ENABLED=true</code>, manage encryption keys via the API:</p>
+<pre class="mb-3"><code class="language-bash"># Create a new KMS key
+curl -X POST {{ api_base }}/kms/keys \
+  -H "Content-Type: application/json" \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;" \
+  -d '{"alias": "my-key", "description": "Production key"}'
+
+# List all keys
+curl {{ api_base }}/kms/keys \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;"
+
+# Rotate a key (creates new key material)
+curl -X POST {{ api_base }}/kms/keys/{key-id}/rotate \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;"
+
+# Disable/Enable a key
+curl -X POST {{ api_base }}/kms/keys/{key-id}/disable \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;"
+
+# Schedule key deletion (30-day waiting period)
+curl -X DELETE "{{ api_base }}/kms/keys/{key-id}?waiting_period_days=30" \
+  -H "X-Access-Key: &lt;key&gt;" -H "X-Secret-Key: &lt;secret&gt;"</code></pre>
+
+        <h3 class="h6 text-uppercase text-muted mt-4">How It Works</h3>
+        <p class="small text-muted mb-0">
+          <strong>Envelope Encryption:</strong> Each object is encrypted with a unique Data Encryption Key (DEK). The DEK is then encrypted (wrapped) by the master key or KMS key and stored alongside the ciphertext. On read, the DEK is unwrapped and used to decrypt the object transparently.
+        </p>
+      </div>
+    </article>
     <article id="troubleshooting" class="card shadow-sm docs-section">
       <div class="card-body">
         <div class="d-flex align-items-center gap-2 mb-3">
-          <span class="docs-section-kicker">09</span>
+          <span class="docs-section-kicker">12</span>
           <h2 class="h4 mb-0">Troubleshooting &amp; tips</h2>
         </div>
         <div class="table-responsive">
@@ -468,6 +700,8 @@ s3.complete_multipart_upload(
           <li><a href="#api">REST endpoints</a></li>
           <li><a href="#examples">API Examples</a></li>
           <li><a href="#replication">Site Replication</a></li>
+          <li><a href="#quotas">Bucket Quotas</a></li>
+          <li><a href="#encryption">Encryption</a></li>
           <li><a href="#troubleshooting">Troubleshooting</a></li>
         </ul>
         <div class="docs-sidebar-callouts">

templates/iam.html

@@ -509,7 +509,7 @@
         full: [
           {
             bucket: '*',
-            actions: ['list', 'read', 'write', 'delete', 'share', 'policy', 'iam:list_users', 'iam:*'],
+            actions: ['list', 'read', 'write', 'delete', 'share', 'policy', 'replication', 'iam:list_users', 'iam:*'],
           },
         ],
         readonly: [
@@ -543,7 +543,7 @@
         full: [
           {
             bucket: '*',
-            actions: ['list', 'read', 'write', 'delete', 'share', 'policy', 'iam:list_users', 'iam:*'],
+            actions: ['list', 'read', 'write', 'delete', 'share', 'policy', 'replication', 'iam:list_users', 'iam:*'],
           },
         ],
         readonly: [
@@ -688,7 +688,9 @@
             rotateDoneBtn.classList.remove('d-none');
             
         } catch (err) {
-            alert(err.message);
+            if (window.showToast) {
+              window.showToast(err.message, 'Error', 'danger');
+            }
             rotateSecretModal.hide();
         } finally {
             confirmRotateBtn.disabled = false;

templates/metrics.html

@@ -126,7 +126,6 @@
     <div class="card shadow-sm border-0">
       <div class="card-header bg-transparent border-0 pt-4 px-4 d-flex justify-content-between align-items-center">
         <h5 class="card-title mb-0 fw-semibold">System Overview</h5>
-        <span class="badge bg-primary-subtle text-primary">Live</span>
       </div>
       <div class="card-body p-4">
         <div class="table-responsive">
@@ -233,14 +232,14 @@
             <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" fill="currentColor" class="bi bi-check-circle-fill me-1" viewBox="0 0 16 16">
               <path d="M16 8A8 8 0 1 1 0 8a8 8 0 0 1 16 0zm-3.97-3.03a.75.75 0 0 0-1.08.022L7.477 9.417 5.384 7.323a.75.75 0 0 0-1.06 1.06L6.97 11.03a.75.75 0 0 0 1.079-.02l3.992-4.99a.75.75 0 0 0-.01-1.05z"/>
             </svg>
-            Healthy
+            v{{ app.version }}
           </span>
         </div>
         <h4 class="card-title fw-bold mb-3">System Status</h4>
         <p class="card-text opacity-90 mb-4">All systems operational. Your storage infrastructure is running smoothly with no detected issues.</p>
         <div class="d-flex gap-4">
           <div>
-            <div class="h3 fw-bold mb-0">99.9%</div>
+            <div class="h3 fw-bold mb-0">{{ app.uptime_days }}d</div>
             <small class="opacity-75">Uptime</small>
           </div>
           <div>

tests/test_encryption.py

@@ -0,0 +1,763 @@
+"""Tests for encryption functionality."""
+from __future__ import annotations
+
+import base64
+import io
+import json
+import os
+import secrets
+import tempfile
+from pathlib import Path
+
+import pytest
+
+
+class TestLocalKeyEncryption:
+    """Tests for LocalKeyEncryption provider."""
+    
+    def test_create_master_key(self, tmp_path):
+        """Test that master key is created if it doesn't exist."""
+        from app.encryption import LocalKeyEncryption
+        
+        key_path = tmp_path / "keys" / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        
+        # Access master key to trigger creation
+        key = provider.master_key
+        
+        assert key_path.exists()
+        assert len(key) == 32  # 256-bit key
+    
+    def test_load_existing_master_key(self, tmp_path):
+        """Test loading an existing master key."""
+        from app.encryption import LocalKeyEncryption
+        
+        key_path = tmp_path / "master.key"
+        original_key = secrets.token_bytes(32)
+        key_path.write_text(base64.b64encode(original_key).decode())
+        
+        provider = LocalKeyEncryption(key_path)
+        loaded_key = provider.master_key
+        
+        assert loaded_key == original_key
+    
+    def test_encrypt_decrypt_roundtrip(self, tmp_path):
+        """Test that data can be encrypted and decrypted correctly."""
+        from app.encryption import LocalKeyEncryption
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        
+        plaintext = b"Hello, World! This is a test message."
+        
+        # Encrypt
+        result = provider.encrypt(plaintext)
+        
+        assert result.ciphertext != plaintext
+        assert result.key_id == "local"
+        assert len(result.nonce) == 12
+        assert len(result.encrypted_data_key) > 0
+        
+        # Decrypt
+        decrypted = provider.decrypt(
+            result.ciphertext,
+            result.nonce,
+            result.encrypted_data_key,
+            result.key_id,
+        )
+        
+        assert decrypted == plaintext
+    
+    def test_different_data_keys_per_encryption(self, tmp_path):
+        """Test that each encryption uses a different data key."""
+        from app.encryption import LocalKeyEncryption
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        
+        plaintext = b"Same message"
+        
+        result1 = provider.encrypt(plaintext)
+        result2 = provider.encrypt(plaintext)
+        
+        # Different encrypted data keys
+        assert result1.encrypted_data_key != result2.encrypted_data_key
+        # Different nonces
+        assert result1.nonce != result2.nonce
+        # Different ciphertexts
+        assert result1.ciphertext != result2.ciphertext
+    
+    def test_generate_data_key(self, tmp_path):
+        """Test data key generation."""
+        from app.encryption import LocalKeyEncryption
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        
+        plaintext_key, encrypted_key = provider.generate_data_key()
+        
+        assert len(plaintext_key) == 32
+        assert len(encrypted_key) > 32  # nonce + ciphertext + tag
+        
+        # Verify we can decrypt the key
+        decrypted_key = provider._decrypt_data_key(encrypted_key)
+        assert decrypted_key == plaintext_key
+    
+    def test_decrypt_with_wrong_key_fails(self, tmp_path):
+        """Test that decryption fails with wrong master key."""
+        from app.encryption import LocalKeyEncryption, EncryptionError
+        
+        # Create two providers with different keys
+        key_path1 = tmp_path / "master1.key"
+        key_path2 = tmp_path / "master2.key"
+        
+        provider1 = LocalKeyEncryption(key_path1)
+        provider2 = LocalKeyEncryption(key_path2)
+        
+        # Encrypt with provider1
+        plaintext = b"Secret message"
+        result = provider1.encrypt(plaintext)
+        
+        # Try to decrypt with provider2
+        with pytest.raises(EncryptionError):
+            provider2.decrypt(
+                result.ciphertext,
+                result.nonce,
+                result.encrypted_data_key,
+                result.key_id,
+            )
+
+
+class TestEncryptionMetadata:
+    """Tests for EncryptionMetadata class."""
+    
+    def test_to_dict(self):
+        """Test converting metadata to dictionary."""
+        from app.encryption import EncryptionMetadata
+        
+        nonce = secrets.token_bytes(12)
+        encrypted_key = secrets.token_bytes(60)
+        
+        metadata = EncryptionMetadata(
+            algorithm="AES256",
+            key_id="local",
+            nonce=nonce,
+            encrypted_data_key=encrypted_key,
+        )
+        
+        result = metadata.to_dict()
+        
+        assert result["x-amz-server-side-encryption"] == "AES256"
+        assert result["x-amz-encryption-key-id"] == "local"
+        assert base64.b64decode(result["x-amz-encryption-nonce"]) == nonce
+        assert base64.b64decode(result["x-amz-encrypted-data-key"]) == encrypted_key
+    
+    def test_from_dict(self):
+        """Test creating metadata from dictionary."""
+        from app.encryption import EncryptionMetadata
+        
+        nonce = secrets.token_bytes(12)
+        encrypted_key = secrets.token_bytes(60)
+        
+        data = {
+            "x-amz-server-side-encryption": "AES256",
+            "x-amz-encryption-key-id": "local",
+            "x-amz-encryption-nonce": base64.b64encode(nonce).decode(),
+            "x-amz-encrypted-data-key": base64.b64encode(encrypted_key).decode(),
+        }
+        
+        metadata = EncryptionMetadata.from_dict(data)
+        
+        assert metadata is not None
+        assert metadata.algorithm == "AES256"
+        assert metadata.key_id == "local"
+        assert metadata.nonce == nonce
+        assert metadata.encrypted_data_key == encrypted_key
+    
+    def test_from_dict_returns_none_for_unencrypted(self):
+        """Test that from_dict returns None for unencrypted objects."""
+        from app.encryption import EncryptionMetadata
+        
+        data = {"some-other-key": "value"}
+        
+        metadata = EncryptionMetadata.from_dict(data)
+        
+        assert metadata is None
+
+
+class TestStreamingEncryptor:
+    """Tests for streaming encryption."""
+    
+    def test_encrypt_decrypt_stream(self, tmp_path):
+        """Test streaming encryption and decryption."""
+        from app.encryption import LocalKeyEncryption, StreamingEncryptor
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        encryptor = StreamingEncryptor(provider, chunk_size=1024)
+        
+        # Create test data
+        original_data = b"A" * 5000 + b"B" * 5000 + b"C" * 5000  # 15KB
+        stream = io.BytesIO(original_data)
+        
+        # Encrypt
+        encrypted_stream, metadata = encryptor.encrypt_stream(stream)
+        encrypted_data = encrypted_stream.read()
+        
+        assert encrypted_data != original_data
+        assert metadata.algorithm == "AES256"
+        
+        # Decrypt
+        encrypted_stream = io.BytesIO(encrypted_data)
+        decrypted_stream = encryptor.decrypt_stream(encrypted_stream, metadata)
+        decrypted_data = decrypted_stream.read()
+        
+        assert decrypted_data == original_data
+    
+    def test_encrypt_small_data(self, tmp_path):
+        """Test encrypting data smaller than chunk size."""
+        from app.encryption import LocalKeyEncryption, StreamingEncryptor
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        encryptor = StreamingEncryptor(provider, chunk_size=1024)
+        
+        original_data = b"Small data"
+        stream = io.BytesIO(original_data)
+        
+        encrypted_stream, metadata = encryptor.encrypt_stream(stream)
+        encrypted_stream.seek(0)
+        
+        decrypted_stream = encryptor.decrypt_stream(encrypted_stream, metadata)
+        decrypted_data = decrypted_stream.read()
+        
+        assert decrypted_data == original_data
+    
+    def test_encrypt_empty_data(self, tmp_path):
+        """Test encrypting empty data."""
+        from app.encryption import LocalKeyEncryption, StreamingEncryptor
+        
+        key_path = tmp_path / "master.key"
+        provider = LocalKeyEncryption(key_path)
+        encryptor = StreamingEncryptor(provider)
+        
+        stream = io.BytesIO(b"")
+        
+        encrypted_stream, metadata = encryptor.encrypt_stream(stream)
+        encrypted_stream.seek(0)
+        
+        decrypted_stream = encryptor.decrypt_stream(encrypted_stream, metadata)
+        decrypted_data = decrypted_stream.read()
+        
+        assert decrypted_data == b""
+
+
+class TestEncryptionManager:
+    """Tests for EncryptionManager."""
+    
+    def test_encryption_disabled_by_default(self, tmp_path):
+        """Test that encryption is disabled by default."""
+        from app.encryption import EncryptionManager
+        
+        config = {
+            "encryption_enabled": False,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+        }
+        
+        manager = EncryptionManager(config)
+        
+        assert not manager.enabled
+    
+    def test_encryption_enabled(self, tmp_path):
+        """Test enabling encryption."""
+        from app.encryption import EncryptionManager
+        
+        config = {
+            "encryption_enabled": True,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+            "default_encryption_algorithm": "AES256",
+        }
+        
+        manager = EncryptionManager(config)
+        
+        assert manager.enabled
+        assert manager.default_algorithm == "AES256"
+    
+    def test_encrypt_decrypt_object(self, tmp_path):
+        """Test encrypting and decrypting an object."""
+        from app.encryption import EncryptionManager
+        
+        config = {
+            "encryption_enabled": True,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+        }
+        
+        manager = EncryptionManager(config)
+        
+        plaintext = b"Object data to encrypt"
+        
+        ciphertext, metadata = manager.encrypt_object(plaintext)
+        
+        assert ciphertext != plaintext
+        assert metadata.algorithm == "AES256"
+        
+        decrypted = manager.decrypt_object(ciphertext, metadata)
+        
+        assert decrypted == plaintext
+
+
+class TestClientEncryptionHelper:
+    """Tests for client-side encryption helpers."""
+    
+    def test_generate_client_key(self):
+        """Test generating a client encryption key."""
+        from app.encryption import ClientEncryptionHelper
+        
+        key_info = ClientEncryptionHelper.generate_client_key()
+        
+        assert "key" in key_info
+        assert key_info["algorithm"] == "AES-256-GCM"
+        assert "created_at" in key_info
+        
+        # Verify key is 256 bits
+        key = base64.b64decode(key_info["key"])
+        assert len(key) == 32
+    
+    def test_encrypt_with_key(self):
+        """Test encrypting data with a client key."""
+        from app.encryption import ClientEncryptionHelper
+        
+        key = base64.b64encode(secrets.token_bytes(32)).decode()
+        plaintext = b"Client-side encrypted data"
+        
+        result = ClientEncryptionHelper.encrypt_with_key(plaintext, key)
+        
+        assert "ciphertext" in result
+        assert "nonce" in result
+        assert result["algorithm"] == "AES-256-GCM"
+    
+    def test_encrypt_decrypt_with_key(self):
+        """Test round-trip client-side encryption."""
+        from app.encryption import ClientEncryptionHelper
+        
+        key = base64.b64encode(secrets.token_bytes(32)).decode()
+        plaintext = b"Client-side encrypted data"
+        
+        encrypted = ClientEncryptionHelper.encrypt_with_key(plaintext, key)
+        
+        decrypted = ClientEncryptionHelper.decrypt_with_key(
+            encrypted["ciphertext"],
+            encrypted["nonce"],
+            key,
+        )
+        
+        assert decrypted == plaintext
+    
+    def test_wrong_key_fails(self):
+        """Test that decryption with wrong key fails."""
+        from app.encryption import ClientEncryptionHelper, EncryptionError
+        
+        key1 = base64.b64encode(secrets.token_bytes(32)).decode()
+        key2 = base64.b64encode(secrets.token_bytes(32)).decode()
+        plaintext = b"Secret data"
+        
+        encrypted = ClientEncryptionHelper.encrypt_with_key(plaintext, key1)
+        
+        with pytest.raises(EncryptionError):
+            ClientEncryptionHelper.decrypt_with_key(
+                encrypted["ciphertext"],
+                encrypted["nonce"],
+                key2,
+            )
+
+
+class TestKMSManager:
+    """Tests for KMS key management."""
+    
+    def test_create_key(self, tmp_path):
+        """Test creating a KMS key."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        key = kms.create_key("Test key", key_id="test-key-1")
+        
+        assert key.key_id == "test-key-1"
+        assert key.description == "Test key"
+        assert key.enabled
+        assert keys_path.exists()
+    
+    def test_list_keys(self, tmp_path):
+        """Test listing KMS keys."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Key 1", key_id="key-1")
+        kms.create_key("Key 2", key_id="key-2")
+        
+        keys = kms.list_keys()
+        
+        assert len(keys) == 2
+        key_ids = {k.key_id for k in keys}
+        assert "key-1" in key_ids
+        assert "key-2" in key_ids
+    
+    def test_get_key(self, tmp_path):
+        """Test getting a specific key."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        
+        key = kms.get_key("test-key")
+        
+        assert key is not None
+        assert key.key_id == "test-key"
+        
+        # Non-existent key
+        assert kms.get_key("non-existent") is None
+    
+    def test_enable_disable_key(self, tmp_path):
+        """Test enabling and disabling keys."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        
+        # Initially enabled
+        assert kms.get_key("test-key").enabled
+        
+        # Disable
+        kms.disable_key("test-key")
+        assert not kms.get_key("test-key").enabled
+        
+        # Enable
+        kms.enable_key("test-key")
+        assert kms.get_key("test-key").enabled
+    
+    def test_delete_key(self, tmp_path):
+        """Test deleting a key."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        assert kms.get_key("test-key") is not None
+        
+        kms.delete_key("test-key")
+        assert kms.get_key("test-key") is None
+    
+    def test_encrypt_decrypt(self, tmp_path):
+        """Test KMS encrypt and decrypt."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        key = kms.create_key("Test key", key_id="test-key")
+        
+        plaintext = b"Secret data to encrypt"
+        
+        ciphertext = kms.encrypt("test-key", plaintext)
+        
+        assert ciphertext != plaintext
+        
+        decrypted, key_id = kms.decrypt(ciphertext)
+        
+        assert decrypted == plaintext
+        assert key_id == "test-key"
+    
+    def test_encrypt_with_context(self, tmp_path):
+        """Test encryption with encryption context."""
+        from app.kms import KMSManager, EncryptionError
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        
+        plaintext = b"Secret data"
+        context = {"bucket": "test-bucket", "key": "test-key"}
+        
+        ciphertext = kms.encrypt("test-key", plaintext, context)
+        
+        # Decrypt with same context succeeds
+        decrypted, _ = kms.decrypt(ciphertext, context)
+        assert decrypted == plaintext
+        
+        # Decrypt with different context fails
+        with pytest.raises(EncryptionError):
+            kms.decrypt(ciphertext, {"different": "context"})
+    
+    def test_generate_data_key(self, tmp_path):
+        """Test generating a data key."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        
+        plaintext_key, encrypted_key = kms.generate_data_key("test-key")
+        
+        assert len(plaintext_key) == 32
+        assert len(encrypted_key) > 0
+        
+        # Decrypt the encrypted key
+        decrypted_key = kms.decrypt_data_key("test-key", encrypted_key)
+        
+        assert decrypted_key == plaintext_key
+    
+    def test_disabled_key_cannot_encrypt(self, tmp_path):
+        """Test that disabled keys cannot be used for encryption."""
+        from app.kms import KMSManager, EncryptionError
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Test key", key_id="test-key")
+        kms.disable_key("test-key")
+        
+        with pytest.raises(EncryptionError, match="disabled"):
+            kms.encrypt("test-key", b"data")
+    
+    def test_re_encrypt(self, tmp_path):
+        """Test re-encrypting data with a different key."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        kms.create_key("Key 1", key_id="key-1")
+        kms.create_key("Key 2", key_id="key-2")
+        
+        plaintext = b"Data to re-encrypt"
+        
+        # Encrypt with key-1
+        ciphertext1 = kms.encrypt("key-1", plaintext)
+        
+        # Re-encrypt with key-2
+        ciphertext2 = kms.re_encrypt(ciphertext1, "key-2")
+        
+        # Decrypt with key-2
+        decrypted, key_id = kms.decrypt(ciphertext2)
+        
+        assert decrypted == plaintext
+        assert key_id == "key-2"
+    
+    def test_generate_random(self, tmp_path):
+        """Test generating random bytes."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        
+        random1 = kms.generate_random(32)
+        random2 = kms.generate_random(32)
+        
+        assert len(random1) == 32
+        assert len(random2) == 32
+        assert random1 != random2  # Very unlikely to be equal
+    
+    def test_keys_persist_across_instances(self, tmp_path):
+        """Test that keys persist and can be loaded by new instances."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        # Create key with first instance
+        kms1 = KMSManager(keys_path, master_key_path)
+        kms1.create_key("Test key", key_id="test-key")
+        
+        plaintext = b"Persistent encryption test"
+        ciphertext = kms1.encrypt("test-key", plaintext)
+        
+        # Create new instance and verify key works
+        kms2 = KMSManager(keys_path, master_key_path)
+        
+        decrypted, key_id = kms2.decrypt(ciphertext)
+        
+        assert decrypted == plaintext
+        assert key_id == "test-key"
+
+
+class TestKMSEncryptionProvider:
+    """Tests for KMS encryption provider."""
+    
+    def test_kms_encryption_provider(self, tmp_path):
+        """Test using KMS as an encryption provider."""
+        from app.kms import KMSManager
+        
+        keys_path = tmp_path / "kms_keys.json"
+        master_key_path = tmp_path / "master.key"
+        
+        kms = KMSManager(keys_path, master_key_path)
+        kms.create_key("Test key", key_id="test-key")
+        
+        provider = kms.get_provider("test-key")
+        
+        plaintext = b"Data encrypted with KMS provider"
+        
+        result = provider.encrypt(plaintext)
+        
+        assert result.key_id == "test-key"
+        assert result.ciphertext != plaintext
+        
+        decrypted = provider.decrypt(
+            result.ciphertext,
+            result.nonce,
+            result.encrypted_data_key,
+            result.key_id,
+        )
+        
+        assert decrypted == plaintext
+
+
+class TestEncryptedStorage:
+    """Tests for encrypted storage layer."""
+    
+    def test_put_and_get_encrypted_object(self, tmp_path):
+        """Test storing and retrieving an encrypted object."""
+        from app.storage import ObjectStorage
+        from app.encryption import EncryptionManager
+        from app.encrypted_storage import EncryptedObjectStorage
+        
+        storage_root = tmp_path / "storage"
+        storage = ObjectStorage(storage_root)
+        
+        config = {
+            "encryption_enabled": True,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+            "default_encryption_algorithm": "AES256",
+        }
+        encryption = EncryptionManager(config)
+        
+        encrypted_storage = EncryptedObjectStorage(storage, encryption)
+        
+        # Create bucket with encryption config
+        storage.create_bucket("test-bucket")
+        storage.set_bucket_encryption("test-bucket", {
+            "Rules": [{"SSEAlgorithm": "AES256"}]
+        })
+        
+        # Put object
+        original_data = b"This is secret data that should be encrypted"
+        stream = io.BytesIO(original_data)
+        
+        meta = encrypted_storage.put_object(
+            "test-bucket",
+            "secret.txt",
+            stream,
+        )
+        
+        assert meta is not None
+        
+        # Verify file on disk is encrypted (not plaintext)
+        file_path = storage_root / "test-bucket" / "secret.txt"
+        stored_data = file_path.read_bytes()
+        assert stored_data != original_data
+        
+        # Get object - should be decrypted
+        data, metadata = encrypted_storage.get_object_data("test-bucket", "secret.txt")
+        
+        assert data == original_data
+    
+    def test_no_encryption_without_config(self, tmp_path):
+        """Test that objects are not encrypted without bucket config."""
+        from app.storage import ObjectStorage
+        from app.encryption import EncryptionManager
+        from app.encrypted_storage import EncryptedObjectStorage
+        
+        storage_root = tmp_path / "storage"
+        storage = ObjectStorage(storage_root)
+        
+        config = {
+            "encryption_enabled": True,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+        }
+        encryption = EncryptionManager(config)
+        
+        encrypted_storage = EncryptedObjectStorage(storage, encryption)
+        
+        storage.create_bucket("test-bucket")
+        # No encryption config
+        
+        original_data = b"Unencrypted data"
+        stream = io.BytesIO(original_data)
+        
+        encrypted_storage.put_object("test-bucket", "plain.txt", stream)
+        
+        # Verify file on disk is NOT encrypted
+        file_path = storage_root / "test-bucket" / "plain.txt"
+        stored_data = file_path.read_bytes()
+        assert stored_data == original_data
+    
+    def test_explicit_encryption_request(self, tmp_path):
+        """Test explicitly requesting encryption."""
+        from app.storage import ObjectStorage
+        from app.encryption import EncryptionManager
+        from app.encrypted_storage import EncryptedObjectStorage
+        
+        storage_root = tmp_path / "storage"
+        storage = ObjectStorage(storage_root)
+        
+        config = {
+            "encryption_enabled": True,
+            "encryption_master_key_path": str(tmp_path / "master.key"),
+        }
+        encryption = EncryptionManager(config)
+        
+        encrypted_storage = EncryptedObjectStorage(storage, encryption)
+        
+        storage.create_bucket("test-bucket")
+        
+        original_data = b"Explicitly encrypted data"
+        stream = io.BytesIO(original_data)
+        
+        # Request encryption explicitly
+        encrypted_storage.put_object(
+            "test-bucket",
+            "encrypted.txt",
+            stream,
+            server_side_encryption="AES256",
+        )
+        
+        # Verify file is encrypted
+        file_path = storage_root / "test-bucket" / "encrypted.txt"
+        stored_data = file_path.read_bytes()
+        assert stored_data != original_data
+        
+        # Get object - should be decrypted
+        data, _ = encrypted_storage.get_object_data("test-bucket", "encrypted.txt")
+        assert data == original_data

tests/test_kms_api.py

@@ -0,0 +1,506 @@
+"""Tests for KMS API endpoints."""
+from __future__ import annotations
+
+import base64
+import json
+import secrets
+
+import pytest
+
+
+@pytest.fixture
+def kms_client(tmp_path):
+    """Create a test client with KMS enabled."""
+    from app import create_app
+    
+    app = create_app({
+        "TESTING": True,
+        "STORAGE_ROOT": str(tmp_path / "storage"),
+        "IAM_CONFIG": str(tmp_path / "iam.json"),
+        "BUCKET_POLICY_PATH": str(tmp_path / "policies.json"),
+        "ENCRYPTION_ENABLED": True,
+        "KMS_ENABLED": True,
+        "ENCRYPTION_MASTER_KEY_PATH": str(tmp_path / "master.key"),
+        "KMS_KEYS_PATH": str(tmp_path / "kms_keys.json"),
+    })
+    
+    # Create default IAM config with admin user
+    iam_config = {
+        "users": [
+            {
+                "access_key": "test-access-key",
+                "secret_key": "test-secret-key",
+                "display_name": "Test User",
+                "permissions": ["*"]
+            }
+        ]
+    }
+    (tmp_path / "iam.json").write_text(json.dumps(iam_config))
+    
+    return app.test_client()
+
+
+@pytest.fixture
+def auth_headers():
+    """Get authentication headers."""
+    return {
+        "X-Access-Key": "test-access-key",
+        "X-Secret-Key": "test-secret-key",
+    }
+
+
+class TestKMSKeyManagement:
+    """Tests for KMS key management endpoints."""
+    
+    def test_create_key(self, kms_client, auth_headers):
+        """Test creating a KMS key."""
+        response = kms_client.post(
+            "/kms/keys",
+            json={"Description": "Test encryption key"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "KeyMetadata" in data
+        assert data["KeyMetadata"]["Description"] == "Test encryption key"
+        assert data["KeyMetadata"]["Enabled"] is True
+        assert "KeyId" in data["KeyMetadata"]
+    
+    def test_create_key_with_custom_id(self, kms_client, auth_headers):
+        """Test creating a key with a custom ID."""
+        response = kms_client.post(
+            "/kms/keys",
+            json={"KeyId": "my-custom-key", "Description": "Custom key"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert data["KeyMetadata"]["KeyId"] == "my-custom-key"
+    
+    def test_list_keys(self, kms_client, auth_headers):
+        """Test listing KMS keys."""
+        # Create some keys
+        kms_client.post("/kms/keys", json={"Description": "Key 1"}, headers=auth_headers)
+        kms_client.post("/kms/keys", json={"Description": "Key 2"}, headers=auth_headers)
+        
+        response = kms_client.get("/kms/keys", headers=auth_headers)
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "Keys" in data
+        assert len(data["Keys"]) == 2
+    
+    def test_get_key(self, kms_client, auth_headers):
+        """Test getting a specific key."""
+        # Create a key
+        create_response = kms_client.post(
+            "/kms/keys",
+            json={"KeyId": "test-key", "Description": "Test key"},
+            headers=auth_headers,
+        )
+        
+        response = kms_client.get("/kms/keys/test-key", headers=auth_headers)
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert data["KeyMetadata"]["KeyId"] == "test-key"
+        assert data["KeyMetadata"]["Description"] == "Test key"
+    
+    def test_get_nonexistent_key(self, kms_client, auth_headers):
+        """Test getting a key that doesn't exist."""
+        response = kms_client.get("/kms/keys/nonexistent", headers=auth_headers)
+        
+        assert response.status_code == 404
+    
+    def test_delete_key(self, kms_client, auth_headers):
+        """Test deleting a key."""
+        # Create a key
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        # Delete it
+        response = kms_client.delete("/kms/keys/test-key", headers=auth_headers)
+        
+        assert response.status_code == 204
+        
+        # Verify it's gone
+        get_response = kms_client.get("/kms/keys/test-key", headers=auth_headers)
+        assert get_response.status_code == 404
+    
+    def test_enable_disable_key(self, kms_client, auth_headers):
+        """Test enabling and disabling a key."""
+        # Create a key
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        # Disable
+        response = kms_client.post("/kms/keys/test-key/disable", headers=auth_headers)
+        assert response.status_code == 200
+        
+        # Verify disabled
+        get_response = kms_client.get("/kms/keys/test-key", headers=auth_headers)
+        assert get_response.get_json()["KeyMetadata"]["Enabled"] is False
+        
+        # Enable
+        response = kms_client.post("/kms/keys/test-key/enable", headers=auth_headers)
+        assert response.status_code == 200
+        
+        # Verify enabled
+        get_response = kms_client.get("/kms/keys/test-key", headers=auth_headers)
+        assert get_response.get_json()["KeyMetadata"]["Enabled"] is True
+
+
+class TestKMSEncryption:
+    """Tests for KMS encryption operations."""
+    
+    def test_encrypt_decrypt(self, kms_client, auth_headers):
+        """Test encrypting and decrypting data."""
+        # Create a key
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        plaintext = b"Hello, World!"
+        plaintext_b64 = base64.b64encode(plaintext).decode()
+        
+        # Encrypt
+        encrypt_response = kms_client.post(
+            "/kms/encrypt",
+            json={"KeyId": "test-key", "Plaintext": plaintext_b64},
+            headers=auth_headers,
+        )
+        
+        assert encrypt_response.status_code == 200
+        encrypt_data = encrypt_response.get_json()
+        
+        assert "CiphertextBlob" in encrypt_data
+        assert encrypt_data["KeyId"] == "test-key"
+        
+        # Decrypt
+        decrypt_response = kms_client.post(
+            "/kms/decrypt",
+            json={"CiphertextBlob": encrypt_data["CiphertextBlob"]},
+            headers=auth_headers,
+        )
+        
+        assert decrypt_response.status_code == 200
+        decrypt_data = decrypt_response.get_json()
+        
+        decrypted = base64.b64decode(decrypt_data["Plaintext"])
+        assert decrypted == plaintext
+    
+    def test_encrypt_with_context(self, kms_client, auth_headers):
+        """Test encryption with encryption context."""
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        plaintext = b"Contextualized data"
+        plaintext_b64 = base64.b64encode(plaintext).decode()
+        context = {"purpose": "testing", "bucket": "my-bucket"}
+        
+        # Encrypt with context
+        encrypt_response = kms_client.post(
+            "/kms/encrypt",
+            json={
+                "KeyId": "test-key",
+                "Plaintext": plaintext_b64,
+                "EncryptionContext": context,
+            },
+            headers=auth_headers,
+        )
+        
+        assert encrypt_response.status_code == 200
+        ciphertext = encrypt_response.get_json()["CiphertextBlob"]
+        
+        # Decrypt with same context succeeds
+        decrypt_response = kms_client.post(
+            "/kms/decrypt",
+            json={
+                "CiphertextBlob": ciphertext,
+                "EncryptionContext": context,
+            },
+            headers=auth_headers,
+        )
+        
+        assert decrypt_response.status_code == 200
+        
+        # Decrypt with wrong context fails
+        wrong_context_response = kms_client.post(
+            "/kms/decrypt",
+            json={
+                "CiphertextBlob": ciphertext,
+                "EncryptionContext": {"wrong": "context"},
+            },
+            headers=auth_headers,
+        )
+        
+        assert wrong_context_response.status_code == 400
+    
+    def test_encrypt_missing_key_id(self, kms_client, auth_headers):
+        """Test encryption without KeyId."""
+        response = kms_client.post(
+            "/kms/encrypt",
+            json={"Plaintext": base64.b64encode(b"data").decode()},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 400
+        assert "KeyId is required" in response.get_json()["message"]
+    
+    def test_encrypt_missing_plaintext(self, kms_client, auth_headers):
+        """Test encryption without Plaintext."""
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        response = kms_client.post(
+            "/kms/encrypt",
+            json={"KeyId": "test-key"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 400
+        assert "Plaintext is required" in response.get_json()["message"]
+
+
+class TestKMSDataKey:
+    """Tests for KMS data key generation."""
+    
+    def test_generate_data_key(self, kms_client, auth_headers):
+        """Test generating a data key."""
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        response = kms_client.post(
+            "/kms/generate-data-key",
+            json={"KeyId": "test-key"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "Plaintext" in data
+        assert "CiphertextBlob" in data
+        assert data["KeyId"] == "test-key"
+        
+        # Verify plaintext key is 256 bits (32 bytes)
+        plaintext_key = base64.b64decode(data["Plaintext"])
+        assert len(plaintext_key) == 32
+    
+    def test_generate_data_key_aes_128(self, kms_client, auth_headers):
+        """Test generating an AES-128 data key."""
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        response = kms_client.post(
+            "/kms/generate-data-key",
+            json={"KeyId": "test-key", "KeySpec": "AES_128"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        # Verify plaintext key is 128 bits (16 bytes)
+        plaintext_key = base64.b64decode(data["Plaintext"])
+        assert len(plaintext_key) == 16
+    
+    def test_generate_data_key_without_plaintext(self, kms_client, auth_headers):
+        """Test generating a data key without plaintext."""
+        kms_client.post("/kms/keys", json={"KeyId": "test-key"}, headers=auth_headers)
+        
+        response = kms_client.post(
+            "/kms/generate-data-key-without-plaintext",
+            json={"KeyId": "test-key"},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "CiphertextBlob" in data
+        assert "Plaintext" not in data
+
+
+class TestKMSReEncrypt:
+    """Tests for KMS re-encryption."""
+    
+    def test_re_encrypt(self, kms_client, auth_headers):
+        """Test re-encrypting data with a different key."""
+        # Create two keys
+        kms_client.post("/kms/keys", json={"KeyId": "key-1"}, headers=auth_headers)
+        kms_client.post("/kms/keys", json={"KeyId": "key-2"}, headers=auth_headers)
+        
+        # Encrypt with key-1
+        plaintext = b"Data to re-encrypt"
+        encrypt_response = kms_client.post(
+            "/kms/encrypt",
+            json={
+                "KeyId": "key-1",
+                "Plaintext": base64.b64encode(plaintext).decode(),
+            },
+            headers=auth_headers,
+        )
+        
+        ciphertext = encrypt_response.get_json()["CiphertextBlob"]
+        
+        # Re-encrypt with key-2
+        re_encrypt_response = kms_client.post(
+            "/kms/re-encrypt",
+            json={
+                "CiphertextBlob": ciphertext,
+                "DestinationKeyId": "key-2",
+            },
+            headers=auth_headers,
+        )
+        
+        assert re_encrypt_response.status_code == 200
+        data = re_encrypt_response.get_json()
+        
+        assert data["SourceKeyId"] == "key-1"
+        assert data["KeyId"] == "key-2"
+        
+        # Verify new ciphertext can be decrypted
+        decrypt_response = kms_client.post(
+            "/kms/decrypt",
+            json={"CiphertextBlob": data["CiphertextBlob"]},
+            headers=auth_headers,
+        )
+        
+        decrypted = base64.b64decode(decrypt_response.get_json()["Plaintext"])
+        assert decrypted == plaintext
+
+
+class TestKMSRandom:
+    """Tests for random number generation."""
+    
+    def test_generate_random(self, kms_client, auth_headers):
+        """Test generating random bytes."""
+        response = kms_client.post(
+            "/kms/generate-random",
+            json={"NumberOfBytes": 64},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        random_bytes = base64.b64decode(data["Plaintext"])
+        assert len(random_bytes) == 64
+    
+    def test_generate_random_default_size(self, kms_client, auth_headers):
+        """Test generating random bytes with default size."""
+        response = kms_client.post(
+            "/kms/generate-random",
+            json={},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        random_bytes = base64.b64decode(data["Plaintext"])
+        assert len(random_bytes) == 32  # Default is 32 bytes
+
+
+class TestClientSideEncryption:
+    """Tests for client-side encryption helpers."""
+    
+    def test_generate_client_key(self, kms_client, auth_headers):
+        """Test generating a client encryption key."""
+        response = kms_client.post(
+            "/kms/client/generate-key",
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "key" in data
+        assert data["algorithm"] == "AES-256-GCM"
+        
+        key = base64.b64decode(data["key"])
+        assert len(key) == 32
+    
+    def test_client_encrypt_decrypt(self, kms_client, auth_headers):
+        """Test client-side encryption and decryption."""
+        # Generate a key
+        key_response = kms_client.post("/kms/client/generate-key", headers=auth_headers)
+        key = key_response.get_json()["key"]
+        
+        # Encrypt
+        plaintext = b"Client-side encrypted data"
+        encrypt_response = kms_client.post(
+            "/kms/client/encrypt",
+            json={
+                "Plaintext": base64.b64encode(plaintext).decode(),
+                "Key": key,
+            },
+            headers=auth_headers,
+        )
+        
+        assert encrypt_response.status_code == 200
+        encrypted = encrypt_response.get_json()
+        
+        # Decrypt
+        decrypt_response = kms_client.post(
+            "/kms/client/decrypt",
+            json={
+                "Ciphertext": encrypted["ciphertext"],
+                "Nonce": encrypted["nonce"],
+                "Key": key,
+            },
+            headers=auth_headers,
+        )
+        
+        assert decrypt_response.status_code == 200
+        decrypted = base64.b64decode(decrypt_response.get_json()["Plaintext"])
+        assert decrypted == plaintext
+
+
+class TestEncryptionMaterials:
+    """Tests for S3 encryption materials endpoint."""
+    
+    def test_get_encryption_materials(self, kms_client, auth_headers):
+        """Test getting encryption materials for client-side S3 encryption."""
+        # Create a key
+        kms_client.post("/kms/keys", json={"KeyId": "s3-key"}, headers=auth_headers)
+        
+        response = kms_client.post(
+            "/kms/materials/s3-key",
+            json={},
+            headers=auth_headers,
+        )
+        
+        assert response.status_code == 200
+        data = response.get_json()
+        
+        assert "PlaintextKey" in data
+        assert "EncryptedKey" in data
+        assert data["KeyId"] == "s3-key"
+        assert data["Algorithm"] == "AES-256-GCM"
+        
+        # Verify key is 256 bits
+        key = base64.b64decode(data["PlaintextKey"])
+        assert len(key) == 32
+
+
+class TestKMSAuthentication:
+    """Tests for KMS authentication requirements."""
+    
+    def test_unauthenticated_request_fails(self, kms_client):
+        """Test that unauthenticated requests are rejected."""
+        response = kms_client.get("/kms/keys")
+        
+        # Should fail with 403 (no credentials)
+        assert response.status_code == 403
+    
+    def test_invalid_credentials_fail(self, kms_client):
+        """Test that invalid credentials are rejected."""
+        response = kms_client.get(
+            "/kms/keys",
+            headers={
+                "X-Access-Key": "wrong-key",
+                "X-Secret-Key": "wrong-secret",
+            },
+        )
+        
+        assert response.status_code == 403

tests/test_security.py

@@ -116,7 +116,12 @@ def test_path_traversal_in_key(client, signer):
 
 def test_storage_path_traversal(app):
     storage = app.extensions["object_storage"]
-    from app.storage import StorageError
+    from app.storage import StorageError, ObjectStorage
+    from app.encrypted_storage import EncryptedObjectStorage
+    
+    # Get the underlying ObjectStorage if wrapped
+    if isinstance(storage, EncryptedObjectStorage):
+        storage = storage.storage
     
     with pytest.raises(StorageError, match="Object key contains parent directory references"):
         storage._sanitize_object_key("folder/../file.txt")

tests/test_ui_encryption.py

@@ -0,0 +1,268 @@
+"""Tests for UI-based encryption configuration."""
+import json
+from pathlib import Path
+
+import pytest
+
+from app import create_app
+
+
+def get_csrf_token(response):
+    """Extract CSRF token from response HTML."""
+    html = response.data.decode("utf-8")
+    import re
+    match = re.search(r'name="csrf_token"\s+value="([^"]+)"', html)
+    return match.group(1) if match else None
+
+
+def _make_encryption_app(tmp_path: Path, *, kms_enabled: bool = True):
+    """Create an app with encryption enabled."""
+    storage_root = tmp_path / "data"
+    iam_config = tmp_path / "iam.json"
+    bucket_policies = tmp_path / "bucket_policies.json"
+    iam_payload = {
+        "users": [
+            {
+                "access_key": "test",
+                "secret_key": "secret",
+                "display_name": "Test User",
+                "policies": [{"bucket": "*", "actions": ["list", "read", "write", "delete", "policy"]}],
+            },
+            {
+                "access_key": "readonly",
+                "secret_key": "secret",
+                "display_name": "Read Only User",
+                "policies": [{"bucket": "*", "actions": ["list", "read"]}],
+            },
+        ]
+    }
+    iam_config.write_text(json.dumps(iam_payload))
+    
+    config = {
+        "TESTING": True,
+        "STORAGE_ROOT": storage_root,
+        "IAM_CONFIG": iam_config,
+        "BUCKET_POLICY_PATH": bucket_policies,
+        "API_BASE_URL": "http://testserver",
+        "SECRET_KEY": "testing",
+        "ENCRYPTION_ENABLED": True,
+    }
+    
+    if kms_enabled:
+        config["KMS_ENABLED"] = True
+        config["KMS_KEYS_PATH"] = str(tmp_path / "kms_keys.json")
+        config["ENCRYPTION_MASTER_KEY_PATH"] = str(tmp_path / "master.key")
+    
+    app = create_app(config)
+    storage = app.extensions["object_storage"]
+    storage.create_bucket("test-bucket")
+    return app
+
+
+class TestUIBucketEncryption:
+    """Test bucket encryption configuration via UI."""
+    
+    def test_bucket_detail_shows_encryption_card(self, tmp_path):
+        """Encryption card should be visible on bucket detail page."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login first
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        assert response.status_code == 200
+        
+        html = response.data.decode("utf-8")
+        assert "Default Encryption" in html
+        assert "Encryption Algorithm" in html or "Default encryption disabled" in html
+    
+    def test_enable_aes256_encryption(self, tmp_path):
+        """Should be able to enable AES-256 encryption."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        # Get CSRF token
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        # Enable AES-256 encryption
+        response = client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "AES256",
+            },
+            follow_redirects=True,
+        )
+        
+        assert response.status_code == 200
+        html = response.data.decode("utf-8")
+        # Should see success message or enabled state
+        assert "AES-256" in html or "encryption enabled" in html.lower()
+    
+    def test_enable_kms_encryption(self, tmp_path):
+        """Should be able to enable KMS encryption."""
+        app = _make_encryption_app(tmp_path, kms_enabled=True)
+        client = app.test_client()
+        
+        # Create a KMS key first
+        with app.app_context():
+            kms = app.extensions.get("kms")
+            if kms:
+                key = kms.create_key("test-key")
+                key_id = key.key_id
+            else:
+                pytest.skip("KMS not available")
+        
+        # Login
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        # Get CSRF token
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        # Enable KMS encryption
+        response = client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "aws:kms",
+                "kms_key_id": key_id,
+            },
+            follow_redirects=True,
+        )
+        
+        assert response.status_code == 200
+        html = response.data.decode("utf-8")
+        assert "KMS" in html or "encryption enabled" in html.lower()
+    
+    def test_disable_encryption(self, tmp_path):
+        """Should be able to disable encryption."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        # First enable encryption
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "AES256",
+            },
+        )
+        
+        # Now disable it
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        response = client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "disable",
+            },
+            follow_redirects=True,
+        )
+        
+        assert response.status_code == 200
+        html = response.data.decode("utf-8")
+        assert "disabled" in html.lower() or "Default encryption disabled" in html
+    
+    def test_invalid_algorithm_rejected(self, tmp_path):
+        """Invalid encryption algorithm should be rejected."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        response = client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "INVALID",
+            },
+            follow_redirects=True,
+        )
+        
+        assert response.status_code == 200
+        html = response.data.decode("utf-8")
+        assert "Invalid" in html or "danger" in html
+    
+    def test_encryption_persists_in_config(self, tmp_path):
+        """Encryption config should persist in bucket config."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login
+        client.post("/ui/login", data={"access_key": "test", "secret_key": "secret"}, follow_redirects=True)
+        
+        # Enable encryption
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "AES256",
+            },
+        )
+        
+        # Verify it's stored
+        with app.app_context():
+            storage = app.extensions["object_storage"]
+            config = storage.get_bucket_encryption("test-bucket")
+            
+            assert "Rules" in config
+            assert len(config["Rules"]) == 1
+            assert config["Rules"][0]["ApplyServerSideEncryptionByDefault"]["SSEAlgorithm"] == "AES256"
+
+
+class TestUIEncryptionWithoutPermission:
+    """Test encryption UI when user lacks permissions."""
+    
+    def test_readonly_user_cannot_change_encryption(self, tmp_path):
+        """Read-only user should not be able to change encryption settings."""
+        app = _make_encryption_app(tmp_path)
+        client = app.test_client()
+        
+        # Login as readonly user
+        client.post("/ui/login", data={"access_key": "readonly", "secret_key": "secret"}, follow_redirects=True)
+        
+        # This should fail or be rejected
+        response = client.get("/ui/buckets/test-bucket?tab=properties")
+        csrf_token = get_csrf_token(response)
+        
+        response = client.post(
+            "/ui/buckets/test-bucket/encryption",
+            data={
+                "csrf_token": csrf_token,
+                "action": "enable",
+                "algorithm": "AES256",
+            },
+            follow_redirects=True,
+        )
+        
+        # Should either redirect with error or show permission denied
+        assert response.status_code == 200
+        html = response.data.decode("utf-8")
+        # Should contain error about permission denied
+        assert "Access denied" in html or "permission" in html.lower() or "not authorized" in html.lower()