41bbd8c182
Complete rewrite from task management to full-featured chat system: Core Features: - Real-time WebSocket messaging with connection management - Direct messages and group chats with admin controls - Message types: text, images, videos, audio, documents - Message status tracking: sent, delivered, read receipts - Typing indicators and user presence (online/offline) - Message replies, editing, and deletion Security & Encryption: - End-to-end encryption with RSA + AES hybrid approach - JWT authentication for API and WebSocket connections - Secure file storage with access control - Automatic RSA key pair generation per user Media & File Sharing: - Multi-format file upload (images, videos, audio, documents) - Automatic thumbnail generation for images/videos - File size validation and MIME type checking - Secure download endpoints with permission checks Notifications & Alerts: - Real-time WebSocket notifications - Push notifications via Firebase integration - @username mention alerts with notification history - Unread message and mention counting - Custom notification types (message, mention, group invite) Advanced Features: - Group chat management with roles (member, admin, owner) - User search and chat member management - Message pagination and chat history - Last seen timestamps and activity tracking - Comprehensive API documentation with WebSocket events Architecture: - Clean layered architecture with services, models, schemas - WebSocket connection manager for real-time features - Modular notification system with multiple channels - Comprehensive error handling and validation - Production-ready with Docker support Technologies: FastAPI, WebSocket, SQLAlchemy, SQLite, Cryptography, Firebase, Pillow
208 lines
8.2 KiB
Python
208 lines
8.2 KiB
Python
import json
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import base64
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from typing import Dict
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from cryptography.hazmat.primitives import hashes, serialization
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from cryptography.hazmat.primitives.asymmetric import rsa, padding
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.hazmat.primitives.serialization import load_pem_public_key, load_pem_private_key
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from sqlalchemy.orm import Session
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from app.models.user import User
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from app.models.chat_member import ChatMember
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import os
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class EncryptionService:
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def __init__(self):
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self.algorithm = hashes.SHA256()
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def generate_rsa_key_pair(self) -> tuple[str, str]:
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"""Generate RSA key pair for E2E encryption"""
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private_key = rsa.generate_private_key(
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public_exponent=65537,
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key_size=2048,
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)
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public_key = private_key.public_key()
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# Serialize keys
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private_pem = private_key.private_bytes(
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encoding=serialization.Encoding.PEM,
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format=serialization.PrivateFormat.PKCS8,
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encryption_algorithm=serialization.NoEncryption()
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)
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public_pem = public_key.public_bytes(
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encoding=serialization.Encoding.PEM,
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format=serialization.PublicFormat.SubjectPublicKeyInfo
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)
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return private_pem.decode(), public_pem.decode()
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def encrypt_message_for_chat(self, message: str, chat_id: int, db: Session) -> Dict[str, str]:
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"""
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Encrypt message for all chat members
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Returns a dict with user_id as key and encrypted message as value
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"""
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# Get all chat members with their public keys
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members = db.query(ChatMember).join(User).filter(
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ChatMember.chat_id == chat_id,
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User.public_key.isnot(None)
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).all()
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encrypted_messages = {}
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for member in members:
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user = member.user
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if user.public_key:
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try:
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encrypted_msg = self.encrypt_message(message, user.public_key)
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encrypted_messages[str(user.id)] = encrypted_msg
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except Exception as e:
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print(f"Failed to encrypt for user {user.id}: {e}")
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# Store unencrypted as fallback
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encrypted_messages[str(user.id)] = message
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else:
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# No public key, store unencrypted
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encrypted_messages[str(user.id)] = message
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return encrypted_messages
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def encrypt_message(self, message: str, public_key_pem: str) -> str:
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"""Encrypt message using recipient's public key"""
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try:
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public_key = load_pem_public_key(public_key_pem.encode())
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# For messages longer than RSA key size, use hybrid encryption
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if len(message.encode()) > 190: # RSA 2048 can encrypt ~190 bytes
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return self._hybrid_encrypt(message, public_key)
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else:
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encrypted = public_key.encrypt(
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message.encode(),
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padding.OAEP(
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mgf=padding.MGF1(algorithm=hashes.SHA256()),
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algorithm=hashes.SHA256(),
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label=None
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)
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)
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return base64.b64encode(encrypted).decode()
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except Exception as e:
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print(f"Encryption failed: {e}")
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return message # Fallback to unencrypted
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def decrypt_message(self, encrypted_message: str, private_key_pem: str) -> str:
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"""Decrypt message using recipient's private key"""
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try:
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private_key = load_pem_private_key(private_key_pem.encode(), password=None)
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# Check if it's hybrid encryption (contains ':')
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if ':' in encrypted_message:
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return self._hybrid_decrypt(encrypted_message, private_key)
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else:
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encrypted_bytes = base64.b64decode(encrypted_message.encode())
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decrypted = private_key.decrypt(
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encrypted_bytes,
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padding.OAEP(
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mgf=padding.MGF1(algorithm=hashes.SHA256()),
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algorithm=hashes.SHA256(),
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label=None
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)
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)
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return decrypted.decode()
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except Exception as e:
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print(f"Decryption failed: {e}")
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return encrypted_message # Return encrypted if decryption fails
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def _hybrid_encrypt(self, message: str, public_key) -> str:
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"""
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Hybrid encryption: Use AES for message, RSA for AES key
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Format: base64(encrypted_aes_key):base64(encrypted_message)
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"""
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# Generate AES key
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aes_key = os.urandom(32) # 256-bit key
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iv = os.urandom(16) # 128-bit IV
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# Encrypt message with AES
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cipher = Cipher(algorithms.AES(aes_key), modes.CBC(iv))
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encryptor = cipher.encryptor()
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# Pad message to multiple of 16 bytes
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padded_message = self._pad_message(message.encode())
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encrypted_message = encryptor.update(padded_message) + encryptor.finalize()
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# Encrypt AES key + IV with RSA
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key_iv = aes_key + iv
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encrypted_key_iv = public_key.encrypt(
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key_iv,
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padding.OAEP(
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mgf=padding.MGF1(algorithm=hashes.SHA256()),
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algorithm=hashes.SHA256(),
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label=None
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)
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)
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# Combine encrypted key and message
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encrypted_key_b64 = base64.b64encode(encrypted_key_iv).decode()
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encrypted_msg_b64 = base64.b64encode(encrypted_message).decode()
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return f"{encrypted_key_b64}:{encrypted_msg_b64}"
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def _hybrid_decrypt(self, encrypted_data: str, private_key) -> str:
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"""Hybrid decryption: Decrypt AES key with RSA, then message with AES"""
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try:
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encrypted_key_b64, encrypted_msg_b64 = encrypted_data.split(':', 1)
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# Decrypt AES key + IV
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encrypted_key_iv = base64.b64decode(encrypted_key_b64.encode())
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key_iv = private_key.decrypt(
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encrypted_key_iv,
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padding.OAEP(
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mgf=padding.MGF1(algorithm=hashes.SHA256()),
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algorithm=hashes.SHA256(),
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label=None
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)
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)
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aes_key = key_iv[:32]
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iv = key_iv[32:]
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# Decrypt message with AES
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encrypted_message = base64.b64decode(encrypted_msg_b64.encode())
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cipher = Cipher(algorithms.AES(aes_key), modes.CBC(iv))
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decryptor = cipher.decryptor()
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padded_message = decryptor.update(encrypted_message) + decryptor.finalize()
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message = self._unpad_message(padded_message).decode()
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return message
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except Exception as e:
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print(f"Hybrid decryption failed: {e}")
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return encrypted_data
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def _pad_message(self, message: bytes) -> bytes:
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"""PKCS7 padding"""
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padding_length = 16 - (len(message) % 16)
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padding = bytes([padding_length] * padding_length)
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return message + padding
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def _unpad_message(self, padded_message: bytes) -> bytes:
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"""Remove PKCS7 padding"""
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padding_length = padded_message[-1]
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return padded_message[:-padding_length]
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def get_user_encrypted_message(self, encrypted_messages: Dict[str, str], user_id: int) -> str:
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"""Get encrypted message for specific user"""
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return encrypted_messages.get(str(user_id), "")
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def encrypt_file_metadata(self, metadata: Dict, public_key_pem: str) -> str:
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"""Encrypt file metadata"""
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metadata_json = json.dumps(metadata)
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return self.encrypt_message(metadata_json, public_key_pem)
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def decrypt_file_metadata(self, encrypted_metadata: str, private_key_pem: str) -> Dict:
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"""Decrypt file metadata"""
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try:
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metadata_json = self.decrypt_message(encrypted_metadata, private_key_pem)
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return json.loads(metadata_json)
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except Exception:
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return {}
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# Global encryption service instance
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encryption_service = EncryptionService() |