Our application implements a robust encryption system to protect sensitive user data. Here's how it works:

1. User-Specific Salts

   • Each user has a unique 32-byte salt stored in the database
   • Salts are generated using cryptographically secure random bytes
   • Salts are protected by Row Level Security (RLS) policies

2. Key Derivation

   • Uses PBKDF2 (Password-Based Key Derivation Function 2) with:
     • 1000 iterations
     • SHA-256 hash function
     • User-specific salt
   • This makes brute force and rainbow table attacks computationally expensive

3. Encryption Algorithm

   • Uses AES-GCM (Advanced Encryption Standard in Galois/Counter Mode)
   • 256-bit key length
   • Provides both confidentiality and authenticity
   • Includes a random IV (Initialization Vector) for each encryption operation

4. Data Protection

   • Sensitive fields are encrypted before storage
   • Each encrypted data block includes:
     • Version number for future compatibility
     • Timestamp for audit purposes
     • Random IV for each encryption operation

sequenceDiagram
    participant User
    participant Client
    participant Database
    participant CryptoAPI

    Note over User,Database: User Authentication
    User->>Client: Login
    Client->>Database: Authenticate
    Database-->>Client: Session Token

    Note over User,Database: Data Encryption Flow
    User->>Client: Submit sensitive data
    Client->>Database: Request user salt
    Database-->>Client: Return encrypted salt
    Client->>CryptoAPI: Derive encryption key (PBKDF2)
    Client->>CryptoAPI: Generate random IV
    Client->>CryptoAPI: Encrypt data (AES-GCM)
    Client->>Database: Store encrypted data

    Note over User,Database: Data Decryption Flow
    User->>Client: Request data
    Client->>Database: Request encrypted data
    Database-->>Client: Return encrypted data
    Client->>Database: Request user salt
    Database-->>Client: Return encrypted salt
    Client->>CryptoAPI: Derive decryption key (PBKDF2)
    Client->>CryptoAPI: Decrypt data (AES-GCM)
    Client-->>User: Display decrypted data

1. Resistance to Rainbow Table Attacks

   • Each user's unique salt means attackers would need to create separate rainbow tables for each user
   • The computational cost of creating these tables makes the attack impractical

2. Protection Against Brute Force

   • PBKDF2's 1000 iterations significantly increase the computational cost of brute force attacks
   • The 256-bit key length provides a massive keyspace (2^256 possible keys)

3. Data Integrity

   • AES-GCM provides authenticated encryption
   • Any tampering with the encrypted data will be detected during decryption

4. Forward Secrecy

   • Each encryption operation uses a unique IV
   • Even if one key is compromised, other encrypted data remains secure

5. Access Control

   • Row Level Security ensures users can only access their own data
   • Salts are protected by RLS policies
   • Authentication is required for all data operations

1. Key Management

   • Keys are never stored, only derived when needed
   • Keys are scoped to specific operations (encrypt/decrypt)
   • Keys are cleared from memory after use

2. Error Handling

   • Failed decryption attempts return null instead of partial data
   • All errors are logged for security auditing
   • No sensitive information is exposed in error messages

3. Data Validation

   • All encrypted data includes version and timestamp
   • Invalid or tampered data is rejected during decryption
   • Data structure is validated before processing

1. Key Derivation Improvements

   • Increase PBKDF2 iterations to at least 10,000 (current NIST recommendation)
   • Consider using Argon2 or scrypt for better resistance against hardware-accelerated attacks

2. Key Rotation

   • Implement periodic key rotation for enhanced security
   • Add support for multiple key versions

3. Enhanced Protection

   • Implement rate limiting for decryption attempts
   • Add support for hardware security modules (HSMs)

4. Audit Trail

   • Implement comprehensive logging of encryption/decryption operations
   • Add support for security event monitoring