What encryption algorithms does VPN use? How is key management performed?

VPN security relies on encryption algorithms and key management. Choosing appropriate encryption algorithms and implementing effective key management are critical to ensuring VPN security.

VPN Encryption Algorithms:

1. Symmetric Encryption Algorithms

   • AES (Advanced Encryption Standard)
     • Key lengths: 128, 192, 256 bits
     • Pros: High security, good performance, widely supported
     • Applications: Mainstream VPN protocols like OpenVPN, IPsec
   • ChaCha20
     • Key length: 256 bits
     • Pros: Excellent performance on mobile devices, resistant to side-channel attacks
     • Applications: WireGuard, OpenVPN
   • 3DES (Triple DES)
     • Key length: 168 bits (effective 112 bits)
     • Cons: Considered insufficiently secure, being phased out

2. Asymmetric Encryption Algorithms

   • RSA
     • Key lengths: 2048, 4096 bits
     • Purpose: Key exchange, digital signatures
     • Cons: High computational overhead
   • ECC (Elliptic Curve Cryptography)
     • Curve types: Curve25519, P-256, etc.
     • Pros: Shorter keys at same security level, better performance
     • Applications: WireGuard, modern IPsec

3. Hash Algorithms

   • SHA-256: Used for data integrity verification
   • HMAC: Message authentication code, ensures data hasn't been tampered with

Key Management:

1. Key Generation

   • Use cryptographically secure random number generators
   • Follow recommendations from standards organizations like NIST
   • Regularly rotate keys

2. Key Exchange

   • Diffie-Hellman: Traditional key exchange method
   • ECDH: Elliptic curve-based key exchange
   • IKE (Internet Key Exchange): Key exchange protocol used by IPsec

3. Key Storage

   • Use Hardware Security Modules (HSM) to protect keys
   • Set appropriate permissions on key files
   • Avoid hardcoding keys

4. Key Rotation

   • Regularly update encryption keys
   • Perfect Forward Secrecy (PFS): Even if long-term keys are compromised, past sessions remain secure
   • Use short-term session keys

Security Best Practices:

• Use at least 256-bit AES or ChaCha20 encryption
• Enable Perfect Forward Secrecy
• Use strong authentication mechanisms
• Regularly update VPN software
• Disable weak encryption algorithms and protocols
• Implement multi-factor authentication