Encryption Algorithms and Methods Overview

Based on my knowledge and industry usage, here's a comprehensive overview of encryption algorithms and methods that are commonly used:

Symmetric Encryption Algorithms

1. AES (Advanced Encryption Standard)

• Key Sizes: 128, 192, 256 bits
• Block Size: 128 bits
• Usage: Most widely used symmetric encryption standard
• Applications: File encryption, database encryption, VPNs, messaging apps
• Strength: Considered highly secure when properly implemented

2. DES (Data Encryption Standard) / 3DES (Triple DES)

• Key Sizes: 56 bits (DES), 168 bits (3DES)
• Block Size: 64 bits
• Usage: Legacy systems, financial transactions (3DES)
• Status: DES is deprecated, 3DES being phased out

3. Blowfish

• Key Sizes: 32-448 bits
• Block Size: 64 bits
• Usage: Embedded systems, password management
• Strength: Fast but limited by small block size

4. Twofish

• Key Sizes: 128, 192, 256 bits
• Block Size: 128 bits
• Usage: Alternative to AES, less common
• Strength: Strong but slower than AES

5. ChaCha20

• Key Size: 256 bits
• Usage: Stream cipher, mobile applications, TLS
• Strength: Fast, secure, resistant to timing attacks

Asymmetric (Public Key) Encryption Algorithms

1. RSA (Rivest-Shamir-Adleman)

• Key Sizes: 1024, 2048, 4096+ bits
• Usage: Digital signatures, key exchange, SSL/TLS certificates
• Status: 2048-bit minimum recommended today

2. ECC (Elliptic Curve Cryptography)

• Key Sizes: 256-521 bits (equivalent to 3072+ bit RSA)
• Curves: P-256, P-384, P-521, Curve25519, Ed25519
• Usage: Mobile devices, blockchain, modern TLS
• Strength: Same security with smaller keys than RSA

3. DSA (Digital Signature Algorithm)

• Key Sizes: 1024-3072 bits
• Usage: Digital signatures
• Status: Being replaced by ECDSA and EdDSA

4. ElGamal

• Usage: Key exchange, encryption
• Status: Less common, mostly academic use

Hash Functions

1. SHA-2 Family

• Variants: SHA-256, SHA-384, SHA-512
• Output Sizes: 256, 384, 512 bits
• Usage: Digital signatures, blockchain, password hashing
• Status: Current standard

2. SHA-3

• Variants: SHA3-256, SHA3-384, SHA3-512
• Usage: Alternative to SHA-2
• Status: Modern standard, less deployed

3. MD5

• Output Size: 128 bits
• Status: Cryptographically broken, not for security

4. SHA-1

• Output Size: 160 bits
• Status: Deprecated, collision attacks demonstrated

Key Exchange Protocols

1. Diffie-Hellman (DH)

• Usage: Key exchange, perfect forward secrecy
• Variants: Finite field DH, Elliptic Curve DH (ECDH)

2. RSA Key Exchange

• Usage: TLS key exchange (being phased out)

Modern Encryption Methods

1. Authenticated Encryption

• Algorithms: AES-GCM, ChaCha20-Poly1305
• Usage: Provides both confidentiality and integrity
• Applications: TLS 1.3, encrypted messaging

2. Homomorphic Encryption

• Types: Partial, Somewhat, Fully Homomorphic
• Usage: Computation on encrypted data
• Status: Emerging technology, performance challenges

3. Quantum-Resistant Cryptography

• Algorithms: Lattice-based, Hash-based, Code-based
• Status: NIST standardization in progress
• Need: Protection against quantum computers

Most Commonly Used Today

1. AES-256 - For symmetric encryption
2. RSA-2048/4096 - For digital signatures and key exchange
3. ECC (P-256, Curve25519) - For mobile and modern applications
4. SHA-256/512 - For hashing
5. AES-GCM/ChaCha20-Poly1305 - For authenticated encryption
6. ECDHE - For key exchange with forward secrecy

Implementation Considerations

• Always use well-vetted libraries rather than implementing algorithms yourself
• Proper key management is as important as algorithm choice
• Algorithm selection depends on use case, performance requirements, and threat model
• Stay updated with NIST and industry recommendations
• Consider quantum resistance for long-term security needs

Next Implementation

• Golang Implementation
• Rust Implementation
• Python Implementation
• Java Implementation