Advanced Cryptography Fundamentals
Cryptography is the practice and study of techniques for secure communication in the presence of adversarial behavior. It involves the use of mathematical algorithms to transform information into a form that is unintelligible to unauthorized parties.
Symmetric Encryption
Symmetric encryption uses the same key for both encryption and decryption:
- AES (Advanced Encryption Standard): Widely used block cipher with 128, 192, or 256-bit keys
- ChaCha20: Stream cipher designed for high-speed encryption
- 3DES (Triple DES): Legacy standard using three iterations of DES
- Blowfish: Fast block cipher with variable key length
Asymmetric Encryption
Asymmetric encryption uses different keys for encryption and decryption:
- RSA: Based on the difficulty of factoring large integers
- ECC (Elliptic Curve Cryptography): More efficient than RSA for equivalent security
- Diffie-Hellman: Key exchange protocol for secure communication
- ElGamal: Public key cryptosystem based on discrete logarithms
Hash Functions
Hash functions produce fixed-size output from variable-size input:
- SHA-256: Secure Hash Algorithm producing 256-bit output
- SHA-3: Latest SHA standard with improved security
- BLAKE2: Fast cryptographic hash function
- MD5: Legacy hash function (deprecated for security)
Digital Signatures
Digital signatures provide authentication, integrity, and non-repudiation:
- RSA Signatures: Based on RSA encryption
- ECDSA: Elliptic Curve Digital Signature Algorithm
- EdDSA: Edwards Curve Digital Signature Algorithm
- DSA: Digital Signature Algorithm
Key Management
Proper key management is crucial for cryptographic security:
- Key Generation: Creating cryptographically secure random keys
- Key Distribution: Secure methods for sharing keys
- Key Storage: Protecting keys from unauthorized access
- Key Rotation: Regularly updating keys for security