Cryptography
Protecting information through encryption and related techniques
Cryptography is the practice of securing information by transforming it into an unreadable format, ensuring confidentiality, integrity, authentication, and non-repudiation.
Core Concepts
- Symmetric Encryption - Same key for encryption and decryption (AES, 3DES)
- Asymmetric Encryption - Public/private key pairs (RSA, ECC)
- Hashing - One-way functions for integrity verification (SHA-256, SHA-3)
- Digital Signatures - Authentication and non-repudiation
- Key Exchange - Secure key distribution (Diffie-Hellman)
Applications
- TLS/SSL for secure communications
- Disk and file encryption
- Digital certificates and PKI
- Password storage and verification
- Blockchain and cryptocurrencies
Security Considerations
- Key management and lifecycle
- Algorithm selection and deprecation
- Random number generation
- Side-channel attack protection
- Post-quantum cryptography readiness
