Cryptography is the art of secret writing. Modern encryption protects data confidentiality and integrity across networks and at rest.
Symmetric Encryption
Same key for encryption and decryption. Fast and efficient for bulk data.
- AES-256-GCM: Current standard for data encryption
- ChaCha20-Poly1305: Modern alternative, often faster on mobile
Asymmetric Encryption
Different keys: public key encrypts, private key decrypts (or vice versa for signing).
- RSA 2048+: Still used for key exchange
- ECC: Smaller keys with equivalent security, becoming standard
Hashing
One-way function mapping arbitrary input to fixed output.
- SHA-256/SHA-3: Current standards
- MD5/SHA-1: Broken, do not use
Modern Protocols
- TLS 1.3: Latest secure transport protocol
- HKDF: Key derivation function for forward secrecy