Cryptography Essentials for Practitioners
Cryptography Essentials for Practitioners Cryptography helps protect data in motion and at rest. For practitioners, the goal is to apply solid, proven choices consistently rather than chase every new gadget. Start with three goals: confidentiality, integrity, and authenticity. These map to encryption, hashes, and signatures, but real systems mix them across layers. Core ideas you should know include the following. Use symmetric encryption for fast confidentiality, such as AES-256 in GCM mode, with a unique nonce for each message. For key exchange and identity, rely on asymmetric schemes like ECC or RSA and prefer modern signatures such as EdDSA or ECDSA. Hash functions like SHA-256 or SHA-3 support integrity, and with a keyed MAC you gain strong authenticity. Key derivation and randomness matter: HKDF helps derive keys safely, and cryptographically strong random numbers are essential for nonces, salts, and keys. Always prefer authenticated encryption, which provides both secrecy and integrity in one step. ...