Cryptographic Key

A cryptographic key is a string of bits used by a cryptographic algorithm to transform data: in symmetric cryptography the same key encrypts and decrypts (e.g., AES-128/192/256), while in asymmetric cryptography a key pair consists of a private key and a mathematically related public key (e.g., RSA-2048, ECDSA P-256, Ed25519). Key strength depends on length, randomness, and algorithm; current NIST guidance considers 128-bit symmetric keys, 3072-bit RSA, and 256-bit elliptic-curve keys as roughly equivalent at the 128-bit security level. Keys must be generated from a cryptographically secure RNG, stored in protected storage (HSM, TPM, secure enclave, KMS) and managed across their full lifecycle: generation, distribution, use, rotation, escrow, archival, revocation and destruction.