Générateur de clé de chiffrement AES

AES-128, AES-192, and AES-256 refer to the key lengths in bits — 128, 192, and 256 respectively. All three use the same block cipher algorithm on 128-bit blocks but differ in the number of rounds: 10, 12, and 14 rounds respectively. AES-256 offers the highest security margin but is about 40% slower than AES-128. For most applications, AES-128 with a strong random key is considered secure.

AES-GCM (Galois/Counter Mode) is an authenticated encryption mode that provides both confidentiality and integrity/authenticity in a single operation, producing a ciphertext and an authentication tag. AES-CBC (Cipher Block Chaining) provides only confidentiality and requires a separate MAC (e.g., HMAC) for integrity. AES-GCM is preferred in modern protocols like TLS 1.3 because it is faster in hardware and avoids padding oracle vulnerabilities.

AES security depends entirely on the key being unpredictable. A Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) like crypto.getRandomValues() produces output that is computationally indistinguishable from true randomness, making exhaustive key search infeasible. Using Math.random() or time-based seeds produces predictable keys that can be cracked trivially.

AES keys should never be stored in source code, environment variables in plain text, or version control. Use a dedicated secrets manager (AWS KMS, HashiCorp Vault, Azure Key Vault) for key storage. For long-lived data, use envelope encryption: encrypt data with a data encryption key (DEK), then encrypt the DEK with a key encryption key (KEK) stored in the KMS. Rotate keys regularly and audit all key access.