Module aes256_cbc_hmac_sha256_aead 

AES-256-CBC-HMAC-SHA256 operations

An extended construction of AES-256-CBC-HMAC-SHA256. It is used when an AES256-CBC-HMAC-SHA256 key is used for authenticated encryption in the context of COSE.

Structs

Aes256CbcHmacSha256Aead 🔒

AES-256-CBC-HMAC-SHA256 authenticated encryption with associated data.

Aes256CbcHmacSha256AeadCiphertext 🔒

Aes256CbcHmacSha256AeadNonce 🔒

A 128-bit AES-256-CBC-HMAC-SHA256 IV.

Constants

ENC_KEY_SIZE 🔒

KEY_SIZE 🔒

MAC_DOMAIN_SEPARATOR 🔒

Domain separation label prefixed to the MAC input. It distinguishes this construction from the legacy Aes256CbcHmacSha256 Encrypt-then-MAC construction, which MACs iv || ciphertext under the same MAC sub-key, so that a tag produced by one construction can never be a valid tag for the other.

MAC_KEY_SIZE 🔒

MAC_SIZE 🔒

NONCE_SIZE 🔒

Functions

calculate_mac_with_aad 🔒

Computes the HMAC-SHA256 MAC over MAC_DOMAIN_SEPARATOR || iv || len(data) || data || len(associated_data) || associated_data, where lengths are encoded as 8-byte big-endian u64s.

split_to_subkeys 🔒

Splits the 64-byte composite key into zero-copy views over its encryption and MAC halves.

Type Aliases

HmacSha256 🔒