Message Authentication Code

Message Authentication Code: Cryptographic checksum used to ensure the integrity and authenticity of a message. Secure implementation depends, in particular, on suitable algorithms, correct key management, verified implementationsImplementationThe practical realization of a security design, requirement, or control in a system or process., and a controlled chain of trust.

How it works and where it fits

The security of Message Authentication Code comes from the combination of algorithm, parameters, keys, protocol, and implementation. A mathematically strong primitive can be defeated by an unsuitable mode, weak randomness, incorrect certificate validation, or exposed keys. The intended objective must therefore be explicit: confidentiality, integrity, authenticity, or non-repudiation.

Practical security relevance

In practice, key and certificate management is often more decisive than algorithm choice alone. Generation, storage, distribution, rotation, revocation, and destruction require defined controls and monitoring. Compatible parameters, maintained libraries, migration capability, and a response process for compromised keys are also necessary; proprietary cryptographic constructions should be avoided.

Related concepts

• IntegrityIntegrityProperty ensuring that data is complete, accurate, and unaltered.: Property ensuring that data is complete, accurate, and unaltered.
• Hash FunctionHash FunctionMaps data deterministically to a fixed checksum or hash value.: Maps data deterministically to a fixed checksum or hash value.
• CryptographyCryptographyMethods for protecting information through encryption, signatures, and hash functions.: Methods for protecting information through encryption, signatures, and hash functions.
• AES-GCMAES-GCMAuthenticated encryption mode that combines confidentiality and integrity.: Authenticated encryption mode that combines confidentiality and integrity.