Message Authentication Code (MAC) Security Pattern This pattern encapsulates common considerations for using Message Authentication Codes (MAC) to ensure the integrity of messages and authenticate the identity of the provider. What is a MAC? A Message Authentication Code (MAC) is a tag computed from a message using a special hash function whose output depends on a secret cryptographic key. Generating a MAC requires: 1. The message itself 2. Possession of a secret key Only parties possessing the agreed-upon secret key can generate and verify valid MACs. Properties Provided Appending a MAC to a…