What does HMAC stand for?

HMAC stands for Hash-based Message Authentication Code. This term refers to a specific construction for creating a message authentication code (MAC) based on a cryptographic hash function. HMAC combines the hash function with a secret key, ensuring both integrity and authenticity of the data being transmitted. The primary purpose of HMAC is to verify that the message comes from the claimed sender (authenticity) and that it has not been altered in transit (integrity).

This method is widely used in various security protocols, including SSL/TLS and IPsec, due to its efficiency and security features. It is designed to be resistant to various attack vectors, including collision and length-extension attacks, as long as a secure hash function is employed. The identification of "Hash-based Message Authentication Code" aligns perfectly with the core function of HMAC in providing a way to ensure that data has not been modified and originated from an authorized source.