Hash-based Message Authentication Codes (HMACs)

A Hash-based Message Authentication Code (HMAC) is a method to verify the sender of a message and that the message has not been tampered with, often used in combination with public-key cryptography.

HMAC works by using a cryptographic hash function and a shared secret, or salt. The sender computes the the hash value for the original message using the salt, then sends the original message and hash value to the receiver as a single message. The receiver then recomputes the hash value of the original message using the same hash function and salt. If the message was tampered with or if a different salt was used, a different hash value will result thus invalidating the message.

Broader Topics Related to Hash-based Message Authentication Codes (HMAC)

Hash Functions

Hash functions

Cryptography

Techniques to secure communication

Cybersecurity

Methods for protecting information systems from unauthorized and malicious use