HMAC (Hash-Based Message Authentication Codes) Definition | Okta

Hash-based message authentication code (or HMAC) is a cryptographic authentication technique that usesa hash function and a secret key.With HMAC, you can achieve authentication and verify that data is correct and authentic with shared secrets, as opposed to approaches that use signatures and asymmetric cryptography.How HMAC WorksTwo parties want to communicate, but they want to ensure that the contents of their connection remain private. They also distrust the internet, and they need a way to verify that the packets they receive haven't been tampered with. HMAC is a valid solution.HMAC keys consist of two parts. These are:Cryptographic keys. An encryption algorithm alters data, and a recipient needs a specific code (or key) to make it readable once more. HMAC relies on a shared sets of secret keys.Hash function. A hash algorithm alters or digests the message once more. HMAC uses generic cryptographic hash functions, such as SHA-1, MD5, or RIPEMD-128/60.A pair using this system must agr...