hash-based message authentication code (IP) (HMAC)
Hash-based Message Authentication Code (HMAC) is a messageauthentication method in which the Message Authenthication Code( MAC) is calculated using a cryptic hash function in combination with a secret key.
Like other MAC codes, HMAC can be used for simultaneous verification of data integrity and message authenticity.
HMAC can be used with various iterative hashing methods such as MD5 or the SHA algorithm (SHA-1) in combination with a key. The security of HMAC encryption depends mainly on the properties of the hash function used.