perl-Digest-HMAC

Keyed-Hashing for Message Authentication

HMAC is used for message integrity checks between two parties that share a secret key, and works in combination with some other Digest algorithm, usually MD5 or SHA-1. The HMAC mechanism is described in RFC 2104. HMAC follow the common 'Digest::' interface, but the constructor takes the secret key and the name of some other simple 'Digest::' as argument. The hmac() and hmac_hex() functions and the Digest::HMAC->new() constructor takes an optional $blocksize argument as well. The HMAC algorithm assumes the digester to hash by iterating a basic compression function on blocks of data and the $blocksize should match the byte-length of such blocks. The default $blocksize is 64 which is suitable for the MD5 and SHA-1 digest functions. For stronger algorithms the blocksize probably needs to be increased.