phpman > perldoc > Digest::HMAC

NAME
    Digest::HMAC - Keyed-Hashing for Message Authentication

SYNOPSIS
     # Functional style
     use Digest::HMAC qw(hmac hmac_hex);
     $digest = hmac($data, $key, \&myhash);
     print hmac_hex($data, $key, \&myhash);

     # OO style
     use Digest::HMAC;
     $hmac = Digest::HMAC->new($key, "Digest::MyHash");

     $hmac->add($data);
     $hmac->addfile(*FILE);

     $digest = $hmac->digest;
     $digest = $hmac->hexdigest;
     $digest = $hmac->b64digest;

DESCRIPTION
    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.

SEE ALSO
    Digest::HMAC_MD5, Digest::HMAC_SHA1

    RFC 2104

MAINTAINER
    Andrew Rodland <arodland AT cpan.org>

ORIGINAL AUTHORS
    Graham Barr <gbarr AT ti.com>, Gisle Aas <gisle AT aas.no>