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
AUTHORS¶
Graham Barr <gbarr@ti.com>, Gisle Aas <gisle@aas.no>