Digest::HMAC(3pm)					User Contributed Perl Documentation					 Digest::HMAC(3pm)

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>

perl v5.12.4							    2011-07-25							 Digest::HMAC(3pm)