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

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 AT ti.com>, Gisle Aas <gisle AT aas.no>

perl v5.16.3                      2011-07-25                   Digest::HMAC(3)