Ubuntu Manpage: Digest::MD5::Perl - Perl implementation of Ron Rivests MD5 Algorithm

Provided by: libdigest-perl-md5-perl_1.9-1_all

NAME

       Digest::MD5::Perl - Perl implementation of Ron Rivests MD5 Algorithm

DISCLAIMER

       This is not an interface (like "Digest::MD5") but a Perl implementation of MD5.  It is
       written in perl only and because of this it is slow but it works without C-Code.  You
       should use "Digest::MD5" instead of this module if it is available.  This module is only
       useful for

       •   computers where you cannot install "Digest::MD5" (e.g. lack of a C-Compiler)

       •   encrypting only small amounts of data (less than one million bytes). I use it to hash
           passwords.

       •   educational purposes

SYNOPSIS

        # Functional style
        use Digest::MD5  qw(md5 md5_hex md5_base64);

        $hash = md5 $data;
        $hash = md5_hex $data;
        $hash = md5_base64 $data;

        # OO style
        use Digest::MD5;

        $ctx = Digest::MD5->new;

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

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

DESCRIPTION

       This modules has the same interface as the much faster "Digest::MD5". So you can easily
       exchange them, e.g.

               BEGIN {
                 eval {
                   require Digest::MD5;
                   import Digest::MD5 'md5_hex'
                 };
                 if ($@) { # ups, no Digest::MD5
                   require Digest::Perl::MD5;
                   import Digest::Perl::MD5 'md5_hex'
                 }
               }

       If the "Digest::MD5" module is available it is used and if not you take
       "Digest::Perl::MD5".

       You can also install the Perl part of Digest::MD5 together with Digest::Perl::MD5 and use
       Digest::MD5 as normal, it falls back to Digest::Perl::MD5 if it cannot load its object
       files.

       For a detailed Documentation see the "Digest::MD5" module.

EXAMPLES

       The simplest way to use this library is to import the md5_hex() function (or one of its
       cousins):

           use Digest::Perl::MD5 'md5_hex';
           print 'Digest is ', md5_hex('foobarbaz'), "\n";

       The above example would print out the message

           Digest is 6df23dc03f9b54cc38a0fc1483df6e21

       provided that the implementation is working correctly.  The same checksum can also be
       calculated in OO style:

           use Digest::MD5;

           $md5 = Digest::MD5->new;
           $md5->add('foo', 'bar');
           $md5->add('baz');
           $digest = $md5->hexdigest;

           print "Digest is $digest\n";

       The digest methods are destructive. That means you can only call them once and the $md5
       objects is reset after use. You can make a copy with clone:

               $md5->clone->hexdigest

LIMITATIONS

       This implementation of the MD5 algorithm has some limitations:

       •   It's slow, very slow. I've done my very best but Digest::MD5 is still about 100 times
           faster.  You can only encrypt Data up to one million bytes in an acceptable time. But
           it's very useful for encrypting small amounts of data like passwords.

       •   You can only encrypt up to 2^32 bits = 512 MB on 32bit archs. But You should use
           "Digest::MD5" for those amounts of data anyway.

COPYRIGHT

This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.

The MD5 algorithm is defined in RFC 1321. The basic C code implementing the algorithm is
derived from that in the RFC and is covered by the following copyright:

License to copy and use this software is granted provided that it is identified as the
"RSA Data Security, Inc. MD5 Message-Digest Algorithm" in all material mentioning or
referencing this software or this function.

License is also granted to make and use derivative works provided that such works are
identified as "derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm"
in all material mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either the merchantability
of this software or the suitability of this software for any particular purpose. It is
provided "as is" without express or implied warranty of any kind.

These notices must be retained in any copies of any part of this documentation and/or
software.

This copyright does not prohibit distribution of any version of Perl containing this
extension under the terms of the GNU or Artistic licenses.

AUTHORS

       The original MD5 interface was written by Neil Winton (<N.Winton (at) axion.bt.co.uk>).

       "Digest::MD5" was made by Gisle Aas <gisle (at) aas.no> (I took his Interface and part of
       the documentation).

       Thanks to Guido Flohr for his 'use integer'-hint.

       This release was made by Christian Lackas <delta (at) lackas.net>.