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 usefull 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 usefull 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.
SEE ALSO the Digest::MD5 manpage
the md5(1) manpage
RFC 1321
tools/md5: a small BSD compatible md5 tool written in pure perl.
COPYRIGHT This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Copyright 2000 Christian Lackas, Imperia Software Solutions
Copyright 1998-1999 Gisle Aas.
Copyright 1995-1996 Neil Winton.
Copyright 1991-1992 RSA Data Security, Inc.
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:
Copyright (C) 1991-1992, RSA Data Security, Inc. Created 1991. All
rights reserved.
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>.