4 use vars qw($VERSION @ISA @EXPORT_OK);
9 *import = \&Exporter::import;
10 @EXPORT_OK = qw(md5 md5_hex md5_base64);
14 push(@ISA, 'Digest::base');
18 *add_bits = sub { die $err };
24 XSLoader::load('Digest::MD5', $VERSION);
29 # Try to load the pure perl version
30 require Digest::Perl::MD5;
32 Digest::Perl::MD5->import(qw(md5 md5_hex md5_base64));
33 push(@ISA, "Digest::Perl::MD5"); # make OO interface work
36 # restore the original error
49 Digest::MD5 - Perl interface to the MD5 Algorithm
54 use Digest::MD5 qw(md5 md5_hex md5_base64);
57 $digest = md5_hex($data);
58 $digest = md5_base64($data);
63 $ctx = Digest::MD5->new;
68 $digest = $ctx->digest;
69 $digest = $ctx->hexdigest;
70 $digest = $ctx->b64digest;
74 The C<Digest::MD5> module allows you to use the RSA Data Security
75 Inc. MD5 Message Digest algorithm from within Perl programs. The
76 algorithm takes as input a message of arbitrary length and produces as
77 output a 128-bit "fingerprint" or "message digest" of the input.
79 Note that the MD5 algorithm is not as strong as it used to be. It has
80 since 2005 been easy to generate different messages that produce the
81 same MD5 digest. It still seems hard to generate messages that
82 produce a given digest, but it is probably wise to move to stronger
83 algorithms for applications that depend on the digest to uniquely identify
86 The C<Digest::MD5> module provide a procedural interface for simple
87 use, as well as an object oriented interface that can handle messages
88 of arbitrary length and which can read files directly.
92 The following functions are provided by the C<Digest::MD5> module.
93 None of these functions are exported by default.
99 This function will concatenate all arguments, calculate the MD5 digest
100 of this "message", and return it in binary form. The returned string
101 will be 16 bytes long.
103 The result of md5("a", "b", "c") will be exactly the same as the
104 result of md5("abc").
106 =item md5_hex($data,...)
108 Same as md5(), but will return the digest in hexadecimal form. The
109 length of the returned string will be 32 and it will only contain
110 characters from this set: '0'..'9' and 'a'..'f'.
112 =item md5_base64($data,...)
114 Same as md5(), but will return the digest as a base64 encoded string.
115 The length of the returned string will be 22 and it will only contain
116 characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and
119 Note that the base64 encoded string returned is not padded to be a
120 multiple of 4 bytes long. If you want interoperability with other
121 base64 encoded md5 digests you might want to append the redundant
122 string "==" to the result.
128 The object oriented interface to C<Digest::MD5> is described in this
129 section. After a C<Digest::MD5> object has been created, you will add
130 data to it and finally ask for the digest in a suitable format. A
131 single object can be used to calculate multiple digests.
133 The following methods are provided:
137 =item $md5 = Digest::MD5->new
139 The constructor returns a new C<Digest::MD5> object which encapsulate
140 the state of the MD5 message-digest algorithm.
142 If called as an instance method (i.e. $md5->new) it will just reset the
143 state the object to the state of a newly created object. No new
144 object is created in this case.
148 This is just an alias for $md5->new.
152 This a copy of the $md5 object. It is useful when you do not want to
153 destroy the digests state, but need an intermediate value of the
154 digest, e.g. when calculating digests iteratively on a continuous data
157 my $md5 = Digest::MD5->new;
160 print "Line $.: ", $md5->clone->hexdigest, "\n";
163 =item $md5->add($data,...)
165 The $data provided as argument are appended to the message we
166 calculate the digest for. The return value is the $md5 object itself.
168 All these lines will have the same effect on the state of the $md5
171 $md5->add("a"); $md5->add("b"); $md5->add("c");
172 $md5->add("a")->add("b")->add("c");
173 $md5->add("a", "b", "c");
176 =item $md5->addfile($io_handle)
178 The $io_handle will be read until EOF and its content appended to the
179 message we calculate the digest for. The return value is the $md5
182 The addfile() method will croak() if it fails reading data for some
183 reason. If it croaks it is unpredictable what the state of the $md5
184 object will be in. The addfile() method might have been able to read
185 the file partially before it failed. It is probably wise to discard
186 or reset the $md5 object if this occurs.
188 In most cases you want to make sure that the $io_handle is in
189 C<binmode> before you pass it as argument to the addfile() method.
191 =item $md5->add_bits($data, $nbits)
193 =item $md5->add_bits($bitstring)
195 Since the MD5 algorithm is byte oriented you might only add bits as
196 multiples of 8, so you probably want to just use add() instead. The
197 add_bits() method is provided for compatibility with other digest
198 implementations. See L<Digest> for description of the arguments
199 that add_bits() take.
203 Return the binary digest for the message. The returned string will be
206 Note that the C<digest> operation is effectively a destructive,
207 read-once operation. Once it has been performed, the C<Digest::MD5>
208 object is automatically C<reset> and can be used to calculate another
209 digest value. Call $md5->clone->digest if you want to calculate the
210 digest without resetting the digest state.
212 =item $md5->hexdigest
214 Same as $md5->digest, but will return the digest in hexadecimal
215 form. The length of the returned string will be 32 and it will only
216 contain characters from this set: '0'..'9' and 'a'..'f'.
218 =item $md5->b64digest
220 Same as $md5->digest, but will return the digest as a base64 encoded
221 string. The length of the returned string will be 22 and it will only
222 contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+'
226 The base64 encoded string returned is not padded to be a multiple of 4
227 bytes long. If you want interoperability with other base64 encoded
228 md5 digests you might want to append the string "==" to the result.
235 The simplest way to use this library is to import the md5_hex()
236 function (or one of its cousins):
238 use Digest::MD5 qw(md5_hex);
239 print "Digest is ", md5_hex("foobarbaz"), "\n";
241 The above example would print out the message:
243 Digest is 6df23dc03f9b54cc38a0fc1483df6e21
245 The same checksum can also be calculated in OO style:
249 $md5 = Digest::MD5->new;
250 $md5->add('foo', 'bar');
252 $digest = $md5->hexdigest;
254 print "Digest is $digest\n";
256 With OO style you can break the message arbitrary. This means that we
257 are no longer limited to have space for the whole message in memory, i.e.
258 we can handle messages of any size.
260 This is useful when calculating checksum for files:
264 my $file = shift || "/etc/passwd";
265 open(FILE, $file) or die "Can't open '$file': $!";
268 $md5 = Digest::MD5->new;
273 print $md5->b64digest, " $file\n";
275 Or we can use the addfile method for more efficient reading of
280 my $file = shift || "/etc/passwd";
281 open(FILE, $file) or die "Can't open '$file': $!";
284 print Digest::MD5->new->addfile(*FILE)->hexdigest, " $file\n";
286 Perl 5.8 support Unicode characters in strings. Since the MD5
287 algorithm is only defined for strings of bytes, it can not be used on
288 strings that contains chars with ordinal number above 255. The MD5
289 functions and methods will croak if you try to feed them such input
292 use Digest::MD5 qw(md5_hex);
294 my $str = "abc\x{300}";
295 print md5_hex($str), "\n"; # croaks
296 # Wide character in subroutine entry
298 What you can do is calculate the MD5 checksum of the UTF-8
299 representation of such strings. This is achieved by filtering the
300 string through encode_utf8() function:
302 use Digest::MD5 qw(md5_hex);
303 use Encode qw(encode_utf8);
305 my $str = "abc\x{300}";
306 print md5_hex(encode_utf8($str)), "\n";
307 # 8c2d46911f3f5a326455f0ed7a8ed3b3
320 http://en.wikipedia.org/wiki/MD5
322 The paper "How to Break MD5 and Other Hash Functions" by Xiaoyun Wang
327 This library is free software; you can redistribute it and/or
328 modify it under the same terms as Perl itself.
330 Copyright 1998-2003 Gisle Aas.
331 Copyright 1995-1996 Neil Winton.
332 Copyright 1991-1992 RSA Data Security, Inc.
334 The MD5 algorithm is defined in RFC 1321. This implementation is
335 derived from the reference C code in RFC 1321 which is covered by
336 the following copyright statement:
342 Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
345 License to copy and use this software is granted provided that it
346 is identified as the "RSA Data Security, Inc. MD5 Message-Digest
347 Algorithm" in all material mentioning or referencing this software
350 License is also granted to make and use derivative works provided
351 that such works are identified as "derived from the RSA Data
352 Security, Inc. MD5 Message-Digest Algorithm" in all material
353 mentioning or referencing the derived work.
355 RSA Data Security, Inc. makes no representations concerning either
356 the merchantability of this software or the suitability of this
357 software for any particular purpose. It is provided "as is"
358 without express or implied warranty of any kind.
360 These notices must be retained in any copies of any part of this
361 documentation and/or software.
365 This copyright does not prohibit distribution of any version of Perl
366 containing this extension under the terms of the GNU or Artistic
371 The original C<MD5> interface was written by Neil Winton
372 (C<N.Winton@axion.bt.co.uk>).
374 The C<Digest::MD5> module is written by Gisle Aas <gisle@ActiveState.com>.