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1 | package Digest::MD5; |
2 | |
3 | use strict; |
4 | use vars qw($VERSION @ISA @EXPORT_OK); |
5 | |
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6 | $VERSION = '2.36_01'; # $Date: 2005/11/30 13:46:47 $ |
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7 | |
8 | require Exporter; |
9 | *import = \&Exporter::import; |
10 | @EXPORT_OK = qw(md5 md5_hex md5_base64); |
11 | |
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12 | eval { |
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13 | require Digest::base; |
14 | push(@ISA, 'Digest::base'); |
15 | }; |
16 | if ($@) { |
17 | my $err = $@; |
18 | *add_bits = sub { die $err }; |
19 | } |
20 | |
21 | |
22 | eval { |
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23 | require XSLoader; |
24 | XSLoader::load('Digest::MD5', $VERSION); |
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25 | }; |
26 | if ($@) { |
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27 | my $olderr = $@; |
28 | eval { |
29 | # Try to load the pure perl version |
30 | require Digest::Perl::MD5; |
31 | |
32 | Digest::Perl::MD5->import(qw(md5 md5_hex md5_base64)); |
33 | push(@ISA, "Digest::Perl::MD5"); # make OO interface work |
34 | }; |
35 | if ($@) { |
36 | # restore the original error |
37 | die $olderr; |
38 | } |
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39 | } |
40 | else { |
41 | *reset = \&new; |
42 | } |
43 | |
44 | 1; |
45 | __END__ |
46 | |
47 | =head1 NAME |
48 | |
49 | Digest::MD5 - Perl interface to the MD5 Algorithm |
50 | |
51 | =head1 SYNOPSIS |
52 | |
53 | # Functional style |
ac70dec1 |
54 | use Digest::MD5 qw(md5 md5_hex md5_base64); |
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55 | |
56 | $digest = md5($data); |
57 | $digest = md5_hex($data); |
58 | $digest = md5_base64($data); |
59 | |
60 | # OO style |
61 | use Digest::MD5; |
62 | |
63 | $ctx = Digest::MD5->new; |
64 | |
65 | $ctx->add($data); |
66 | $ctx->addfile(*FILE); |
67 | |
68 | $digest = $ctx->digest; |
69 | $digest = $ctx->hexdigest; |
70 | $digest = $ctx->b64digest; |
71 | |
72 | =head1 DESCRIPTION |
73 | |
74 | The C<Digest::MD5> module allows you to use the RSA Data Security |
75 | Inc. MD5 Message Digest algorithm from within Perl programs. The |
76 | algorithm takes as input a message of arbitrary length and produces as |
77 | output a 128-bit "fingerprint" or "message digest" of the input. |
78 | |
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79 | Note that the MD5 algorithm is not as strong as it used to be. It has |
80 | since 2005 been easy to generate different messages that produce the |
81 | same MD5 digest. It still seems hard to generate messages that |
82 | produce a given digest, but it is probably wise to move to stronger |
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83 | algorithms for applications that depend on the digest to uniquely identify |
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84 | a message. |
85 | |
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86 | The C<Digest::MD5> module provide a procedural interface for simple |
87 | use, as well as an object oriented interface that can handle messages |
88 | of arbitrary length and which can read files directly. |
89 | |
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90 | =head1 FUNCTIONS |
91 | |
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92 | The following functions are provided by the C<Digest::MD5> module. |
93 | None of these functions are exported by default. |
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94 | |
95 | =over 4 |
96 | |
97 | =item md5($data,...) |
98 | |
99 | This function will concatenate all arguments, calculate the MD5 digest |
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100 | of this "message", and return it in binary form. The returned string |
101 | will be 16 bytes long. |
102 | |
103 | The result of md5("a", "b", "c") will be exactly the same as the |
104 | result of md5("abc"). |
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105 | |
106 | =item md5_hex($data,...) |
107 | |
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108 | Same as md5(), but will return the digest in hexadecimal form. The |
109 | length of the returned string will be 32 and it will only contain |
110 | characters from this set: '0'..'9' and 'a'..'f'. |
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111 | |
112 | =item md5_base64($data,...) |
113 | |
114 | Same as md5(), but will return the digest as a base64 encoded string. |
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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 |
117 | '/'. |
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118 | |
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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 |
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122 | string "==" to the result. |
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123 | |
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124 | =back |
125 | |
126 | =head1 METHODS |
127 | |
ac70dec1 |
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. |
132 | |
133 | The following methods are provided: |
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134 | |
135 | =over 4 |
136 | |
137 | =item $md5 = Digest::MD5->new |
138 | |
139 | The constructor returns a new C<Digest::MD5> object which encapsulate |
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140 | the state of the MD5 message-digest algorithm. |
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141 | |
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142 | If called as an instance method (i.e. $md5->new) it will just reset the |
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143 | state the object to the state of a newly created object. No new |
144 | object is created in this case. |
145 | |
146 | =item $md5->reset |
147 | |
148 | This is just an alias for $md5->new. |
149 | |
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150 | =item $md5->clone |
151 | |
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 |
155 | stream. Example: |
156 | |
157 | my $md5 = Digest::MD5->new; |
158 | while (<>) { |
159 | $md5->add($_); |
160 | print "Line $.: ", $md5->clone->hexdigest, "\n"; |
161 | } |
162 | |
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163 | =item $md5->add($data,...) |
164 | |
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. |
167 | |
ac70dec1 |
168 | All these lines will have the same effect on the state of the $md5 |
169 | object: |
170 | |
171 | $md5->add("a"); $md5->add("b"); $md5->add("c"); |
172 | $md5->add("a")->add("b")->add("c"); |
173 | $md5->add("a", "b", "c"); |
174 | $md5->add("abc"); |
175 | |
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176 | =item $md5->addfile($io_handle) |
177 | |
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178 | The $io_handle will be read until EOF and its content appended to the |
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179 | message we calculate the digest for. The return value is the $md5 |
180 | object itself. |
181 | |
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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. |
187 | |
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. |
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190 | |
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191 | =item $md5->add_bits($data, $nbits) |
192 | |
193 | =item $md5->add_bits($bitstring) |
194 | |
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 |
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198 | implementations. See L<Digest> for description of the arguments |
199 | that add_bits() take. |
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200 | |
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201 | =item $md5->digest |
202 | |
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203 | Return the binary digest for the message. The returned string will be |
204 | 16 bytes long. |
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205 | |
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 |
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209 | digest value. Call $md5->clone->digest if you want to calculate the |
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210 | digest without resetting the digest state. |
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211 | |
212 | =item $md5->hexdigest |
213 | |
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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'. |
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217 | |
218 | =item $md5->b64digest |
219 | |
220 | Same as $md5->digest, but will return the digest as a base64 encoded |
ac70dec1 |
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', '+' |
223 | and '/'. |
224 | |
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225 | |
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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. |
229 | |
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230 | =back |
231 | |
232 | |
233 | =head1 EXAMPLES |
234 | |
235 | The simplest way to use this library is to import the md5_hex() |
236 | function (or one of its cousins): |
237 | |
238 | use Digest::MD5 qw(md5_hex); |
239 | print "Digest is ", md5_hex("foobarbaz"), "\n"; |
240 | |
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241 | The above example would print out the message: |
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242 | |
243 | Digest is 6df23dc03f9b54cc38a0fc1483df6e21 |
244 | |
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245 | The same checksum can also be calculated in OO style: |
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246 | |
247 | use Digest::MD5; |
248 | |
249 | $md5 = Digest::MD5->new; |
250 | $md5->add('foo', 'bar'); |
251 | $md5->add('baz'); |
252 | $digest = $md5->hexdigest; |
253 | |
254 | print "Digest is $digest\n"; |
255 | |
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. |
259 | |
260 | This is useful when calculating checksum for files: |
261 | |
262 | use Digest::MD5; |
263 | |
264 | my $file = shift || "/etc/passwd"; |
265 | open(FILE, $file) or die "Can't open '$file': $!"; |
266 | binmode(FILE); |
267 | |
268 | $md5 = Digest::MD5->new; |
269 | while (<FILE>) { |
270 | $md5->add($_); |
271 | } |
272 | close(FILE); |
273 | print $md5->b64digest, " $file\n"; |
274 | |
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275 | Or we can use the addfile method for more efficient reading of |
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276 | the file: |
277 | |
278 | use Digest::MD5; |
279 | |
280 | my $file = shift || "/etc/passwd"; |
281 | open(FILE, $file) or die "Can't open '$file': $!"; |
282 | binmode(FILE); |
283 | |
284 | print Digest::MD5->new->addfile(*FILE)->hexdigest, " $file\n"; |
285 | |
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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 |
290 | data: |
291 | |
292 | use Digest::MD5 qw(md5_hex); |
293 | |
294 | my $str = "abc\x{300}"; |
295 | print md5_hex($str), "\n"; # croaks |
296 | # Wide character in subroutine entry |
297 | |
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: |
301 | |
302 | use Digest::MD5 qw(md5_hex); |
303 | use Encode qw(encode_utf8); |
304 | |
305 | my $str = "abc\x{300}"; |
306 | print md5_hex(encode_utf8($str)), "\n"; |
307 | # 8c2d46911f3f5a326455f0ed7a8ed3b3 |
308 | |
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309 | =head1 SEE ALSO |
310 | |
311 | L<Digest>, |
312 | L<Digest::MD2>, |
313 | L<Digest::SHA1>, |
314 | L<Digest::HMAC> |
315 | |
316 | L<md5sum(1)> |
317 | |
318 | RFC 1321 |
319 | |
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320 | http://en.wikipedia.org/wiki/MD5 |
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321 | |
322 | The paper "How to Break MD5 and Other Hash Functions" by Xiaoyun Wang |
323 | and Hongbo Yu. |
324 | |
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325 | =head1 COPYRIGHT |
326 | |
327 | This library is free software; you can redistribute it and/or |
328 | modify it under the same terms as Perl itself. |
329 | |
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330 | Copyright 1998-2003 Gisle Aas. |
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331 | Copyright 1995-1996 Neil Winton. |
332 | Copyright 1991-1992 RSA Data Security, Inc. |
333 | |
ac70dec1 |
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: |
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337 | |
338 | =over 4 |
339 | |
340 | =item |
341 | |
342 | Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All |
343 | rights reserved. |
344 | |
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 |
348 | or this function. |
349 | |
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. |
354 | |
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. |
359 | |
360 | These notices must be retained in any copies of any part of this |
361 | documentation and/or software. |
362 | |
363 | =back |
364 | |
365 | This copyright does not prohibit distribution of any version of Perl |
366 | containing this extension under the terms of the GNU or Artistic |
367 | licenses. |
368 | |
369 | =head1 AUTHORS |
370 | |
ac70dec1 |
371 | The original C<MD5> interface was written by Neil Winton |
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372 | (C<N.Winton@axion.bt.co.uk>). |
373 | |
ac70dec1 |
374 | The C<Digest::MD5> module is written by Gisle Aas <gisle@ActiveState.com>. |
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375 | |
376 | =cut |