1package Digest::MD5; 2 3use strict; 4use vars qw($VERSION @ISA @EXPORT_OK); 5 6$VERSION = '2.53'; 7 8require Exporter; 9*import = \&Exporter::import; 10@EXPORT_OK = qw(md5 md5_hex md5_base64); 11 12eval { 13 require Digest::base; 14 push(@ISA, 'Digest::base'); 15}; 16if ($@) { 17 my $err = $@; 18 *add_bits = sub { die $err }; 19} 20 21 22eval { 23 require XSLoader; 24 XSLoader::load('Digest::MD5', $VERSION); 25}; 26if ($@) { 27 my $olderr = $@; 28 eval { 29 # Try to load the pure perl version 30 require Digest::Perl::MD5; 31 32 Digest::Perl::MD5->import(qw(md5 md5_hex md5_base64)); 33 unshift(@ISA, "Digest::Perl::MD5"); # make OO interface work 34 }; 35 if ($@) { 36 # restore the original error 37 die $olderr; 38 } 39} 40else { 41 *reset = \&new; 42} 43 441; 45__END__ 46 47=head1 NAME 48 49Digest::MD5 - Perl interface to the MD5 Algorithm 50 51=head1 SYNOPSIS 52 53 # Functional style 54 use Digest::MD5 qw(md5 md5_hex md5_base64); 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_handle); 67 68 $digest = $ctx->digest; 69 $digest = $ctx->hexdigest; 70 $digest = $ctx->b64digest; 71 72=head1 DESCRIPTION 73 74The C<Digest::MD5> module allows you to use the RSA Data Security 75Inc. MD5 Message Digest algorithm from within Perl programs. The 76algorithm takes as input a message of arbitrary length and produces as 77output a 128-bit "fingerprint" or "message digest" of the input. 78 79Note that the MD5 algorithm is not as strong as it used to be. It has 80since 2005 been easy to generate different messages that produce the 81same MD5 digest. It still seems hard to generate messages that 82produce a given digest, but it is probably wise to move to stronger 83algorithms for applications that depend on the digest to uniquely identify 84a message. 85 86The C<Digest::MD5> module provide a procedural interface for simple 87use, as well as an object oriented interface that can handle messages 88of arbitrary length and which can read files directly. 89 90=head1 FUNCTIONS 91 92The following functions are provided by the C<Digest::MD5> module. 93None of these functions are exported by default. 94 95=over 4 96 97=item md5($data,...) 98 99This function will concatenate all arguments, calculate the MD5 digest 100of this "message", and return it in binary form. The returned string 101will be 16 bytes long. 102 103The result of md5("a", "b", "c") will be exactly the same as the 104result of md5("abc"). 105 106=item md5_hex($data,...) 107 108Same as md5(), but will return the digest in hexadecimal form. The 109length of the returned string will be 32 and it will only contain 110characters from this set: '0'..'9' and 'a'..'f'. 111 112=item md5_base64($data,...) 113 114Same as md5(), but will return the digest as a base64 encoded string. 115The length of the returned string will be 22 and it will only contain 116characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and 117'/'. 118 119Note that the base64 encoded string returned is not padded to be a 120multiple of 4 bytes long. If you want interoperability with other 121base64 encoded md5 digests you might want to append the redundant 122string "==" to the result. 123 124=back 125 126=head1 METHODS 127 128The object oriented interface to C<Digest::MD5> is described in this 129section. After a C<Digest::MD5> object has been created, you will add 130data to it and finally ask for the digest in a suitable format. A 131single object can be used to calculate multiple digests. 132 133The following methods are provided: 134 135=over 4 136 137=item $md5 = Digest::MD5->new 138 139The constructor returns a new C<Digest::MD5> object which encapsulate 140the state of the MD5 message-digest algorithm. 141 142If called as an instance method (i.e. $md5->new) it will just reset the 143state the object to the state of a newly created object. No new 144object is created in this case. 145 146=item $md5->reset 147 148This is just an alias for $md5->new. 149 150=item $md5->clone 151 152This a copy of the $md5 object. It is useful when you do not want to 153destroy the digests state, but need an intermediate value of the 154digest, e.g. when calculating digests iteratively on a continuous data 155stream. Example: 156 157 my $md5 = Digest::MD5->new; 158 while (<>) { 159 $md5->add($_); 160 print "Line $.: ", $md5->clone->hexdigest, "\n"; 161 } 162 163=item $md5->add($data,...) 164 165The $data provided as argument are appended to the message we 166calculate the digest for. The return value is the $md5 object itself. 167 168All these lines will have the same effect on the state of the $md5 169object: 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"); 175 176=item $md5->addfile($io_handle) 177 178The $io_handle will be read until EOF and its content appended to the 179message we calculate the digest for. The return value is the $md5 180object itself. 181 182The addfile() method will croak() if it fails reading data for some 183reason. If it croaks it is unpredictable what the state of the $md5 184object will be in. The addfile() method might have been able to read 185the file partially before it failed. It is probably wise to discard 186or reset the $md5 object if this occurs. 187 188In most cases you want to make sure that the $io_handle is in 189C<binmode> before you pass it as argument to the addfile() method. 190 191=item $md5->add_bits($data, $nbits) 192 193=item $md5->add_bits($bitstring) 194 195Since the MD5 algorithm is byte oriented you might only add bits as 196multiples of 8, so you probably want to just use add() instead. The 197add_bits() method is provided for compatibility with other digest 198implementations. See L<Digest> for description of the arguments 199that add_bits() take. 200 201=item $md5->digest 202 203Return the binary digest for the message. The returned string will be 20416 bytes long. 205 206Note that the C<digest> operation is effectively a destructive, 207read-once operation. Once it has been performed, the C<Digest::MD5> 208object is automatically C<reset> and can be used to calculate another 209digest value. Call $md5->clone->digest if you want to calculate the 210digest without resetting the digest state. 211 212=item $md5->hexdigest 213 214Same as $md5->digest, but will return the digest in hexadecimal 215form. The length of the returned string will be 32 and it will only 216contain characters from this set: '0'..'9' and 'a'..'f'. 217 218=item $md5->b64digest 219 220Same as $md5->digest, but will return the digest as a base64 encoded 221string. The length of the returned string will be 22 and it will only 222contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' 223and '/'. 224 225 226The base64 encoded string returned is not padded to be a multiple of 4 227bytes long. If you want interoperability with other base64 encoded 228md5 digests you might want to append the string "==" to the result. 229 230=back 231 232 233=head1 EXAMPLES 234 235The simplest way to use this library is to import the md5_hex() 236function (or one of its cousins): 237 238 use Digest::MD5 qw(md5_hex); 239 print "Digest is ", md5_hex("foobarbaz"), "\n"; 240 241The above example would print out the message: 242 243 Digest is 6df23dc03f9b54cc38a0fc1483df6e21 244 245The same checksum can also be calculated in OO style: 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 256With OO style, you can break the message arbitrarily. This means that we 257are no longer limited to have space for the whole message in memory, i.e. 258we can handle messages of any size. 259 260This is useful when calculating checksum for files: 261 262 use Digest::MD5; 263 264 my $filename = shift || "/etc/passwd"; 265 open (my $fh, '<', $filename) or die "Can't open '$filename': $!"; 266 binmode($fh); 267 268 $md5 = Digest::MD5->new; 269 while (<$fh>) { 270 $md5->add($_); 271 } 272 close($fh); 273 print $md5->b64digest, " $filename\n"; 274 275Or we can use the addfile method for more efficient reading of 276the file: 277 278 use Digest::MD5; 279 280 my $filename = shift || "/etc/passwd"; 281 open (my $fh, '<', $filename) or die "Can't open '$filename': $!"; 282 binmode ($fh); 283 284 print Digest::MD5->new->addfile($fh)->hexdigest, " $filename\n"; 285 286Since the MD5 algorithm is only defined for strings of bytes, it can not be 287used on strings that contains chars with ordinal number above 255 (Unicode 288strings). The MD5 functions and methods will croak if you try to feed them 289such input data: 290 291 use Digest::MD5 qw(md5_hex); 292 293 my $str = "abc\x{300}"; 294 print md5_hex($str), "\n"; # croaks 295 # Wide character in subroutine entry 296 297What you can do is calculate the MD5 checksum of the UTF-8 298representation of such strings. This is achieved by filtering the 299string through encode_utf8() function: 300 301 use Digest::MD5 qw(md5_hex); 302 use Encode qw(encode_utf8); 303 304 my $str = "abc\x{300}"; 305 print md5_hex(encode_utf8($str)), "\n"; 306 # 8c2d46911f3f5a326455f0ed7a8ed3b3 307 308=head1 SEE ALSO 309 310L<Digest>, 311L<Digest::MD2>, 312L<Digest::SHA>, 313L<Digest::HMAC> 314 315L<md5sum(1)> 316 317RFC 1321 318 319http://en.wikipedia.org/wiki/MD5 320 321The paper "How to Break MD5 and Other Hash Functions" by Xiaoyun Wang 322and Hongbo Yu. 323 324=head1 COPYRIGHT 325 326This library is free software; you can redistribute it and/or 327modify it under the same terms as Perl itself. 328 329 Copyright 1998-2003 Gisle Aas. 330 Copyright 1995-1996 Neil Winton. 331 Copyright 1991-1992 RSA Data Security, Inc. 332 333The MD5 algorithm is defined in RFC 1321. This implementation is 334derived from the reference C code in RFC 1321 which is covered by 335the following copyright statement: 336 337=over 4 338 339=item 340 341Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All 342rights reserved. 343 344License to copy and use this software is granted provided that it 345is identified as the "RSA Data Security, Inc. MD5 Message-Digest 346Algorithm" in all material mentioning or referencing this software 347or this function. 348 349License is also granted to make and use derivative works provided 350that such works are identified as "derived from the RSA Data 351Security, Inc. MD5 Message-Digest Algorithm" in all material 352mentioning or referencing the derived work. 353 354RSA Data Security, Inc. makes no representations concerning either 355the merchantability of this software or the suitability of this 356software for any particular purpose. It is provided "as is" 357without express or implied warranty of any kind. 358 359These notices must be retained in any copies of any part of this 360documentation and/or software. 361 362=back 363 364This copyright does not prohibit distribution of any version of Perl 365containing this extension under the terms of the GNU or Artistic 366licenses. 367 368=head1 AUTHORS 369 370The original C<MD5> interface was written by Neil Winton 371(C<N.Winton@axion.bt.co.uk>). 372 373The C<Digest::MD5> module is written by Gisle Aas <gisle@ActiveState.com>. 374 375=cut 376