1package Digest::MD5; 2 3use strict; 4use warnings; 5 6our $VERSION = '2.58'; 7 8require Exporter; 9*import = \&Exporter::import; 10our @EXPORT_OK = qw(md5 md5_hex md5_base64); 11 12our @ISA; 13eval { 14 require Digest::base; 15 @ISA = qw/Digest::base/; 16}; 17if ($@) { 18 my $err = $@; 19 *add_bits = sub { die $err }; 20} 21 22 23eval { 24 require XSLoader; 25 XSLoader::load('Digest::MD5', $VERSION); 26}; 27if ($@) { 28 my $olderr = $@; 29 eval { 30 # Try to load the pure perl version 31 require Digest::Perl::MD5; 32 33 Digest::Perl::MD5->import(qw(md5 md5_hex md5_base64)); 34 unshift(@ISA, "Digest::Perl::MD5"); # make OO interface work 35 }; 36 if ($@) { 37 # restore the original error 38 die $olderr; 39 } 40} 41else { 42 *reset = \&new; 43} 44 451; 46__END__ 47 48=head1 NAME 49 50Digest::MD5 - Perl interface to the MD5 Algorithm 51 52=head1 SYNOPSIS 53 54 # Functional style 55 use Digest::MD5 qw(md5 md5_hex md5_base64); 56 57 $digest = md5($data); 58 $digest = md5_hex($data); 59 $digest = md5_base64($data); 60 61 # OO style 62 use Digest::MD5; 63 64 $ctx = Digest::MD5->new; 65 66 $ctx->add($data); 67 $ctx->addfile($file_handle); 68 69 $digest = $ctx->digest; 70 $digest = $ctx->hexdigest; 71 $digest = $ctx->b64digest; 72 73=head1 DESCRIPTION 74 75The C<Digest::MD5> module allows you to use the RSA Data Security 76Inc. MD5 Message Digest algorithm from within Perl programs. The 77algorithm takes as input a message of arbitrary length and produces as 78output a 128-bit "fingerprint" or "message digest" of the input. 79 80Note that the MD5 algorithm is not as strong as it used to be. It has 81since 2005 been easy to generate different messages that produce the 82same MD5 digest. It still seems hard to generate messages that 83produce a given digest, but it is probably wise to move to stronger 84algorithms for applications that depend on the digest to uniquely identify 85a message. 86 87The C<Digest::MD5> module provide a procedural interface for simple 88use, as well as an object oriented interface that can handle messages 89of arbitrary length and which can read files directly. 90 91=head1 FUNCTIONS 92 93The following functions are provided by the C<Digest::MD5> module. 94None of these functions are exported by default. 95 96=over 4 97 98=item md5($data,...) 99 100This function will concatenate all arguments, calculate the MD5 digest 101of this "message", and return it in binary form. The returned string 102will be 16 bytes long. 103 104The result of md5("a", "b", "c") will be exactly the same as the 105result of md5("abc"). 106 107=item md5_hex($data,...) 108 109Same as md5(), but will return the digest in hexadecimal form. The 110length of the returned string will be 32 and it will only contain 111characters from this set: '0'..'9' and 'a'..'f'. 112 113=item md5_base64($data,...) 114 115Same as md5(), but will return the digest as a base64 encoded string. 116The length of the returned string will be 22 and it will only contain 117characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and 118'/'. 119 120Note that the base64 encoded string returned is not padded to be a 121multiple of 4 bytes long. If you want interoperability with other 122base64 encoded md5 digests you might want to append the redundant 123string "==" to the result. 124 125=back 126 127=head1 METHODS 128 129The object oriented interface to C<Digest::MD5> is described in this 130section. After a C<Digest::MD5> object has been created, you will add 131data to it and finally ask for the digest in a suitable format. A 132single object can be used to calculate multiple digests. 133 134The following methods are provided: 135 136=over 4 137 138=item $md5 = Digest::MD5->new 139 140The constructor returns a new C<Digest::MD5> object which encapsulate 141the state of the MD5 message-digest algorithm. 142 143If called as an instance method (i.e. $md5->new) it will just reset the 144state the object to the state of a newly created object. No new 145object is created in this case. 146 147=item $md5->reset 148 149This is just an alias for $md5->new. 150 151=item $md5->clone 152 153This a copy of the $md5 object. It is useful when you do not want to 154destroy the digests state, but need an intermediate value of the 155digest, e.g. when calculating digests iteratively on a continuous data 156stream. Example: 157 158 my $md5 = Digest::MD5->new; 159 while (<>) { 160 $md5->add($_); 161 print "Line $.: ", $md5->clone->hexdigest, "\n"; 162 } 163 164=item $md5->add($data,...) 165 166The $data provided as argument are appended to the message we 167calculate the digest for. The return value is the $md5 object itself. 168 169All these lines will have the same effect on the state of the $md5 170object: 171 172 $md5->add("a"); $md5->add("b"); $md5->add("c"); 173 $md5->add("a")->add("b")->add("c"); 174 $md5->add("a", "b", "c"); 175 $md5->add("abc"); 176 177=item $md5->addfile($io_handle) 178 179The $io_handle will be read until EOF and its content appended to the 180message we calculate the digest for. The return value is the $md5 181object itself. 182 183The addfile() method will croak() if it fails reading data for some 184reason. If it croaks it is unpredictable what the state of the $md5 185object will be in. The addfile() method might have been able to read 186the file partially before it failed. It is probably wise to discard 187or reset the $md5 object if this occurs. 188 189In most cases you want to make sure that the $io_handle is in 190C<binmode> before you pass it as argument to the addfile() method. 191 192=item $md5->add_bits($data, $nbits) 193 194=item $md5->add_bits($bitstring) 195 196Since the MD5 algorithm is byte oriented you might only add bits as 197multiples of 8, so you probably want to just use add() instead. The 198add_bits() method is provided for compatibility with other digest 199implementations. See L<Digest> for description of the arguments 200that add_bits() take. 201 202=item $md5->digest 203 204Return the binary digest for the message. The returned string will be 20516 bytes long. 206 207Note that the C<digest> operation is effectively a destructive, 208read-once operation. Once it has been performed, the C<Digest::MD5> 209object is automatically C<reset> and can be used to calculate another 210digest value. Call $md5->clone->digest if you want to calculate the 211digest without resetting the digest state. 212 213=item $md5->hexdigest 214 215Same as $md5->digest, but will return the digest in hexadecimal 216form. The length of the returned string will be 32 and it will only 217contain characters from this set: '0'..'9' and 'a'..'f'. 218 219=item $md5->b64digest 220 221Same as $md5->digest, but will return the digest as a base64 encoded 222string. The length of the returned string will be 22 and it will only 223contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' 224and '/'. 225 226 227The base64 encoded string returned is not padded to be a multiple of 4 228bytes long. If you want interoperability with other base64 encoded 229md5 digests you might want to append the string "==" to the result. 230 231=item @ctx = $md5->context 232 233=item $md5->context(@ctx) 234 235Saves or restores the internal state. 236When called with no arguments, returns a list: 237number of blocks processed, 238a 16-byte internal state buffer, 239then optionally up to 63 bytes of unprocessed data if there are any. 240When passed those same arguments, restores the state. 241This is only useful for specialised operations. 242 243=back 244 245 246=head1 EXAMPLES 247 248The simplest way to use this library is to import the md5_hex() 249function (or one of its cousins): 250 251 use Digest::MD5 qw(md5_hex); 252 print "Digest is ", md5_hex("foobarbaz"), "\n"; 253 254The above example would print out the message: 255 256 Digest is 6df23dc03f9b54cc38a0fc1483df6e21 257 258The same checksum can also be calculated in OO style: 259 260 use Digest::MD5; 261 262 $md5 = Digest::MD5->new; 263 $md5->add('foo', 'bar'); 264 $md5->add('baz'); 265 $digest = $md5->hexdigest; 266 267 print "Digest is $digest\n"; 268 269With OO style, you can break the message arbitrarily. This means that we 270are no longer limited to have space for the whole message in memory, i.e. 271we can handle messages of any size. 272 273This is useful when calculating checksum for files: 274 275 use Digest::MD5; 276 277 my $filename = shift || "/etc/passwd"; 278 open (my $fh, '<', $filename) or die "Can't open '$filename': $!"; 279 binmode($fh); 280 281 $md5 = Digest::MD5->new; 282 while (<$fh>) { 283 $md5->add($_); 284 } 285 close($fh); 286 print $md5->b64digest, " $filename\n"; 287 288Or we can use the addfile method for more efficient reading of 289the file: 290 291 use Digest::MD5; 292 293 my $filename = shift || "/etc/passwd"; 294 open (my $fh, '<', $filename) or die "Can't open '$filename': $!"; 295 binmode ($fh); 296 297 print Digest::MD5->new->addfile($fh)->hexdigest, " $filename\n"; 298 299Since the MD5 algorithm is only defined for strings of bytes, it can not be 300used on strings that contains chars with ordinal number above 255 (Unicode 301strings). The MD5 functions and methods will croak if you try to feed them 302such input data: 303 304 use Digest::MD5 qw(md5_hex); 305 306 my $str = "abc\x{300}"; 307 print md5_hex($str), "\n"; # croaks 308 # Wide character in subroutine entry 309 310What you can do is calculate the MD5 checksum of the UTF-8 311representation of such strings. This is achieved by filtering the 312string through encode_utf8() function: 313 314 use Digest::MD5 qw(md5_hex); 315 use Encode qw(encode_utf8); 316 317 my $str = "abc\x{300}"; 318 print md5_hex(encode_utf8($str)), "\n"; 319 # 8c2d46911f3f5a326455f0ed7a8ed3b3 320 321=head1 SEE ALSO 322 323L<Digest>, 324L<Digest::MD2>, 325L<Digest::SHA>, 326L<Digest::HMAC> 327 328L<md5sum(1)> 329 330RFC 1321 331 332http://en.wikipedia.org/wiki/MD5 333 334The paper "How to Break MD5 and Other Hash Functions" by Xiaoyun Wang 335and Hongbo Yu. 336 337=head1 COPYRIGHT 338 339This library is free software; you can redistribute it and/or 340modify it under the same terms as Perl itself. 341 342 Copyright 1998-2003 Gisle Aas. 343 Copyright 1995-1996 Neil Winton. 344 Copyright 1991-1992 RSA Data Security, Inc. 345 346The MD5 algorithm is defined in RFC 1321. This implementation is 347derived from the reference C code in RFC 1321 which is covered by 348the following copyright statement: 349 350=over 4 351 352=item 353 354Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All 355rights reserved. 356 357License to copy and use this software is granted provided that it 358is identified as the "RSA Data Security, Inc. MD5 Message-Digest 359Algorithm" in all material mentioning or referencing this software 360or this function. 361 362License is also granted to make and use derivative works provided 363that such works are identified as "derived from the RSA Data 364Security, Inc. MD5 Message-Digest Algorithm" in all material 365mentioning or referencing the derived work. 366 367RSA Data Security, Inc. makes no representations concerning either 368the merchantability of this software or the suitability of this 369software for any particular purpose. It is provided "as is" 370without express or implied warranty of any kind. 371 372These notices must be retained in any copies of any part of this 373documentation and/or software. 374 375=back 376 377This copyright does not prohibit distribution of any version of Perl 378containing this extension under the terms of the GNU or Artistic 379licenses. 380 381=head1 AUTHORS 382 383The original C<MD5> interface was written by Neil Winton 384(C<N.Winton@axion.bt.co.uk>). 385 386The C<Digest::MD5> module is written by Gisle Aas <gisle@ActiveState.com>. 387 388=cut 389