1MD4(3) User Contributed Perl Documentation MD4(3)
2
6 Digest::MD4 - Perl interface to the MD4 Algorithm
7
9 # Functional style
10 use Digest::MD4 qw(md4 md4_hex md4_base64);
11 $digest = md4($data);
13 $digest = md4_hex($data);
14 $digest = md4_base64($data);
15 # OO style
17 use Digest::MD4;
18 $ctx = Digest::MD4->new;
20 $ctx->add($data);
22 $ctx->addfile(*FILE);
23 $digest = $ctx->digest;
25 $digest = $ctx->hexdigest;
26 $digest = $ctx->b64digest;
27
29 The "Digest::MD4" module allows you to use the RSA Data Security Inc.
30 MD4 Message Digest algorithm from within Perl programs. The algorithm
31 takes as input a message of arbitrary length and produces as output a
32 128-bit "fingerprint" or "message digest" of the input.
33 The "Digest::MD4" module provide a procedural interface for simple use,
35 as well as an object oriented interface that can handle messages of
36 arbitrary length and which can read files directly.
37
39 The following functions are provided by the "Digest::MD4" module. None
40 of these functions are exported by default.
41 md4($data,...)
43 This function will concatenate all arguments, calculate the MD4
44 digest of this "message", and return it in binary form. The
45 returned string will be 16 bytes long.
46 The result of md4("a", "b", "c") will be exactly the same as the
48 result of md4("abc").
49 md4_hex($data,...)
51 Same as md4(), but will return the digest in hexadecimal form. The
52 length of the returned string will be 32 and it will only contain
53 characters from this set: '0'..'9' and 'a'..'f'.
54 md4_base64($data,...)
56 Same as md4(), but will return the digest as a base64 encoded
57 string. The length of the returned string will be 22 and it will
58 only contain characters from this set: 'A'..'Z', 'a'..'z',
59 '0'..'9', '+' and '/'.
60 Note that the base64 encoded string returned is not padded to be a
62 multiple of 4 bytes long. If you want interoperability with other
63 base64 encoded md4 digests you might want to append the redundant
64 string "==" to the result.
65
67 The object oriented interface to "Digest::MD4" is described in this
68 section. After a "Digest::MD4" object has been created, you will add
69 data to it and finally ask for the digest in a suitable format. A
70 single object can be used to calculate multiple digests.
71 The following methods are provided:
73 $md4 = Digest::MD4->new
75 The constructor returns a new "Digest::MD4" object which
76 encapsulate the state of the MD4 message-digest algorithm.
77 If called as an instance method (i.e. $md4->new) it will just reset
79 the state the object to the state of a newly created object. No
80 new object is created in this case.
81 $md4->reset
83 This is just an alias for $md4->new.
84 $md4->clone
86 This a copy of the $md4 object. It is useful when you do not want
87 to destroy the digests state, but need an intermediate value of the
88 digest, e.g. when calculating digests iteratively on a continuous
89 data stream. Example:
90 my $md4 = Digest::MD4->new;
92 while (<>) {
93 $md4->add($_);
94 print "Line $.: ", $md4->clone->hexdigest, "\n";
95 }
96 $md4->add($data,...)
98 The $data provided as argument are appended to the message we
99 calculate the digest for. The return value is the $md4 object
100 itself.
101 All these lines will have the same effect on the state of the $md4
103 object:
104 $md4->add("a"); $md4->add("b"); $md4->add("c");
106 $md4->add("a")->add("b")->add("c");
107 $md4->add("a", "b", "c");
108 $md4->add("abc");
109 $md4->addfile($io_handle)
111 The $io_handle will be read until EOF and its content appended to
112 the message we calculate the digest for. The return value is the
113 $md4 object itself.
114 The addfile() method will croak() if it fails reading data for some
116 reason. If it croaks it is unpredictable what the state of the
117 $md4 object will be in. The addfile() method might have been able
118 to read the file partially before it failed. It is probably wise
119 to discard or reset the $md4 object if this occurs.
120 In most cases you want to make sure that the $io_handle is in
122 "binmode" before you pass it as argument to the addfile() method.
123 $md4->digest
125 Return the binary digest for the message. The returned string will
126 be 16 bytes long.
127 Note that the "digest" operation is effectively a destructive,
129 read-once operation. Once it has been performed, the "Digest::MD4"
130 object is automatically "reset" and can be used to calculate
131 another digest value. Call $md4->clone->digest if you want to
132 calculate the digest without reseting the digest state.
133 $md4->hexdigest
135 Same as $md4->digest, but will return the digest in hexadecimal
136 form. The length of the returned string will be 32 and it will only
137 contain characters from this set: '0'..'9' and 'a'..'f'.
138 $md4->b64digest
140 Same as $md4->digest, but will return the digest as a base64
141 encoded string. The length of the returned string will be 22 and
142 it will only contain characters from this set: 'A'..'Z', 'a'..'z',
143 '0'..'9', '+' and '/'.
144 The base64 encoded string returned is not padded to be a multiple
146 of 4 bytes long. If you want interoperability with other base64
147 encoded md4 digests you might want to append the string "==" to the
148 result.
149
151 The simplest way to use this library is to import the md4_hex()
152 function (or one of its cousins):
153 use Digest::MD4 qw(md4_hex);
155 print "Digest is ", md4_hex("foobarbaz"), "\n";
156 The above example would print out the message:
158 Digest is b2b2b528f632f554ae9cb2c02c904eeb
160 The same checksum can also be calculated in OO style:
162 use Digest::MD4;
164 $md4 = Digest::MD4->new;
166 $md4->add('foo', 'bar');
167 $md4->add('baz');
168 $digest = $md4->hexdigest;
169 print "Digest is $digest\n";
171 With OO style you can break the message arbitrary. This means that we
173 are no longer limited to have space for the whole message in memory,
174 i.e. we can handle messages of any size.
175 This is useful when calculating checksum for files:
177 use Digest::MD4;
179 my $file = shift || "/etc/passwd";
181 open(FILE, $file) or die "Can't open '$file': $!";
182 binmode(FILE);
183 $md4 = Digest::MD4->new;
185 while (<FILE>) {
186 $md4->add($_);
187 }
188 close(FILE);
189 print $md4->b64digest, " $file\n";
190 Or we can use the addfile method for more efficient reading of the
192 file:
193 use Digest::MD4;
195 my $file = shift || "/etc/passwd";
197 open(FILE, $file) or die "Can't open '$file': $!";
198 binmode(FILE);
199 print Digest::MD4->new->addfile(*FILE)->hexdigest, " $file\n";
201 Perl 5.8 support Unicode characters in strings. Since the MD4
203 algorithm is only defined for strings of bytes, it can not be used on
204 strings that contains chars with ordinal number above 255. The MD4
205 functions and methods will croak if you try to feed them such input
206 data:
207 use Digest::MD4 qw(md4_hex);
209 my $str = "abc\x{300}";
211 print md4_hex($str), "\n"; # croaks
212 # Wide character in subroutine entry
213 What you can do is calculate the MD4 checksum of the UTF-8
215 representation of such strings. This is achieved by filtering the
216 string through encode_utf8() function:
217 use Digest::MD4 qw(md4_hex);
219 use Encode qw(encode_utf8);
220 my $str = "abc\x{300}";
222 print md4_hex(encode_utf8($str)), "\n";
223 # fc2ef2836f9bc3f44ed6d7adee2f1533
224
226 Digest, Digest::MD2, Digest::SHA1, Digest::HMAC
227 md4sum(1)
229 RFC 1320
231
233 This library is free software; you can redistribute it and/or modify it
234 under the same terms as Perl itself.
235 Copyright 1998-2003 Gisle Aas.
237 Copyright 1995-1996 Neil Winton.
238 Copyright 1991-1992 RSA Data Security, Inc.
239 The MD4 algorithm is defined in RFC 1320. This implementation is
241 derived from the reference C code in RFC 1320 which is covered by the
242 following copyright statement:
243 ยท
245 Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved.
248 License to copy and use this software is granted provided that it
250 is identified as the "RSA Data Security, Inc. MD4 Message-Digest
251 Algorithm" in all material mentioning or referencing this software
252 or this function.
253 License is also granted to make and use derivative works provided
255 that such works are identified as "derived from the RSA Data
256 Security, Inc. MD4 Message-Digest Algorithm" in all material
257 mentioning or referencing the derived work.
258 RSA Data Security, Inc. makes no representations concerning either
260 the merchantability of this software or the suitability of this
261 software for any particular purpose. It is provided "as is"
262 without express or implied warranty of any kind.
263 These notices must be retained in any copies of any part of this
265 documentation and/or software.
266 This copyright does not prohibit distribution of any version of Perl
268 containing this extension under the terms of the GNU or Artistic
269 licenses.
270
272 The original "MD5" interface was written by Neil Winton
273 ("N.Winton@axion.bt.co.uk").
274 The "Digest::MD5" module is written by Gisle Aas
276 <gisle@ActiveState.com>.
277 The "Digest::MD4" module is derived from Digest::MD5 by Mike McCauley
279 (mikem@airspayce.com)
280perl v5.28.0 2013-03-22 MD4(3)