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1 ;;; md5.el -- MD5 Message Digest Algorithm
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2 ;;; Gareth Rees <gdr11@cl.cam.ac.uk>
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3
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4 ;; LCD Archive Entry:
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5 ;; md5|Gareth Rees|gdr11@cl.cam.ac.uk|
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6 ;; MD5 cryptographic message digest algorithm|
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7 ;; 13-Nov-95|1.0|~/misc/md5.el.Z|
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8
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9 ;;; Details: ------------------------------------------------------------------
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10
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11 ;; This is a direct translation into Emacs LISP of the reference C
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12 ;; implementation of the MD5 Message-Digest Algorithm written by RSA
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13 ;; Data Security, Inc.
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14 ;;
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15 ;; The algorithm takes a message (that is, a string of bytes) and
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16 ;; computes a 16-byte checksum or "digest" for the message. This digest
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17 ;; is supposed to be cryptographically strong in the sense that if you
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18 ;; are given a 16-byte digest D, then there is no easier way to
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19 ;; construct a message whose digest is D than to exhaustively search the
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20 ;; space of messages. However, the robustness of the algorithm has not
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21 ;; been proven, and a similar algorithm (MD4) was shown to be unsound,
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22 ;; so treat with caution!
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23 ;;
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24 ;; The C algorithm uses 32-bit integers; because GNU Emacs
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25 ;; implementations provide 28-bit integers (with 24-bit integers on
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26 ;; versions prior to 19.29), the code represents a 32-bit integer as the
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27 ;; cons of two 16-bit integers. The most significant word is stored in
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28 ;; the car and the least significant in the cdr. The algorithm requires
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29 ;; at least 17 bits of integer representation in order to represent the
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30 ;; carry from a 16-bit addition.
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31
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32 ;;; Usage: --------------------------------------------------------------------
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33
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34 ;; To compute the MD5 Message Digest for a message M (represented as a
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35 ;; string or as a vector of bytes), call
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36 ;;
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37 ;; (md5-encode M)
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38 ;;
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39 ;; which returns the message digest as a vector of 16 bytes. If you
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40 ;; need to supply the message in pieces M1, M2, ... Mn, then call
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41 ;;
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42 ;; (md5-init)
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43 ;; (md5-update M1)
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44 ;; (md5-update M2)
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45 ;; ...
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46 ;; (md5-update Mn)
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47 ;; (md5-final)
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48
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49 ;;; Copyright and licence: ----------------------------------------------------
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50
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51 ;; Copyright (C) 1995, 1996, 1997 by Gareth Rees
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52 ;; Derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm
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53 ;;
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54 ;; md5.el is free software; you can redistribute it and/or modify it
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55 ;; under the terms of the GNU General Public License as published by the
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56 ;; Free Software Foundation; either version 2, or (at your option) any
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57 ;; later version.
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58 ;;
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59 ;; md5.el is distributed in the hope that it will be useful, but WITHOUT
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60 ;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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61 ;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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62 ;; for more details.
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63 ;;
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64 ;; The original copyright notice is given below, as required by the
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65 ;; licence for the original code. This code is distributed under *both*
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66 ;; RSA's original licence and the GNU General Public Licence. (There
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67 ;; should be no problems, as the former is more liberal than the
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68 ;; latter).
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69
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70 ;;; Original copyright notice: ------------------------------------------------
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71
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72 ;; Copyright (C) 1990, RSA Data Security, Inc. All rights reserved.
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73 ;;
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74 ;; License to copy and use this software is granted provided that it is
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75 ;; identified as the "RSA Data Security, Inc. MD5 Message- Digest
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76 ;; Algorithm" in all material mentioning or referencing this software or
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77 ;; this function.
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78 ;;
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79 ;; License is also granted to make and use derivative works provided
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80 ;; that such works are identified as "derived from the RSA Data
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81 ;; Security, Inc. MD5 Message-Digest Algorithm" in all material
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82 ;; mentioning or referencing the derived work.
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83 ;;
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84 ;; RSA Data Security, Inc. makes no representations concerning either
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85 ;; the merchantability of this software or the suitability of this
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86 ;; software for any particular purpose. It is provided "as is" without
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87 ;; express or implied warranty of any kind.
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88 ;;
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89 ;; These notices must be retained in any copies of any part of this
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90 ;; documentation and/or software.
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91
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92 ;;; Code: ---------------------------------------------------------------------
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93
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94 (defvar md5-program "md5"
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95 "*Program that reads a message on its standard input and writes an
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96 MD5 digest on its output.")
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97
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98 (defvar md5-maximum-internal-length 4096
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99 "*The maximum size of a piece of data that should use the MD5 routines
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100 written in lisp. If a message exceeds this, it will be run through an
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101 external filter for processing. Also see the `md5-program' variable.
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102 This variable has no effect if you call the md5-init|update|final
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103 functions - only used by the `md5' function's simpler interface.")
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104
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105 (defvar md5-bits (make-vector 4 0)
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106 "Number of bits handled, modulo 2^64.
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107 Represented as four 16-bit numbers, least significant first.")
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108 (defvar md5-buffer (make-vector 4 '(0 . 0))
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109 "Scratch buffer (four 32-bit integers).")
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110 (defvar md5-input (make-vector 64 0)
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111 "Input buffer (64 bytes).")
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112
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113 (defun md5-unhex (x)
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114 (if (> x ?9)
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115 (if (>= x ?a)
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116 (+ 10 (- x ?a))
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117 (+ 10 (- x ?A)))
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118 (- x ?0)))
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119
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120 (defun md5-encode (message)
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121 "Encodes MESSAGE using the MD5 message digest algorithm.
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122 MESSAGE must be a string or an array of bytes.
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123 Returns a vector of 16 bytes containing the message digest."
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124 (if (<= (length message) md5-maximum-internal-length)
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125 (progn
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126 (md5-init)
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127 (md5-update message)
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128 (md5-final))
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129 (save-excursion
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130 (set-buffer (get-buffer-create " *md5-work*"))
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131 (erase-buffer)
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132 (insert message)
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133 (call-process-region (point-min) (point-max)
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134 md5-program
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135 t (current-buffer))
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136 ;; MD5 digest is 32 chars long
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137 ;; mddriver adds a newline to make neaten output for tty
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138 ;; viewing, make sure we leave it behind.
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139 (let ((data (buffer-substring (point-min) (+ (point-min) 32)))
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140 (vec (make-vector 16 0))
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141 (ctr 0))
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142 (while (< ctr 16)
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143 (aset vec ctr (+ (* 16 (md5-unhex (aref data (* ctr 2))))
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144 (md5-unhex (aref data (1+ (* ctr 2))))))
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145 (setq ctr (1+ ctr)))))))
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146
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147 (defsubst md5-add (x y)
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148 "Return 32-bit sum of 32-bit integers X and Y."
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149 (let ((m (+ (car x) (car y)))
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150 (l (+ (cdr x) (cdr y))))
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151 (cons (logand 65535 (+ m (lsh l -16))) (logand l 65535))))
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152
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153 ;; FF, GG, HH and II are basic MD5 functions, providing transformations
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154 ;; for rounds 1, 2, 3 and 4 respectively. Each function follows this
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155 ;; pattern of computation (where ROTATE(x,y) means rotate 32-bit value x
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156 ;; by y bits to the left):
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157 ;;
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158 ;; FF(a,b,c,d,x,s,ac) = ROTATE(a + F(b,c,d) + x + ac,s) + b
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159 ;;
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160 ;; so we use the macro `md5-make-step' to construct each one. The
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161 ;; helper functions F, G, H and I operate on 16-bit numbers; the full
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162 ;; operation splits its inputs, operates on the halves separately and
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163 ;; then puts the results together.
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164
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165 (defsubst md5-F (x y z) (logior (logand x y) (logand (lognot x) z)))
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166 (defsubst md5-G (x y z) (logior (logand x z) (logand y (lognot z))))
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167 (defsubst md5-H (x y z) (logxor x y z))
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168 (defsubst md5-I (x y z) (logxor y (logior x (logand 65535 (lognot z)))))
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169
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170 (defmacro md5-make-step (name func)
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171 (`
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172 (defun (, name) (a b c d x s ac)
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173 (let*
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174 ((m1 (+ (car a) ((, func) (car b) (car c) (car d)) (car x) (car ac)))
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175 (l1 (+ (cdr a) ((, func) (cdr b) (cdr c) (cdr d)) (cdr x) (cdr ac)))
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176 (m2 (logand 65535 (+ m1 (lsh l1 -16))))
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177 (l2 (logand 65535 l1))
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178 (m3 (logand 65535 (if (> s 15)
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179 (+ (lsh m2 (- s 32)) (lsh l2 (- s 16)))
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180 (+ (lsh m2 s) (lsh l2 (- s 16))))))
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181 (l3 (logand 65535 (if (> s 15)
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182 (+ (lsh l2 (- s 32)) (lsh m2 (- s 16)))
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183 (+ (lsh l2 s) (lsh m2 (- s 16)))))))
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184 (md5-add (cons m3 l3) b)))))
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185
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186 (md5-make-step md5-FF md5-F)
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187 (md5-make-step md5-GG md5-G)
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188 (md5-make-step md5-HH md5-H)
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189 (md5-make-step md5-II md5-I)
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190
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191 (defun md5-init ()
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192 "Initialise the state of the message-digest routines."
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193 (aset md5-bits 0 0)
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194 (aset md5-bits 1 0)
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195 (aset md5-bits 2 0)
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196 (aset md5-bits 3 0)
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197 (aset md5-buffer 0 '(26437 . 8961))
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198 (aset md5-buffer 1 '(61389 . 43913))
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199 (aset md5-buffer 2 '(39098 . 56574))
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200 (aset md5-buffer 3 '( 4146 . 21622)))
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201
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202 (defun md5-update (string)
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203 "Update the current MD5 state with STRING (an array of bytes)."
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204 (let ((len (length string))
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205 (i 0)
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206 (j 0))
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207 (while (< i len)
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208 ;; Compute number of bytes modulo 64
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209 (setq j (% (/ (aref md5-bits 0) 8) 64))
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210
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211 ;; Store this byte (truncating to 8 bits to be sure)
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212 (aset md5-input j (logand 255 (aref string i)))
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213
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214 ;; Update number of bits by 8 (modulo 2^64)
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215 (let ((c 8) (k 0))
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216 (while (and (> c 0) (< k 4))
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217 (let ((b (aref md5-bits k)))
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218 (aset md5-bits k (logand 65535 (+ b c)))
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219 (setq c (if (> b (- 65535 c)) 1 0)
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220 k (1+ k)))))
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221
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222 ;; Increment number of bytes processed
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223 (setq i (1+ i))
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224
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225 ;; When 64 bytes accumulated, pack them into sixteen 32-bit
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226 ;; integers in the array `in' and then tranform them.
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227 (if (= j 63)
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228 (let ((in (make-vector 16 (cons 0 0)))
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229 (k 0)
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230 (kk 0))
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231 (while (< k 16)
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232 (aset in k (md5-pack md5-input kk))
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233 (setq k (+ k 1) kk (+ kk 4)))
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234 (md5-transform in))))))
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235
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236 (defun md5-pack (array i)
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237 "Pack the four bytes at ARRAY reference I to I+3 into a 32-bit integer."
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238 (cons (+ (lsh (aref array (+ i 3)) 8) (aref array (+ i 2)))
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239 (+ (lsh (aref array (+ i 1)) 8) (aref array (+ i 0)))))
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240
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241 (defun md5-byte (array n b)
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242 "Unpack byte B (0 to 3) from Nth member of ARRAY of 32-bit integers."
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243 (let ((e (aref array n)))
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244 (cond ((eq b 0) (logand 255 (cdr e)))
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245 ((eq b 1) (lsh (cdr e) -8))
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246 ((eq b 2) (logand 255 (car e)))
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247 ((eq b 3) (lsh (car e) -8)))))
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248
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249 (defun md5-final ()
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250 (let ((in (make-vector 16 (cons 0 0)))
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251 (j 0)
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252 (digest (make-vector 16 0))
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253 (padding))
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254
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255 ;; Save the number of bits in the message
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256 (aset in 14 (cons (aref md5-bits 1) (aref md5-bits 0)))
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257 (aset in 15 (cons (aref md5-bits 3) (aref md5-bits 2)))
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258
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259 ;; Compute number of bytes modulo 64
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260 (setq j (% (/ (aref md5-bits 0) 8) 64))
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261
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262 ;; Pad out computation to 56 bytes modulo 64
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263 (setq padding (make-vector (if (< j 56) (- 56 j) (- 120 j)) 0))
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264 (aset padding 0 128)
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265 (md5-update padding)
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266
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267 ;; Append length in bits and transform
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268 (let ((k 0) (kk 0))
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269 (while (< k 14)
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270 (aset in k (md5-pack md5-input kk))
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271 (setq k (+ k 1) kk (+ kk 4))))
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272 (md5-transform in)
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273
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274 ;; Store the results in the digest
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275 (let ((k 0) (kk 0))
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276 (while (< k 4)
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277 (aset digest (+ kk 0) (md5-byte md5-buffer k 0))
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278 (aset digest (+ kk 1) (md5-byte md5-buffer k 1))
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279 (aset digest (+ kk 2) (md5-byte md5-buffer k 2))
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280 (aset digest (+ kk 3) (md5-byte md5-buffer k 3))
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281 (setq k (+ k 1) kk (+ kk 4))))
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282
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283 ;; Return digest
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284 digest))
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285
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286 ;; It says in the RSA source, "Note that if the Mysterious Constants are
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287 ;; arranged backwards in little-endian order and decrypted with the DES
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288 ;; they produce OCCULT MESSAGES!" Security through obscurity?
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289
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290 (defun md5-transform (in)
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291 "Basic MD5 step. Transform md5-buffer based on array IN."
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292 (let ((a (aref md5-buffer 0))
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293 (b (aref md5-buffer 1))
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294 (c (aref md5-buffer 2))
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295 (d (aref md5-buffer 3)))
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296 (setq
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297 a (md5-FF a b c d (aref in 0) 7 '(55146 . 42104))
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298 d (md5-FF d a b c (aref in 1) 12 '(59591 . 46934))
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299 c (md5-FF c d a b (aref in 2) 17 '( 9248 . 28891))
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300 b (md5-FF b c d a (aref in 3) 22 '(49597 . 52974))
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301 a (md5-FF a b c d (aref in 4) 7 '(62844 . 4015))
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302 d (md5-FF d a b c (aref in 5) 12 '(18311 . 50730))
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303 c (md5-FF c d a b (aref in 6) 17 '(43056 . 17939))
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304 b (md5-FF b c d a (aref in 7) 22 '(64838 . 38145))
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305 a (md5-FF a b c d (aref in 8) 7 '(27008 . 39128))
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306 d (md5-FF d a b c (aref in 9) 12 '(35652 . 63407))
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307 c (md5-FF c d a b (aref in 10) 17 '(65535 . 23473))
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308 b (md5-FF b c d a (aref in 11) 22 '(35164 . 55230))
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309 a (md5-FF a b c d (aref in 12) 7 '(27536 . 4386))
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310 d (md5-FF d a b c (aref in 13) 12 '(64920 . 29075))
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311 c (md5-FF c d a b (aref in 14) 17 '(42617 . 17294))
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312 b (md5-FF b c d a (aref in 15) 22 '(18868 . 2081))
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313 a (md5-GG a b c d (aref in 1) 5 '(63006 . 9570))
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314 d (md5-GG d a b c (aref in 6) 9 '(49216 . 45888))
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315 c (md5-GG c d a b (aref in 11) 14 '( 9822 . 23121))
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316 b (md5-GG b c d a (aref in 0) 20 '(59830 . 51114))
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317 a (md5-GG a b c d (aref in 5) 5 '(54831 . 4189))
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318 d (md5-GG d a b c (aref in 10) 9 '( 580 . 5203))
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319 c (md5-GG c d a b (aref in 15) 14 '(55457 . 59009))
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320 b (md5-GG b c d a (aref in 4) 20 '(59347 . 64456))
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321 a (md5-GG a b c d (aref in 9) 5 '( 8673 . 52710))
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322 d (md5-GG d a b c (aref in 14) 9 '(49975 . 2006))
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323 c (md5-GG c d a b (aref in 3) 14 '(62677 . 3463))
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324 b (md5-GG b c d a (aref in 8) 20 '(17754 . 5357))
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325 a (md5-GG a b c d (aref in 13) 5 '(43491 . 59653))
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326 d (md5-GG d a b c (aref in 2) 9 '(64751 . 41976))
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327 c (md5-GG c d a b (aref in 7) 14 '(26479 . 729))
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328 b (md5-GG b c d a (aref in 12) 20 '(36138 . 19594))
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329 a (md5-HH a b c d (aref in 5) 4 '(65530 . 14658))
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330 d (md5-HH d a b c (aref in 8) 11 '(34673 . 63105))
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331 c (md5-HH c d a b (aref in 11) 16 '(28061 . 24866))
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332 b (md5-HH b c d a (aref in 14) 23 '(64997 . 14348))
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333 a (md5-HH a b c d (aref in 1) 4 '(42174 . 59972))
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334 d (md5-HH d a b c (aref in 4) 11 '(19422 . 53161))
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335 c (md5-HH c d a b (aref in 7) 16 '(63163 . 19296))
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336 b (md5-HH b c d a (aref in 10) 23 '(48831 . 48240))
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337 a (md5-HH a b c d (aref in 13) 4 '(10395 . 32454))
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338 d (md5-HH d a b c (aref in 0) 11 '(60065 . 10234))
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339 c (md5-HH c d a b (aref in 3) 16 '(54511 . 12421))
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340 b (md5-HH b c d a (aref in 6) 23 '( 1160 . 7429))
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341 a (md5-HH a b c d (aref in 9) 4 '(55764 . 53305))
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342 d (md5-HH d a b c (aref in 12) 11 '(59099 . 39397))
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343 c (md5-HH c d a b (aref in 15) 16 '( 8098 . 31992))
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344 b (md5-HH b c d a (aref in 2) 23 '(50348 . 22117))
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345 a (md5-II a b c d (aref in 0) 6 '(62505 . 8772))
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346 d (md5-II d a b c (aref in 7) 10 '(17194 . 65431))
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347 c (md5-II c d a b (aref in 14) 15 '(43924 . 9127))
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348 b (md5-II b c d a (aref in 5) 21 '(64659 . 41017))
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349 a (md5-II a b c d (aref in 12) 6 '(25947 . 22979))
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350 d (md5-II d a b c (aref in 3) 10 '(36620 . 52370))
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351 c (md5-II c d a b (aref in 10) 15 '(65519 . 62589))
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352 b (md5-II b c d a (aref in 1) 21 '(34180 . 24017))
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353 a (md5-II a b c d (aref in 8) 6 '(28584 . 32335))
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354 d (md5-II d a b c (aref in 15) 10 '(65068 . 59104))
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355 c (md5-II c d a b (aref in 6) 15 '(41729 . 17172))
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356 b (md5-II b c d a (aref in 13) 21 '(19976 . 4513))
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357 a (md5-II a b c d (aref in 4) 6 '(63315 . 32386))
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358 d (md5-II d a b c (aref in 11) 10 '(48442 . 62005))
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359 c (md5-II c d a b (aref in 2) 15 '(10967 . 53947))
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360 b (md5-II b c d a (aref in 9) 21 '(60294 . 54161)))
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361
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362 (aset md5-buffer 0 (md5-add (aref md5-buffer 0) a))
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363 (aset md5-buffer 1 (md5-add (aref md5-buffer 1) b))
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364 (aset md5-buffer 2 (md5-add (aref md5-buffer 2) c))
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365 (aset md5-buffer 3 (md5-add (aref md5-buffer 3) d))))
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366
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367 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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368 ;;; Here begins the merger with the XEmacs API and the md5.el from the URL
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369 ;;; package. Courtesy wmperry@cs.indiana.edu
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370 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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371 (defun md5 (object &optional start end)
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372 "Return the MD5 (a secure message digest algorithm) of an object.
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373 OBJECT is either a string or a buffer.
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374 Optional arguments START and END denote buffer positions for computing the
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375 hash of a portion of OBJECT."
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376 (let ((buffer nil))
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377 (unwind-protect
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378 (save-excursion
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379 (setq buffer (generate-new-buffer " *md5-work*"))
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380 (set-buffer buffer)
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381 (cond
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382 ((bufferp object)
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383 (insert-buffer-substring object start end))
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384 ((stringp object)
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385 (insert (if (or start end)
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386 (substring object start end)
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387 object)))
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388 (t nil))
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389 (prog1
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390 (if (<= (point-max) md5-maximum-internal-length)
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391 (mapconcat
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392 (function (lambda (node) (format "%02x" node)))
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393 (md5-encode (buffer-string))
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394 "")
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395 (call-process-region (point-min) (point-max)
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396 (or shell-file-name "/bin/sh")
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397 t buffer nil
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398 "-c" md5-program)
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399 ;; MD5 digest is 32 chars long
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400 ;; mddriver adds a newline to make neaten output for tty
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401 ;; viewing, make sure we leave it behind.
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402 (buffer-substring (point-min) (+ (point-min) 32)))
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403 (kill-buffer buffer)))
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404 (and buffer (kill-buffer buffer) nil))))
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405
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406 (provide 'md5)
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407
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408 ;;; md5.el ends here ----------------------------------------------------------
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