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