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[u/mdw/catacomb] / counter-def.h
1 /* -*-c-*-
2 *
3 * $Id: counter-def.h,v 1.3 2004/04/02 01:03:49 mdw Exp $
4 *
5 * Block cipher counter mode (or long cycle mode)
6 *
7 * (c) 2000 Straylight/Edgeware
8 */
9
10 /*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Catacomb.
13 *
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
30 /*----- Revision history --------------------------------------------------*
31 *
32 * $Log: counter-def.h,v $
33 * Revision 1.3 2004/04/02 01:03:49 mdw
34 * Miscellaneous constification.
35 *
36 * Revision 1.2 2001/06/17 00:10:51 mdw
37 * Typesetting fixes
38 *
39 * Revision 1.1 2000/06/17 10:51:42 mdw
40 * Counter mode ciphers and pseudo-random generator.
41 *
42 */
43
44 #ifndef CATACOMB_COUNTER_DEF_H
45 #define CATACOMB_COUNTER_DEF_H
46
47 #ifdef __cplusplus
48 extern "C" {
49 #endif
50
51 /*----- Header files ------------------------------------------------------*/
52
53 #include <stdarg.h>
54 #include <string.h>
55
56 #include <mLib/bits.h>
57 #include <mLib/sub.h>
58
59 #ifndef CATACOMB_ARENA_H
60 # include "arena.h"
61 #endif
62
63 #ifndef CATACOMB_BLKC_H
64 # include "blkc.h"
65 #endif
66
67 #ifndef CATACOMB_GCIPHER_H
68 # include "gcipher.h"
69 #endif
70
71 #ifndef CATACOMB_PARANOIA_H
72 # include "paranoia.h"
73 #endif
74
75 /*----- Macros ------------------------------------------------------------*/
76
77 /* --- @COUNTER_DEF@ --- *
78 *
79 * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
80 *
81 * Use: Creates definitions for counter mode.
82 */
83
84 #define COUNTER_DEF(PRE, pre) \
85 \
86 /* --- @pre_countergetiv@ --- * \
87 * \
88 * Arguments: @const pre_counterctx *ctx@ = pointer to counter \
89 * context \
90 * @void *iv@ = pointer to output data block \
91 * \
92 * Returns: --- \
93 * \
94 * Use: Reads the currently set IV. Reading and setting an IV \
95 * is not transparent to the cipher. It will add a `step' \
96 * which must be matched by a similar operation during \
97 * decryption. \
98 */ \
99 \
100 void pre##_countergetiv(const pre##_counterctx *ctx, void *iv) \
101 { \
102 BLKC_STORE(PRE, iv, ctx->n); \
103 } \
104 \
105 /* --- @pre_countersetiv@ --- * \
106 * \
107 * Arguments: @pre_counterctx *ctx@ = pointer to counter context \
108 * @cnost void *iv@ = pointer to IV to set \
109 * \
110 * Returns: --- \
111 * \
112 * Use: Sets the IV to use for subsequent encryption. \
113 */ \
114 \
115 void pre##_countersetiv(pre##_counterctx *ctx, const void *iv) \
116 { \
117 BLKC_LOAD(PRE, ctx->n, iv); \
118 ctx->off = PRE##_BLKSZ; \
119 } \
120 \
121 /* --- @pre_counterbdry@ --- * \
122 * \
123 * Arguments: @pre_counterctx *ctx@ = pointer to counter context \
124 * \
125 * Returns: --- \
126 * \
127 * Use: Inserts a boundary during encryption. Successful \
128 * decryption must place a similar boundary. \
129 */ \
130 \
131 void pre##_counterbdry(pre##_counterctx *ctx) \
132 { \
133 BLKC_STEP(PRE, ctx->n); \
134 ctx->off = PRE##_BLKSZ; \
135 } \
136 \
137 /* --- @pre_countersetkey@ --- * \
138 * \
139 * Arguments: @pre_counterctx *ctx@ = pointer to counter context \
140 * @const pre_ctx *k@ = pointer to cipher context \
141 * \
142 * Returns: --- \
143 * \
144 * Use: Sets the counter context to use a different cipher key. \
145 */ \
146 \
147 void pre##_countersetkey(pre##_counterctx *ctx, const pre##_ctx *k) \
148 { \
149 ctx->ctx = *k; \
150 } \
151 \
152 /* --- @pre_counterinit@ --- * \
153 * \
154 * Arguments: @pre_counterctx *ctx@ = pointer to cipher context \
155 * @const void *key@ = pointer to the key buffer \
156 * @size_t sz@ = size of the key \
157 * @const void *iv@ = pointer to initialization vector \
158 * \
159 * Returns: --- \
160 * \
161 * Use: Initializes a counter context ready for use. You \
162 * should ensure that the IV chosen is unique: reusing an \
163 * IV will compromise the security of the entire \
164 * plaintext. This is equivalent to calls to @pre_init@, \
165 * @pre_countersetkey@ and @pre_countersetiv@. \
166 */ \
167 \
168 void pre##_counterinit(pre##_counterctx *ctx, \
169 const void *key, size_t sz, \
170 const void *iv) \
171 { \
172 static const octet zero[PRE##_BLKSZ] = { 0 }; \
173 pre##_init(&ctx->ctx, key, sz); \
174 pre##_countersetiv(ctx, iv ? iv : zero); \
175 } \
176 \
177 /* --- @pre_counterencrypt@ --- * \
178 * \
179 * Arguments: @pre_counterctx *ctx@ = pointer to counter context \
180 * @const void *src@ = pointer to source data \
181 * @void *dest@ = pointer to destination data \
182 * @size_t sz@ = size of block to be encrypted \
183 * \
184 * Returns: --- \
185 * \
186 * Use: Encrypts or decrypts a block with a block cipher in \
187 * counter mode: encryption and decryption are the same in \
188 * counter. The destination may be null to just churn the \
189 * feedback round for a bit. The source may be null to \
190 * use the cipher as a random data generator. \
191 */ \
192 \
193 void pre##_counterencrypt(pre##_counterctx *ctx, \
194 const void *src, void *dest, \
195 size_t sz) \
196 { \
197 const octet *s = src; \
198 octet *d = dest; \
199 unsigned off = ctx->off; \
200 \
201 /* --- Empty blocks are trivial --- */ \
202 \
203 if (!sz) \
204 return; \
205 \
206 /* --- If I can deal with the block from my buffer, do that --- */ \
207 \
208 if (sz < PRE##_BLKSZ - off) \
209 goto small; \
210 \
211 /* --- Finish off what's left in my buffer --- */ \
212 \
213 if (!d) \
214 sz -= PRE##_BLKSZ - off; \
215 else { \
216 while (off < PRE##_BLKSZ) { \
217 register octet x = s ? *s++ : 0; \
218 *d++ = ctx->buf[off++] ^ x; \
219 sz--; \
220 } \
221 } \
222 \
223 /* --- Main encryption loop --- */ \
224 \
225 { \
226 uint32 n[PRE##_BLKSZ / 4]; \
227 \
228 for (;;) { \
229 pre##_eblk(&ctx->ctx, ctx->n, n); \
230 BLKC_STEP(PRE, ctx->n); \
231 if (sz < PRE##_BLKSZ) \
232 break; \
233 if (d) { \
234 if (!s) \
235 BLKC_STORE(PRE, d, n); \
236 else { \
237 uint32 x[PRE##_BLKSZ / 4]; \
238 BLKC_LOAD(PRE, x, s); \
239 BLKC_XSTORE(PRE, d, n, x); \
240 s += PRE##_BLKSZ; \
241 } \
242 d += PRE##_BLKSZ; \
243 } \
244 sz -= PRE##_BLKSZ; \
245 } \
246 \
247 BLKC_STORE(PRE, ctx->buf, n); \
248 off = 0; \
249 } \
250 \
251 /* --- Tidying up the tail end --- */ \
252 \
253 if (sz) { \
254 small: \
255 if (!d) \
256 off += sz; \
257 else do { \
258 register octet x = s ? *s++ : 0; \
259 *d++ = ctx->buf[off++] ^ x; \
260 sz--; \
261 } while (sz); \
262 } \
263 \
264 /* --- Done --- */ \
265 \
266 ctx->off = off; \
267 return; \
268 } \
269 \
270 /* --- Generic cipher interface --- */ \
271 \
272 static const gcipher_ops gops; \
273 \
274 typedef struct gctx { \
275 gcipher c; \
276 pre##_counterctx k; \
277 } gctx; \
278 \
279 static gcipher *ginit(const void *k, size_t sz) \
280 { \
281 gctx *g = S_CREATE(gctx); \
282 g->c.ops = &gops; \
283 pre##_counterinit(&g->k, k, sz, 0); \
284 return (&g->c); \
285 } \
286 \
287 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \
288 { \
289 gctx *g = (gctx *)c; \
290 pre##_counterencrypt(&g->k, s, t, sz); \
291 } \
292 \
293 static void gdestroy(gcipher *c) \
294 { \
295 gctx *g = (gctx *)c; \
296 BURN(*g); \
297 S_DESTROY(g); \
298 } \
299 \
300 static void gsetiv(gcipher *c, const void *iv) \
301 { \
302 gctx *g = (gctx *)c; \
303 pre##_countersetiv(&g->k, iv); \
304 } \
305 \
306 static void gbdry(gcipher *c) \
307 { \
308 gctx *g = (gctx *)c; \
309 pre##_counterbdry(&g->k); \
310 } \
311 \
312 static const gcipher_ops gops = { \
313 &pre##_counter, \
314 gencrypt, gencrypt, gdestroy, gsetiv, gbdry \
315 }; \
316 \
317 const gccipher pre##_counter = { \
318 #pre "-counter", pre##_keysz, PRE##_BLKSZ, \
319 ginit \
320 }; \
321 \
322 /* --- Generic random number generator interface --- */ \
323 \
324 typedef struct grctx { \
325 grand r; \
326 pre##_counterctx k; \
327 } grctx; \
328 \
329 static void grdestroy(grand *r) \
330 { \
331 grctx *g = (grctx *)r; \
332 BURN(*g); \
333 S_DESTROY(g); \
334 } \
335 \
336 static int grmisc(grand *r, unsigned op, ...) \
337 { \
338 grctx *g = (grctx *)r; \
339 va_list ap; \
340 int rc = 0; \
341 octet buf[PRE##_BLKSZ]; \
342 va_start(ap, op); \
343 \
344 switch (op) { \
345 case GRAND_CHECK: \
346 switch (va_arg(ap, unsigned)) { \
347 case GRAND_CHECK: \
348 case GRAND_SEEDINT: \
349 case GRAND_SEEDUINT32: \
350 case GRAND_SEEDBLOCK: \
351 case GRAND_SEEDRAND: \
352 rc = 1; \
353 break; \
354 default: \
355 rc = 0; \
356 break; \
357 } \
358 break; \
359 case GRAND_SEEDINT: \
360 BLKC_SET(PRE, g->k.n, va_arg(ap, unsigned)); \
361 g->k.off = PRE##_BLKSZ; \
362 break; \
363 case GRAND_SEEDUINT32: \
364 BLKC_SET(PRE, g->k.n, va_arg(ap, uint32)); \
365 g->k.off = PRE##_BLKSZ; \
366 break; \
367 case GRAND_SEEDBLOCK: { \
368 const void *p = va_arg(ap, const void *); \
369 size_t sz = va_arg(ap, size_t); \
370 if (sz < sizeof(buf)) { \
371 memset(buf, 0, sizeof(buf)); \
372 memcpy(buf, p, sz); \
373 p = buf; \
374 } \
375 pre##_countersetiv(&g->k, p); \
376 } break; \
377 case GRAND_SEEDRAND: { \
378 grand *rr = va_arg(ap, grand *); \
379 rr->ops->fill(rr, buf, sizeof(buf)); \
380 pre##_countersetiv(&g->k, buf); \
381 } break; \
382 default: \
383 GRAND_BADOP; \
384 break; \
385 } \
386 \
387 va_end(ap); \
388 return (rc); \
389 } \
390 \
391 static octet grbyte(grand *r) \
392 { \
393 grctx *g = (grctx *)r; \
394 octet o; \
395 pre##_counterencrypt(&g->k, 0, &o, 1); \
396 return (o); \
397 } \
398 \
399 static uint32 grword(grand *r) \
400 { \
401 grctx *g = (grctx *)r; \
402 octet b[4]; \
403 pre##_counterencrypt(&g->k, 0, b, sizeof(b)); \
404 return (LOAD32(b)); \
405 } \
406 \
407 static void grfill(grand *r, void *p, size_t sz) \
408 { \
409 grctx *g = (grctx *)r; \
410 pre##_counterencrypt(&g->k, 0, p, sz); \
411 } \
412 \
413 static const grand_ops grops = { \
414 #pre "-counter", \
415 GRAND_CRYPTO, 0, \
416 grmisc, grdestroy, \
417 grword, grbyte, grword, grand_range, grfill \
418 }; \
419 \
420 /* --- @pre_counterrand@ --- * \
421 * \
422 * Arguments: @const void *k@ = pointer to key material \
423 * @size_t sz@ = size of key material \
424 * \
425 * Returns: Pointer to generic random number generator interface. \
426 * \
427 * Use: Creates a random number interface wrapper around an \
428 * counter-mode block cipher. \
429 */ \
430 \
431 grand *pre##_counterrand(const void *k, size_t sz) \
432 { \
433 grctx *g = S_CREATE(grctx); \
434 g->r.ops = &grops; \
435 pre##_counterinit(&g->k, k, sz, 0); \
436 return (&g->r); \
437 } \
438 \
439 COUNTER_TEST(PRE, pre)
440
441 /*----- Test rig ----------------------------------------------------------*/
442
443 #ifdef TEST_RIG
444
445 #include <stdio.h>
446
447 #include "daftstory.h"
448
449 /* --- @COUNTER_TEST@ --- *
450 *
451 * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
452 *
453 * Use: Standard test rig for counter functions.
454 */
455
456 #define COUNTER_TEST(PRE, pre) \
457 \
458 /* --- Initial plaintext for the test --- */ \
459 \
460 static const octet text[] = TEXT; \
461 \
462 /* --- Key and IV to use --- */ \
463 \
464 static const octet key[] = KEY; \
465 static const octet iv[] = IV; \
466 \
467 /* --- Buffers for encryption and decryption output --- */ \
468 \
469 static octet ct[sizeof(text)]; \
470 static octet pt[sizeof(text)]; \
471 \
472 static void hexdump(const octet *p, size_t sz) \
473 { \
474 const octet *q = p + sz; \
475 for (sz = 0; p < q; p++, sz++) { \
476 printf("%02x", *p); \
477 if ((sz + 1) % PRE##_BLKSZ == 0) \
478 putchar(':'); \
479 } \
480 } \
481 \
482 int main(void) \
483 { \
484 size_t sz = 0, rest; \
485 pre##_counterctx ctx; \
486 int status = 0; \
487 int done = 0; \
488 pre##_ctx k; \
489 \
490 size_t keysz = PRE##_KEYSZ ? \
491 PRE##_KEYSZ : strlen((const char *)key); \
492 \
493 fputs(#pre "-counter: ", stdout); \
494 \
495 pre##_init(&k, key, keysz); \
496 pre##_countersetkey(&ctx, &k); \
497 \
498 while (sz <= sizeof(text)) { \
499 rest = sizeof(text) - sz; \
500 memcpy(ct, text, sizeof(text)); \
501 pre##_countersetiv(&ctx, iv); \
502 pre##_counterencrypt(&ctx, ct, ct, sz); \
503 pre##_counterencrypt(&ctx, ct + sz, ct + sz, rest); \
504 memcpy(pt, ct, sizeof(text)); \
505 pre##_countersetiv(&ctx, iv); \
506 pre##_counterencrypt(&ctx, pt, pt, rest); \
507 pre##_counterencrypt(&ctx, pt + rest, pt + rest, sz); \
508 if (memcmp(pt, text, sizeof(text)) == 0) { \
509 done++; \
510 if (sizeof(text) < 40 || done % 8 == 0) \
511 fputc('.', stdout); \
512 if (done % 480 == 0) \
513 fputs("\n\t", stdout); \
514 fflush(stdout); \
515 } else { \
516 printf("\nError (sz = %lu)\n", (unsigned long)sz); \
517 status = 1; \
518 printf("\tplaintext = "); hexdump(text, sz); \
519 printf(", "); hexdump(text + sz, rest); \
520 fputc('\n', stdout); \
521 printf("\tciphertext = "); hexdump(ct, sz); \
522 printf(", "); hexdump(ct + sz, rest); \
523 fputc('\n', stdout); \
524 printf("\trecovered text = "); hexdump(pt, sz); \
525 printf(", "); hexdump(pt + sz, rest); \
526 fputc('\n', stdout); \
527 fputc('\n', stdout); \
528 } \
529 if (sz < 63) \
530 sz++; \
531 else \
532 sz += 9; \
533 } \
534 \
535 fputs(status ? " failed\n" : " ok\n", stdout); \
536 return (status); \
537 }
538
539 #else
540 # define COUNTER_TEST(PRE, pre)
541 #endif
542
543 /*----- That's all, folks -------------------------------------------------*/
544
545 #ifdef __cplusplus
546 }
547 #endif
548
549 #endif
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)