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