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1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: counter-def.h,v 1.4 2004/04/08 01:36:15 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 | |
35d66180 |
30 | #ifndef CATACOMB_COUNTER_DEF_H |
31 | #define CATACOMB_COUNTER_DEF_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include <stdarg.h> |
40 | #include <string.h> |
41 | |
42 | #include <mLib/bits.h> |
43 | #include <mLib/sub.h> |
44 | |
45 | #ifndef CATACOMB_ARENA_H |
46 | # include "arena.h" |
47 | #endif |
48 | |
49 | #ifndef CATACOMB_BLKC_H |
50 | # include "blkc.h" |
51 | #endif |
52 | |
53 | #ifndef CATACOMB_GCIPHER_H |
54 | # include "gcipher.h" |
55 | #endif |
56 | |
57 | #ifndef CATACOMB_PARANOIA_H |
58 | # include "paranoia.h" |
59 | #endif |
60 | |
61 | /*----- Macros ------------------------------------------------------------*/ |
62 | |
63 | /* --- @COUNTER_DEF@ --- * |
64 | * |
65 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
66 | * |
67 | * Use: Creates definitions for counter mode. |
68 | */ |
69 | |
70 | #define COUNTER_DEF(PRE, pre) \ |
71 | \ |
72 | /* --- @pre_countergetiv@ --- * \ |
73 | * \ |
74 | * Arguments: @const pre_counterctx *ctx@ = pointer to counter \ |
75 | * context \ |
4efe32ba |
76 | * @void *iv@ = pointer to output data block \ |
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77 | * \ |
78 | * Returns: --- \ |
79 | * \ |
80 | * Use: Reads the currently set IV. Reading and setting an IV \ |
81 | * is not transparent to the cipher. It will add a `step' \ |
82 | * which must be matched by a similar operation during \ |
83 | * decryption. \ |
84 | */ \ |
85 | \ |
86 | void pre##_countergetiv(const pre##_counterctx *ctx, void *iv) \ |
87 | { \ |
88 | BLKC_STORE(PRE, iv, ctx->n); \ |
89 | } \ |
90 | \ |
91 | /* --- @pre_countersetiv@ --- * \ |
92 | * \ |
93 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
94 | * @cnost void *iv@ = pointer to IV to set \ |
95 | * \ |
96 | * Returns: --- \ |
97 | * \ |
98 | * Use: Sets the IV to use for subsequent encryption. \ |
99 | */ \ |
100 | \ |
101 | void pre##_countersetiv(pre##_counterctx *ctx, const void *iv) \ |
102 | { \ |
103 | BLKC_LOAD(PRE, ctx->n, iv); \ |
104 | ctx->off = PRE##_BLKSZ; \ |
105 | } \ |
106 | \ |
107 | /* --- @pre_counterbdry@ --- * \ |
108 | * \ |
109 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
110 | * \ |
111 | * Returns: --- \ |
112 | * \ |
113 | * Use: Inserts a boundary during encryption. Successful \ |
114 | * decryption must place a similar boundary. \ |
115 | */ \ |
116 | \ |
117 | void pre##_counterbdry(pre##_counterctx *ctx) \ |
118 | { \ |
119 | BLKC_STEP(PRE, ctx->n); \ |
120 | ctx->off = PRE##_BLKSZ; \ |
121 | } \ |
122 | \ |
123 | /* --- @pre_countersetkey@ --- * \ |
124 | * \ |
125 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
126 | * @const pre_ctx *k@ = pointer to cipher context \ |
127 | * \ |
128 | * Returns: --- \ |
129 | * \ |
130 | * Use: Sets the counter context to use a different cipher key. \ |
131 | */ \ |
132 | \ |
133 | void pre##_countersetkey(pre##_counterctx *ctx, const pre##_ctx *k) \ |
134 | { \ |
135 | ctx->ctx = *k; \ |
136 | } \ |
137 | \ |
138 | /* --- @pre_counterinit@ --- * \ |
139 | * \ |
140 | * Arguments: @pre_counterctx *ctx@ = pointer to cipher context \ |
141 | * @const void *key@ = pointer to the key buffer \ |
142 | * @size_t sz@ = size of the key \ |
143 | * @const void *iv@ = pointer to initialization vector \ |
144 | * \ |
145 | * Returns: --- \ |
146 | * \ |
147 | * Use: Initializes a counter context ready for use. You \ |
148 | * should ensure that the IV chosen is unique: reusing an \ |
149 | * IV will compromise the security of the entire \ |
150 | * plaintext. This is equivalent to calls to @pre_init@, \ |
151 | * @pre_countersetkey@ and @pre_countersetiv@. \ |
152 | */ \ |
153 | \ |
154 | void pre##_counterinit(pre##_counterctx *ctx, \ |
155 | const void *key, size_t sz, \ |
156 | const void *iv) \ |
157 | { \ |
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158 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
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159 | pre##_init(&ctx->ctx, key, sz); \ |
160 | pre##_countersetiv(ctx, iv ? iv : zero); \ |
161 | } \ |
162 | \ |
163 | /* --- @pre_counterencrypt@ --- * \ |
164 | * \ |
165 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
166 | * @const void *src@ = pointer to source data \ |
167 | * @void *dest@ = pointer to destination data \ |
168 | * @size_t sz@ = size of block to be encrypted \ |
169 | * \ |
170 | * Returns: --- \ |
171 | * \ |
172 | * Use: Encrypts or decrypts a block with a block cipher in \ |
173 | * counter mode: encryption and decryption are the same in \ |
174 | * counter. The destination may be null to just churn the \ |
175 | * feedback round for a bit. The source may be null to \ |
176 | * use the cipher as a random data generator. \ |
177 | */ \ |
178 | \ |
179 | void pre##_counterencrypt(pre##_counterctx *ctx, \ |
180 | const void *src, void *dest, \ |
181 | size_t sz) \ |
182 | { \ |
183 | const octet *s = src; \ |
184 | octet *d = dest; \ |
185 | unsigned off = ctx->off; \ |
186 | \ |
187 | /* --- Empty blocks are trivial --- */ \ |
188 | \ |
189 | if (!sz) \ |
190 | return; \ |
191 | \ |
192 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
193 | \ |
194 | if (sz < PRE##_BLKSZ - off) \ |
195 | goto small; \ |
196 | \ |
197 | /* --- Finish off what's left in my buffer --- */ \ |
198 | \ |
199 | if (!d) \ |
200 | sz -= PRE##_BLKSZ - off; \ |
201 | else { \ |
202 | while (off < PRE##_BLKSZ) { \ |
203 | register octet x = s ? *s++ : 0; \ |
204 | *d++ = ctx->buf[off++] ^ x; \ |
205 | sz--; \ |
206 | } \ |
207 | } \ |
208 | \ |
209 | /* --- Main encryption loop --- */ \ |
210 | \ |
211 | { \ |
212 | uint32 n[PRE##_BLKSZ / 4]; \ |
213 | \ |
214 | for (;;) { \ |
215 | pre##_eblk(&ctx->ctx, ctx->n, n); \ |
216 | BLKC_STEP(PRE, ctx->n); \ |
217 | if (sz < PRE##_BLKSZ) \ |
218 | break; \ |
219 | if (d) { \ |
220 | if (!s) \ |
221 | BLKC_STORE(PRE, d, n); \ |
222 | else { \ |
223 | uint32 x[PRE##_BLKSZ / 4]; \ |
224 | BLKC_LOAD(PRE, x, s); \ |
225 | BLKC_XSTORE(PRE, d, n, x); \ |
226 | s += PRE##_BLKSZ; \ |
227 | } \ |
228 | d += PRE##_BLKSZ; \ |
229 | } \ |
230 | sz -= PRE##_BLKSZ; \ |
231 | } \ |
232 | \ |
233 | BLKC_STORE(PRE, ctx->buf, n); \ |
234 | off = 0; \ |
235 | } \ |
236 | \ |
237 | /* --- Tidying up the tail end --- */ \ |
238 | \ |
239 | if (sz) { \ |
240 | small: \ |
241 | if (!d) \ |
242 | off += sz; \ |
243 | else do { \ |
244 | register octet x = s ? *s++ : 0; \ |
245 | *d++ = ctx->buf[off++] ^ x; \ |
246 | sz--; \ |
247 | } while (sz); \ |
248 | } \ |
249 | \ |
250 | /* --- Done --- */ \ |
251 | \ |
252 | ctx->off = off; \ |
253 | return; \ |
254 | } \ |
255 | \ |
256 | /* --- Generic cipher interface --- */ \ |
257 | \ |
258 | static const gcipher_ops gops; \ |
259 | \ |
260 | typedef struct gctx { \ |
261 | gcipher c; \ |
262 | pre##_counterctx k; \ |
263 | } gctx; \ |
264 | \ |
265 | static gcipher *ginit(const void *k, size_t sz) \ |
266 | { \ |
267 | gctx *g = S_CREATE(gctx); \ |
268 | g->c.ops = &gops; \ |
269 | pre##_counterinit(&g->k, k, sz, 0); \ |
270 | return (&g->c); \ |
271 | } \ |
272 | \ |
273 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
274 | { \ |
275 | gctx *g = (gctx *)c; \ |
276 | pre##_counterencrypt(&g->k, s, t, sz); \ |
277 | } \ |
278 | \ |
279 | static void gdestroy(gcipher *c) \ |
280 | { \ |
281 | gctx *g = (gctx *)c; \ |
282 | BURN(*g); \ |
283 | S_DESTROY(g); \ |
284 | } \ |
285 | \ |
286 | static void gsetiv(gcipher *c, const void *iv) \ |
287 | { \ |
288 | gctx *g = (gctx *)c; \ |
289 | pre##_countersetiv(&g->k, iv); \ |
290 | } \ |
291 | \ |
292 | static void gbdry(gcipher *c) \ |
293 | { \ |
294 | gctx *g = (gctx *)c; \ |
295 | pre##_counterbdry(&g->k); \ |
296 | } \ |
297 | \ |
298 | static const gcipher_ops gops = { \ |
299 | &pre##_counter, \ |
300 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
301 | }; \ |
302 | \ |
303 | const gccipher pre##_counter = { \ |
304 | #pre "-counter", pre##_keysz, PRE##_BLKSZ, \ |
305 | ginit \ |
306 | }; \ |
307 | \ |
308 | /* --- Generic random number generator interface --- */ \ |
309 | \ |
310 | typedef struct grctx { \ |
311 | grand r; \ |
312 | pre##_counterctx k; \ |
313 | } grctx; \ |
314 | \ |
315 | static void grdestroy(grand *r) \ |
316 | { \ |
317 | grctx *g = (grctx *)r; \ |
318 | BURN(*g); \ |
319 | S_DESTROY(g); \ |
320 | } \ |
321 | \ |
322 | static int grmisc(grand *r, unsigned op, ...) \ |
323 | { \ |
324 | grctx *g = (grctx *)r; \ |
325 | va_list ap; \ |
326 | int rc = 0; \ |
327 | octet buf[PRE##_BLKSZ]; \ |
328 | va_start(ap, op); \ |
329 | \ |
330 | switch (op) { \ |
331 | case GRAND_CHECK: \ |
332 | switch (va_arg(ap, unsigned)) { \ |
333 | case GRAND_CHECK: \ |
334 | case GRAND_SEEDINT: \ |
335 | case GRAND_SEEDUINT32: \ |
336 | case GRAND_SEEDBLOCK: \ |
337 | case GRAND_SEEDRAND: \ |
338 | rc = 1; \ |
339 | break; \ |
340 | default: \ |
341 | rc = 0; \ |
342 | break; \ |
343 | } \ |
344 | break; \ |
345 | case GRAND_SEEDINT: \ |
346 | BLKC_SET(PRE, g->k.n, va_arg(ap, unsigned)); \ |
347 | g->k.off = PRE##_BLKSZ; \ |
348 | break; \ |
349 | case GRAND_SEEDUINT32: \ |
350 | BLKC_SET(PRE, g->k.n, va_arg(ap, uint32)); \ |
351 | g->k.off = PRE##_BLKSZ; \ |
352 | break; \ |
353 | case GRAND_SEEDBLOCK: { \ |
354 | const void *p = va_arg(ap, const void *); \ |
355 | size_t sz = va_arg(ap, size_t); \ |
356 | if (sz < sizeof(buf)) { \ |
357 | memset(buf, 0, sizeof(buf)); \ |
358 | memcpy(buf, p, sz); \ |
359 | p = buf; \ |
360 | } \ |
361 | pre##_countersetiv(&g->k, p); \ |
362 | } break; \ |
363 | case GRAND_SEEDRAND: { \ |
364 | grand *rr = va_arg(ap, grand *); \ |
365 | rr->ops->fill(rr, buf, sizeof(buf)); \ |
366 | pre##_countersetiv(&g->k, buf); \ |
367 | } break; \ |
368 | default: \ |
369 | GRAND_BADOP; \ |
370 | break; \ |
371 | } \ |
372 | \ |
373 | va_end(ap); \ |
374 | return (rc); \ |
375 | } \ |
376 | \ |
377 | static octet grbyte(grand *r) \ |
378 | { \ |
379 | grctx *g = (grctx *)r; \ |
380 | octet o; \ |
381 | pre##_counterencrypt(&g->k, 0, &o, 1); \ |
382 | return (o); \ |
383 | } \ |
384 | \ |
385 | static uint32 grword(grand *r) \ |
386 | { \ |
387 | grctx *g = (grctx *)r; \ |
388 | octet b[4]; \ |
389 | pre##_counterencrypt(&g->k, 0, b, sizeof(b)); \ |
390 | return (LOAD32(b)); \ |
391 | } \ |
392 | \ |
393 | static void grfill(grand *r, void *p, size_t sz) \ |
394 | { \ |
395 | grctx *g = (grctx *)r; \ |
396 | pre##_counterencrypt(&g->k, 0, p, sz); \ |
397 | } \ |
398 | \ |
399 | static const grand_ops grops = { \ |
400 | #pre "-counter", \ |
401 | GRAND_CRYPTO, 0, \ |
402 | grmisc, grdestroy, \ |
403 | grword, grbyte, grword, grand_range, grfill \ |
404 | }; \ |
405 | \ |
406 | /* --- @pre_counterrand@ --- * \ |
407 | * \ |
408 | * Arguments: @const void *k@ = pointer to key material \ |
409 | * @size_t sz@ = size of key material \ |
410 | * \ |
411 | * Returns: Pointer to generic random number generator interface. \ |
412 | * \ |
413 | * Use: Creates a random number interface wrapper around an \ |
414 | * counter-mode block cipher. \ |
415 | */ \ |
416 | \ |
417 | grand *pre##_counterrand(const void *k, size_t sz) \ |
418 | { \ |
419 | grctx *g = S_CREATE(grctx); \ |
420 | g->r.ops = &grops; \ |
421 | pre##_counterinit(&g->k, k, sz, 0); \ |
422 | return (&g->r); \ |
423 | } \ |
424 | \ |
425 | COUNTER_TEST(PRE, pre) |
426 | |
427 | /*----- Test rig ----------------------------------------------------------*/ |
428 | |
429 | #ifdef TEST_RIG |
430 | |
431 | #include <stdio.h> |
432 | |
433 | #include "daftstory.h" |
434 | |
435 | /* --- @COUNTER_TEST@ --- * |
436 | * |
437 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
438 | * |
439 | * Use: Standard test rig for counter functions. |
440 | */ |
441 | |
442 | #define COUNTER_TEST(PRE, pre) \ |
443 | \ |
444 | /* --- Initial plaintext for the test --- */ \ |
445 | \ |
446 | static const octet text[] = TEXT; \ |
447 | \ |
448 | /* --- Key and IV to use --- */ \ |
449 | \ |
450 | static const octet key[] = KEY; \ |
451 | static const octet iv[] = IV; \ |
452 | \ |
453 | /* --- Buffers for encryption and decryption output --- */ \ |
454 | \ |
455 | static octet ct[sizeof(text)]; \ |
456 | static octet pt[sizeof(text)]; \ |
457 | \ |
458 | static void hexdump(const octet *p, size_t sz) \ |
459 | { \ |
460 | const octet *q = p + sz; \ |
461 | for (sz = 0; p < q; p++, sz++) { \ |
462 | printf("%02x", *p); \ |
463 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
464 | putchar(':'); \ |
465 | } \ |
466 | } \ |
467 | \ |
468 | int main(void) \ |
469 | { \ |
470 | size_t sz = 0, rest; \ |
471 | pre##_counterctx ctx; \ |
472 | int status = 0; \ |
473 | int done = 0; \ |
474 | pre##_ctx k; \ |
475 | \ |
476 | size_t keysz = PRE##_KEYSZ ? \ |
477 | PRE##_KEYSZ : strlen((const char *)key); \ |
478 | \ |
479 | fputs(#pre "-counter: ", stdout); \ |
480 | \ |
481 | pre##_init(&k, key, keysz); \ |
482 | pre##_countersetkey(&ctx, &k); \ |
483 | \ |
484 | while (sz <= sizeof(text)) { \ |
485 | rest = sizeof(text) - sz; \ |
486 | memcpy(ct, text, sizeof(text)); \ |
487 | pre##_countersetiv(&ctx, iv); \ |
488 | pre##_counterencrypt(&ctx, ct, ct, sz); \ |
489 | pre##_counterencrypt(&ctx, ct + sz, ct + sz, rest); \ |
490 | memcpy(pt, ct, sizeof(text)); \ |
491 | pre##_countersetiv(&ctx, iv); \ |
492 | pre##_counterencrypt(&ctx, pt, pt, rest); \ |
493 | pre##_counterencrypt(&ctx, pt + rest, pt + rest, sz); \ |
494 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
495 | done++; \ |
496 | if (sizeof(text) < 40 || done % 8 == 0) \ |
497 | fputc('.', stdout); \ |
498 | if (done % 480 == 0) \ |
499 | fputs("\n\t", stdout); \ |
500 | fflush(stdout); \ |
501 | } else { \ |
502 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
503 | status = 1; \ |
504 | printf("\tplaintext = "); hexdump(text, sz); \ |
505 | printf(", "); hexdump(text + sz, rest); \ |
506 | fputc('\n', stdout); \ |
507 | printf("\tciphertext = "); hexdump(ct, sz); \ |
508 | printf(", "); hexdump(ct + sz, rest); \ |
509 | fputc('\n', stdout); \ |
510 | printf("\trecovered text = "); hexdump(pt, sz); \ |
511 | printf(", "); hexdump(pt + sz, rest); \ |
512 | fputc('\n', stdout); \ |
513 | fputc('\n', stdout); \ |
514 | } \ |
515 | if (sz < 63) \ |
516 | sz++; \ |
517 | else \ |
518 | sz += 9; \ |
519 | } \ |
520 | \ |
521 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
522 | return (status); \ |
523 | } |
524 | |
525 | #else |
526 | # define COUNTER_TEST(PRE, pre) |
527 | #endif |
528 | |
529 | /*----- That's all, folks -------------------------------------------------*/ |
530 | |
531 | #ifdef __cplusplus |
532 | } |
533 | #endif |
534 | |
535 | #endif |