79ba130c |
1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: ofb-def.h,v 1.7 2004/04/08 01:36:15 mdw Exp $ |
79ba130c |
4 | * |
5 | * Definitions for output feedback mode |
6 | * |
7 | * (c) 1999 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 | |
79ba130c |
30 | #ifndef CATACOMB_OFB_DEF_H |
31 | #define CATACOMB_OFB_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 | |
2af20fa2 |
45 | #ifndef CATACOMB_ARENA_H |
46 | # include "arena.h" |
47 | #endif |
48 | |
79ba130c |
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 | /* --- @OFB_DEF@ --- * |
64 | * |
65 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
66 | * |
67 | * Use: Creates definitions for output feedback mode. |
68 | */ |
69 | |
70 | #define OFB_DEF(PRE, pre) \ |
71 | \ |
72 | /* --- @pre_ofbgetiv@ --- * \ |
73 | * \ |
74 | * Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \ |
4efe32ba |
75 | * @void *iv@ = pointer to output data block \ |
79ba130c |
76 | * \ |
77 | * Returns: --- \ |
78 | * \ |
79 | * Use: Reads the currently set IV. Reading and setting an IV \ |
80 | * is not transparent to the cipher. It will add a `step' \ |
81 | * which must be matched by a similar operation during \ |
82 | * decryption. \ |
83 | */ \ |
84 | \ |
85 | void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv) \ |
86 | { \ |
87 | octet *p = iv; \ |
2af20fa2 |
88 | unsigned off = ctx->off; \ |
89 | unsigned rest = PRE##_BLKSZ - off; \ |
79ba130c |
90 | memcpy(p, ctx->iv + off, rest); \ |
91 | memcpy(p + rest, ctx->iv, off); \ |
92 | } \ |
93 | \ |
94 | /* --- @pre_ofbsetiv@ --- * \ |
95 | * \ |
96 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
97 | * @cnost void *iv@ = pointer to IV to set \ |
98 | * \ |
99 | * Returns: --- \ |
100 | * \ |
101 | * Use: Sets the IV to use for subsequent encryption. \ |
102 | */ \ |
103 | \ |
104 | void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv) \ |
105 | { \ |
2af20fa2 |
106 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
107 | ctx->off = PRE##_BLKSZ; \ |
79ba130c |
108 | } \ |
109 | \ |
110 | /* --- @pre_ofbbdry@ --- * \ |
111 | * \ |
112 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
113 | * \ |
114 | * Returns: --- \ |
115 | * \ |
116 | * Use: Inserts a boundary during encryption. Successful \ |
117 | * decryption must place a similar boundary. \ |
118 | */ \ |
119 | \ |
120 | void pre##_ofbbdry(pre##_ofbctx *ctx) \ |
121 | { \ |
2af20fa2 |
122 | uint32 niv[PRE##_BLKSZ / 4]; \ |
123 | BLKC_LOAD(PRE, niv, ctx->iv); \ |
124 | pre##_eblk(&ctx->ctx, niv, niv); \ |
125 | BLKC_STORE(PRE, ctx->iv, niv); \ |
126 | ctx->off = PRE##_BLKSZ; \ |
127 | BURN(niv); \ |
79ba130c |
128 | } \ |
129 | \ |
130 | /* --- @pre_ofbsetkey@ --- * \ |
131 | * \ |
132 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
133 | * @const pre_ctx *k@ = pointer to cipher context \ |
134 | * \ |
135 | * Returns: --- \ |
136 | * \ |
137 | * Use: Sets the OFB context to use a different cipher key. \ |
138 | */ \ |
139 | \ |
140 | void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k) \ |
141 | { \ |
142 | ctx->ctx = *k; \ |
143 | } \ |
144 | \ |
145 | /* --- @pre_ofbinit@ --- * \ |
146 | * \ |
147 | * Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \ |
148 | * @const void *key@ = pointer to the key buffer \ |
149 | * @size_t sz@ = size of the key \ |
150 | * @const void *iv@ = pointer to initialization vector \ |
151 | * \ |
152 | * Returns: --- \ |
153 | * \ |
154 | * Use: Initializes a OFB context ready for use. You should \ |
155 | * ensure that the IV chosen is unique: reusing an IV will \ |
156 | * compromise the security of the entire plaintext. This \ |
157 | * is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \ |
158 | * and @pre_ofbsetiv@. \ |
159 | */ \ |
160 | \ |
161 | void pre##_ofbinit(pre##_ofbctx *ctx, \ |
162 | const void *key, size_t sz, \ |
163 | const void *iv) \ |
164 | { \ |
4e66da02 |
165 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
79ba130c |
166 | pre##_init(&ctx->ctx, key, sz); \ |
167 | pre##_ofbsetiv(ctx, iv ? iv : zero); \ |
168 | } \ |
169 | \ |
170 | /* --- @pre_ofbencrypt@ --- * \ |
171 | * \ |
172 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
173 | * @const void *src@ = pointer to source data \ |
174 | * @void *dest@ = pointer to destination data \ |
175 | * @size_t sz@ = size of block to be encrypted \ |
176 | * \ |
177 | * Returns: --- \ |
178 | * \ |
179 | * Use: Encrypts or decrypts a block with a block cipher in OFB \ |
180 | * mode: encryption and decryption are the same in OFB. \ |
181 | * The destination may be null to just churn the feedback \ |
182 | * round for a bit. The source may be null to use the \ |
183 | * cipher as a random data generator. \ |
184 | */ \ |
185 | \ |
186 | void pre##_ofbencrypt(pre##_ofbctx *ctx, \ |
187 | const void *src, void *dest, \ |
188 | size_t sz) \ |
189 | { \ |
190 | const octet *s = src; \ |
191 | octet *d = dest; \ |
2af20fa2 |
192 | unsigned off = ctx->off; \ |
79ba130c |
193 | \ |
194 | /* --- Empty blocks are trivial --- */ \ |
195 | \ |
196 | if (!sz) \ |
197 | return; \ |
198 | \ |
199 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
200 | \ |
201 | if (sz < PRE##_BLKSZ - off) \ |
202 | goto small; \ |
203 | \ |
204 | /* --- Finish off what's left in my buffer --- */ \ |
205 | \ |
206 | if (!d) \ |
2af20fa2 |
207 | sz -= PRE##_BLKSZ - off; \ |
79ba130c |
208 | else { \ |
209 | while (off < PRE##_BLKSZ) { \ |
210 | register octet x = s ? *s++ : 0; \ |
211 | *d++ = ctx->iv[off++] ^ x; \ |
212 | sz--; \ |
213 | } \ |
214 | } \ |
215 | \ |
216 | /* --- Main encryption loop --- */ \ |
217 | \ |
218 | { \ |
219 | uint32 iv[PRE##_BLKSZ / 4]; \ |
220 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
221 | \ |
222 | for (;;) { \ |
223 | pre##_eblk(&ctx->ctx, iv, iv); \ |
224 | if (sz < PRE##_BLKSZ) \ |
225 | break; \ |
226 | if (d) { \ |
227 | if (!s) \ |
228 | BLKC_STORE(PRE, d, iv); \ |
229 | else { \ |
230 | uint32 x[PRE##_BLKSZ / 4]; \ |
231 | BLKC_LOAD(PRE, x, s); \ |
232 | BLKC_XSTORE(PRE, d, iv, x); \ |
233 | s += PRE##_BLKSZ; \ |
234 | } \ |
235 | d += PRE##_BLKSZ; \ |
236 | } \ |
237 | sz -= PRE##_BLKSZ; \ |
238 | } \ |
239 | \ |
240 | BLKC_STORE(PRE, ctx->iv, iv); \ |
241 | off = 0; \ |
242 | } \ |
243 | \ |
244 | /* --- Tidying up the tail end --- */ \ |
245 | \ |
246 | if (sz) { \ |
247 | small: \ |
248 | if (!d) \ |
249 | off += sz; \ |
250 | else do { \ |
251 | register octet x = s ? *s++ : 0; \ |
252 | *d++ = ctx->iv[off++] ^ x; \ |
253 | sz--; \ |
254 | } while (sz); \ |
255 | } \ |
256 | \ |
257 | /* --- Done --- */ \ |
258 | \ |
259 | ctx->off = off; \ |
260 | return; \ |
261 | } \ |
262 | \ |
263 | /* --- Generic cipher interface --- */ \ |
264 | \ |
265 | static const gcipher_ops gops; \ |
266 | \ |
267 | typedef struct gctx { \ |
268 | gcipher c; \ |
269 | pre##_ofbctx k; \ |
270 | } gctx; \ |
271 | \ |
272 | static gcipher *ginit(const void *k, size_t sz) \ |
273 | { \ |
2af20fa2 |
274 | gctx *g = S_CREATE(gctx); \ |
79ba130c |
275 | g->c.ops = &gops; \ |
276 | pre##_ofbinit(&g->k, k, sz, 0); \ |
277 | return (&g->c); \ |
278 | } \ |
279 | \ |
280 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
281 | { \ |
282 | gctx *g = (gctx *)c; \ |
283 | pre##_ofbencrypt(&g->k, s, t, sz); \ |
284 | } \ |
285 | \ |
286 | static void gdestroy(gcipher *c) \ |
287 | { \ |
288 | gctx *g = (gctx *)c; \ |
2af20fa2 |
289 | BURN(*g); \ |
290 | S_DESTROY(g); \ |
79ba130c |
291 | } \ |
292 | \ |
293 | static void gsetiv(gcipher *c, const void *iv) \ |
294 | { \ |
295 | gctx *g = (gctx *)c; \ |
296 | pre##_ofbsetiv(&g->k, iv); \ |
297 | } \ |
298 | \ |
299 | static void gbdry(gcipher *c) \ |
300 | { \ |
301 | gctx *g = (gctx *)c; \ |
302 | pre##_ofbbdry(&g->k); \ |
303 | } \ |
304 | \ |
305 | static const gcipher_ops gops = { \ |
2af20fa2 |
306 | &pre##_ofb, \ |
79ba130c |
307 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
308 | }; \ |
309 | \ |
310 | const gccipher pre##_ofb = { \ |
2af20fa2 |
311 | #pre "-ofb", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c |
312 | ginit \ |
313 | }; \ |
314 | \ |
315 | /* --- Generic random number generator interface --- */ \ |
316 | \ |
317 | typedef struct grctx { \ |
318 | grand r; \ |
319 | pre##_ofbctx k; \ |
320 | } grctx; \ |
321 | \ |
322 | static void grdestroy(grand *r) \ |
323 | { \ |
324 | grctx *g = (grctx *)r; \ |
2af20fa2 |
325 | BURN(*g); \ |
326 | S_DESTROY(g); \ |
79ba130c |
327 | } \ |
328 | \ |
329 | static int grmisc(grand *r, unsigned op, ...) \ |
330 | { \ |
331 | grctx *g = (grctx *)r; \ |
332 | va_list ap; \ |
333 | int rc = 0; \ |
360c232e |
334 | uint32 i; \ |
79ba130c |
335 | octet buf[PRE##_BLKSZ]; \ |
336 | va_start(ap, op); \ |
337 | \ |
338 | switch (op) { \ |
339 | case GRAND_CHECK: \ |
340 | switch (va_arg(ap, unsigned)) { \ |
341 | case GRAND_CHECK: \ |
342 | case GRAND_SEEDINT: \ |
343 | case GRAND_SEEDUINT32: \ |
344 | case GRAND_SEEDBLOCK: \ |
4ab1268f |
345 | case GRAND_SEEDRAND: \ |
79ba130c |
346 | rc = 1; \ |
347 | break; \ |
348 | default: \ |
349 | rc = 0; \ |
350 | break; \ |
351 | } \ |
352 | break; \ |
353 | case GRAND_SEEDINT: \ |
354 | memset(buf, 0, sizeof(buf)); \ |
360c232e |
355 | i = va_arg(ap, unsigned); \ |
356 | STORE32(buf, i); \ |
79ba130c |
357 | pre##_ofbsetiv(&g->k, buf); \ |
358 | break; \ |
359 | case GRAND_SEEDUINT32: \ |
360 | memset(buf, 0, sizeof(buf)); \ |
360c232e |
361 | i = va_arg(ap, uint32); \ |
362 | STORE32(buf, i); \ |
79ba130c |
363 | pre##_ofbsetiv(&g->k, buf); \ |
364 | break; \ |
365 | case GRAND_SEEDBLOCK: { \ |
366 | const void *p = va_arg(ap, const void *); \ |
367 | size_t sz = va_arg(ap, size_t); \ |
368 | if (sz < sizeof(buf)) { \ |
369 | memset(buf, 0, sizeof(buf)); \ |
370 | memcpy(buf, p, sz); \ |
371 | p = buf; \ |
372 | } \ |
373 | pre##_ofbsetiv(&g->k, p); \ |
374 | } break; \ |
4ab1268f |
375 | case GRAND_SEEDRAND: { \ |
376 | grand *rr = va_arg(ap, grand *); \ |
377 | rr->ops->fill(rr, buf, sizeof(buf)); \ |
378 | pre##_ofbsetiv(&g->k, buf); \ |
379 | } break; \ |
380 | default: \ |
381 | GRAND_BADOP; \ |
382 | break; \ |
79ba130c |
383 | } \ |
384 | \ |
385 | va_end(ap); \ |
386 | return (rc); \ |
387 | } \ |
388 | \ |
389 | static octet grbyte(grand *r) \ |
390 | { \ |
391 | grctx *g = (grctx *)r; \ |
392 | octet o; \ |
393 | pre##_ofbencrypt(&g->k, 0, &o, 1); \ |
394 | return (o); \ |
395 | } \ |
396 | \ |
397 | static uint32 grword(grand *r) \ |
398 | { \ |
399 | grctx *g = (grctx *)r; \ |
400 | octet b[4]; \ |
401 | pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \ |
402 | return (LOAD32(b)); \ |
403 | } \ |
404 | \ |
405 | static void grfill(grand *r, void *p, size_t sz) \ |
406 | { \ |
407 | grctx *g = (grctx *)r; \ |
408 | pre##_ofbencrypt(&g->k, 0, p, sz); \ |
409 | } \ |
410 | \ |
411 | static const grand_ops grops = { \ |
412 | #pre "-ofb", \ |
2af20fa2 |
413 | GRAND_CRYPTO, 0, \ |
79ba130c |
414 | grmisc, grdestroy, \ |
415 | grword, grbyte, grword, grand_range, grfill \ |
416 | }; \ |
417 | \ |
418 | /* --- @pre_ofbrand@ --- * \ |
419 | * \ |
420 | * Arguments: @const void *k@ = pointer to key material \ |
421 | * @size_t sz@ = size of key material \ |
422 | * \ |
423 | * Returns: Pointer to generic random number generator interface. \ |
424 | * \ |
425 | * Use: Creates a random number interface wrapper around an \ |
426 | * OFB-mode block cipher. \ |
427 | */ \ |
428 | \ |
429 | grand *pre##_ofbrand(const void *k, size_t sz) \ |
430 | { \ |
2af20fa2 |
431 | grctx *g = S_CREATE(grctx); \ |
79ba130c |
432 | g->r.ops = &grops; \ |
433 | pre##_ofbinit(&g->k, k, sz, 0); \ |
434 | return (&g->r); \ |
435 | } \ |
436 | \ |
437 | OFB_TEST(PRE, pre) |
438 | |
439 | /*----- Test rig ----------------------------------------------------------*/ |
440 | |
441 | #ifdef TEST_RIG |
442 | |
443 | #include <stdio.h> |
444 | |
445 | #include "daftstory.h" |
446 | |
447 | /* --- @OFB_TEST@ --- * |
448 | * |
449 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
450 | * |
451 | * Use: Standard test rig for OFB functions. |
452 | */ |
453 | |
454 | #define OFB_TEST(PRE, pre) \ |
455 | \ |
456 | /* --- Initial plaintext for the test --- */ \ |
457 | \ |
458 | static const octet text[] = TEXT; \ |
459 | \ |
460 | /* --- Key and IV to use --- */ \ |
461 | \ |
462 | static const octet key[] = KEY; \ |
463 | static const octet iv[] = IV; \ |
464 | \ |
465 | /* --- Buffers for encryption and decryption output --- */ \ |
466 | \ |
467 | static octet ct[sizeof(text)]; \ |
468 | static octet pt[sizeof(text)]; \ |
469 | \ |
470 | static void hexdump(const octet *p, size_t sz) \ |
471 | { \ |
472 | const octet *q = p + sz; \ |
473 | for (sz = 0; p < q; p++, sz++) { \ |
474 | printf("%02x", *p); \ |
475 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
476 | putchar(':'); \ |
477 | } \ |
478 | } \ |
479 | \ |
480 | int main(void) \ |
481 | { \ |
482 | size_t sz = 0, rest; \ |
483 | pre##_ofbctx ctx; \ |
484 | int status = 0; \ |
485 | int done = 0; \ |
486 | pre##_ctx k; \ |
487 | \ |
488 | size_t keysz = PRE##_KEYSZ ? \ |
489 | PRE##_KEYSZ : strlen((const char *)key); \ |
490 | \ |
491 | fputs(#pre "-ofb: ", stdout); \ |
492 | \ |
493 | pre##_init(&k, key, keysz); \ |
494 | pre##_ofbsetkey(&ctx, &k); \ |
495 | \ |
496 | while (sz <= sizeof(text)) { \ |
497 | rest = sizeof(text) - sz; \ |
498 | memcpy(ct, text, sizeof(text)); \ |
499 | pre##_ofbsetiv(&ctx, iv); \ |
500 | pre##_ofbencrypt(&ctx, ct, ct, sz); \ |
501 | pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
502 | memcpy(pt, ct, sizeof(text)); \ |
503 | pre##_ofbsetiv(&ctx, iv); \ |
504 | pre##_ofbencrypt(&ctx, pt, pt, rest); \ |
505 | pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz); \ |
506 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
507 | done++; \ |
508 | if (sizeof(text) < 40 || done % 8 == 0) \ |
509 | fputc('.', stdout); \ |
510 | if (done % 480 == 0) \ |
511 | fputs("\n\t", stdout); \ |
512 | fflush(stdout); \ |
513 | } else { \ |
514 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
515 | status = 1; \ |
516 | printf("\tplaintext = "); hexdump(text, sz); \ |
517 | printf(", "); hexdump(text + sz, rest); \ |
518 | fputc('\n', stdout); \ |
519 | printf("\tciphertext = "); hexdump(ct, sz); \ |
520 | printf(", "); hexdump(ct + sz, rest); \ |
521 | fputc('\n', stdout); \ |
522 | printf("\trecovered text = "); hexdump(pt, sz); \ |
523 | printf(", "); hexdump(pt + sz, rest); \ |
524 | fputc('\n', stdout); \ |
525 | fputc('\n', stdout); \ |
526 | } \ |
527 | if (sz < 63) \ |
528 | sz++; \ |
529 | else \ |
530 | sz += 9; \ |
531 | } \ |
532 | \ |
533 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
534 | return (status); \ |
535 | } |
536 | |
537 | #else |
538 | # define OFB_TEST(PRE, pre) |
539 | #endif |
540 | |
541 | /*----- That's all, folks -------------------------------------------------*/ |
542 | |
543 | #ifdef __cplusplus |
544 | } |
545 | #endif |
546 | |
547 | #endif |