79ba130c |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: ofb-def.h,v 1.1 1999/12/10 23:16:40 mdw Exp $ |
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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: ofb-def.h,v $ |
33 | * Revision 1.1 1999/12/10 23:16:40 mdw |
34 | * Split mode macros into interface and implementation. |
35 | * |
36 | */ |
37 | |
38 | #ifndef CATACOMB_OFB_DEF_H |
39 | #define CATACOMB_OFB_DEF_H |
40 | |
41 | #ifdef __cplusplus |
42 | extern "C" { |
43 | #endif |
44 | |
45 | /*----- Header files ------------------------------------------------------*/ |
46 | |
47 | #include <stdarg.h> |
48 | #include <string.h> |
49 | |
50 | #include <mLib/bits.h> |
51 | #include <mLib/sub.h> |
52 | |
53 | #ifndef CATACOMB_BLKC_H |
54 | # include "blkc.h" |
55 | #endif |
56 | |
57 | #ifndef CATACOMB_GCIPHER_H |
58 | # include "gcipher.h" |
59 | #endif |
60 | |
61 | #ifndef CATACOMB_PARANOIA_H |
62 | # include "paranoia.h" |
63 | #endif |
64 | |
65 | /*----- Macros ------------------------------------------------------------*/ |
66 | |
67 | /* --- @OFB_DEF@ --- * |
68 | * |
69 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
70 | * |
71 | * Use: Creates definitions for output feedback mode. |
72 | */ |
73 | |
74 | #define OFB_DEF(PRE, pre) \ |
75 | \ |
76 | /* --- @pre_ofbgetiv@ --- * \ |
77 | * \ |
78 | * Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \ |
79 | * @void *iv#@ = pointer to output data block \ |
80 | * \ |
81 | * Returns: --- \ |
82 | * \ |
83 | * Use: Reads the currently set IV. Reading and setting an IV \ |
84 | * is not transparent to the cipher. It will add a `step' \ |
85 | * which must be matched by a similar operation during \ |
86 | * decryption. \ |
87 | */ \ |
88 | \ |
89 | void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv) \ |
90 | { \ |
91 | octet *p = iv; \ |
92 | int off = ctx->off; \ |
93 | int rest = PRE##_BLKSZ - off; \ |
94 | memcpy(p, ctx->iv + off, rest); \ |
95 | memcpy(p + rest, ctx->iv, off); \ |
96 | } \ |
97 | \ |
98 | /* --- @pre_ofbsetiv@ --- * \ |
99 | * \ |
100 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
101 | * @cnost void *iv@ = pointer to IV to set \ |
102 | * \ |
103 | * Returns: --- \ |
104 | * \ |
105 | * Use: Sets the IV to use for subsequent encryption. \ |
106 | */ \ |
107 | \ |
108 | void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv) \ |
109 | { \ |
110 | uint32 niv[PRE##_BLKSZ / 4]; \ |
111 | BLKC_LOAD(PRE, niv, iv); \ |
112 | pre##_eblk(&ctx->ctx, niv, niv); \ |
113 | BLKC_STORE(PRE, ctx->iv, niv); \ |
114 | ctx->off = 0; \ |
115 | } \ |
116 | \ |
117 | /* --- @pre_ofbbdry@ --- * \ |
118 | * \ |
119 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
120 | * \ |
121 | * Returns: --- \ |
122 | * \ |
123 | * Use: Inserts a boundary during encryption. Successful \ |
124 | * decryption must place a similar boundary. \ |
125 | */ \ |
126 | \ |
127 | void pre##_ofbbdry(pre##_ofbctx *ctx) \ |
128 | { \ |
129 | octet iv[PRE##_BLKSZ]; \ |
130 | pre##_ofbgetiv(ctx, iv); \ |
131 | pre##_ofbsetiv(ctx, iv); \ |
132 | BURN(iv); \ |
133 | } \ |
134 | \ |
135 | /* --- @pre_ofbsetkey@ --- * \ |
136 | * \ |
137 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
138 | * @const pre_ctx *k@ = pointer to cipher context \ |
139 | * \ |
140 | * Returns: --- \ |
141 | * \ |
142 | * Use: Sets the OFB context to use a different cipher key. \ |
143 | */ \ |
144 | \ |
145 | void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k) \ |
146 | { \ |
147 | ctx->ctx = *k; \ |
148 | } \ |
149 | \ |
150 | /* --- @pre_ofbinit@ --- * \ |
151 | * \ |
152 | * Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \ |
153 | * @const void *key@ = pointer to the key buffer \ |
154 | * @size_t sz@ = size of the key \ |
155 | * @const void *iv@ = pointer to initialization vector \ |
156 | * \ |
157 | * Returns: --- \ |
158 | * \ |
159 | * Use: Initializes a OFB context ready for use. You should \ |
160 | * ensure that the IV chosen is unique: reusing an IV will \ |
161 | * compromise the security of the entire plaintext. This \ |
162 | * is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \ |
163 | * and @pre_ofbsetiv@. \ |
164 | */ \ |
165 | \ |
166 | void pre##_ofbinit(pre##_ofbctx *ctx, \ |
167 | const void *key, size_t sz, \ |
168 | const void *iv) \ |
169 | { \ |
170 | static octet zero[PRE##_BLKSZ] = { 0 }; \ |
171 | pre##_init(&ctx->ctx, key, sz); \ |
172 | pre##_ofbsetiv(ctx, iv ? iv : zero); \ |
173 | } \ |
174 | \ |
175 | /* --- @pre_ofbencrypt@ --- * \ |
176 | * \ |
177 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
178 | * @const void *src@ = pointer to source data \ |
179 | * @void *dest@ = pointer to destination data \ |
180 | * @size_t sz@ = size of block to be encrypted \ |
181 | * \ |
182 | * Returns: --- \ |
183 | * \ |
184 | * Use: Encrypts or decrypts a block with a block cipher in OFB \ |
185 | * mode: encryption and decryption are the same in OFB. \ |
186 | * The destination may be null to just churn the feedback \ |
187 | * round for a bit. The source may be null to use the \ |
188 | * cipher as a random data generator. \ |
189 | */ \ |
190 | \ |
191 | void pre##_ofbencrypt(pre##_ofbctx *ctx, \ |
192 | const void *src, void *dest, \ |
193 | size_t sz) \ |
194 | { \ |
195 | const octet *s = src; \ |
196 | octet *d = dest; \ |
197 | int off = ctx->off; \ |
198 | \ |
199 | /* --- Empty blocks are trivial --- */ \ |
200 | \ |
201 | if (!sz) \ |
202 | return; \ |
203 | \ |
204 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
205 | \ |
206 | if (sz < PRE##_BLKSZ - off) \ |
207 | goto small; \ |
208 | \ |
209 | /* --- Finish off what's left in my buffer --- */ \ |
210 | \ |
211 | if (!d) \ |
212 | sz -= off; \ |
213 | else { \ |
214 | while (off < PRE##_BLKSZ) { \ |
215 | register octet x = s ? *s++ : 0; \ |
216 | *d++ = ctx->iv[off++] ^ x; \ |
217 | sz--; \ |
218 | } \ |
219 | } \ |
220 | \ |
221 | /* --- Main encryption loop --- */ \ |
222 | \ |
223 | { \ |
224 | uint32 iv[PRE##_BLKSZ / 4]; \ |
225 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
226 | \ |
227 | for (;;) { \ |
228 | pre##_eblk(&ctx->ctx, iv, iv); \ |
229 | if (sz < PRE##_BLKSZ) \ |
230 | break; \ |
231 | if (d) { \ |
232 | if (!s) \ |
233 | BLKC_STORE(PRE, d, iv); \ |
234 | else { \ |
235 | uint32 x[PRE##_BLKSZ / 4]; \ |
236 | BLKC_LOAD(PRE, x, s); \ |
237 | BLKC_XSTORE(PRE, d, iv, x); \ |
238 | s += PRE##_BLKSZ; \ |
239 | } \ |
240 | d += PRE##_BLKSZ; \ |
241 | } \ |
242 | sz -= PRE##_BLKSZ; \ |
243 | } \ |
244 | \ |
245 | BLKC_STORE(PRE, ctx->iv, iv); \ |
246 | off = 0; \ |
247 | } \ |
248 | \ |
249 | /* --- Tidying up the tail end --- */ \ |
250 | \ |
251 | if (sz) { \ |
252 | small: \ |
253 | if (!d) \ |
254 | off += sz; \ |
255 | else do { \ |
256 | register octet x = s ? *s++ : 0; \ |
257 | *d++ = ctx->iv[off++] ^ x; \ |
258 | sz--; \ |
259 | } while (sz); \ |
260 | } \ |
261 | \ |
262 | /* --- Done --- */ \ |
263 | \ |
264 | ctx->off = off; \ |
265 | return; \ |
266 | } \ |
267 | \ |
268 | /* --- Generic cipher interface --- */ \ |
269 | \ |
270 | static const gcipher_ops gops; \ |
271 | \ |
272 | typedef struct gctx { \ |
273 | gcipher c; \ |
274 | pre##_ofbctx k; \ |
275 | } gctx; \ |
276 | \ |
277 | static gcipher *ginit(const void *k, size_t sz) \ |
278 | { \ |
279 | gctx *g = CREATE(gctx); \ |
280 | g->c.ops = &gops; \ |
281 | pre##_ofbinit(&g->k, k, sz, 0); \ |
282 | return (&g->c); \ |
283 | } \ |
284 | \ |
285 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
286 | { \ |
287 | gctx *g = (gctx *)c; \ |
288 | pre##_ofbencrypt(&g->k, s, t, sz); \ |
289 | } \ |
290 | \ |
291 | static void gdestroy(gcipher *c) \ |
292 | { \ |
293 | gctx *g = (gctx *)c; \ |
294 | DESTROY(g); \ |
295 | } \ |
296 | \ |
297 | static void gsetiv(gcipher *c, const void *iv) \ |
298 | { \ |
299 | gctx *g = (gctx *)c; \ |
300 | pre##_ofbsetiv(&g->k, iv); \ |
301 | } \ |
302 | \ |
303 | static void gbdry(gcipher *c) \ |
304 | { \ |
305 | gctx *g = (gctx *)c; \ |
306 | pre##_ofbbdry(&g->k); \ |
307 | } \ |
308 | \ |
309 | static const gcipher_ops gops = { \ |
310 | &pre##_ofb.b, \ |
311 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
312 | }; \ |
313 | \ |
314 | const gccipher pre##_ofb = { \ |
315 | { #pre "-ofb", PRE##_KEYSZ, PRE##_BLKSZ }, \ |
316 | ginit \ |
317 | }; \ |
318 | \ |
319 | /* --- Generic random number generator interface --- */ \ |
320 | \ |
321 | typedef struct grctx { \ |
322 | grand r; \ |
323 | pre##_ofbctx k; \ |
324 | } grctx; \ |
325 | \ |
326 | static void grdestroy(grand *r) \ |
327 | { \ |
328 | grctx *g = (grctx *)r; \ |
329 | DESTROY(g); \ |
330 | } \ |
331 | \ |
332 | static int grmisc(grand *r, unsigned op, ...) \ |
333 | { \ |
334 | grctx *g = (grctx *)r; \ |
335 | va_list ap; \ |
336 | int rc = 0; \ |
337 | octet buf[PRE##_BLKSZ]; \ |
338 | va_start(ap, op); \ |
339 | \ |
340 | switch (op) { \ |
341 | case GRAND_CHECK: \ |
342 | switch (va_arg(ap, unsigned)) { \ |
343 | case GRAND_CHECK: \ |
344 | case GRAND_SEEDINT: \ |
345 | case GRAND_SEEDUINT32: \ |
346 | case GRAND_SEEDBLOCK: \ |
347 | rc = 1; \ |
348 | break; \ |
349 | default: \ |
350 | rc = 0; \ |
351 | break; \ |
352 | } \ |
353 | break; \ |
354 | case GRAND_SEEDINT: \ |
355 | memset(buf, 0, sizeof(buf)); \ |
356 | STORE32(buf, va_arg(ap, unsigned)); \ |
357 | pre##_ofbsetiv(&g->k, buf); \ |
358 | break; \ |
359 | case GRAND_SEEDUINT32: \ |
360 | memset(buf, 0, sizeof(buf)); \ |
361 | STORE32(buf, va_arg(ap, uint32)); \ |
362 | pre##_ofbsetiv(&g->k, buf); \ |
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##_ofbsetiv(&g->k, p); \ |
373 | } break; \ |
374 | } \ |
375 | \ |
376 | va_end(ap); \ |
377 | return (rc); \ |
378 | } \ |
379 | \ |
380 | static octet grbyte(grand *r) \ |
381 | { \ |
382 | grctx *g = (grctx *)r; \ |
383 | octet o; \ |
384 | pre##_ofbencrypt(&g->k, 0, &o, 1); \ |
385 | return (o); \ |
386 | } \ |
387 | \ |
388 | static uint32 grword(grand *r) \ |
389 | { \ |
390 | grctx *g = (grctx *)r; \ |
391 | octet b[4]; \ |
392 | pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \ |
393 | return (LOAD32(b)); \ |
394 | } \ |
395 | \ |
396 | static void grfill(grand *r, void *p, size_t sz) \ |
397 | { \ |
398 | grctx *g = (grctx *)r; \ |
399 | pre##_ofbencrypt(&g->k, 0, p, sz); \ |
400 | } \ |
401 | \ |
402 | static const grand_ops grops = { \ |
403 | #pre "-ofb", \ |
404 | 0, \ |
405 | grmisc, grdestroy, \ |
406 | grword, grbyte, grword, grand_range, grfill \ |
407 | }; \ |
408 | \ |
409 | /* --- @pre_ofbrand@ --- * \ |
410 | * \ |
411 | * Arguments: @const void *k@ = pointer to key material \ |
412 | * @size_t sz@ = size of key material \ |
413 | * \ |
414 | * Returns: Pointer to generic random number generator interface. \ |
415 | * \ |
416 | * Use: Creates a random number interface wrapper around an \ |
417 | * OFB-mode block cipher. \ |
418 | */ \ |
419 | \ |
420 | grand *pre##_ofbrand(const void *k, size_t sz) \ |
421 | { \ |
422 | grctx *g = CREATE(grctx); \ |
423 | g->r.ops = &grops; \ |
424 | pre##_ofbinit(&g->k, k, sz, 0); \ |
425 | return (&g->r); \ |
426 | } \ |
427 | \ |
428 | OFB_TEST(PRE, pre) |
429 | |
430 | /*----- Test rig ----------------------------------------------------------*/ |
431 | |
432 | #ifdef TEST_RIG |
433 | |
434 | #include <stdio.h> |
435 | |
436 | #include "daftstory.h" |
437 | |
438 | /* --- @OFB_TEST@ --- * |
439 | * |
440 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
441 | * |
442 | * Use: Standard test rig for OFB functions. |
443 | */ |
444 | |
445 | #define OFB_TEST(PRE, pre) \ |
446 | \ |
447 | /* --- Initial plaintext for the test --- */ \ |
448 | \ |
449 | static const octet text[] = TEXT; \ |
450 | \ |
451 | /* --- Key and IV to use --- */ \ |
452 | \ |
453 | static const octet key[] = KEY; \ |
454 | static const octet iv[] = IV; \ |
455 | \ |
456 | /* --- Buffers for encryption and decryption output --- */ \ |
457 | \ |
458 | static octet ct[sizeof(text)]; \ |
459 | static octet pt[sizeof(text)]; \ |
460 | \ |
461 | static void hexdump(const octet *p, size_t sz) \ |
462 | { \ |
463 | const octet *q = p + sz; \ |
464 | for (sz = 0; p < q; p++, sz++) { \ |
465 | printf("%02x", *p); \ |
466 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
467 | putchar(':'); \ |
468 | } \ |
469 | } \ |
470 | \ |
471 | int main(void) \ |
472 | { \ |
473 | size_t sz = 0, rest; \ |
474 | pre##_ofbctx ctx; \ |
475 | int status = 0; \ |
476 | int done = 0; \ |
477 | pre##_ctx k; \ |
478 | \ |
479 | size_t keysz = PRE##_KEYSZ ? \ |
480 | PRE##_KEYSZ : strlen((const char *)key); \ |
481 | \ |
482 | fputs(#pre "-ofb: ", stdout); \ |
483 | \ |
484 | pre##_init(&k, key, keysz); \ |
485 | pre##_ofbsetkey(&ctx, &k); \ |
486 | \ |
487 | while (sz <= sizeof(text)) { \ |
488 | rest = sizeof(text) - sz; \ |
489 | memcpy(ct, text, sizeof(text)); \ |
490 | pre##_ofbsetiv(&ctx, iv); \ |
491 | pre##_ofbencrypt(&ctx, ct, ct, sz); \ |
492 | pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
493 | memcpy(pt, ct, sizeof(text)); \ |
494 | pre##_ofbsetiv(&ctx, iv); \ |
495 | pre##_ofbencrypt(&ctx, pt, pt, rest); \ |
496 | pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz); \ |
497 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
498 | done++; \ |
499 | if (sizeof(text) < 40 || done % 8 == 0) \ |
500 | fputc('.', stdout); \ |
501 | if (done % 480 == 0) \ |
502 | fputs("\n\t", stdout); \ |
503 | fflush(stdout); \ |
504 | } else { \ |
505 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
506 | status = 1; \ |
507 | printf("\tplaintext = "); hexdump(text, sz); \ |
508 | printf(", "); hexdump(text + sz, rest); \ |
509 | fputc('\n', stdout); \ |
510 | printf("\tciphertext = "); hexdump(ct, sz); \ |
511 | printf(", "); hexdump(ct + sz, rest); \ |
512 | fputc('\n', stdout); \ |
513 | printf("\trecovered text = "); hexdump(pt, sz); \ |
514 | printf(", "); hexdump(pt + sz, rest); \ |
515 | fputc('\n', stdout); \ |
516 | fputc('\n', stdout); \ |
517 | } \ |
518 | if (sz < 63) \ |
519 | sz++; \ |
520 | else \ |
521 | sz += 9; \ |
522 | } \ |
523 | \ |
524 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
525 | return (status); \ |
526 | } |
527 | |
528 | #else |
529 | # define OFB_TEST(PRE, pre) |
530 | #endif |
531 | |
532 | /*----- That's all, folks -------------------------------------------------*/ |
533 | |
534 | #ifdef __cplusplus |
535 | } |
536 | #endif |
537 | |
538 | #endif |