79ba130c |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: cfb-def.h,v 1.1 1999/12/10 23:16:39 mdw Exp $ |
4 | * |
5 | * Definitions for ciphertext 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: cfb-def.h,v $ |
33 | * Revision 1.1 1999/12/10 23:16:39 mdw |
34 | * Split mode macros into interface and implementation. |
35 | * |
36 | */ |
37 | |
38 | #ifndef CATACOMB_CFB_DEF_H |
39 | #define CATACOMB_CFB_DEF_H |
40 | |
41 | #ifdef __cplusplus |
42 | extern "C" { |
43 | #endif |
44 | |
45 | /*----- Header files ------------------------------------------------------*/ |
46 | |
47 | #include <string.h> |
48 | |
49 | #include <mLib/bits.h> |
50 | #include <mLib/sub.h> |
51 | |
52 | #ifndef CATACOMB_BLKC_H |
53 | # include "blkc.h" |
54 | #endif |
55 | |
56 | #ifndef CATACOMB_GCIPHER_H |
57 | # include "gcipher.h" |
58 | #endif |
59 | |
60 | #ifndef CATACOMB_PARANOIA_H |
61 | # include "paranoia.h" |
62 | #endif |
63 | |
64 | /*----- Macros ------------------------------------------------------------*/ |
65 | |
66 | /* --- @CFB_DEF@ --- * |
67 | * |
68 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
69 | * |
70 | * Use: Creates an implementation for CFB mode. |
71 | */ |
72 | |
73 | #define CFB_DEF(PRE, pre) \ |
74 | \ |
75 | /* --- @pre_cfbgetiv@ --- * \ |
76 | * \ |
77 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ |
78 | * @void *iv#@ = pointer to output data block \ |
79 | * \ |
80 | * Returns: --- \ |
81 | * \ |
82 | * Use: Reads the currently set IV. Reading and setting an IV \ |
83 | * is not transparent to the cipher. It will add a `step' \ |
84 | * which must be matched by a similar operation during \ |
85 | * decryption. \ |
86 | */ \ |
87 | \ |
88 | void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \ |
89 | { \ |
90 | octet *p = iv; \ |
91 | int off = ctx->off; \ |
92 | int rest = PRE##_BLKSZ - off; \ |
93 | memcpy(p, ctx->iv + off, rest); \ |
94 | memcpy(p + rest, ctx->iv, off); \ |
95 | } \ |
96 | \ |
97 | /* --- @pre_cfbsetiv@ --- * \ |
98 | * \ |
99 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
100 | * @cnost void *iv@ = pointer to IV to set \ |
101 | * \ |
102 | * Returns: --- \ |
103 | * \ |
104 | * Use: Sets the IV to use for subsequent encryption. \ |
105 | */ \ |
106 | \ |
107 | void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \ |
108 | { \ |
109 | uint32 niv[PRE##_BLKSZ / 4]; \ |
110 | BLKC_LOAD(PRE, niv, iv); \ |
111 | pre##_eblk(&ctx->ctx, niv, niv); \ |
112 | BLKC_STORE(PRE, ctx->iv, niv); \ |
113 | ctx->off = 0; \ |
114 | } \ |
115 | \ |
116 | /* --- @pre_cfbbdry@ --- * \ |
117 | * \ |
118 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
119 | * \ |
120 | * Returns: --- \ |
121 | * \ |
122 | * Use: Inserts a boundary during encryption. Successful \ |
123 | * decryption must place a similar boundary. \ |
124 | */ \ |
125 | \ |
126 | void pre##_cfbbdry(pre##_cfbctx *ctx) \ |
127 | { \ |
128 | octet iv[PRE##_BLKSZ]; \ |
129 | pre##_cfbgetiv(ctx, iv); \ |
130 | pre##_cfbsetiv(ctx, iv); \ |
131 | BURN(iv); \ |
132 | } \ |
133 | \ |
134 | /* --- @pre_cfbsetkey@ --- * \ |
135 | * \ |
136 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
137 | * @const pre_ctx *k@ = pointer to cipher context \ |
138 | * \ |
139 | * Returns: --- \ |
140 | * \ |
141 | * Use: Sets the CFB context to use a different cipher key. \ |
142 | */ \ |
143 | \ |
144 | void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \ |
145 | { \ |
146 | ctx->ctx = *k; \ |
147 | } \ |
148 | \ |
149 | /* --- @pre_cfbinit@ --- * \ |
150 | * \ |
151 | * Arguments: @pre_cfbctx *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 CFB context ready for use. You should \ |
159 | * ensure that the IV chosen is unique: reusing an IV will \ |
160 | * compromise the security of at least the first block \ |
161 | * encrypted. This is equivalent to calls to @pre_init@, \ |
162 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ |
163 | */ \ |
164 | \ |
165 | void pre##_cfbinit(pre##_cfbctx *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##_cfbsetiv(ctx, iv ? iv : zero); \ |
172 | } \ |
173 | \ |
174 | /* --- @pre_cfbencrypt@ --- * \ |
175 | * \ |
176 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
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 a block with a block cipher in CFB mode. The \ |
184 | * input block may be arbitrary in size. CFB mode is not \ |
185 | * sensitive to block boundaries. \ |
186 | */ \ |
187 | \ |
188 | void pre##_cfbencrypt(pre##_cfbctx *ctx, \ |
189 | const void *src, void *dest, \ |
190 | size_t sz) \ |
191 | { \ |
192 | const octet *s = src; \ |
193 | octet *d = dest; \ |
194 | int off = ctx->off; \ |
195 | \ |
196 | /* --- Empty blocks are trivial --- */ \ |
197 | \ |
198 | if (!sz) \ |
199 | return; \ |
200 | \ |
201 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
202 | \ |
203 | if (sz < PRE##_BLKSZ - off) \ |
204 | goto small; \ |
205 | \ |
206 | /* --- Finish off what's left in my buffer --- */ \ |
207 | \ |
208 | while (off < PRE##_BLKSZ) { \ |
209 | register octet x = *s++; \ |
210 | *d++ = ctx->iv[off++] ^= x; \ |
211 | sz--; \ |
212 | } \ |
213 | \ |
214 | /* --- Main encryption loop --- */ \ |
215 | \ |
216 | { \ |
217 | uint32 iv[PRE##_BLKSZ / 4]; \ |
218 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
219 | \ |
220 | for (;;) { \ |
221 | pre##_eblk(&ctx->ctx, iv, iv); \ |
222 | if (sz < PRE##_BLKSZ) \ |
223 | break; \ |
224 | BLKC_XLOAD(PRE, iv, s); \ |
225 | BLKC_STORE(PRE, d, iv); \ |
226 | s += PRE##_BLKSZ; \ |
227 | d += PRE##_BLKSZ; \ |
228 | sz -= PRE##_BLKSZ; \ |
229 | } \ |
230 | off = 0; \ |
231 | BLKC_STORE(PRE, ctx->iv, iv); \ |
232 | } \ |
233 | \ |
234 | /* --- Tidying up the tail end --- */ \ |
235 | \ |
236 | if (sz) { \ |
237 | small: \ |
238 | do { \ |
239 | register octet x = *s++; \ |
240 | *d++ = ctx->iv[off++] ^= x; \ |
241 | sz--; \ |
242 | } while (sz); \ |
243 | } \ |
244 | \ |
245 | /* --- Done --- */ \ |
246 | \ |
247 | ctx->off = off; \ |
248 | return; \ |
249 | } \ |
250 | \ |
251 | /* --- @pre_cfbencrypt@ --- * \ |
252 | * \ |
253 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
254 | * @const void *src@ = pointer to source data \ |
255 | * @void *dest@ = pointer to destination data \ |
256 | * @size_t sz@ = size of block to be encrypted \ |
257 | * \ |
258 | * Returns: --- \ |
259 | * \ |
260 | * Use: Decrypts a block with a block cipher in CFB mode. The \ |
261 | * input block may be arbitrary in size. CFB mode is not \ |
262 | * sensitive to block boundaries. \ |
263 | */ \ |
264 | \ |
265 | void pre##_cfbdecrypt(pre##_cfbctx *ctx, \ |
266 | const void *src, void *dest, \ |
267 | size_t sz) \ |
268 | { \ |
269 | const octet *s = src; \ |
270 | octet *d = dest; \ |
271 | int off = ctx->off; \ |
272 | \ |
273 | /* --- Empty blocks are trivial --- */ \ |
274 | \ |
275 | if (!sz) \ |
276 | return; \ |
277 | \ |
278 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
279 | \ |
280 | if (sz < PRE##_BLKSZ - off) \ |
281 | goto small; \ |
282 | \ |
283 | /* --- Finish off what's left in my buffer --- */ \ |
284 | \ |
285 | while (off < PRE##_BLKSZ) { \ |
286 | register octet x = *s++; \ |
287 | *d++ = ctx->iv[off] ^ x; \ |
288 | ctx->iv[off++] = x; \ |
289 | sz--; \ |
290 | } \ |
291 | \ |
292 | /* --- Main encryption loop --- */ \ |
293 | \ |
294 | { \ |
295 | uint32 iv[PRE##_BLKSZ / 4]; \ |
296 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
297 | \ |
298 | for (;;) { \ |
299 | uint32 x[PRE##_BLKSZ / 4]; \ |
300 | pre##_eblk(&ctx->ctx, iv, iv); \ |
301 | if (sz < PRE##_BLKSZ) \ |
302 | break; \ |
303 | BLKC_LOAD(PRE, x, s); \ |
304 | BLKC_XSTORE(PRE, d, iv, x); \ |
305 | BLKC_MOVE(PRE, iv, x); \ |
306 | s += PRE##_BLKSZ; \ |
307 | d += PRE##_BLKSZ; \ |
308 | sz -= PRE##_BLKSZ; \ |
309 | } \ |
310 | off = 0; \ |
311 | BLKC_STORE(PRE, ctx->iv, iv); \ |
312 | } \ |
313 | \ |
314 | /* --- Tidying up the tail end --- */ \ |
315 | \ |
316 | if (sz) { \ |
317 | small: \ |
318 | do { \ |
319 | register octet x = *s++; \ |
320 | *d++ = ctx->iv[off] ^ x; \ |
321 | ctx->iv[off++] = x; \ |
322 | sz--; \ |
323 | } while (sz); \ |
324 | } \ |
325 | \ |
326 | /* --- Done --- */ \ |
327 | \ |
328 | ctx->off = off; \ |
329 | return; \ |
330 | } \ |
331 | \ |
332 | /* --- Generic cipher interface --- */ \ |
333 | \ |
334 | static const gcipher_ops gops; \ |
335 | \ |
336 | typedef struct gctx { \ |
337 | gcipher c; \ |
338 | pre##_cfbctx k; \ |
339 | } gctx; \ |
340 | \ |
341 | static gcipher *ginit(const void *k, size_t sz) \ |
342 | { \ |
343 | gctx *g = CREATE(gctx); \ |
344 | g->c.ops = &gops; \ |
345 | pre##_cfbinit(&g->k, k, sz, 0); \ |
346 | return (&g->c); \ |
347 | } \ |
348 | \ |
349 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
350 | { \ |
351 | gctx *g = (gctx *)c; \ |
352 | pre##_cfbencrypt(&g->k, s, t, sz); \ |
353 | } \ |
354 | \ |
355 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
356 | { \ |
357 | gctx *g = (gctx *)c; \ |
358 | pre##_cfbdecrypt(&g->k, s, t, sz); \ |
359 | } \ |
360 | \ |
361 | static void gdestroy(gcipher *c) \ |
362 | { \ |
363 | gctx *g = (gctx *)c; \ |
364 | DESTROY(g); \ |
365 | } \ |
366 | \ |
367 | static void gsetiv(gcipher *c, const void *iv) \ |
368 | { \ |
369 | gctx *g = (gctx *)c; \ |
370 | pre##_cfbsetiv(&g->k, iv); \ |
371 | } \ |
372 | \ |
373 | static void gbdry(gcipher *c) \ |
374 | { \ |
375 | gctx *g = (gctx *)c; \ |
376 | pre##_cfbbdry(&g->k); \ |
377 | } \ |
378 | \ |
379 | static const gcipher_ops gops = { \ |
380 | &pre##_cfb.b, \ |
381 | gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \ |
382 | }; \ |
383 | \ |
384 | const gccipher pre##_cfb = { \ |
385 | { #pre "-cfb", PRE##_KEYSZ, PRE##_BLKSZ }, \ |
386 | ginit \ |
387 | }; \ |
388 | \ |
389 | CFB_TEST(PRE, pre) |
390 | |
391 | /*----- Test rig ----------------------------------------------------------*/ |
392 | |
393 | #ifdef TEST_RIG |
394 | |
395 | #include <stdio.h> |
396 | |
397 | #include "daftstory.h" |
398 | |
399 | /* --- @CFB_TEST@ --- * |
400 | * |
401 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
402 | * |
403 | * Use: Standard test rig for CFB functions. |
404 | */ |
405 | |
406 | #define CFB_TEST(PRE, pre) \ |
407 | \ |
408 | /* --- Initial plaintext for the test --- */ \ |
409 | \ |
410 | static const octet text[] = TEXT; \ |
411 | \ |
412 | /* --- Key and IV to use --- */ \ |
413 | \ |
414 | static const octet key[] = KEY; \ |
415 | static const octet iv[] = IV; \ |
416 | \ |
417 | /* --- Buffers for encryption and decryption output --- */ \ |
418 | \ |
419 | static octet ct[sizeof(text)]; \ |
420 | static octet pt[sizeof(text)]; \ |
421 | \ |
422 | static void hexdump(const octet *p, size_t sz) \ |
423 | { \ |
424 | const octet *q = p + sz; \ |
425 | for (sz = 0; p < q; p++, sz++) { \ |
426 | printf("%02x", *p); \ |
427 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
428 | putchar(':'); \ |
429 | } \ |
430 | } \ |
431 | \ |
432 | int main(void) \ |
433 | { \ |
434 | size_t sz = 0, rest; \ |
435 | pre##_cfbctx ctx; \ |
436 | int status = 0; \ |
437 | int done = 0; \ |
438 | pre##_ctx k; \ |
439 | \ |
440 | size_t keysz = PRE##_KEYSZ ? \ |
441 | PRE##_KEYSZ : strlen((const char *)key); \ |
442 | \ |
443 | fputs(#pre "-cfb: ", stdout); \ |
444 | \ |
445 | pre##_init(&k, key, keysz); \ |
446 | pre##_cfbsetkey(&ctx, &k); \ |
447 | \ |
448 | while (sz <= sizeof(text)) { \ |
449 | rest = sizeof(text) - sz; \ |
450 | memcpy(ct, text, sizeof(text)); \ |
451 | pre##_cfbsetiv(&ctx, iv); \ |
452 | pre##_cfbencrypt(&ctx, ct, ct, sz); \ |
453 | pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
454 | memcpy(pt, ct, sizeof(text)); \ |
455 | pre##_cfbsetiv(&ctx, iv); \ |
456 | pre##_cfbdecrypt(&ctx, pt, pt, rest); \ |
457 | pre##_cfbdecrypt(&ctx, pt + rest, pt + rest, sz); \ |
458 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
459 | done++; \ |
460 | if (sizeof(text) < 40 || done % 8 == 0) \ |
461 | fputc('.', stdout); \ |
462 | if (done % 480 == 0) \ |
463 | fputs("\n\t", stdout); \ |
464 | fflush(stdout); \ |
465 | } else { \ |
466 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
467 | status = 1; \ |
468 | printf("\tplaintext = "); hexdump(text, sz); \ |
469 | printf(", "); hexdump(text + sz, rest); \ |
470 | fputc('\n', stdout); \ |
471 | printf("\tciphertext = "); hexdump(ct, sz); \ |
472 | printf(", "); hexdump(ct + sz, rest); \ |
473 | fputc('\n', stdout); \ |
474 | printf("\trecovered text = "); hexdump(pt, sz); \ |
475 | printf(", "); hexdump(pt + sz, rest); \ |
476 | fputc('\n', stdout); \ |
477 | fputc('\n', stdout); \ |
478 | } \ |
479 | if (sz < 63) \ |
480 | sz++; \ |
481 | else \ |
482 | sz += 9; \ |
483 | } \ |
484 | \ |
485 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
486 | return (status); \ |
487 | } |
488 | |
489 | #else |
490 | # define CFB_TEST(PRE, pre) |
491 | #endif |
492 | |
493 | /*----- That's all, folks -------------------------------------------------*/ |
494 | |
495 | #ifdef __cplusplus |
496 | } |
497 | #endif |
498 | |
499 | #endif |