3 * $Id: cbc-def.h,v 1.1 1999/12/10 23:16:39 mdw Exp $
5 * Definitions for cipher block chaining mode
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.1 1999/12/10 23:16:39 mdw
34 * Split mode macros into interface and implementation.
38 #ifndef CATACOMB_CBC_DEF_H
39 #define CATACOMB_CBC_DEF_H
45 /*----- Header files ------------------------------------------------------*/
49 #include <mLib/bits.h>
52 #ifndef CATACOMB_BLKC_H
56 #ifndef CATACOMB_GCIPHER_H
60 /*----- Macros ------------------------------------------------------------*/
62 /* --- @CBC_DEF@ --- *
64 * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
66 * Use: Creates an implementation for CBC stealing mode.
69 #define CBC_DEF(PRE, pre) \
71 /* --- @pre_cbcgetiv@ --- * \
73 * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \
74 * @void *iv#@ = pointer to output data block \
78 * Use: Reads the currently set IV. Reading and setting an IV \
79 * is transparent to the CBC encryption or decryption \
83 void pre##_cbcgetiv(const pre##_cbcctx *ctx, void *iv) \
85 BLKC_STORE(PRE, iv, ctx->iv); \
88 /* --- @pre_cbcsetiv@ --- * \
90 * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
91 * @cnost void *iv@ = pointer to IV to set \
95 * Use: Sets the IV to use for subsequent encryption. \
98 void pre##_cbcsetiv(pre##_cbcctx *ctx, const void *iv) \
100 BLKC_LOAD(PRE, ctx->iv, iv); \
103 /* --- @pre_cbcsetkey@ --- * \
105 * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
106 * @const pre_ctx *k@ = pointer to cipher context \
110 * Use: Sets the CBC context to use a different cipher key. \
113 void pre##_cbcsetkey(pre##_cbcctx *ctx, const pre##_ctx *k) \
118 /* --- @pre_cbcinit@ --- * \
120 * Arguments: @pre_cbcctx *ctx@ = pointer to cipher context \
121 * @const void *key@ = pointer to the key buffer \
122 * @size_t sz@ = size of the key \
123 * @const void *iv@ = pointer to initialization vector \
127 * Use: Initializes a CBC context ready for use. The @iv@ \
128 * argument may be passed as a null pointer to set a zero \
129 * IV. Apart from that, this call is equivalent to calls \
130 * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \
133 void pre##_cbcinit(pre##_cbcctx *ctx, \
134 const void *key, size_t sz, \
137 static octet zero[PRE##_BLKSZ] = { 0 }; \
138 pre##_init(&ctx->ctx, key, sz); \
139 BLKC_LOAD(PRE, ctx->iv, iv ? iv : zero); \
142 /* --- @pre_cbcencrypt@ --- * \
144 * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
145 * @const void *src@ = pointer to source data \
146 * @void *dest@ = pointer to destination data \
147 * @size_t sz@ = size of block to be encrypted \
151 * Use: Encrypts a block with a block cipher in CBC mode, with \
152 * ciphertext stealing and other clever tricks. \
153 * Essentially, data can be encrypted in arbitrary sized \
154 * chunks, although decryption must use the same chunks. \
157 void pre##_cbcencrypt(pre##_cbcctx *ctx, \
158 const void *src, void *dest, \
161 const octet *s = src; \
164 /* --- Empty blocks are trivial --- */ \
169 /* --- Extra magical case for a short block --- * \
171 * Encrypt the IV, then exclusive-or the plaintext with the octets \
172 * of the encrypted IV, shifting ciphertext octets in instead. This \
173 * basically switches over to CFB. \
176 if (sz < PRE##_BLKSZ) { \
177 octet b[PRE##_BLKSZ]; \
180 pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
181 BLKC_STORE(PRE, b, ctx->iv); \
182 for (i = 0; i < sz; i++) \
183 d[i] = b[i] ^ s[i]; \
184 memmove(b, b + sz, PRE##_BLKSZ - sz); \
185 memcpy(b + PRE##_BLKSZ - sz, d, sz); \
186 BLKC_LOAD(PRE, ctx->iv, b); \
190 /* --- Do the main chunk of encryption --- * \
192 * This will do the whole lot if it's a whole number of blocks. For \
193 * each block, XOR it with the previous ciphertext in @iv@, encrypt, \
194 * and keep a copy of the ciphertext for the next block. \
197 while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
198 BLKC_XLOAD(PRE, ctx->iv, s); \
199 pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
200 BLKC_STORE(PRE, d, ctx->iv); \
206 /* --- Do the tail-end block and bit-left-over --- * \
208 * This isn't very efficient. That shouldn't matter much. \
212 octet b[PRE##_BLKSZ]; \
215 /* --- Let @sz@ be the size of the partial block --- */ \
219 /* --- First stage --- * \
221 * XOR the complete block with the current IV, and encrypt it. The \
222 * first part of the result is the partial ciphertext block. Don't \
223 * write that out yet, because I've not read the partial plaintext \
227 BLKC_XLOAD(PRE, ctx->iv, s); \
228 pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
229 BLKC_STORE(PRE, b, ctx->iv); \
231 /* --- Second stage --- * \
233 * Now XOR in the partial plaintext block, writing out the \
234 * ciphertext as I go. Then encrypt, and write the complete \
235 * ciphertext block. \
240 for (i = 0; i < sz; i++) { \
241 register octet x = b[i]; \
245 BLKC_LOAD(PRE, ctx->iv, b); \
246 pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
247 BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->iv); \
255 /* --- @pre_cbcdecrypt@ --- * \
257 * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
258 * @const void *src@ = pointer to source data \
259 * @void *dest@ = pointer to destination data \
260 * @size_t sz@ = size of block to be encrypted \
264 * Use: Decrypts a block with a block cipher in CBC mode, with \
265 * ciphertext stealing and other clever tricks. \
266 * Essentially, data can be encrypted in arbitrary sized \
267 * chunks, although decryption must use the same chunks. \
270 void pre##_cbcdecrypt(pre##_cbcctx *ctx, \
271 const void *src, void *dest, \
274 const octet *s = src; \
277 /* --- Empty blocks are trivial --- */ \
282 /* --- Extra magical case for a short block --- * \
284 * Encrypt the IV, then exclusive-or the ciphertext with the octets \
285 * of the encrypted IV, shifting ciphertext octets in instead. This \
286 * basically switches over to CFB. \
289 if (sz < PRE##_BLKSZ) { \
290 octet b[PRE##_BLKSZ], c[PRE##_BLKSZ]; \
293 pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
294 BLKC_STORE(PRE, b, ctx->iv); \
295 for (i = 0; i < sz; i++) { \
296 register octet x = s[i]; \
300 memmove(b, b + sz, PRE##_BLKSZ - sz); \
301 memcpy(b + PRE##_BLKSZ - sz, c, sz); \
302 BLKC_LOAD(PRE, ctx->iv, b); \
306 /* --- Do the main chunk of decryption --- * \
308 * This will do the whole lot if it's a whole number of blocks. For \
309 * each block, decrypt, XOR it with the previous ciphertext in @iv@, \
310 * and keep a copy of the ciphertext for the next block. \
313 while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
314 uint32 b[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
315 BLKC_LOAD(PRE, niv, s); \
316 pre##_dblk(&ctx->ctx, niv, b); \
317 BLKC_XSTORE(PRE, d, b, ctx->iv); \
318 BLKC_MOVE(PRE, ctx->iv, niv); \
324 /* --- Do the tail-end block and bit-left-over --- * \
326 * This isn't very efficient. That shouldn't matter much. \
330 octet b[PRE##_BLKSZ]; \
331 uint32 bk[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
334 /* --- Let @sz@ be the size of the partial block --- */ \
338 /* --- First stage --- * \
340 * Take the complete ciphertext block, and decrypt it. This block \
341 * is carried over for the next encryption operation. \
344 BLKC_LOAD(PRE, niv, s); \
345 pre##_dblk(&ctx->ctx, niv, bk); \
347 /* --- Second stage --- * \
349 * XORing the first few bytes of this with the partial ciphertext \
350 * block recovers the partial plaintext block. At the same time, \
351 * write the partial ciphertext block's contents in ready for stage \
355 BLKC_STORE(PRE, b, bk); \
358 for (i = 0; i < sz; i++) { \
359 register octet x = s[i]; \
364 /* --- Third stage --- * \
366 * Decrypt the block we've got left, and XOR with the initial IV to \
367 * recover the complete plaintext block. \
370 BLKC_LOAD(PRE, bk, b); \
371 pre##_dblk(&ctx->ctx, bk, bk); \
372 BLKC_XSTORE(PRE, d - PRE##_BLKSZ, bk, ctx->iv); \
373 BLKC_MOVE(PRE, ctx->iv, niv); \
381 /* --- Generic cipher interface --- */ \
383 static const gcipher_ops gops; \
385 typedef struct gctx { \
390 static gcipher *ginit(const void *k, size_t sz) \
392 gctx *g = CREATE(gctx); \
394 pre##_cbcinit(&g->k, k, sz, 0); \
398 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \
400 gctx *g = (gctx *)c; \
401 pre##_cbcencrypt(&g->k, s, t, sz); \
404 static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \
406 gctx *g = (gctx *)c; \
407 pre##_cbcdecrypt(&g->k, s, t, sz); \
410 static void gdestroy(gcipher *c) \
412 gctx *g = (gctx *)c; \
416 static void gsetiv(gcipher *c, const void *iv) \
418 gctx *g = (gctx *)c; \
419 pre##_cbcsetiv(&g->k, iv); \
422 static const gcipher_ops gops = { \
424 gencrypt, gdecrypt, gdestroy, gsetiv, 0 \
427 const gccipher pre##_cbc = { \
428 { #pre "-cbc", PRE##_KEYSZ, PRE##_BLKSZ }, \
434 /*----- Test rig ----------------------------------------------------------*/
440 #include "daftstory.h"
442 /* --- @CBC_TEST@ --- *
444 * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
446 * Use: Standard test rig for CBC functions.
449 #define CBC_TEST(PRE, pre) \
451 /* --- Initial plaintext for the test --- */ \
453 static const octet text[] = TEXT; \
455 /* --- Key and IV to use --- */ \
457 static const octet key[] = KEY; \
458 static const octet iv[] = IV; \
460 /* --- Buffers for encryption and decryption output --- */ \
462 static octet ct[sizeof(text)]; \
463 static octet pt[sizeof(text)]; \
465 static void hexdump(const octet *p, size_t sz) \
467 const octet *q = p + sz; \
468 for (sz = 0; p < q; p++, sz++) { \
469 printf("%02x", *p); \
470 if ((sz + 1) % PRE##_BLKSZ == 0) \
477 size_t sz = 0, rest; \
483 size_t keysz = PRE##_KEYSZ ? \
484 PRE##_KEYSZ : strlen((const char *)key); \
486 fputs(#pre "-cbc: ", stdout); \
488 pre##_init(&k, key, keysz); \
489 pre##_cbcsetkey(&ctx, &k); \
491 while (sz <= sizeof(text)) { \
492 rest = sizeof(text) - sz; \
493 memcpy(ct, text, sizeof(text)); \
494 pre##_cbcsetiv(&ctx, iv); \
495 pre##_cbcencrypt(&ctx, ct, ct, sz); \
496 pre##_cbcencrypt(&ctx, ct + sz, ct + sz, rest); \
497 memcpy(pt, ct, sizeof(text)); \
498 pre##_cbcsetiv(&ctx, iv); \
499 pre##_cbcdecrypt(&ctx, pt, pt, sz); \
500 pre##_cbcdecrypt(&ctx, pt + sz, pt + sz, rest); \
501 if (memcmp(pt, text, sizeof(text)) == 0) { \
503 if (sizeof(text) < 40 || done % 8 == 0) \
504 fputc('.', stdout); \
505 if (done % 480 == 0) \
506 fputs("\n\t", stdout); \
509 printf("\nError (sz = %lu)\n", (unsigned long)sz); \
511 printf("\tplaintext = "); hexdump(text, sz); \
512 printf(", "); hexdump(text + sz, rest); \
513 fputc('\n', stdout); \
514 printf("\tciphertext = "); hexdump(ct, sz); \
515 printf(", "); hexdump(ct + sz, rest); \
516 fputc('\n', stdout); \
517 printf("\trecovered text = "); hexdump(pt, sz); \
518 printf(", "); hexdump(pt + sz, rest); \
519 fputc('\n', stdout); \
520 fputc('\n', stdout); \
528 fputs(status ? " failed\n" : " ok\n", stdout); \
533 # define CBC_TEST(PRE, pre)
536 /*----- That's all, folks -------------------------------------------------*/