chiark - git - mdw - catacomb/blob - counter-def.h

   1 /* -*-c-*-
   2  *
   3  * $Id: counter-def.h,v 1.2 2001/06/17 00:10:51 mdw Exp $
   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
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: counter-def.h,v $
  33  * Revision 1.2  2001/06/17 00:10:51  mdw
  34  * Typesetting fixes
  35  *
  36  * Revision 1.1  2000/06/17 10:51:42  mdw
  37  * Counter mode ciphers and pseudo-random generator.
  38  *
  39  */
  40
  41 #ifndef CATACOMB_COUNTER_DEF_H
  42 #define CATACOMB_COUNTER_DEF_H
  43
  44 #ifdef __cplusplus
  45   extern "C" {
  46 #endif
  47
  48 /*----- Header files ------------------------------------------------------*/
  49
  50 #include <stdarg.h>
  51 #include <string.h>
  52
  53 #include <mLib/bits.h>
  54 #include <mLib/sub.h>
  55
  56 #ifndef CATACOMB_ARENA_H
  57 #  include "arena.h"
  58 #endif
  59
  60 #ifndef CATACOMB_BLKC_H
  61 #  include "blkc.h"
  62 #endif
  63
  64 #ifndef CATACOMB_GCIPHER_H
  65 #  include "gcipher.h"
  66 #endif
  67
  68 #ifndef CATACOMB_PARANOIA_H
  69 #  include "paranoia.h"
  70 #endif
  71
  72 /*----- Macros ------------------------------------------------------------*/
  73
  74 /* --- @COUNTER_DEF@ --- *
  75  *
  76  * Arguments:   @PRE@, @pre@ = prefixes for the underlying block cipher
  77  *
  78  * Use:         Creates definitions for counter mode.
  79  */
  80
  81 #define COUNTER_DEF(PRE, pre)                                           \
  82                                                                         \
  83 /* --- @pre_countergetiv@ --- *                                         \
  84  *                                                                      \
  85  * Arguments:   @const pre_counterctx *ctx@ = pointer to counter        \
  86  *                      context                                         \
  87  *              @void *iv@ = pointer to output data block               \
  88  *                                                                      \
  89  * Returns:     ---                                                     \
  90  *                                                                      \
  91  * Use:         Reads the currently set IV.  Reading and setting an IV  \
  92  *              is not transparent to the cipher.  It will add a `step' \
  93  *              which must be matched by a similar operation during     \
  94  *              decryption.                                             \
  95  */                                                                     \
  96                                                                         \
  97 void pre##_countergetiv(const pre##_counterctx *ctx, void *iv)          \
  98 {                                                                       \
  99   BLKC_STORE(PRE, iv, ctx->n);                                          \
 100 }                                                                       \
 101                                                                         \
 102 /* --- @pre_countersetiv@ --- *                                         \
 103  *                                                                      \
 104  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 105  *              @cnost void *iv@ = pointer to IV to set                 \
 106  *                                                                      \
 107  * Returns:     ---                                                     \
 108  *                                                                      \
 109  * Use:         Sets the IV to use for subsequent encryption.           \
 110  */                                                                     \
 111                                                                         \
 112 void pre##_countersetiv(pre##_counterctx *ctx, const void *iv)          \
 113 {                                                                       \
 114   BLKC_LOAD(PRE, ctx->n, iv);                                           \
 115   ctx->off = PRE##_BLKSZ;                                               \
 116 }                                                                       \
 117                                                                         \
 118 /* --- @pre_counterbdry@ --- *                                          \
 119  *                                                                      \
 120  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 121  *                                                                      \
 122  * Returns:     ---                                                     \
 123  *                                                                      \
 124  * Use:         Inserts a boundary during encryption.  Successful       \
 125  *              decryption must place a similar boundary.               \
 126  */                                                                     \
 127                                                                         \
 128 void pre##_counterbdry(pre##_counterctx *ctx)                           \
 129 {                                                                       \
 130   BLKC_STEP(PRE, ctx->n);                                               \
 131   ctx->off = PRE##_BLKSZ;                                               \
 132 }                                                                       \
 133                                                                         \
 134 /* --- @pre_countersetkey@ --- *                                        \
 135  *                                                                      \
 136  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 137  *              @const pre_ctx *k@ = pointer to cipher context          \
 138  *                                                                      \
 139  * Returns:     ---                                                     \
 140  *                                                                      \
 141  * Use:         Sets the counter context to use a different cipher key. \
 142  */                                                                     \
 143                                                                         \
 144 void pre##_countersetkey(pre##_counterctx *ctx, const pre##_ctx *k)     \
 145 {                                                                       \
 146   ctx->ctx = *k;                                                        \
 147 }                                                                       \
 148                                                                         \
 149 /* --- @pre_counterinit@ --- *                                          \
 150  *                                                                      \
 151  * Arguments:   @pre_counterctx *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 counter context ready for use.  You       \
 159  *              should ensure that the IV chosen is unique: reusing an  \
 160  *              IV will compromise the security of the entire           \
 161  *              plaintext.  This is equivalent to calls to @pre_init@,  \
 162  *              @pre_countersetkey@ and @pre_countersetiv@.             \
 163  */                                                                     \
 164                                                                         \
 165 void pre##_counterinit(pre##_counterctx *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##_countersetiv(ctx, iv ? iv : zero);                              \
 172 }                                                                       \
 173                                                                         \
 174 /* --- @pre_counterencrypt@ --- *                                       \
 175  *                                                                      \
 176  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 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 or decrypts a block with a block cipher in     \
 184  *              counter mode: encryption and decryption are the same in \
 185  *              counter.  The destination may be null to just churn the \
 186  *              feedback round for a bit.  The source may be null to    \
 187  *              use the cipher as a random data generator.              \
 188  */                                                                     \
 189                                                                         \
 190 void pre##_counterencrypt(pre##_counterctx *ctx,                        \
 191                           const void *src, void *dest,                  \
 192                           size_t sz)                                    \
 193 {                                                                       \
 194   const octet *s = src;                                                 \
 195   octet *d = dest;                                                      \
 196   unsigned off = ctx->off;                                              \
 197                                                                         \
 198   /* --- Empty blocks are trivial --- */                                \
 199                                                                         \
 200   if (!sz)                                                              \
 201     return;                                                             \
 202                                                                         \
 203   /* --- If I can deal with the block from my buffer, do that --- */    \
 204                                                                         \
 205   if (sz < PRE##_BLKSZ - off)                                           \
 206     goto small;                                                         \
 207                                                                         \
 208   /* --- Finish off what's left in my buffer --- */                     \
 209                                                                         \
 210   if (!d)                                                               \
 211     sz -= PRE##_BLKSZ - off;                                            \
 212   else {                                                                \
 213     while (off < PRE##_BLKSZ) {                                         \
 214       register octet x = s ? *s++ : 0;                                  \
 215       *d++ = ctx->buf[off++] ^ x;                                       \
 216       sz--;                                                             \
 217     }                                                                   \
 218   }                                                                     \
 219                                                                         \
 220   /* --- Main encryption loop --- */                                    \
 221                                                                         \
 222   {                                                                     \
 223     uint32 n[PRE##_BLKSZ / 4];                                          \
 224                                                                         \
 225     for (;;) {                                                          \
 226       pre##_eblk(&ctx->ctx, ctx->n, n);                                 \
 227       BLKC_STEP(PRE, ctx->n);                                           \
 228       if (sz < PRE##_BLKSZ)                                             \
 229         break;                                                          \
 230       if (d) {                                                          \
 231         if (!s)                                                         \
 232           BLKC_STORE(PRE, d, n);                                        \
 233         else {                                                          \
 234           uint32 x[PRE##_BLKSZ / 4];                                    \
 235           BLKC_LOAD(PRE, x, s);                                         \
 236           BLKC_XSTORE(PRE, d, n, x);                                    \
 237           s += PRE##_BLKSZ;                                             \
 238         }                                                               \
 239         d += PRE##_BLKSZ;                                               \
 240       }                                                                 \
 241       sz -= PRE##_BLKSZ;                                                \
 242     }                                                                   \
 243                                                                         \
 244     BLKC_STORE(PRE, ctx->buf, n);                                       \
 245     off = 0;                                                            \
 246   }                                                                     \
 247                                                                         \
 248   /* --- Tidying up the tail end --- */                                 \
 249                                                                         \
 250   if (sz) {                                                             \
 251   small:                                                                \
 252     if (!d)                                                             \
 253       off += sz;                                                        \
 254     else do {                                                           \
 255       register octet x = s ? *s++ : 0;                                  \
 256       *d++ = ctx->buf[off++] ^ x;                                       \
 257       sz--;                                                             \
 258     } while (sz);                                                       \
 259   }                                                                     \
 260                                                                         \
 261   /* --- Done --- */                                                    \
 262                                                                         \
 263   ctx->off = off;                                                       \
 264   return;                                                               \
 265 }                                                                       \
 266                                                                         \
 267 /* --- Generic cipher interface --- */                                  \
 268                                                                         \
 269 static const gcipher_ops gops;                                          \
 270                                                                         \
 271 typedef struct gctx {                                                   \
 272   gcipher c;                                                            \
 273   pre##_counterctx k;                                                   \
 274 } gctx;                                                                 \
 275                                                                         \
 276 static gcipher *ginit(const void *k, size_t sz)                         \
 277 {                                                                       \
 278   gctx *g = S_CREATE(gctx);                                             \
 279   g->c.ops = &gops;                                                     \
 280   pre##_counterinit(&g->k, k, sz, 0);                                   \
 281   return (&g->c);                                                       \
 282 }                                                                       \
 283                                                                         \
 284 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz)     \
 285 {                                                                       \
 286   gctx *g = (gctx *)c;                                                  \
 287   pre##_counterencrypt(&g->k, s, t, sz);                                \
 288 }                                                                       \
 289                                                                         \
 290 static void gdestroy(gcipher *c)                                        \
 291 {                                                                       \
 292   gctx *g = (gctx *)c;                                                  \
 293   BURN(*g);                                                             \
 294   S_DESTROY(g);                                                         \
 295 }                                                                       \
 296                                                                         \
 297 static void gsetiv(gcipher *c, const void *iv)                          \
 298 {                                                                       \
 299   gctx *g = (gctx *)c;                                                  \
 300   pre##_countersetiv(&g->k, iv);                                        \
 301 }                                                                       \
 302                                                                         \
 303 static void gbdry(gcipher *c)                                           \
 304 {                                                                       \
 305   gctx *g = (gctx *)c;                                                  \
 306   pre##_counterbdry(&g->k);                                             \
 307 }                                                                       \
 308                                                                         \
 309 static const gcipher_ops gops = {                                       \
 310   &pre##_counter,                                                       \
 311   gencrypt, gencrypt, gdestroy, gsetiv, gbdry                           \
 312 };                                                                      \
 313                                                                         \
 314 const gccipher pre##_counter = {                                        \
 315   #pre "-counter", pre##_keysz, PRE##_BLKSZ,                            \
 316   ginit                                                                 \
 317 };                                                                      \
 318                                                                         \
 319 /* --- Generic random number generator interface --- */                 \
 320                                                                         \
 321 typedef struct grctx {                                                  \
 322   grand r;                                                              \
 323   pre##_counterctx k;                                                   \
 324 } grctx;                                                                \
 325                                                                         \
 326 static void grdestroy(grand *r)                                         \
 327 {                                                                       \
 328   grctx *g = (grctx *)r;                                                \
 329   BURN(*g);                                                             \
 330   S_DESTROY(g);                                                         \
 331 }                                                                       \
 332                                                                         \
 333 static int grmisc(grand *r, unsigned op, ...)                           \
 334 {                                                                       \
 335   grctx *g = (grctx *)r;                                                \
 336   va_list ap;                                                           \
 337   int rc = 0;                                                           \
 338   octet buf[PRE##_BLKSZ];                                               \
 339   va_start(ap, op);                                                     \
 340                                                                         \
 341   switch (op) {                                                         \
 342     case GRAND_CHECK:                                                   \
 343       switch (va_arg(ap, unsigned)) {                                   \
 344         case GRAND_CHECK:                                               \
 345         case GRAND_SEEDINT:                                             \
 346         case GRAND_SEEDUINT32:                                          \
 347         case GRAND_SEEDBLOCK:                                           \
 348         case GRAND_SEEDRAND:                                            \
 349           rc = 1;                                                       \
 350           break;                                                        \
 351         default:                                                        \
 352           rc = 0;                                                       \
 353           break;                                                        \
 354       }                                                                 \
 355       break;                                                            \
 356     case GRAND_SEEDINT:                                                 \
 357       BLKC_SET(PRE, g->k.n, va_arg(ap, unsigned));                      \
 358       g->k.off = PRE##_BLKSZ;                                           \
 359       break;                                                            \
 360     case GRAND_SEEDUINT32:                                              \
 361       BLKC_SET(PRE, g->k.n, va_arg(ap, uint32));                        \
 362       g->k.off = PRE##_BLKSZ;                                           \
 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##_countersetiv(&g->k, p);                                     \
 373     } break;                                                            \
 374     case GRAND_SEEDRAND: {                                              \
 375       grand *rr = va_arg(ap, grand *);                                  \
 376       rr->ops->fill(rr, buf, sizeof(buf));                              \
 377       pre##_countersetiv(&g->k, buf);                                   \
 378     } break;                                                            \
 379     default:                                                            \
 380       GRAND_BADOP;                                                      \
 381       break;                                                            \
 382   }                                                                     \
 383                                                                         \
 384   va_end(ap);                                                           \
 385   return (rc);                                                          \
 386 }                                                                       \
 387                                                                         \
 388 static octet grbyte(grand *r)                                           \
 389 {                                                                       \
 390   grctx *g = (grctx *)r;                                                \
 391   octet o;                                                              \
 392   pre##_counterencrypt(&g->k, 0, &o, 1);                                \
 393   return (o);                                                           \
 394 }                                                                       \
 395                                                                         \
 396 static uint32 grword(grand *r)                                          \
 397 {                                                                       \
 398   grctx *g = (grctx *)r;                                                \
 399   octet b[4];                                                           \
 400   pre##_counterencrypt(&g->k, 0, b, sizeof(b));                         \
 401   return (LOAD32(b));                                                   \
 402 }                                                                       \
 403                                                                         \
 404 static void grfill(grand *r, void *p, size_t sz)                        \
 405 {                                                                       \
 406   grctx *g = (grctx *)r;                                                \
 407   pre##_counterencrypt(&g->k, 0, p, sz);                                \
 408 }                                                                       \
 409                                                                         \
 410 static const grand_ops grops = {                                        \
 411   #pre "-counter",                                                      \
 412   GRAND_CRYPTO, 0,                                                      \
 413   grmisc, grdestroy,                                                    \
 414   grword, grbyte, grword, grand_range, grfill                           \
 415 };                                                                      \
 416                                                                         \
 417 /* --- @pre_counterrand@ --- *                                          \
 418  *                                                                      \
 419  * Arguments:   @const void *k@ = pointer to key material               \
 420  *              @size_t sz@ = size of key material                      \
 421  *                                                                      \
 422  * Returns:     Pointer to generic random number generator interface.   \
 423  *                                                                      \
 424  * Use:         Creates a random number interface wrapper around an     \
 425  *              counter-mode block cipher.                              \
 426  */                                                                     \
 427                                                                         \
 428 grand *pre##_counterrand(const void *k, size_t sz)                      \
 429 {                                                                       \
 430   grctx *g = S_CREATE(grctx);                                           \
 431   g->r.ops = &grops;                                                    \
 432   pre##_counterinit(&g->k, k, sz, 0);                                   \
 433   return (&g->r);                                                       \
 434 }                                                                       \
 435                                                                         \
 436 COUNTER_TEST(PRE, pre)
 437
 438 /*----- Test rig ----------------------------------------------------------*/
 439
 440 #ifdef TEST_RIG
 441
 442 #include <stdio.h>
 443
 444 #include "daftstory.h"
 445
 446 /* --- @COUNTER_TEST@ --- *
 447  *
 448  * Arguments:   @PRE@, @pre@ = prefixes for block cipher definitions
 449  *
 450  * Use:         Standard test rig for counter functions.
 451  */
 452
 453 #define COUNTER_TEST(PRE, pre)                                          \
 454                                                                         \
 455 /* --- Initial plaintext for the test --- */                            \
 456                                                                         \
 457 static const octet text[] = TEXT;                                       \
 458                                                                         \
 459 /* --- Key and IV to use --- */                                         \
 460                                                                         \
 461 static const octet key[] = KEY;                                         \
 462 static const octet iv[] = IV;                                           \
 463                                                                         \
 464 /* --- Buffers for encryption and decryption output --- */              \
 465                                                                         \
 466 static octet ct[sizeof(text)];                                          \
 467 static octet pt[sizeof(text)];                                          \
 468                                                                         \
 469 static void hexdump(const octet *p, size_t sz)                          \
 470 {                                                                       \
 471   const octet *q = p + sz;                                              \
 472   for (sz = 0; p < q; p++, sz++) {                                      \
 473     printf("%02x", *p);                                                 \
 474     if ((sz + 1) % PRE##_BLKSZ == 0)                                    \
 475       putchar(':');                                                     \
 476   }                                                                     \
 477 }                                                                       \
 478                                                                         \
 479 int main(void)                                                          \
 480 {                                                                       \
 481   size_t sz = 0, rest;                                                  \
 482   pre##_counterctx ctx;                                                 \
 483   int status = 0;                                                       \
 484   int done = 0;                                                         \
 485   pre##_ctx k;                                                          \
 486                                                                         \
 487   size_t keysz = PRE##_KEYSZ ?                                          \
 488     PRE##_KEYSZ : strlen((const char *)key);                            \
 489                                                                         \
 490   fputs(#pre "-counter: ", stdout);                                     \
 491                                                                         \
 492   pre##_init(&k, key, keysz);                                           \
 493   pre##_countersetkey(&ctx, &k);                                        \
 494                                                                         \
 495   while (sz <= sizeof(text)) {                                          \
 496     rest = sizeof(text) - sz;                                           \
 497     memcpy(ct, text, sizeof(text));                                     \
 498     pre##_countersetiv(&ctx, iv);                                       \
 499     pre##_counterencrypt(&ctx, ct, ct, sz);                             \
 500     pre##_counterencrypt(&ctx, ct + sz, ct + sz, rest);                 \
 501     memcpy(pt, ct, sizeof(text));                                       \
 502     pre##_countersetiv(&ctx, iv);                                       \
 503     pre##_counterencrypt(&ctx, pt, pt, rest);                           \
 504     pre##_counterencrypt(&ctx, pt + rest, pt + rest, sz);               \
 505     if (memcmp(pt, text, sizeof(text)) == 0) {                          \
 506       done++;                                                           \
 507       if (sizeof(text) < 40 || done % 8 == 0)                           \
 508         fputc('.', stdout);                                             \
 509       if (done % 480 == 0)                                              \
 510         fputs("\n\t", stdout);                                          \
 511       fflush(stdout);                                                   \
 512     } else {                                                            \
 513       printf("\nError (sz = %lu)\n", (unsigned long)sz);                \
 514       status = 1;                                                       \
 515       printf("\tplaintext      = "); hexdump(text, sz);                 \
 516         printf(", "); hexdump(text + sz, rest);                         \
 517         fputc('\n', stdout);                                            \
 518       printf("\tciphertext     = "); hexdump(ct, sz);                   \
 519         printf(", "); hexdump(ct + sz, rest);                           \
 520         fputc('\n', stdout);                                            \
 521       printf("\trecovered text = "); hexdump(pt, sz);                   \
 522         printf(", "); hexdump(pt + sz, rest);                           \
 523         fputc('\n', stdout);                                            \
 524       fputc('\n', stdout);                                              \
 525     }                                                                   \
 526     if (sz < 63)                                                        \
 527       sz++;                                                             \
 528     else                                                                \
 529       sz += 9;                                                          \
 530   }                                                                     \
 531                                                                         \
 532   fputs(status ? " failed\n" : " ok\n", stdout);                        \
 533   return (status);                                                      \
 534 }
 535
 536 #else
 537 #  define COUNTER_TEST(PRE, pre)
 538 #endif
 539
 540 /*----- That's all, folks -------------------------------------------------*/
 541
 542 #ifdef __cplusplus
 543   }
 544 #endif
 545
 546 #endif