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

   1 /* -*-c-*-
   2  *
   3  * $Id: counter-def.h,v 1.1 2000/06/17 10:51:42 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 1.1  2000/06/17 10:51:42  mdw
  34  * Counter mode ciphers and pseudo-random generator.
  35  *
  36  */
  37
  38 #ifndef CATACOMB_COUNTER_DEF_H
  39 #define CATACOMB_COUNTER_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_ARENA_H
  54 #  include "arena.h"
  55 #endif
  56
  57 #ifndef CATACOMB_BLKC_H
  58 #  include "blkc.h"
  59 #endif
  60
  61 #ifndef CATACOMB_GCIPHER_H
  62 #  include "gcipher.h"
  63 #endif
  64
  65 #ifndef CATACOMB_PARANOIA_H
  66 #  include "paranoia.h"
  67 #endif
  68
  69 /*----- Macros ------------------------------------------------------------*/
  70
  71 /* --- @COUNTER_DEF@ --- *
  72  *
  73  * Arguments:   @PRE@, @pre@ = prefixes for the underlying block cipher
  74  *
  75  * Use:         Creates definitions for counter mode.
  76  */
  77
  78 #define COUNTER_DEF(PRE, pre)                                           \
  79                                                                         \
  80 /* --- @pre_countergetiv@ --- *                                         \
  81  *                                                                      \
  82  * Arguments:   @const pre_counterctx *ctx@ = pointer to counter        \
  83  *                      context                                         \
  84  *              @void *iv#@ = pointer to output data block              \
  85  *                                                                      \
  86  * Returns:     ---                                                     \
  87  *                                                                      \
  88  * Use:         Reads the currently set IV.  Reading and setting an IV  \
  89  *              is not transparent to the cipher.  It will add a `step' \
  90  *              which must be matched by a similar operation during     \
  91  *              decryption.                                             \
  92  */                                                                     \
  93                                                                         \
  94 void pre##_countergetiv(const pre##_counterctx *ctx, void *iv)          \
  95 {                                                                       \
  96   BLKC_STORE(PRE, iv, ctx->n);                                          \
  97 }                                                                       \
  98                                                                         \
  99 /* --- @pre_countersetiv@ --- *                                         \
 100  *                                                                      \
 101  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 102  *              @cnost void *iv@ = pointer to IV to set                 \
 103  *                                                                      \
 104  * Returns:     ---                                                     \
 105  *                                                                      \
 106  * Use:         Sets the IV to use for subsequent encryption.           \
 107  */                                                                     \
 108                                                                         \
 109 void pre##_countersetiv(pre##_counterctx *ctx, const void *iv)          \
 110 {                                                                       \
 111   BLKC_LOAD(PRE, ctx->n, iv);                                           \
 112   ctx->off = PRE##_BLKSZ;                                               \
 113 }                                                                       \
 114                                                                         \
 115 /* --- @pre_counterbdry@ --- *                                          \
 116  *                                                                      \
 117  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 118  *                                                                      \
 119  * Returns:     ---                                                     \
 120  *                                                                      \
 121  * Use:         Inserts a boundary during encryption.  Successful       \
 122  *              decryption must place a similar boundary.               \
 123  */                                                                     \
 124                                                                         \
 125 void pre##_counterbdry(pre##_counterctx *ctx)                           \
 126 {                                                                       \
 127   BLKC_STEP(PRE, ctx->n);                                               \
 128   ctx->off = PRE##_BLKSZ;                                               \
 129 }                                                                       \
 130                                                                         \
 131 /* --- @pre_countersetkey@ --- *                                        \
 132  *                                                                      \
 133  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 134  *              @const pre_ctx *k@ = pointer to cipher context          \
 135  *                                                                      \
 136  * Returns:     ---                                                     \
 137  *                                                                      \
 138  * Use:         Sets the counter context to use a different cipher key. \
 139  */                                                                     \
 140                                                                         \
 141 void pre##_countersetkey(pre##_counterctx *ctx, const pre##_ctx *k)     \
 142 {                                                                       \
 143   ctx->ctx = *k;                                                        \
 144 }                                                                       \
 145                                                                         \
 146 /* --- @pre_counterinit@ --- *                                          \
 147  *                                                                      \
 148  * Arguments:   @pre_counterctx *ctx@ = pointer to cipher context       \
 149  *              @const void *key@ = pointer to the key buffer           \
 150  *              @size_t sz@ = size of the key                           \
 151  *              @const void *iv@ = pointer to initialization vector     \
 152  *                                                                      \
 153  * Returns:     ---                                                     \
 154  *                                                                      \
 155  * Use:         Initializes a counter context ready for use.  You       \
 156  *              should ensure that the IV chosen is unique: reusing an  \
 157  *              IV will compromise the security of the entire           \
 158  *              plaintext.  This is equivalent to calls to @pre_init@,  \
 159  *              @pre_countersetkey@ and @pre_countersetiv@.             \
 160  */                                                                     \
 161                                                                         \
 162 void pre##_counterinit(pre##_counterctx *ctx,                           \
 163                        const void *key, size_t sz,                      \
 164                        const void *iv)                                  \
 165 {                                                                       \
 166   static octet zero[PRE##_BLKSZ] = { 0 };                               \
 167   pre##_init(&ctx->ctx, key, sz);                                       \
 168   pre##_countersetiv(ctx, iv ? iv : zero);                              \
 169 }                                                                       \
 170                                                                         \
 171 /* --- @pre_counterencrypt@ --- *                                       \
 172  *                                                                      \
 173  * Arguments:   @pre_counterctx *ctx@ = pointer to counter context      \
 174  *              @const void *src@ = pointer to source data              \
 175  *              @void *dest@ = pointer to destination data              \
 176  *              @size_t sz@ = size of block to be encrypted             \
 177  *                                                                      \
 178  * Returns:     ---                                                     \
 179  *                                                                      \
 180  * Use:         Encrypts or decrypts a block with a block cipher in     \
 181  *              counter mode: encryption and decryption are the same in \
 182  *              counter.  The destination may be null to just churn the \
 183  *              feedback round for a bit.  The source may be null to    \
 184  *              use the cipher as a random data generator.              \
 185  */                                                                     \
 186                                                                         \
 187 void pre##_counterencrypt(pre##_counterctx *ctx,                        \
 188                           const void *src, void *dest,                  \
 189                           size_t sz)                                    \
 190 {                                                                       \
 191   const octet *s = src;                                                 \
 192   octet *d = dest;                                                      \
 193   unsigned off = ctx->off;                                              \
 194                                                                         \
 195   /* --- Empty blocks are trivial --- */                                \
 196                                                                         \
 197   if (!sz)                                                              \
 198     return;                                                             \
 199                                                                         \
 200   /* --- If I can deal with the block from my buffer, do that --- */    \
 201                                                                         \
 202   if (sz < PRE##_BLKSZ - off)                                           \
 203     goto small;                                                         \
 204                                                                         \
 205   /* --- Finish off what's left in my buffer --- */                     \
 206                                                                         \
 207   if (!d)                                                               \
 208     sz -= PRE##_BLKSZ - off;                                            \
 209   else {                                                                \
 210     while (off < PRE##_BLKSZ) {                                         \
 211       register octet x = s ? *s++ : 0;                                  \
 212       *d++ = ctx->buf[off++] ^ x;                                       \
 213       sz--;                                                             \
 214     }                                                                   \
 215   }                                                                     \
 216                                                                         \
 217   /* --- Main encryption loop --- */                                    \
 218                                                                         \
 219   {                                                                     \
 220     uint32 n[PRE##_BLKSZ / 4];                                          \
 221                                                                         \
 222     for (;;) {                                                          \
 223       pre##_eblk(&ctx->ctx, ctx->n, n);                                 \
 224       BLKC_STEP(PRE, ctx->n);                                           \
 225       if (sz < PRE##_BLKSZ)                                             \
 226         break;                                                          \
 227       if (d) {                                                          \
 228         if (!s)                                                         \
 229           BLKC_STORE(PRE, d, n);                                        \
 230         else {                                                          \
 231           uint32 x[PRE##_BLKSZ / 4];                                    \
 232           BLKC_LOAD(PRE, x, s);                                         \
 233           BLKC_XSTORE(PRE, d, n, x);                                    \
 234           s += PRE##_BLKSZ;                                             \
 235         }                                                               \
 236         d += PRE##_BLKSZ;                                               \
 237       }                                                                 \
 238       sz -= PRE##_BLKSZ;                                                \
 239     }                                                                   \
 240                                                                         \
 241     BLKC_STORE(PRE, ctx->buf, n);                                       \
 242     off = 0;                                                            \
 243   }                                                                     \
 244                                                                         \
 245   /* --- Tidying up the tail end --- */                                 \
 246                                                                         \
 247   if (sz) {                                                             \
 248   small:                                                                \
 249     if (!d)                                                             \
 250       off += sz;                                                        \
 251     else do {                                                           \
 252       register octet x = s ? *s++ : 0;                                  \
 253       *d++ = ctx->buf[off++] ^ x;                                       \
 254       sz--;                                                             \
 255     } while (sz);                                                       \
 256   }                                                                     \
 257                                                                         \
 258   /* --- Done --- */                                                    \
 259                                                                         \
 260   ctx->off = off;                                                       \
 261   return;                                                               \
 262 }                                                                       \
 263                                                                         \
 264 /* --- Generic cipher interface --- */                                  \
 265                                                                         \
 266 static const gcipher_ops gops;                                          \
 267                                                                         \
 268 typedef struct gctx {                                                   \
 269   gcipher c;                                                            \
 270   pre##_counterctx k;                                                   \
 271 } gctx;                                                                 \
 272                                                                         \
 273 static gcipher *ginit(const void *k, size_t sz)                         \
 274 {                                                                       \
 275   gctx *g = S_CREATE(gctx);                                             \
 276   g->c.ops = &gops;                                                     \
 277   pre##_counterinit(&g->k, k, sz, 0);                                   \
 278   return (&g->c);                                                       \
 279 }                                                                       \
 280                                                                         \
 281 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz)     \
 282 {                                                                       \
 283   gctx *g = (gctx *)c;                                                  \
 284   pre##_counterencrypt(&g->k, s, t, sz);                                \
 285 }                                                                       \
 286                                                                         \
 287 static void gdestroy(gcipher *c)                                        \
 288 {                                                                       \
 289   gctx *g = (gctx *)c;                                                  \
 290   BURN(*g);                                                             \
 291   S_DESTROY(g);                                                         \
 292 }                                                                       \
 293                                                                         \
 294 static void gsetiv(gcipher *c, const void *iv)                          \
 295 {                                                                       \
 296   gctx *g = (gctx *)c;                                                  \
 297   pre##_countersetiv(&g->k, iv);                                        \
 298 }                                                                       \
 299                                                                         \
 300 static void gbdry(gcipher *c)                                           \
 301 {                                                                       \
 302   gctx *g = (gctx *)c;                                                  \
 303   pre##_counterbdry(&g->k);                                             \
 304 }                                                                       \
 305                                                                         \
 306 static const gcipher_ops gops = {                                       \
 307   &pre##_counter,                                                       \
 308   gencrypt, gencrypt, gdestroy, gsetiv, gbdry                           \
 309 };                                                                      \
 310                                                                         \
 311 const gccipher pre##_counter = {                                        \
 312   #pre "-counter", pre##_keysz, PRE##_BLKSZ,                            \
 313   ginit                                                                 \
 314 };                                                                      \
 315                                                                         \
 316 /* --- Generic random number generator interface --- */                 \
 317                                                                         \
 318 typedef struct grctx {                                                  \
 319   grand r;                                                              \
 320   pre##_counterctx k;                                                   \
 321 } grctx;                                                                \
 322                                                                         \
 323 static void grdestroy(grand *r)                                         \
 324 {                                                                       \
 325   grctx *g = (grctx *)r;                                                \
 326   BURN(*g);                                                             \
 327   S_DESTROY(g);                                                         \
 328 }                                                                       \
 329                                                                         \
 330 static int grmisc(grand *r, unsigned op, ...)                           \
 331 {                                                                       \
 332   grctx *g = (grctx *)r;                                                \
 333   va_list ap;                                                           \
 334   int rc = 0;                                                           \
 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:                                           \
 345         case GRAND_SEEDRAND:                                            \
 346           rc = 1;                                                       \
 347           break;                                                        \
 348         default:                                                        \
 349           rc = 0;                                                       \
 350           break;                                                        \
 351       }                                                                 \
 352       break;                                                            \
 353     case GRAND_SEEDINT:                                                 \
 354       BLKC_SET(PRE, g->k.n, va_arg(ap, unsigned));                      \
 355       g->k.off = PRE##_BLKSZ;                                           \
 356       break;                                                            \
 357     case GRAND_SEEDUINT32:                                              \
 358       BLKC_SET(PRE, g->k.n, va_arg(ap, uint32));                        \
 359       g->k.off = PRE##_BLKSZ;                                           \
 360       break;                                                            \
 361     case GRAND_SEEDBLOCK: {                                             \
 362       const void *p = va_arg(ap, const void *);                         \
 363       size_t sz = va_arg(ap, size_t);                                   \
 364       if (sz < sizeof(buf)) {                                           \
 365         memset(buf, 0, sizeof(buf));                                    \
 366         memcpy(buf, p, sz);                                             \
 367         p = buf;                                                        \
 368       }                                                                 \
 369       pre##_countersetiv(&g->k, p);                                     \
 370     } break;                                                            \
 371     case GRAND_SEEDRAND: {                                              \
 372       grand *rr = va_arg(ap, grand *);                                  \
 373       rr->ops->fill(rr, buf, sizeof(buf));                              \
 374       pre##_countersetiv(&g->k, buf);                                   \
 375     } break;                                                            \
 376     default:                                                            \
 377       GRAND_BADOP;                                                      \
 378       break;                                                            \
 379   }                                                                     \
 380                                                                         \
 381   va_end(ap);                                                           \
 382   return (rc);                                                          \
 383 }                                                                       \
 384                                                                         \
 385 static octet grbyte(grand *r)                                           \
 386 {                                                                       \
 387   grctx *g = (grctx *)r;                                                \
 388   octet o;                                                              \
 389   pre##_counterencrypt(&g->k, 0, &o, 1);                                \
 390   return (o);                                                           \
 391 }                                                                       \
 392                                                                         \
 393 static uint32 grword(grand *r)                                          \
 394 {                                                                       \
 395   grctx *g = (grctx *)r;                                                \
 396   octet b[4];                                                           \
 397   pre##_counterencrypt(&g->k, 0, b, sizeof(b));                         \
 398   return (LOAD32(b));                                                   \
 399 }                                                                       \
 400                                                                         \
 401 static void grfill(grand *r, void *p, size_t sz)                        \
 402 {                                                                       \
 403   grctx *g = (grctx *)r;                                                \
 404   pre##_counterencrypt(&g->k, 0, p, sz);                                \
 405 }                                                                       \
 406                                                                         \
 407 static const grand_ops grops = {                                        \
 408   #pre "-counter",                                                      \
 409   GRAND_CRYPTO, 0,                                                      \
 410   grmisc, grdestroy,                                                    \
 411   grword, grbyte, grword, grand_range, grfill                           \
 412 };                                                                      \
 413                                                                         \
 414 /* --- @pre_counterrand@ --- *                                          \
 415  *                                                                      \
 416  * Arguments:   @const void *k@ = pointer to key material               \
 417  *              @size_t sz@ = size of key material                      \
 418  *                                                                      \
 419  * Returns:     Pointer to generic random number generator interface.   \
 420  *                                                                      \
 421  * Use:         Creates a random number interface wrapper around an     \
 422  *              counter-mode block cipher.                              \
 423  */                                                                     \
 424                                                                         \
 425 grand *pre##_counterrand(const void *k, size_t sz)                      \
 426 {                                                                       \
 427   grctx *g = S_CREATE(grctx);                                           \
 428   g->r.ops = &grops;                                                    \
 429   pre##_counterinit(&g->k, k, sz, 0);                                   \
 430   return (&g->r);                                                       \
 431 }                                                                       \
 432                                                                         \
 433 COUNTER_TEST(PRE, pre)
 434
 435 /*----- Test rig ----------------------------------------------------------*/
 436
 437 #ifdef TEST_RIG
 438
 439 #include <stdio.h>
 440
 441 #include "daftstory.h"
 442
 443 /* --- @COUNTER_TEST@ --- *
 444  *
 445  * Arguments:   @PRE@, @pre@ = prefixes for block cipher definitions
 446  *
 447  * Use:         Standard test rig for counter functions.
 448  */
 449
 450 #define COUNTER_TEST(PRE, pre)                                          \
 451                                                                         \
 452 /* --- Initial plaintext for the test --- */                            \
 453                                                                         \
 454 static const octet text[] = TEXT;                                       \
 455                                                                         \
 456 /* --- Key and IV to use --- */                                         \
 457                                                                         \
 458 static const octet key[] = KEY;                                         \
 459 static const octet iv[] = IV;                                           \
 460                                                                         \
 461 /* --- Buffers for encryption and decryption output --- */              \
 462                                                                         \
 463 static octet ct[sizeof(text)];                                          \
 464 static octet pt[sizeof(text)];                                          \
 465                                                                         \
 466 static void hexdump(const octet *p, size_t sz)                          \
 467 {                                                                       \
 468   const octet *q = p + sz;                                              \
 469   for (sz = 0; p < q; p++, sz++) {                                      \
 470     printf("%02x", *p);                                                 \
 471     if ((sz + 1) % PRE##_BLKSZ == 0)                                    \
 472       putchar(':');                                                     \
 473   }                                                                     \
 474 }                                                                       \
 475                                                                         \
 476 int main(void)                                                          \
 477 {                                                                       \
 478   size_t sz = 0, rest;                                                  \
 479   pre##_counterctx ctx;                                                 \
 480   int status = 0;                                                       \
 481   int done = 0;                                                         \
 482   pre##_ctx k;                                                          \
 483                                                                         \
 484   size_t keysz = PRE##_KEYSZ ?                                          \
 485     PRE##_KEYSZ : strlen((const char *)key);                            \
 486                                                                         \
 487   fputs(#pre "-counter: ", stdout);                                     \
 488                                                                         \
 489   pre##_init(&k, key, keysz);                                           \
 490   pre##_countersetkey(&ctx, &k);                                        \
 491                                                                         \
 492   while (sz <= sizeof(text)) {                                          \
 493     rest = sizeof(text) - sz;                                           \
 494     memcpy(ct, text, sizeof(text));                                     \
 495     pre##_countersetiv(&ctx, iv);                                       \
 496     pre##_counterencrypt(&ctx, ct, ct, sz);                             \
 497     pre##_counterencrypt(&ctx, ct + sz, ct + sz, rest);                 \
 498     memcpy(pt, ct, sizeof(text));                                       \
 499     pre##_countersetiv(&ctx, iv);                                       \
 500     pre##_counterencrypt(&ctx, pt, pt, rest);                           \
 501     pre##_counterencrypt(&ctx, pt + rest, pt + rest, sz);               \
 502     if (memcmp(pt, text, sizeof(text)) == 0) {                          \
 503       done++;                                                           \
 504       if (sizeof(text) < 40 || done % 8 == 0)                           \
 505         fputc('.', stdout);                                             \
 506       if (done % 480 == 0)                                              \
 507         fputs("\n\t", stdout);                                          \
 508       fflush(stdout);                                                   \
 509     } else {                                                            \
 510       printf("\nError (sz = %lu)\n", (unsigned long)sz);                \
 511       status = 1;                                                       \
 512       printf("\tplaintext      = "); hexdump(text, sz);                 \
 513         printf(", "); hexdump(text + sz, rest);                         \
 514         fputc('\n', stdout);                                            \
 515       printf("\tciphertext     = "); hexdump(ct, sz);                   \
 516         printf(", "); hexdump(ct + sz, rest);                           \
 517         fputc('\n', stdout);                                            \
 518       printf("\trecovered text = "); hexdump(pt, sz);                   \
 519         printf(", "); hexdump(pt + sz, rest);                           \
 520         fputc('\n', stdout);                                            \
 521       fputc('\n', stdout);                                              \
 522     }                                                                   \
 523     if (sz < 63)                                                        \
 524       sz++;                                                             \
 525     else                                                                \
 526       sz += 9;                                                          \
 527   }                                                                     \
 528                                                                         \
 529   fputs(status ? " failed\n" : " ok\n", stdout);                        \
 530   return (status);                                                      \
 531 }
 532
 533 #else
 534 #  define COUNTER_TEST(PRE, pre)
 535 #endif
 536
 537 /*----- That's all, folks -------------------------------------------------*/
 538
 539 #ifdef __cplusplus
 540   }
 541 #endif
 542
 543 #endif