crypto/bn/bn_nist.c

   1 /* crypto/bn/bn_nist.c */
   2 /*
   3  * Written by Nils Larsch for the OpenSSL project
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    openssl-core@openssl.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59 #include "bn_lcl.h"
  60 #include "cryptlib.h"
  61
  62 #define BN_NIST_192_TOP (192+BN_BITS2-1)/BN_BITS2
  63 #define BN_NIST_224_TOP (224+BN_BITS2-1)/BN_BITS2
  64 #define BN_NIST_256_TOP (256+BN_BITS2-1)/BN_BITS2
  65 #define BN_NIST_384_TOP (384+BN_BITS2-1)/BN_BITS2
  66 #define BN_NIST_521_TOP (521+BN_BITS2-1)/BN_BITS2
  67
  68 #if BN_BITS2 == 64
  69 static const BN_ULONG _nist_p_192[] =
  70         {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,
  71         0xFFFFFFFFFFFFFFFFULL};
  72 static const BN_ULONG _nist_p_224[] =
  73         {0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
  74         0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL};
  75 static const BN_ULONG _nist_p_256[] =
  76         {0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
  77         0x0000000000000000ULL,0xFFFFFFFF00000001ULL};
  78 static const BN_ULONG _nist_p_384[] =
  79         {0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,
  80         0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL,
  81         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL};
  82 static const BN_ULONG _nist_p_521[] =
  83         {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
  84         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
  85         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
  86         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
  87         0x00000000000001FFULL};
  88 #elif BN_BITS2 == 32
  89 static const BN_ULONG _nist_p_192[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,
  90         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
  91 static const BN_ULONG _nist_p_224[] = {0x00000001,0x00000000,0x00000000,
  92         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
  93 static const BN_ULONG _nist_p_256[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
  94         0x00000000,0x00000000,0x00000000,0x00000001,0xFFFFFFFF};
  95 static const BN_ULONG _nist_p_384[] = {0xFFFFFFFF,0x00000000,0x00000000,
  96         0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
  97         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
  98 static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
  99         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 100         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 101         0xFFFFFFFF,0x000001FF};
 102 #elif BN_BITS2 == 16
 103 static const BN_ULONG _nist_p_192[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFE,
 104         0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};
 105 static const BN_ULONG _nist_p_224[] = {0x0001,0x0000,0x0000,0x0000,0x0000,
 106         0x0000,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};
 107 static const BN_ULONG _nist_p_256[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,
 108         0xFFFF,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0001,0x0000,0xFFFF,
 109         0xFFFF};
 110 static const BN_ULONG _nist_p_384[] = {0xFFFF,0xFFFF,0x0000,0x0000,0x0000,
 111         0x0000,0xFFFF,0xFFFF,0xFFFE,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,
 112         0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};
 113 static const BN_ULONG _nist_p_521[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,
 114         0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,
 115         0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,
 116         0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0x01FF};
 117 #elif BN_BITS2 == 8
 118 static const BN_ULONG _nist_p_192[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 119         0xFE,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 120         0xFF,0xFF};
 121 static const BN_ULONG _nist_p_224[] = {0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
 122         0x00,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 123         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
 124 static const BN_ULONG _nist_p_256[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 125         0xFF,0xFF,0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
 126         0x00,0x00,0x01,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF};
 127 static const BN_ULONG _nist_p_384[] = {0xFF,0xFF,0xFF,0xFF,0x00,0x00,0x00,0x00,
 128         0x00,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFF,0xFF,0xFF,
 129         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 130         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
 131 static const BN_ULONG _nist_p_521[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 132         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 133         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 134         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 135         0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
 136         0xFF,0x01};
 137 #endif
 138
 139 const BIGNUM *BN_get0_nist_prime_192(void)
 140         {
 141         static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,
 142                 BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };
 143         return &const_nist_192;
 144         }
 145
 146 const BIGNUM *BN_get0_nist_prime_224(void)
 147         {
 148         static BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224,
 149                 BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };
 150         return &const_nist_224;
 151         }
 152
 153 const BIGNUM *BN_get0_nist_prime_256(void)
 154         {
 155         static BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256,
 156                 BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };
 157         return &const_nist_256;
 158         }
 159
 160 const BIGNUM *BN_get0_nist_prime_384(void)
 161         {
 162         static BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384,
 163                 BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };
 164         return &const_nist_384;
 165         }
 166
 167 const BIGNUM *BN_get0_nist_prime_521(void)
 168         {
 169         static BIGNUM const_nist_521 = { (BN_ULONG *)_nist_p_521,
 170                 BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };
 171         return &const_nist_521;
 172         }
 173
 174 #define BN_NIST_ADD_ONE(a)      while (!(*(a)=(*(a)+1)&BN_MASK2)) ++(a);
 175
 176 static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)
 177         {
 178         int i;
 179         BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
 180         for (i = (top); i != 0; i--)
 181                 *_tmp1++ = *_tmp2++;
 182         for (i = (max) - (top); i != 0; i--)
 183                 *_tmp1++ = (BN_ULONG) 0;
 184         }
 185
 186 static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
 187         {
 188         int i;
 189         BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
 190         for (i = (top); i != 0; i--)
 191                 *_tmp1++ = *_tmp2++;
 192         }
 193
 194 #if BN_BITS2 == 64
 195 #define bn_cp_64(to, n, from, m)        (to)[n] = (from)[m];
 196 #define bn_64_set_0(to, n)              (to)[n] = (BN_ULONG)0;
 197 /* TBD */
 198 #define bn_cp_32(to, n, from, m)        (to)[n] = (from)[m];
 199 #define bn_32_set_0(to, n)              (to)[n] = (BN_ULONG)0;
 200 #else
 201 #define bn_cp_64(to, n, from, m) \
 202         { \
 203         bn_cp_32(to, (n)*2, from, (m)*2); \
 204         bn_cp_32(to, (n)*2+1, from, (m)*2+1); \
 205         }
 206 #define bn_64_set_0(to, n) \
 207         { \
 208         bn_32_set_0(to, (n)*2); \
 209         bn_32_set_0(to, (n)*2+1); \
 210         }
 211 #if BN_BITS2 == 32
 212 #define bn_cp_32(to, n, from, m)        (to)[n] = (from)[m];
 213 #define bn_32_set_0(to, n)              (to)[n] = (BN_ULONG)0;
 214 #elif BN_BITS2 == 16
 215 #define bn_cp_32(to, n, from, m) \
 216         { \
 217         (to)[(n)*2]   = (from)[(m)*2];  \
 218         (to)[(n)*2+1] = (from)[(m)*2+1];\
 219         }
 220 #define bn_32_set_0(to, n) { (to)[(n)*2] = 0; (to)[(n)*2+1] = 0; }
 221 #elif BN_BITS2 == 8
 222 #define bn_cp_32(to, n, from, m) \
 223         { \
 224         (to)[(n)*4]   = (from)[(m)*4];  \
 225         (to)[(n)*4+1] = (from)[(m)*4+1];\
 226         (to)[(n)*4+2] = (from)[(m)*4+2];\
 227         (to)[(n)*4+3] = (from)[(m)*4+3];\
 228         }
 229 #define bn_32_set_0(to, n) \
 230         { (to)[(n)*4]   = (BN_ULONG)0; (to)[(n)*4+1] = (BN_ULONG)0; \
 231           (to)[(n)*4+2] = (BN_ULONG)0; (to)[(n)*4+3] = (BN_ULONG)0; }
 232 #endif
 233 #endif /* BN_BITS2 != 64 */
 234
 235
 236 #define nist_set_192(to, from, a1, a2, a3) \
 237         { \
 238         if (a3 != 0) bn_cp_64(to, 0, from, (a3) - 3) else bn_64_set_0(to, 0)\
 239         bn_cp_64(to, 1, from, (a2) - 3) \
 240         if (a1 != 0) bn_cp_64(to, 2, from, (a1) - 3) else bn_64_set_0(to, 2)\
 241         }
 242
 243 int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 244         BN_CTX *ctx)
 245         {
 246         int      top = a->top, i;
 247         int      carry;
 248         register BN_ULONG *r_d, *a_d = a->d;
 249         BN_ULONG t_d[BN_NIST_192_TOP],
 250                  buf[BN_NIST_192_TOP],
 251                  c_d[BN_NIST_192_TOP],
 252                 *res;
 253         size_t   mask;
 254
 255         i = BN_ucmp(field, a);
 256         if (i == 0)
 257                 {
 258                 BN_zero(r);
 259                 return 1;
 260                 }
 261         else if (i > 0)
 262                 return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
 263
 264         if (top == BN_NIST_192_TOP)
 265                 return BN_usub(r, a, field);
 266
 267         if (r != a)
 268                 {
 269                 if (!bn_wexpand(r, BN_NIST_192_TOP))
 270                         return 0;
 271                 r_d = r->d;
 272                 nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
 273                 }
 274         else
 275                 r_d = a_d;
 276
 277         nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
 278
 279 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 280 # pragma message save
 281 # pragma message disable BADSUBSCRIPT
 282 #endif
 283
 284         nist_set_192(t_d, buf, 0, 3, 3);
 285         carry = bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 286         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
 287         mask = ~mask | (0-(size_t)carry);
 288         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 289
 290         nist_set_192(t_d, buf, 4, 4, 0);
 291         carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
 292         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
 293         mask = ~mask | (0-(size_t)carry);
 294         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 295
 296 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 297 # pragma message restore
 298 #endif
 299
 300         nist_set_192(t_d, buf, 5, 5, 5)
 301         carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
 302         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
 303         mask = ~mask | (0-(size_t)carry);
 304         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 305
 306         nist_cp_bn(r_d, res, BN_NIST_192_TOP);
 307         r->top = BN_NIST_192_TOP;
 308         bn_correct_top(r);
 309
 310         return 1;
 311         }
 312
 313 #define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
 314         { \
 315         if (a7 != 0) bn_cp_32(to, 0, from, (a7) - 7) else bn_32_set_0(to, 0)\
 316         if (a6 != 0) bn_cp_32(to, 1, from, (a6) - 7) else bn_32_set_0(to, 1)\
 317         if (a5 != 0) bn_cp_32(to, 2, from, (a5) - 7) else bn_32_set_0(to, 2)\
 318         if (a4 != 0) bn_cp_32(to, 3, from, (a4) - 7) else bn_32_set_0(to, 3)\
 319         if (a3 != 0) bn_cp_32(to, 4, from, (a3) - 7) else bn_32_set_0(to, 4)\
 320         if (a2 != 0) bn_cp_32(to, 5, from, (a2) - 7) else bn_32_set_0(to, 5)\
 321         if (a1 != 0) bn_cp_32(to, 6, from, (a1) - 7) else bn_32_set_0(to, 6)\
 322         }
 323
 324 int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 325         BN_CTX *ctx)
 326         {
 327 #if BN_BITS2 == 32
 328         int     top = a->top, i;
 329         int     carry;
 330         BN_ULONG *r_d, *a_d = a->d;
 331         BN_ULONG t_d[BN_NIST_224_TOP],
 332                  buf[BN_NIST_224_TOP],
 333                  c_d[BN_NIST_224_TOP],
 334                 *res;
 335         size_t   mask;
 336
 337         i = BN_ucmp(field, a);
 338         if (i == 0)
 339                 {
 340                 BN_zero(r);
 341                 return 1;
 342                 }
 343         else if (i > 0)
 344                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 345
 346         if (top == BN_NIST_224_TOP)
 347                 return BN_usub(r, a, field);
 348
 349         if (r != a)
 350                 {
 351                 if (!bn_wexpand(r, BN_NIST_224_TOP))
 352                         return 0;
 353                 r_d = r->d;
 354                 nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
 355                 }
 356         else
 357                 r_d = a_d;
 358
 359         nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
 360
 361         nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);
 362         carry = bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 363         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 364         mask = ~mask | (0-(size_t)carry);
 365         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 366
 367         nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);
 368         carry = bn_add_words(r_d, res, t_d, BN_NIST_224_TOP);
 369         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 370         mask = ~mask | (0-(size_t)carry);
 371         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 372
 373         nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
 374 #if BRANCH_FREE
 375         carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
 376         bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 377         mask = 0-(size_t)carry;
 378         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 379 #else
 380         if (bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP))
 381                 bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 382 #endif
 383         nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
 384 #if BRANCH_FREE
 385         carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
 386         bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 387         mask = 0-(size_t)carry;
 388         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 389
 390         nist_cp_bn(r_d, res, BN_NIST_224_TOP);
 391 #else
 392         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP))
 393                 bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
 394 #endif
 395         r->top = BN_NIST_224_TOP;
 396         bn_correct_top(r);
 397
 398         return 1;
 399 #else   /* BN_BITS!=32 */
 400         return 0;
 401 #endif
 402         }
 403
 404 #define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
 405         { \
 406         if (a8 != 0) bn_cp_32(to, 0, from, (a8) - 8) else bn_32_set_0(to, 0)\
 407         if (a7 != 0) bn_cp_32(to, 1, from, (a7) - 8) else bn_32_set_0(to, 1)\
 408         if (a6 != 0) bn_cp_32(to, 2, from, (a6) - 8) else bn_32_set_0(to, 2)\
 409         if (a5 != 0) bn_cp_32(to, 3, from, (a5) - 8) else bn_32_set_0(to, 3)\
 410         if (a4 != 0) bn_cp_32(to, 4, from, (a4) - 8) else bn_32_set_0(to, 4)\
 411         if (a3 != 0) bn_cp_32(to, 5, from, (a3) - 8) else bn_32_set_0(to, 5)\
 412         if (a2 != 0) bn_cp_32(to, 6, from, (a2) - 8) else bn_32_set_0(to, 6)\
 413         if (a1 != 0) bn_cp_32(to, 7, from, (a1) - 8) else bn_32_set_0(to, 7)\
 414         }
 415
 416 int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 417         BN_CTX *ctx)
 418         {
 419 #if BN_BITS2 == 32
 420         int     i, top = a->top;
 421         int     carry = 0;
 422         register BN_ULONG *a_d = a->d, *r_d;
 423         BN_ULONG t_d[BN_NIST_256_TOP],
 424                  buf[BN_NIST_256_TOP],
 425                  c_d[BN_NIST_256_TOP],
 426                 *res;
 427         size_t   mask;
 428
 429         i = BN_ucmp(field, a);
 430         if (i == 0)
 431                 {
 432                 BN_zero(r);
 433                 return 1;
 434                 }
 435         else if (i > 0)
 436                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 437
 438         if (top == BN_NIST_256_TOP)
 439                 return BN_usub(r, a, field);
 440
 441         if (r != a)
 442                 {
 443                 if (!bn_wexpand(r, BN_NIST_256_TOP))
 444                         return 0;
 445                 r_d = r->d;
 446                 nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
 447                 }
 448         else
 449                 r_d = a_d;
 450
 451         nist_cp_bn_0(buf, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
 452
 453         /*S1*/
 454         nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0);
 455         /*S2*/
 456         nist_set_256(c_d,buf, 0, 15, 14, 13, 12, 0, 0, 0);
 457         carry = bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
 458         mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
 459         mask = ~mask | (0-(size_t)carry);
 460         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
 461
 462         carry = bn_add_words(t_d, res, res, BN_NIST_256_TOP);
 463         mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
 464         mask = ~mask | (0-(size_t)carry);
 465         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
 466
 467         carry = bn_add_words(r_d, r_d, res, BN_NIST_256_TOP);
 468         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 469         mask = ~mask | (0-(size_t)carry);
 470         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 471
 472         /*S3*/
 473         nist_set_256(t_d, buf, 15, 14, 0, 0, 0, 10, 9, 8);
 474         carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
 475         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 476         mask = ~mask | (0-(size_t)carry);
 477         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 478
 479         /*S4*/
 480         nist_set_256(t_d, buf, 8, 13, 15, 14, 13, 11, 10, 9);
 481         carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
 482         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 483         mask = ~mask | (0-(size_t)carry);
 484         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 485
 486         /*D1*/
 487         nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11);
 488 #if BRANCH_FREE
 489         carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
 490         bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 491         mask = 0-(size_t)carry;
 492         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 493 #else
 494         if (bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP))
 495                 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 496 #endif
 497         /*D2*/
 498         nist_set_256(t_d, buf, 11, 9, 0, 0, 15, 14, 13, 12);
 499 #if BRANCH_FREE
 500         carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
 501         bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 502         mask = 0-(size_t)carry;
 503         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 504 #else
 505         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
 506                 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 507 #endif
 508         /*D3*/
 509         nist_set_256(t_d, buf, 12, 0, 10, 9, 8, 15, 14, 13);
 510 #if BRANCH_FREE
 511         carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
 512         bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 513         mask = 0-(size_t)carry;
 514         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 515 #else
 516         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
 517                 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 518 #endif
 519         /*D4*/
 520         nist_set_256(t_d, buf, 13, 0, 11, 10, 9, 0, 15, 14);
 521 #if BRANCH_FREE
 522         carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
 523         bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 524         mask = 0-(size_t)carry;
 525         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 526
 527         nist_cp_bn(r_d, res, BN_NIST_384_TOP);
 528 #else
 529         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
 530                 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
 531 #endif
 532         r->top = BN_NIST_256_TOP;
 533         bn_correct_top(r);
 534
 535         return 1;
 536 #else   /* BN_BITS!=32 */
 537         return 0;
 538 #endif
 539         }
 540
 541 #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
 542         { \
 543         if (a12 != 0) bn_cp_32(to, 0, from,  (a12) - 12) else bn_32_set_0(to, 0)\
 544         if (a11 != 0) bn_cp_32(to, 1, from,  (a11) - 12) else bn_32_set_0(to, 1)\
 545         if (a10 != 0) bn_cp_32(to, 2, from,  (a10) - 12) else bn_32_set_0(to, 2)\
 546         if (a9 != 0)  bn_cp_32(to, 3, from,  (a9) - 12)  else bn_32_set_0(to, 3)\
 547         if (a8 != 0)  bn_cp_32(to, 4, from,  (a8) - 12)  else bn_32_set_0(to, 4)\
 548         if (a7 != 0)  bn_cp_32(to, 5, from,  (a7) - 12)  else bn_32_set_0(to, 5)\
 549         if (a6 != 0)  bn_cp_32(to, 6, from,  (a6) - 12)  else bn_32_set_0(to, 6)\
 550         if (a5 != 0)  bn_cp_32(to, 7, from,  (a5) - 12)  else bn_32_set_0(to, 7)\
 551         if (a4 != 0)  bn_cp_32(to, 8, from,  (a4) - 12)  else bn_32_set_0(to, 8)\
 552         if (a3 != 0)  bn_cp_32(to, 9, from,  (a3) - 12)  else bn_32_set_0(to, 9)\
 553         if (a2 != 0)  bn_cp_32(to, 10, from, (a2) - 12)  else bn_32_set_0(to, 10)\
 554         if (a1 != 0)  bn_cp_32(to, 11, from, (a1) - 12)  else bn_32_set_0(to, 11)\
 555         }
 556
 557 int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 558         BN_CTX *ctx)
 559         {
 560 #if BN_BITS2 == 32
 561         int     i, top = a->top;
 562         int     carry = 0;
 563         register BN_ULONG *r_d, *a_d = a->d;
 564         BN_ULONG t_d[BN_NIST_384_TOP],
 565                  buf[BN_NIST_384_TOP],
 566                  c_d[BN_NIST_384_TOP],
 567                 *res;
 568         size_t   mask;
 569
 570         i = BN_ucmp(field, a);
 571         if (i == 0)
 572                 {
 573                 BN_zero(r);
 574                 return 1;
 575                 }
 576         else if (i > 0)
 577                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 578
 579         if (top == BN_NIST_384_TOP)
 580                 return BN_usub(r, a, field);
 581
 582         if (r != a)
 583                 {
 584                 if (!bn_wexpand(r, BN_NIST_384_TOP))
 585                         return 0;
 586                 r_d = r->d;
 587                 nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
 588                 }
 589         else
 590                 r_d = a_d;
 591
 592         nist_cp_bn_0(buf, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
 593
 594         /*S1*/
 595         nist_set_256(t_d, buf, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
 596                 /* left shift */
 597                 {
 598                 register BN_ULONG *ap,t,c;
 599                 ap = t_d;
 600                 c=0;
 601                 for (i = 3; i != 0; --i)
 602                         {
 603                         t= *ap;
 604                         *(ap++)=((t<<1)|c)&BN_MASK2;
 605                         c=(t & BN_TBIT)?1:0;
 606                         }
 607                 *ap=c;
 608                 }
 609         carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
 610                 t_d, BN_NIST_256_TOP);
 611         /*
 612          * we need if (result>=modulus) subtract(result,modulus);
 613          * in n-bit space this can be expressed as
 614          * if (carry || result>=modulus) subtract(result,modulus);
 615          * the catch is that comparison implies subtraction and
 616          * therefore one can write tmp=subtract(result,modulus);
 617          * and then if(carry || !borrow) result=tmp; this's what
 618          * happens below, but without explicit if:-) a.
 619          */
 620         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 621         mask = ~mask | (0-(size_t)carry);
 622         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 623
 624         /*S2 */
 625         carry = bn_add_words(r_d, res, buf, BN_NIST_384_TOP);
 626         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 627         mask = ~mask | (0-(size_t)carry);
 628         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 629
 630         /*S3*/
 631         nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21);
 632         carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
 633         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 634         mask = ~mask | (0-(size_t)carry);
 635         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 636
 637         /*S4*/
 638         nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0);
 639         carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
 640         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 641         mask = ~mask | (0-(size_t)carry);
 642         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 643
 644         /*S5*/
 645         nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0);
 646         carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
 647         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 648         mask = ~mask | (0-(size_t)carry);
 649         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 650
 651         /*S6*/
 652         nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20);
 653         carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
 654         mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 655         mask = ~mask | (0-(size_t)carry);
 656         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 657
 658         /*D1*/
 659         nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23);
 660 #if BRANCH_FREE
 661         carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
 662         bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 663         mask = 0-(size_t)carry;
 664         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 665 #else
 666         if (bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP))
 667                 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 668 #endif
 669         /*D2*/
 670         nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0);
 671 #if BRANCH_FREE
 672         carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
 673         bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 674         mask = 0-(size_t)carry;
 675         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 676 #else
 677         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
 678                 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 679 #endif
 680         /*D3*/
 681         nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0);
 682 #if BRANCH_FREE
 683         carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
 684         bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 685         mask = 0-(size_t)carry;
 686         res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
 687
 688         nist_cp_bn(r_d, res, BN_NIST_384_TOP);
 689 #else
 690         if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
 691                 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
 692 #endif
 693         r->top = BN_NIST_384_TOP;
 694         bn_correct_top(r);
 695
 696         return 1;
 697 #else   /* BN_BITS!=32 */
 698         return 0;
 699 #endif
 700         }
 701
 702 int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 703         BN_CTX *ctx)
 704         {
 705 #if BN_BITS2 == 64
 706 #define BN_NIST_521_TOP_MASK    (BN_ULONG)0x1FF
 707 #elif BN_BITS2 == 32
 708 #define BN_NIST_521_TOP_MASK    (BN_ULONG)0x1FF
 709 #elif BN_BITS2 == 16
 710 #define BN_NIST_521_TOP_MASK    (BN_ULONG)0x1FF
 711 #elif BN_BITS2 == 8
 712 #define BN_NIST_521_TOP_MASK    (BN_ULONG)0x1
 713 #endif
 714         int     top, ret = 0;
 715         BN_ULONG *r_d;
 716         BIGNUM  *tmp;
 717
 718         /* check whether a reduction is necessary */
 719         top = a->top;
 720         if (top < BN_NIST_521_TOP  || ( top == BN_NIST_521_TOP &&
 721            (!(a->d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))))
 722                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 723
 724         BN_CTX_start(ctx);
 725         tmp = BN_CTX_get(ctx);
 726         if (!tmp)
 727                 goto err;
 728
 729         if (!bn_wexpand(tmp, BN_NIST_521_TOP))
 730                 goto err;
 731         nist_cp_bn(tmp->d, a->d, BN_NIST_521_TOP);
 732
 733         tmp->top = BN_NIST_521_TOP;
 734         tmp->d[BN_NIST_521_TOP-1]  &= BN_NIST_521_TOP_MASK;
 735         bn_correct_top(tmp);
 736
 737         if (!BN_rshift(r, a, 521))
 738                 goto err;
 739
 740         if (!BN_uadd(r, tmp, r))
 741                 goto err;
 742         top = r->top;
 743         r_d = r->d;
 744         if (top == BN_NIST_521_TOP  &&
 745            (r_d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))
 746                 {
 747                 BN_NIST_ADD_ONE(r_d)
 748                 r->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;
 749                 }
 750         bn_correct_top(r);
 751
 752         ret = 1;
 753 err:
 754         BN_CTX_end(ctx);
 755
 756         bn_check_top(r);
 757         return ret;
 758         }