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
  63 #define BN_NIST_192_TOP (192+BN_BITS2-1)/BN_BITS2
  64 #define BN_NIST_224_TOP (224+BN_BITS2-1)/BN_BITS2
  65 #define BN_NIST_256_TOP (256+BN_BITS2-1)/BN_BITS2
  66 #define BN_NIST_384_TOP (384+BN_BITS2-1)/BN_BITS2
  67 #define BN_NIST_521_TOP (521+BN_BITS2-1)/BN_BITS2
  68
  69 /* pre-computed tables are "carry-less" values of modulus*(i+1) */
  70 #if BN_BITS2 == 64
  71 static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
  72         {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL},
  73         {0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFDULL,0xFFFFFFFFFFFFFFFFULL},
  74         {0xFFFFFFFFFFFFFFFDULL,0xFFFFFFFFFFFFFFFCULL,0xFFFFFFFFFFFFFFFFULL}
  75         };
  76 static const BN_ULONG _nist_p_192_sqr[] = {
  77         0x0000000000000001ULL,0x0000000000000002ULL,0x0000000000000001ULL,
  78         0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFDULL,0xFFFFFFFFFFFFFFFFULL
  79         };
  80 static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
  81         {0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
  82          0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL},
  83         {0x0000000000000002ULL,0xFFFFFFFE00000000ULL,
  84          0xFFFFFFFFFFFFFFFFULL,0x00000001FFFFFFFFULL} /* this one is "carry-full" */
  85         };
  86 static const BN_ULONG _nist_p_224_sqr[] = {
  87         0x0000000000000001ULL,0xFFFFFFFE00000000ULL,
  88         0xFFFFFFFFFFFFFFFFULL,0x0000000200000000ULL,
  89         0x0000000000000000ULL,0xFFFFFFFFFFFFFFFEULL,
  90         0xFFFFFFFFFFFFFFFFULL
  91         };
  92 static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
  93         {0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
  94          0x0000000000000000ULL,0xFFFFFFFF00000001ULL},
  95         {0xFFFFFFFFFFFFFFFEULL,0x00000001FFFFFFFFULL,
  96          0x0000000000000000ULL,0xFFFFFFFE00000002ULL},
  97         {0xFFFFFFFFFFFFFFFDULL,0x00000002FFFFFFFFULL,
  98          0x0000000000000000ULL,0xFFFFFFFD00000003ULL},
  99         {0xFFFFFFFFFFFFFFFCULL,0x00000003FFFFFFFFULL,
 100          0x0000000000000000ULL,0xFFFFFFFC00000004ULL},
 101         {0xFFFFFFFFFFFFFFFBULL,0x00000004FFFFFFFFULL,
 102          0x0000000000000000ULL,0xFFFFFFFB00000005ULL},
 103         };
 104 static const BN_ULONG _nist_p_256_sqr[] = {
 105         0x0000000000000001ULL,0xFFFFFFFE00000000ULL,
 106         0xFFFFFFFFFFFFFFFFULL,0x00000001FFFFFFFEULL,
 107         0x00000001FFFFFFFEULL,0x00000001FFFFFFFEULL,
 108         0xFFFFFFFE00000001ULL,0xFFFFFFFE00000002ULL
 109         };
 110 static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
 111         {0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,0xFFFFFFFFFFFFFFFEULL,
 112          0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
 113         {0x00000001FFFFFFFEULL,0xFFFFFFFE00000000ULL,0xFFFFFFFFFFFFFFFDULL,
 114          0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
 115         {0x00000002FFFFFFFDULL,0xFFFFFFFD00000000ULL,0xFFFFFFFFFFFFFFFCULL,
 116          0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
 117         {0x00000003FFFFFFFCULL,0xFFFFFFFC00000000ULL,0xFFFFFFFFFFFFFFFBULL,
 118          0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
 119         {0x00000004FFFFFFFBULL,0xFFFFFFFB00000000ULL,0xFFFFFFFFFFFFFFFAULL,
 120          0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
 121         };
 122 static const BN_ULONG _nist_p_384_sqr[] = {
 123         0xFFFFFFFE00000001ULL,0x0000000200000000ULL,0xFFFFFFFE00000000ULL,
 124         0x0000000200000000ULL,0x0000000000000001ULL,0x0000000000000000ULL,
 125         0x00000001FFFFFFFEULL,0xFFFFFFFE00000000ULL,0xFFFFFFFFFFFFFFFDULL,
 126         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL
 127         };
 128 static const BN_ULONG _nist_p_521[] =
 129         {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 130         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 131         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 132         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 133         0x00000000000001FFULL};
 134 static const BN_ULONG _nist_p_521_sqr[] = {
 135         0x0000000000000001ULL,0x0000000000000000ULL,0x0000000000000000ULL,
 136         0x0000000000000000ULL,0x0000000000000000ULL,0x0000000000000000ULL,
 137         0x0000000000000000ULL,0x0000000000000000ULL,0xFFFFFFFFFFFFFC00ULL,
 138         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 139         0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
 140         0xFFFFFFFFFFFFFFFFULL,0x000000000003FFFFULL
 141         };
 142 #elif BN_BITS2 == 32
 143 static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
 144         {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 145         {0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 146         {0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFC,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF}
 147         };
 148 static const BN_ULONG _nist_p_192_sqr[] = {
 149         0x00000001,0x00000000,0x00000002,0x00000000,0x00000001,0x00000000,
 150         0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF
 151         };
 152 static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
 153         {0x00000001,0x00000000,0x00000000,0xFFFFFFFF,
 154          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 155         {0x00000002,0x00000000,0x00000000,0xFFFFFFFE,
 156          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF}
 157         };
 158 static const BN_ULONG _nist_p_224_sqr[] = {
 159         0x00000001,0x00000000,0x00000000,0xFFFFFFFE,
 160         0xFFFFFFFF,0xFFFFFFFF,0x00000000,0x00000002,
 161         0x00000000,0x00000000,0xFFFFFFFE,0xFFFFFFFF,
 162         0xFFFFFFFF,0xFFFFFFFF
 163         };
 164 static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
 165         {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0x00000000,
 166          0x00000000,0x00000000,0x00000001,0xFFFFFFFF},
 167         {0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0x00000001,
 168          0x00000000,0x00000000,0x00000002,0xFFFFFFFE},
 169         {0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFF,0x00000002,
 170          0x00000000,0x00000000,0x00000003,0xFFFFFFFD},
 171         {0xFFFFFFFC,0xFFFFFFFF,0xFFFFFFFF,0x00000003,
 172          0x00000000,0x00000000,0x00000004,0xFFFFFFFC},
 173         {0xFFFFFFFB,0xFFFFFFFF,0xFFFFFFFF,0x00000004,
 174          0x00000000,0x00000000,0x00000005,0xFFFFFFFB},
 175         };
 176 static const BN_ULONG _nist_p_256_sqr[] = {
 177         0x00000001,0x00000000,0x00000000,0xFFFFFFFE,
 178         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,0x00000001,
 179         0xFFFFFFFE,0x00000001,0xFFFFFFFE,0x00000001,
 180         0x00000001,0xFFFFFFFE,0x00000002,0xFFFFFFFE
 181         };
 182 static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
 183         {0xFFFFFFFF,0x00000000,0x00000000,0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,
 184          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 185         {0xFFFFFFFE,0x00000001,0x00000000,0xFFFFFFFE,0xFFFFFFFD,0xFFFFFFFF,
 186          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 187         {0xFFFFFFFD,0x00000002,0x00000000,0xFFFFFFFD,0xFFFFFFFC,0xFFFFFFFF,
 188          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 189         {0xFFFFFFFC,0x00000003,0x00000000,0xFFFFFFFC,0xFFFFFFFB,0xFFFFFFFF,
 190          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 191         {0xFFFFFFFB,0x00000004,0x00000000,0xFFFFFFFB,0xFFFFFFFA,0xFFFFFFFF,
 192          0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
 193         };
 194 static const BN_ULONG _nist_p_384_sqr[] = {
 195         0x00000001,0xFFFFFFFE,0x00000000,0x00000002,0x00000000,0xFFFFFFFE,
 196         0x00000000,0x00000002,0x00000001,0x00000000,0x00000000,0x00000000,
 197         0xFFFFFFFE,0x00000001,0x00000000,0xFFFFFFFE,0xFFFFFFFD,0xFFFFFFFF,
 198         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF
 199         };
 200 static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 201         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 202         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 203         0xFFFFFFFF,0x000001FF};
 204 static const BN_ULONG _nist_p_521_sqr[] = {
 205         0x00000001,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,
 206         0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,
 207         0x00000000,0x00000000,0x00000000,0x00000000,0xFFFFFC00,0xFFFFFFFF,
 208         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 209         0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
 210         0xFFFFFFFF,0xFFFFFFFF,0x0003FFFF
 211         };
 212 #else
 213 #error "unsupported BN_BITS2"
 214 #endif
 215
 216
 217 static const BIGNUM _bignum_nist_p_192 =
 218         {
 219         (BN_ULONG *)_nist_p_192[0],
 220         BN_NIST_192_TOP,
 221         BN_NIST_192_TOP,
 222         0,
 223         BN_FLG_STATIC_DATA
 224         };
 225
 226 static const BIGNUM _bignum_nist_p_224 =
 227         {
 228         (BN_ULONG *)_nist_p_224[0],
 229         BN_NIST_224_TOP,
 230         BN_NIST_224_TOP,
 231         0,
 232         BN_FLG_STATIC_DATA
 233         };
 234
 235 static const BIGNUM _bignum_nist_p_256 =
 236         {
 237         (BN_ULONG *)_nist_p_256[0],
 238         BN_NIST_256_TOP,
 239         BN_NIST_256_TOP,
 240         0,
 241         BN_FLG_STATIC_DATA
 242         };
 243
 244 static const BIGNUM _bignum_nist_p_384 =
 245         {
 246         (BN_ULONG *)_nist_p_384[0],
 247         BN_NIST_384_TOP,
 248         BN_NIST_384_TOP,
 249         0,
 250         BN_FLG_STATIC_DATA
 251         };
 252
 253 static const BIGNUM _bignum_nist_p_521 =
 254         {
 255         (BN_ULONG *)_nist_p_521,
 256         BN_NIST_521_TOP,
 257         BN_NIST_521_TOP,
 258         0,
 259         BN_FLG_STATIC_DATA
 260         };
 261
 262
 263 const BIGNUM *BN_get0_nist_prime_192(void)
 264         {
 265         return &_bignum_nist_p_192;
 266         }
 267
 268 const BIGNUM *BN_get0_nist_prime_224(void)
 269         {
 270         return &_bignum_nist_p_224;
 271         }
 272
 273 const BIGNUM *BN_get0_nist_prime_256(void)
 274         {
 275         return &_bignum_nist_p_256;
 276         }
 277
 278 const BIGNUM *BN_get0_nist_prime_384(void)
 279         {
 280         return &_bignum_nist_p_384;
 281         }
 282
 283 const BIGNUM *BN_get0_nist_prime_521(void)
 284         {
 285         return &_bignum_nist_p_521;
 286         }
 287
 288
 289 static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)
 290         {
 291         int i;
 292         BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
 293
 294 #ifdef BN_DEBUG
 295         OPENSSL_assert(top <= max);
 296 #endif
 297         for (i = (top); i != 0; i--)
 298                 *_tmp1++ = *_tmp2++;
 299         for (i = (max) - (top); i != 0; i--)
 300                 *_tmp1++ = (BN_ULONG) 0;
 301         }
 302
 303 static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
 304         {
 305         int i;
 306         BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
 307         for (i = (top); i != 0; i--)
 308                 *_tmp1++ = *_tmp2++;
 309         }
 310
 311 #if BN_BITS2 == 64
 312 #define bn_cp_64(to, n, from, m)        (to)[n] = (m>=0)?((from)[m]):0;
 313 #define bn_64_set_0(to, n)              (to)[n] = (BN_ULONG)0;
 314 /*
 315  * two following macros are implemented under assumption that they
 316  * are called in a sequence with *ascending* n, i.e. as they are...
 317  */
 318 #define bn_cp_32_naked(to, n, from, m)  (((n)&1)?(to[(n)/2]|=((m)&1)?(from[(m)/2]&BN_MASK2h):(from[(m)/2]<<32))\
 319                                                 :(to[(n)/2] =((m)&1)?(from[(m)/2]>>32):(from[(m)/2]&BN_MASK2l)))
 320 #define bn_32_set_0(to, n)              (((n)&1)?(to[(n)/2]&=BN_MASK2l):(to[(n)/2]=0));
 321 #define bn_cp_32(to,n,from,m)           ((m)>=0)?bn_cp_32_naked(to,n,from,m):bn_32_set_0(to,n)
 322 # if defined(L_ENDIAN)
 323 #  if defined(__arch64__)
 324 #   define NIST_INT64 long
 325 #  else
 326 #   define NIST_INT64 long long
 327 #  endif
 328 # endif
 329 #else
 330 #define bn_cp_64(to, n, from, m) \
 331         { \
 332         bn_cp_32(to, (n)*2, from, (m)*2); \
 333         bn_cp_32(to, (n)*2+1, from, (m)*2+1); \
 334         }
 335 #define bn_64_set_0(to, n) \
 336         { \
 337         bn_32_set_0(to, (n)*2); \
 338         bn_32_set_0(to, (n)*2+1); \
 339         }
 340 #define bn_cp_32(to, n, from, m)        (to)[n] = (m>=0)?((from)[m]):0;
 341 #define bn_32_set_0(to, n)              (to)[n] = (BN_ULONG)0;
 342 # if defined(_WIN32) && !defined(__GNUC__)
 343 #  define NIST_INT64 __int64
 344 # else
 345 #  define NIST_INT64 long long
 346 # endif
 347 #endif /* BN_BITS2 != 64 */
 348
 349
 350 #define nist_set_192(to, from, a1, a2, a3) \
 351         { \
 352         bn_cp_64(to, 0, from, (a3) - 3) \
 353         bn_cp_64(to, 1, from, (a2) - 3) \
 354         bn_cp_64(to, 2, from, (a1) - 3) \
 355         }
 356
 357 int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 358         BN_CTX *ctx)
 359         {
 360         int      top = a->top, i;
 361         int      carry;
 362         register BN_ULONG *r_d, *a_d = a->d;
 363         BN_ULONG buf[BN_NIST_192_TOP],
 364                  c_d[BN_NIST_192_TOP],
 365                 *res;
 366         PTR_SIZE_INT mask;
 367         static const BIGNUM _bignum_nist_p_192_sqr = {
 368                 (BN_ULONG *)_nist_p_192_sqr,
 369                 sizeof(_nist_p_192_sqr)/sizeof(_nist_p_192_sqr[0]),
 370                 sizeof(_nist_p_192_sqr)/sizeof(_nist_p_192_sqr[0]),
 371                 0,BN_FLG_STATIC_DATA };
 372
 373         field = &_bignum_nist_p_192; /* just to make sure */
 374
 375         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_192_sqr)>=0)
 376                 return BN_nnmod(r, a, field, ctx);
 377
 378         i = BN_ucmp(field, a);
 379         if (i == 0)
 380                 {
 381                 BN_zero(r);
 382                 return 1;
 383                 }
 384         else if (i > 0)
 385                 return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
 386
 387         if (r != a)
 388                 {
 389                 if (!bn_wexpand(r, BN_NIST_192_TOP))
 390                         return 0;
 391                 r_d = r->d;
 392                 nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
 393                 }
 394         else
 395                 r_d = a_d;
 396
 397         nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
 398
 399 #if defined(NIST_INT64)
 400         {
 401         NIST_INT64              acc;    /* accumulator */
 402         unsigned int            *rp=(unsigned int *)r_d;
 403         const unsigned int      *bp=(const unsigned int *)buf;
 404
 405         acc  = rp[0];   acc += bp[3*2-6];
 406                         acc += bp[5*2-6]; rp[0] = (unsigned int)acc; acc >>= 32;
 407
 408         acc += rp[1];   acc += bp[3*2-5];
 409                         acc += bp[5*2-5]; rp[1] = (unsigned int)acc; acc >>= 32;
 410
 411         acc += rp[2];   acc += bp[3*2-6];
 412                         acc += bp[4*2-6];
 413                         acc += bp[5*2-6]; rp[2] = (unsigned int)acc; acc >>= 32;
 414
 415         acc += rp[3];   acc += bp[3*2-5];
 416                         acc += bp[4*2-5];
 417                         acc += bp[5*2-5]; rp[3] = (unsigned int)acc; acc >>= 32;
 418
 419         acc += rp[4];   acc += bp[4*2-6];
 420                         acc += bp[5*2-6]; rp[4] = (unsigned int)acc; acc >>= 32;
 421
 422         acc += rp[5];   acc += bp[4*2-5];
 423                         acc += bp[5*2-5]; rp[5] = (unsigned int)acc;
 424
 425         carry = (int)(acc>>32);
 426         }
 427 #else
 428         {
 429         BN_ULONG t_d[BN_NIST_192_TOP];
 430
 431         nist_set_192(t_d, buf, 0, 3, 3);
 432         carry = (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 433         nist_set_192(t_d, buf, 4, 4, 0);
 434         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 435         nist_set_192(t_d, buf, 5, 5, 5)
 436         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 437         }
 438 #endif
 439         if (carry > 0)
 440                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_192[carry-1],BN_NIST_192_TOP);
 441         else
 442                 carry = 1;
 443
 444         /*
 445          * we need 'if (carry==0 || result>=modulus) result-=modulus;'
 446          * as comparison implies subtraction, we can write
 447          * 'tmp=result-modulus; if (!carry || !borrow) result=tmp;'
 448          * this is what happens below, but without explicit if:-) a.
 449          */
 450         mask  = 0-(PTR_SIZE_INT)bn_sub_words(c_d,r_d,_nist_p_192[0],BN_NIST_192_TOP);
 451         mask &= 0-(PTR_SIZE_INT)carry;
 452         res   = (BN_ULONG *)
 453          (((PTR_SIZE_INT)c_d&~mask) | ((PTR_SIZE_INT)r_d&mask));
 454         nist_cp_bn(r_d, res, BN_NIST_192_TOP);
 455         r->top = BN_NIST_192_TOP;
 456         bn_correct_top(r);
 457
 458         return 1;
 459         }
 460
 461 typedef BN_ULONG (*bn_addsub_f)(BN_ULONG *,const BN_ULONG *,const BN_ULONG *,int);
 462
 463 #define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
 464         { \
 465         bn_cp_32(to, 0, from, (a7) - 7) \
 466         bn_cp_32(to, 1, from, (a6) - 7) \
 467         bn_cp_32(to, 2, from, (a5) - 7) \
 468         bn_cp_32(to, 3, from, (a4) - 7) \
 469         bn_cp_32(to, 4, from, (a3) - 7) \
 470         bn_cp_32(to, 5, from, (a2) - 7) \
 471         bn_cp_32(to, 6, from, (a1) - 7) \
 472         }
 473
 474 int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 475         BN_CTX *ctx)
 476         {
 477         int     top = a->top, i;
 478         int     carry;
 479         BN_ULONG *r_d, *a_d = a->d;
 480         BN_ULONG buf[BN_NIST_224_TOP],
 481                  c_d[BN_NIST_224_TOP],
 482                 *res;
 483         PTR_SIZE_INT mask;
 484         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 485         static const BIGNUM _bignum_nist_p_224_sqr = {
 486                 (BN_ULONG *)_nist_p_224_sqr,
 487                 sizeof(_nist_p_224_sqr)/sizeof(_nist_p_224_sqr[0]),
 488                 sizeof(_nist_p_224_sqr)/sizeof(_nist_p_224_sqr[0]),
 489                 0,BN_FLG_STATIC_DATA };
 490
 491
 492         field = &_bignum_nist_p_224; /* just to make sure */
 493
 494         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_224_sqr)>=0)
 495                 return BN_nnmod(r, a, field, ctx);
 496
 497         i = BN_ucmp(field, a);
 498         if (i == 0)
 499                 {
 500                 BN_zero(r);
 501                 return 1;
 502                 }
 503         else if (i > 0)
 504                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 505
 506         if (r != a)
 507                 {
 508                 if (!bn_wexpand(r, BN_NIST_224_TOP))
 509                         return 0;
 510                 r_d = r->d;
 511                 nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
 512                 }
 513         else
 514                 r_d = a_d;
 515
 516 #if BN_BITS2==64
 517         /* copy upper 256 bits of 448 bit number ... */
 518         nist_cp_bn_0(c_d, a_d + (BN_NIST_224_TOP-1), top - (BN_NIST_224_TOP-1), BN_NIST_224_TOP);
 519         /* ... and right shift by 32 to obtain upper 224 bits */
 520         nist_set_224(buf, c_d, 14, 13, 12, 11, 10, 9, 8);
 521         /* truncate lower part to 224 bits too */
 522         r_d[BN_NIST_224_TOP-1] &= BN_MASK2l;
 523 #else
 524         nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
 525 #endif
 526
 527 #if defined(NIST_INT64) && BN_BITS2!=64
 528         {
 529         NIST_INT64              acc;    /* accumulator */
 530         unsigned int            *rp=(unsigned int *)r_d;
 531         const unsigned int      *bp=(const unsigned int *)buf;
 532
 533         acc  = rp[0];   acc -= bp[7-7];
 534                         acc -= bp[11-7]; rp[0] = (unsigned int)acc; acc >>= 32;
 535
 536         acc += rp[1];   acc -= bp[8-7];
 537                         acc -= bp[12-7]; rp[1] = (unsigned int)acc; acc >>= 32;
 538
 539         acc += rp[2];   acc -= bp[9-7];
 540                         acc -= bp[13-7]; rp[2] = (unsigned int)acc; acc >>= 32;
 541
 542         acc += rp[3];   acc += bp[7-7];
 543                         acc += bp[11-7];
 544                         acc -= bp[10-7]; rp[3] = (unsigned int)acc; acc>>= 32;
 545
 546         acc += rp[4];   acc += bp[8-7];
 547                         acc += bp[12-7];
 548                         acc -= bp[11-7]; rp[4] = (unsigned int)acc; acc >>= 32;
 549
 550         acc += rp[5];   acc += bp[9-7];
 551                         acc += bp[13-7];
 552                         acc -= bp[12-7]; rp[5] = (unsigned int)acc; acc >>= 32;
 553
 554         acc += rp[6];   acc += bp[10-7];
 555                         acc -= bp[13-7]; rp[6] = (unsigned int)acc;
 556
 557         carry = (int)(acc>>32);
 558 # if BN_BITS2==64
 559         rp[7] = carry;
 560 # endif
 561         }
 562 #else
 563         {
 564         BN_ULONG t_d[BN_NIST_224_TOP];
 565
 566         nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);
 567         carry = (int)bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 568         nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);
 569         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 570         nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
 571         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 572         nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
 573         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 574
 575 #if BN_BITS2==64
 576         carry = (int)(r_d[BN_NIST_224_TOP-1]>>32);
 577 #endif
 578         }
 579 #endif
 580         u.f = bn_sub_words;
 581         if (carry > 0)
 582                 {
 583                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_224[carry-1],BN_NIST_224_TOP);
 584 #if BN_BITS2==64
 585                 carry=(int)(~(r_d[BN_NIST_224_TOP-1]>>32))&1;
 586 #endif
 587                 }
 588         else if (carry < 0)
 589                 {
 590                 /* it's a bit more comlicated logic in this case.
 591                  * if bn_add_words yields no carry, then result
 592                  * has to be adjusted by unconditionally *adding*
 593                  * the modulus. but if it does, then result has
 594                  * to be compared to the modulus and conditionally
 595                  * adjusted by *subtracting* the latter. */
 596                 carry = (int)bn_add_words(r_d,r_d,_nist_p_224[-carry-1],BN_NIST_224_TOP);
 597                 mask = 0-(PTR_SIZE_INT)carry;
 598                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
 599                  ((PTR_SIZE_INT)bn_add_words&~mask);
 600                 }
 601         else
 602                 carry = 1;
 603
 604         /* otherwise it's effectively same as in BN_nist_mod_192... */
 605         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_224[0],BN_NIST_224_TOP);
 606         mask &= 0-(PTR_SIZE_INT)carry;
 607         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
 608          ((PTR_SIZE_INT)r_d&mask));
 609         nist_cp_bn(r_d, res, BN_NIST_224_TOP);
 610         r->top = BN_NIST_224_TOP;
 611         bn_correct_top(r);
 612
 613         return 1;
 614         }
 615
 616 #define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
 617         { \
 618         bn_cp_32(to, 0, from, (a8) - 8) \
 619         bn_cp_32(to, 1, from, (a7) - 8) \
 620         bn_cp_32(to, 2, from, (a6) - 8) \
 621         bn_cp_32(to, 3, from, (a5) - 8) \
 622         bn_cp_32(to, 4, from, (a4) - 8) \
 623         bn_cp_32(to, 5, from, (a3) - 8) \
 624         bn_cp_32(to, 6, from, (a2) - 8) \
 625         bn_cp_32(to, 7, from, (a1) - 8) \
 626         }
 627
 628 int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 629         BN_CTX *ctx)
 630         {
 631         int     i, top = a->top;
 632         int     carry = 0;
 633         register BN_ULONG *a_d = a->d, *r_d;
 634         BN_ULONG buf[BN_NIST_256_TOP],
 635                  c_d[BN_NIST_256_TOP],
 636                 *res;
 637         PTR_SIZE_INT mask;
 638         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 639         static const BIGNUM _bignum_nist_p_256_sqr = {
 640                 (BN_ULONG *)_nist_p_256_sqr,
 641                 sizeof(_nist_p_256_sqr)/sizeof(_nist_p_256_sqr[0]),
 642                 sizeof(_nist_p_256_sqr)/sizeof(_nist_p_256_sqr[0]),
 643                 0,BN_FLG_STATIC_DATA };
 644
 645         field = &_bignum_nist_p_256; /* just to make sure */
 646
 647         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_256_sqr)>=0)
 648                 return BN_nnmod(r, a, field, ctx);
 649
 650         i = BN_ucmp(field, a);
 651         if (i == 0)
 652                 {
 653                 BN_zero(r);
 654                 return 1;
 655                 }
 656         else if (i > 0)
 657                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 658
 659         if (r != a)
 660                 {
 661                 if (!bn_wexpand(r, BN_NIST_256_TOP))
 662                         return 0;
 663                 r_d = r->d;
 664                 nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
 665                 }
 666         else
 667                 r_d = a_d;
 668
 669         nist_cp_bn_0(buf, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
 670
 671 #if defined(NIST_INT64)
 672         {
 673         NIST_INT64              acc;    /* accumulator */
 674         unsigned int            *rp=(unsigned int *)r_d;
 675         const unsigned int      *bp=(const unsigned int *)buf;
 676
 677         acc = rp[0];    acc += bp[8-8];
 678                         acc += bp[9-8];
 679                         acc -= bp[11-8];
 680                         acc -= bp[12-8];
 681                         acc -= bp[13-8];
 682                         acc -= bp[14-8]; rp[0] = (unsigned int)acc; acc >>= 32;
 683
 684         acc += rp[1];   acc += bp[9-8];
 685                         acc += bp[10-8];
 686                         acc -= bp[12-8];
 687                         acc -= bp[13-8];
 688                         acc -= bp[14-8];
 689                         acc -= bp[15-8]; rp[1] = (unsigned int)acc; acc >>= 32;
 690
 691         acc += rp[2];   acc += bp[10-8];
 692                         acc += bp[11-8];
 693                         acc -= bp[13-8];
 694                         acc -= bp[14-8];
 695                         acc -= bp[15-8]; rp[2] = (unsigned int)acc; acc >>= 32;
 696
 697         acc += rp[3];   acc += bp[11-8];
 698                         acc += bp[11-8];
 699                         acc += bp[12-8];
 700                         acc += bp[12-8];
 701                         acc += bp[13-8];
 702                         acc -= bp[15-8];
 703                         acc -= bp[8-8];
 704                         acc -= bp[9-8];  rp[3] = (unsigned int)acc; acc >>= 32;
 705
 706         acc += rp[4];   acc += bp[12-8];
 707                         acc += bp[12-8];
 708                         acc += bp[13-8];
 709                         acc += bp[13-8];
 710                         acc += bp[14-8];
 711                         acc -= bp[9-8];
 712                         acc -= bp[10-8]; rp[4] = (unsigned int)acc; acc >>= 32;
 713
 714         acc += rp[5];   acc += bp[13-8];
 715                         acc += bp[13-8];
 716                         acc += bp[14-8];
 717                         acc += bp[14-8];
 718                         acc += bp[15-8];
 719                         acc -= bp[10-8];
 720                         acc -= bp[11-8]; rp[5] = (unsigned int)acc; acc >>= 32;
 721
 722         acc += rp[6];   acc += bp[14-8];
 723                         acc += bp[14-8];
 724                         acc += bp[15-8];
 725                         acc += bp[15-8];
 726                         acc += bp[14-8];
 727                         acc += bp[13-8];
 728                         acc -= bp[8-8];
 729                         acc -= bp[9-8];  rp[6] = (unsigned int)acc; acc >>= 32;
 730
 731         acc += rp[7];   acc += bp[15-8];
 732                         acc += bp[15-8];
 733                         acc += bp[15-8];
 734                         acc += bp[8 -8];
 735                         acc -= bp[10-8];
 736                         acc -= bp[11-8];
 737                         acc -= bp[12-8];
 738                         acc -= bp[13-8]; rp[7] = (unsigned int)acc;
 739
 740         carry = (int)(acc>>32);
 741         }
 742 #else
 743         {
 744         BN_ULONG t_d[BN_NIST_256_TOP];
 745
 746         /*S1*/
 747         nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0);
 748         /*S2*/
 749         nist_set_256(c_d, buf, 0, 15, 14, 13, 12, 0, 0, 0);
 750         carry = (int)bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
 751         /* left shift */
 752                 {
 753                 register BN_ULONG *ap,t,c;
 754                 ap = t_d;
 755                 c=0;
 756                 for (i = BN_NIST_256_TOP; i != 0; --i)
 757                         {
 758                         t= *ap;
 759                         *(ap++)=((t<<1)|c)&BN_MASK2;
 760                         c=(t & BN_TBIT)?1:0;
 761                         }
 762                 carry <<= 1;
 763                 carry  |= c;
 764                 }
 765         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 766         /*S3*/
 767         nist_set_256(t_d, buf, 15, 14, 0, 0, 0, 10, 9, 8);
 768         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 769         /*S4*/
 770         nist_set_256(t_d, buf, 8, 13, 15, 14, 13, 11, 10, 9);
 771         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 772         /*D1*/
 773         nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11);
 774         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 775         /*D2*/
 776         nist_set_256(t_d, buf, 11, 9, 0, 0, 15, 14, 13, 12);
 777         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 778         /*D3*/
 779         nist_set_256(t_d, buf, 12, 0, 10, 9, 8, 15, 14, 13);
 780         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 781         /*D4*/
 782         nist_set_256(t_d, buf, 13, 0, 11, 10, 9, 0, 15, 14);
 783         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 784
 785         }
 786 #endif
 787         /* see BN_nist_mod_224 for explanation */
 788         u.f = bn_sub_words;
 789         if (carry > 0)
 790                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_256[carry-1],BN_NIST_256_TOP);
 791         else if (carry < 0)
 792                 {
 793                 carry = (int)bn_add_words(r_d,r_d,_nist_p_256[-carry-1],BN_NIST_256_TOP);
 794                 mask = 0-(PTR_SIZE_INT)carry;
 795                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
 796                  ((PTR_SIZE_INT)bn_add_words&~mask);
 797                 }
 798         else
 799                 carry = 1;
 800
 801         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_256[0],BN_NIST_256_TOP);
 802         mask &= 0-(PTR_SIZE_INT)carry;
 803         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
 804          ((PTR_SIZE_INT)r_d&mask));
 805         nist_cp_bn(r_d, res, BN_NIST_256_TOP);
 806         r->top = BN_NIST_256_TOP;
 807         bn_correct_top(r);
 808
 809         return 1;
 810         }
 811
 812 #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
 813         { \
 814         bn_cp_32(to, 0, from,  (a12) - 12) \
 815         bn_cp_32(to, 1, from,  (a11) - 12) \
 816         bn_cp_32(to, 2, from,  (a10) - 12) \
 817         bn_cp_32(to, 3, from,  (a9) - 12)  \
 818         bn_cp_32(to, 4, from,  (a8) - 12)  \
 819         bn_cp_32(to, 5, from,  (a7) - 12)  \
 820         bn_cp_32(to, 6, from,  (a6) - 12)  \
 821         bn_cp_32(to, 7, from,  (a5) - 12)  \
 822         bn_cp_32(to, 8, from,  (a4) - 12)  \
 823         bn_cp_32(to, 9, from,  (a3) - 12)  \
 824         bn_cp_32(to, 10, from, (a2) - 12)  \
 825         bn_cp_32(to, 11, from, (a1) - 12)  \
 826         }
 827
 828 int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 829         BN_CTX *ctx)
 830         {
 831         int     i, top = a->top;
 832         int     carry = 0;
 833         register BN_ULONG *r_d, *a_d = a->d;
 834         BN_ULONG buf[BN_NIST_384_TOP],
 835                  c_d[BN_NIST_384_TOP],
 836                 *res;
 837         PTR_SIZE_INT mask;
 838         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 839         static const BIGNUM _bignum_nist_p_384_sqr = {
 840                 (BN_ULONG *)_nist_p_384_sqr,
 841                 sizeof(_nist_p_384_sqr)/sizeof(_nist_p_384_sqr[0]),
 842                 sizeof(_nist_p_384_sqr)/sizeof(_nist_p_384_sqr[0]),
 843                 0,BN_FLG_STATIC_DATA };
 844
 845
 846         field = &_bignum_nist_p_384; /* just to make sure */
 847
 848         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_384_sqr)>=0)
 849                 return BN_nnmod(r, a, field, ctx);
 850
 851         i = BN_ucmp(field, a);
 852         if (i == 0)
 853                 {
 854                 BN_zero(r);
 855                 return 1;
 856                 }
 857         else if (i > 0)
 858                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 859
 860         if (r != a)
 861                 {
 862                 if (!bn_wexpand(r, BN_NIST_384_TOP))
 863                         return 0;
 864                 r_d = r->d;
 865                 nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
 866                 }
 867         else
 868                 r_d = a_d;
 869
 870         nist_cp_bn_0(buf, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
 871
 872 #if defined(NIST_INT64)
 873         {
 874         NIST_INT64              acc;    /* accumulator */
 875         unsigned int            *rp=(unsigned int *)r_d;
 876         const unsigned int      *bp=(const unsigned int *)buf;
 877
 878         acc = rp[0];    acc += bp[12-12];
 879                         acc += bp[21-12];
 880                         acc += bp[20-12];
 881                         acc -= bp[23-12]; rp[0] = (unsigned int)acc; acc >>= 32;
 882
 883         acc += rp[1];   acc += bp[13-12];
 884                         acc += bp[22-12];
 885                         acc += bp[23-12];
 886                         acc -= bp[12-12];
 887                         acc -= bp[20-12]; rp[1] = (unsigned int)acc; acc >>= 32;
 888
 889         acc += rp[2];   acc += bp[14-12];
 890                         acc += bp[23-12];
 891                         acc -= bp[13-12];
 892                         acc -= bp[21-12]; rp[2] = (unsigned int)acc; acc >>= 32;
 893
 894         acc += rp[3];   acc += bp[15-12];
 895                         acc += bp[12-12];
 896                         acc += bp[20-12];
 897                         acc += bp[21-12];
 898                         acc -= bp[14-12];
 899                         acc -= bp[22-12];
 900                         acc -= bp[23-12]; rp[3] = (unsigned int)acc; acc >>= 32;
 901
 902         acc += rp[4];   acc += bp[21-12];
 903                         acc += bp[21-12];
 904                         acc += bp[16-12];
 905                         acc += bp[13-12];
 906                         acc += bp[12-12];
 907                         acc += bp[20-12];
 908                         acc += bp[22-12];
 909                         acc -= bp[15-12];
 910                         acc -= bp[23-12];
 911                         acc -= bp[23-12]; rp[4] = (unsigned int)acc; acc >>= 32;
 912
 913         acc += rp[5];   acc += bp[22-12];
 914                         acc += bp[22-12];
 915                         acc += bp[17-12];
 916                         acc += bp[14-12];
 917                         acc += bp[13-12];
 918                         acc += bp[21-12];
 919                         acc += bp[23-12];
 920                         acc -= bp[16-12]; rp[5] = (unsigned int)acc; acc >>= 32;
 921
 922         acc += rp[6];   acc += bp[23-12];
 923                         acc += bp[23-12];
 924                         acc += bp[18-12];
 925                         acc += bp[15-12];
 926                         acc += bp[14-12];
 927                         acc += bp[22-12];
 928                         acc -= bp[17-12]; rp[6] = (unsigned int)acc; acc >>= 32;
 929
 930         acc += rp[7];   acc += bp[19-12];
 931                         acc += bp[16-12];
 932                         acc += bp[15-12];
 933                         acc += bp[23-12];
 934                         acc -= bp[18-12]; rp[7] = (unsigned int)acc; acc >>= 32;
 935
 936         acc += rp[8];   acc += bp[20-12];
 937                         acc += bp[17-12];
 938                         acc += bp[16-12];
 939                         acc -= bp[19-12]; rp[8] = (unsigned int)acc; acc >>= 32;
 940
 941         acc += rp[9];   acc += bp[21-12];
 942                         acc += bp[18-12];
 943                         acc += bp[17-12];
 944                         acc -= bp[20-12]; rp[9] = (unsigned int)acc; acc >>= 32;
 945
 946         acc += rp[10];  acc += bp[22-12];
 947                         acc += bp[19-12];
 948                         acc += bp[18-12];
 949                         acc -= bp[21-12]; rp[10] = (unsigned int)acc; acc >>= 32;
 950
 951         acc += rp[11];  acc += bp[23-12];
 952                         acc += bp[20-12];
 953                         acc += bp[19-12];
 954                         acc -= bp[22-12]; rp[11] = (unsigned int)acc;
 955
 956         carry = (int)(acc>>32);
 957         }
 958 #else
 959         {
 960         BN_ULONG t_d[BN_NIST_384_TOP];
 961
 962         /*S1*/
 963         nist_set_256(t_d, buf, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
 964                 /* left shift */
 965                 {
 966                 register BN_ULONG *ap,t,c;
 967                 ap = t_d;
 968                 c=0;
 969                 for (i = 3; i != 0; --i)
 970                         {
 971                         t= *ap;
 972                         *(ap++)=((t<<1)|c)&BN_MASK2;
 973                         c=(t & BN_TBIT)?1:0;
 974                         }
 975                 *ap=c;
 976                 }
 977         carry = (int)bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
 978                 t_d, BN_NIST_256_TOP);
 979         /*S2 */
 980         carry += (int)bn_add_words(r_d, r_d, buf, BN_NIST_384_TOP);
 981         /*S3*/
 982         nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21);
 983         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 984         /*S4*/
 985         nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0);
 986         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 987         /*S5*/
 988         nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0);
 989         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 990         /*S6*/
 991         nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20);
 992         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 993         /*D1*/
 994         nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23);
 995         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 996         /*D2*/
 997         nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0);
 998         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 999         /*D3*/
1000         nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0);
1001         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
1002
1003         }
1004 #endif
1005         /* see BN_nist_mod_224 for explanation */
1006         u.f = bn_sub_words;
1007         if (carry > 0)
1008                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_384[carry-1],BN_NIST_384_TOP);
1009         else if (carry < 0)
1010                 {
1011                 carry = (int)bn_add_words(r_d,r_d,_nist_p_384[-carry-1],BN_NIST_384_TOP);
1012                 mask = 0-(PTR_SIZE_INT)carry;
1013                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
1014                  ((PTR_SIZE_INT)bn_add_words&~mask);
1015                 }
1016         else
1017                 carry = 1;
1018
1019         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_384[0],BN_NIST_384_TOP);
1020         mask &= 0-(PTR_SIZE_INT)carry;
1021         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
1022          ((PTR_SIZE_INT)r_d&mask));
1023         nist_cp_bn(r_d, res, BN_NIST_384_TOP);
1024         r->top = BN_NIST_384_TOP;
1025         bn_correct_top(r);
1026
1027         return 1;
1028         }
1029
1030 #define BN_NIST_521_RSHIFT      (521%BN_BITS2)
1031 #define BN_NIST_521_LSHIFT      (BN_BITS2-BN_NIST_521_RSHIFT)
1032 #define BN_NIST_521_TOP_MASK    ((BN_ULONG)BN_MASK2>>BN_NIST_521_LSHIFT)
1033
1034 int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
1035         BN_CTX *ctx)
1036         {
1037         int     top = a->top, i;
1038         BN_ULONG *r_d, *a_d = a->d,
1039                  t_d[BN_NIST_521_TOP],
1040                  val,tmp,*res;
1041         PTR_SIZE_INT mask;
1042         static const BIGNUM _bignum_nist_p_521_sqr = {
1043                 (BN_ULONG *)_nist_p_521_sqr,
1044                 sizeof(_nist_p_521_sqr)/sizeof(_nist_p_521_sqr[0]),
1045                 sizeof(_nist_p_521_sqr)/sizeof(_nist_p_521_sqr[0]),
1046                 0,BN_FLG_STATIC_DATA };
1047
1048         field = &_bignum_nist_p_521; /* just to make sure */
1049
1050         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_521_sqr)>=0)
1051                 return BN_nnmod(r, a, field, ctx);
1052
1053         i = BN_ucmp(field, a);
1054         if (i == 0)
1055                 {
1056                 BN_zero(r);
1057                 return 1;
1058                 }
1059         else if (i > 0)
1060                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
1061
1062         if (r != a)
1063                 {
1064                 if (!bn_wexpand(r,BN_NIST_521_TOP))
1065                         return 0;
1066                 r_d = r->d;
1067                 nist_cp_bn(r_d,a_d, BN_NIST_521_TOP);
1068                 }
1069         else
1070                 r_d = a_d;
1071
1072         /* upper 521 bits, copy ... */
1073         nist_cp_bn_0(t_d,a_d + (BN_NIST_521_TOP-1), top - (BN_NIST_521_TOP-1),BN_NIST_521_TOP);
1074         /* ... and right shift */
1075         for (val=t_d[0],i=0; i<BN_NIST_521_TOP-1; i++)
1076                 {
1077                 tmp = val>>BN_NIST_521_RSHIFT;
1078                 val = t_d[i+1];
1079                 t_d[i] = (tmp | val<<BN_NIST_521_LSHIFT) & BN_MASK2;
1080                 }
1081         t_d[i] = val>>BN_NIST_521_RSHIFT;
1082         /* lower 521 bits */
1083         r_d[i] &= BN_NIST_521_TOP_MASK;
1084
1085         bn_add_words(r_d,r_d,t_d,BN_NIST_521_TOP);
1086         mask = 0-(PTR_SIZE_INT)bn_sub_words(t_d,r_d,_nist_p_521,BN_NIST_521_TOP);
1087         res  = (BN_ULONG *)(((PTR_SIZE_INT)t_d&~mask) |
1088          ((PTR_SIZE_INT)r_d&mask));
1089         nist_cp_bn(r_d,res,BN_NIST_521_TOP);
1090         r->top = BN_NIST_521_TOP;
1091         bn_correct_top(r);
1092
1093         return 1;
1094         }
1095
1096 int (*BN_nist_mod_func(const BIGNUM *p))(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, BN_CTX *ctx)
1097         {
1098         if (BN_ucmp(&_bignum_nist_p_192, p) == 0)
1099                 return BN_nist_mod_192;
1100         if (BN_ucmp(&_bignum_nist_p_224, p) == 0)
1101                 return BN_nist_mod_224;
1102         if (BN_ucmp(&_bignum_nist_p_256, p) == 0)
1103                 return BN_nist_mod_256;
1104         if (BN_ucmp(&_bignum_nist_p_384, p) == 0)
1105                 return BN_nist_mod_384;
1106         if (BN_ucmp(&_bignum_nist_p_521, p) == 0)
1107                 return BN_nist_mod_521;
1108         return 0;
1109         }