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 # elif defined(BN_LLONG)
 345 #  define NIST_INT64 long long
 346 # endif
 347 #endif /* BN_BITS2 != 64 */
 348
 349 #define nist_set_192(to, from, a1, a2, a3) \
 350         { \
 351         bn_cp_64(to, 0, from, (a3) - 3) \
 352         bn_cp_64(to, 1, from, (a2) - 3) \
 353         bn_cp_64(to, 2, from, (a1) - 3) \
 354         }
 355
 356 int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 357         BN_CTX *ctx)
 358         {
 359         int      top = a->top, i;
 360         int      carry;
 361         register BN_ULONG *r_d, *a_d = a->d;
 362         union   {
 363                 BN_ULONG        bn[BN_NIST_192_TOP];
 364                 unsigned int    ui[BN_NIST_192_TOP*sizeof(BN_ULONG)/sizeof(unsigned int)];
 365                 } buf;
 366         BN_ULONG c_d[BN_NIST_192_TOP],
 367                 *res;
 368         PTR_SIZE_INT mask;
 369         static const BIGNUM _bignum_nist_p_192_sqr = {
 370                 (BN_ULONG *)_nist_p_192_sqr,
 371                 sizeof(_nist_p_192_sqr)/sizeof(_nist_p_192_sqr[0]),
 372                 sizeof(_nist_p_192_sqr)/sizeof(_nist_p_192_sqr[0]),
 373                 0,BN_FLG_STATIC_DATA };
 374
 375         field = &_bignum_nist_p_192; /* just to make sure */
 376
 377         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_192_sqr)>=0)
 378                 return BN_nnmod(r, a, field, ctx);
 379
 380         i = BN_ucmp(field, a);
 381         if (i == 0)
 382                 {
 383                 BN_zero(r);
 384                 return 1;
 385                 }
 386         else if (i > 0)
 387                 return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
 388
 389         if (r != a)
 390                 {
 391                 if (!bn_wexpand(r, BN_NIST_192_TOP))
 392                         return 0;
 393                 r_d = r->d;
 394                 nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
 395                 }
 396         else
 397                 r_d = a_d;
 398
 399         nist_cp_bn_0(buf.bn, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
 400
 401 #if defined(NIST_INT64)
 402         {
 403         NIST_INT64              acc;    /* accumulator */
 404         unsigned int            *rp=(unsigned int *)r_d;
 405         const unsigned int      *bp=(const unsigned int *)buf.ui;
 406
 407         acc  = rp[0];   acc += bp[3*2-6];
 408                         acc += bp[5*2-6]; rp[0] = (unsigned int)acc; acc >>= 32;
 409
 410         acc += rp[1];   acc += bp[3*2-5];
 411                         acc += bp[5*2-5]; rp[1] = (unsigned int)acc; acc >>= 32;
 412
 413         acc += rp[2];   acc += bp[3*2-6];
 414                         acc += bp[4*2-6];
 415                         acc += bp[5*2-6]; rp[2] = (unsigned int)acc; acc >>= 32;
 416
 417         acc += rp[3];   acc += bp[3*2-5];
 418                         acc += bp[4*2-5];
 419                         acc += bp[5*2-5]; rp[3] = (unsigned int)acc; acc >>= 32;
 420
 421         acc += rp[4];   acc += bp[4*2-6];
 422                         acc += bp[5*2-6]; rp[4] = (unsigned int)acc; acc >>= 32;
 423
 424         acc += rp[5];   acc += bp[4*2-5];
 425                         acc += bp[5*2-5]; rp[5] = (unsigned int)acc;
 426
 427         carry = (int)(acc>>32);
 428         }
 429 #else
 430         {
 431         BN_ULONG t_d[BN_NIST_192_TOP];
 432
 433         nist_set_192(t_d, buf.bn, 0, 3, 3);
 434         carry = (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 435         nist_set_192(t_d, buf.bn, 4, 4, 0);
 436         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 437         nist_set_192(t_d, buf.bn, 5, 5, 5)
 438         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
 439         }
 440 #endif
 441         if (carry > 0)
 442                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_192[carry-1],BN_NIST_192_TOP);
 443         else
 444                 carry = 1;
 445
 446         /*
 447          * we need 'if (carry==0 || result>=modulus) result-=modulus;'
 448          * as comparison implies subtraction, we can write
 449          * 'tmp=result-modulus; if (!carry || !borrow) result=tmp;'
 450          * this is what happens below, but without explicit if:-) a.
 451          */
 452         mask  = 0-(PTR_SIZE_INT)bn_sub_words(c_d,r_d,_nist_p_192[0],BN_NIST_192_TOP);
 453         mask &= 0-(PTR_SIZE_INT)carry;
 454         res   = (BN_ULONG *)
 455          (((PTR_SIZE_INT)c_d&~mask) | ((PTR_SIZE_INT)r_d&mask));
 456         nist_cp_bn(r_d, res, BN_NIST_192_TOP);
 457         r->top = BN_NIST_192_TOP;
 458         bn_correct_top(r);
 459
 460         return 1;
 461         }
 462
 463 typedef BN_ULONG (*bn_addsub_f)(BN_ULONG *,const BN_ULONG *,const BN_ULONG *,int);
 464
 465 #define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
 466         { \
 467         bn_cp_32(to, 0, from, (a7) - 7) \
 468         bn_cp_32(to, 1, from, (a6) - 7) \
 469         bn_cp_32(to, 2, from, (a5) - 7) \
 470         bn_cp_32(to, 3, from, (a4) - 7) \
 471         bn_cp_32(to, 4, from, (a3) - 7) \
 472         bn_cp_32(to, 5, from, (a2) - 7) \
 473         bn_cp_32(to, 6, from, (a1) - 7) \
 474         }
 475
 476 int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 477         BN_CTX *ctx)
 478         {
 479         int     top = a->top, i;
 480         int     carry;
 481         BN_ULONG *r_d, *a_d = a->d;
 482         BN_ULONG buf[BN_NIST_224_TOP],
 483                  c_d[BN_NIST_224_TOP],
 484                 *res;
 485         PTR_SIZE_INT mask;
 486         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 487         static const BIGNUM _bignum_nist_p_224_sqr = {
 488                 (BN_ULONG *)_nist_p_224_sqr,
 489                 sizeof(_nist_p_224_sqr)/sizeof(_nist_p_224_sqr[0]),
 490                 sizeof(_nist_p_224_sqr)/sizeof(_nist_p_224_sqr[0]),
 491                 0,BN_FLG_STATIC_DATA };
 492
 493
 494         field = &_bignum_nist_p_224; /* just to make sure */
 495
 496         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_224_sqr)>=0)
 497                 return BN_nnmod(r, a, field, ctx);
 498
 499         i = BN_ucmp(field, a);
 500         if (i == 0)
 501                 {
 502                 BN_zero(r);
 503                 return 1;
 504                 }
 505         else if (i > 0)
 506                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 507
 508         if (r != a)
 509                 {
 510                 if (!bn_wexpand(r, BN_NIST_224_TOP))
 511                         return 0;
 512                 r_d = r->d;
 513                 nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
 514                 }
 515         else
 516                 r_d = a_d;
 517
 518 #if BN_BITS2==64
 519         /* copy upper 256 bits of 448 bit number ... */
 520         nist_cp_bn_0(c_d, a_d + (BN_NIST_224_TOP-1), top - (BN_NIST_224_TOP-1), BN_NIST_224_TOP);
 521         /* ... and right shift by 32 to obtain upper 224 bits */
 522         nist_set_224(buf, c_d, 14, 13, 12, 11, 10, 9, 8);
 523         /* truncate lower part to 224 bits too */
 524         r_d[BN_NIST_224_TOP-1] &= BN_MASK2l;
 525 #else
 526         nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
 527 #endif
 528
 529 #if defined(NIST_INT64) && BN_BITS2!=64
 530         {
 531         NIST_INT64              acc;    /* accumulator */
 532         unsigned int            *rp=(unsigned int *)r_d;
 533         const unsigned int      *bp=(const unsigned int *)buf;
 534
 535         acc  = rp[0];   acc -= bp[7-7];
 536                         acc -= bp[11-7]; rp[0] = (unsigned int)acc; acc >>= 32;
 537
 538         acc += rp[1];   acc -= bp[8-7];
 539                         acc -= bp[12-7]; rp[1] = (unsigned int)acc; acc >>= 32;
 540
 541         acc += rp[2];   acc -= bp[9-7];
 542                         acc -= bp[13-7]; rp[2] = (unsigned int)acc; acc >>= 32;
 543
 544         acc += rp[3];   acc += bp[7-7];
 545                         acc += bp[11-7];
 546                         acc -= bp[10-7]; rp[3] = (unsigned int)acc; acc>>= 32;
 547
 548         acc += rp[4];   acc += bp[8-7];
 549                         acc += bp[12-7];
 550                         acc -= bp[11-7]; rp[4] = (unsigned int)acc; acc >>= 32;
 551
 552         acc += rp[5];   acc += bp[9-7];
 553                         acc += bp[13-7];
 554                         acc -= bp[12-7]; rp[5] = (unsigned int)acc; acc >>= 32;
 555
 556         acc += rp[6];   acc += bp[10-7];
 557                         acc -= bp[13-7]; rp[6] = (unsigned int)acc;
 558
 559         carry = (int)(acc>>32);
 560 # if BN_BITS2==64
 561         rp[7] = carry;
 562 # endif
 563         }
 564 #else
 565         {
 566         BN_ULONG t_d[BN_NIST_224_TOP];
 567
 568         nist_set_224(t_d, buf, 10, 9, 8, 7, 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, 0, 13, 12, 11, 0, 0, 0);
 571         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 572         nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
 573         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 574         nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
 575         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
 576
 577 #if BN_BITS2==64
 578         carry = (int)(r_d[BN_NIST_224_TOP-1]>>32);
 579 #endif
 580         }
 581 #endif
 582         u.f = bn_sub_words;
 583         if (carry > 0)
 584                 {
 585                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_224[carry-1],BN_NIST_224_TOP);
 586 #if BN_BITS2==64
 587                 carry=(int)(~(r_d[BN_NIST_224_TOP-1]>>32))&1;
 588 #endif
 589                 }
 590         else if (carry < 0)
 591                 {
 592                 /* it's a bit more comlicated logic in this case.
 593                  * if bn_add_words yields no carry, then result
 594                  * has to be adjusted by unconditionally *adding*
 595                  * the modulus. but if it does, then result has
 596                  * to be compared to the modulus and conditionally
 597                  * adjusted by *subtracting* the latter. */
 598                 carry = (int)bn_add_words(r_d,r_d,_nist_p_224[-carry-1],BN_NIST_224_TOP);
 599                 mask = 0-(PTR_SIZE_INT)carry;
 600                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
 601                  ((PTR_SIZE_INT)bn_add_words&~mask);
 602                 }
 603         else
 604                 carry = 1;
 605
 606         /* otherwise it's effectively same as in BN_nist_mod_192... */
 607         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_224[0],BN_NIST_224_TOP);
 608         mask &= 0-(PTR_SIZE_INT)carry;
 609         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
 610          ((PTR_SIZE_INT)r_d&mask));
 611         nist_cp_bn(r_d, res, BN_NIST_224_TOP);
 612         r->top = BN_NIST_224_TOP;
 613         bn_correct_top(r);
 614
 615         return 1;
 616         }
 617
 618 #define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
 619         { \
 620         bn_cp_32(to, 0, from, (a8) - 8) \
 621         bn_cp_32(to, 1, from, (a7) - 8) \
 622         bn_cp_32(to, 2, from, (a6) - 8) \
 623         bn_cp_32(to, 3, from, (a5) - 8) \
 624         bn_cp_32(to, 4, from, (a4) - 8) \
 625         bn_cp_32(to, 5, from, (a3) - 8) \
 626         bn_cp_32(to, 6, from, (a2) - 8) \
 627         bn_cp_32(to, 7, from, (a1) - 8) \
 628         }
 629
 630 int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 631         BN_CTX *ctx)
 632         {
 633         int     i, top = a->top;
 634         int     carry = 0;
 635         register BN_ULONG *a_d = a->d, *r_d;
 636         union   {
 637                 BN_ULONG bn[BN_NIST_256_TOP];
 638                 unsigned int ui[BN_NIST_256_TOP*sizeof(BN_ULONG)/sizeof(unsigned int)];
 639                 } buf;
 640         BN_ULONG c_d[BN_NIST_256_TOP],
 641                 *res;
 642         PTR_SIZE_INT mask;
 643         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 644         static const BIGNUM _bignum_nist_p_256_sqr = {
 645                 (BN_ULONG *)_nist_p_256_sqr,
 646                 sizeof(_nist_p_256_sqr)/sizeof(_nist_p_256_sqr[0]),
 647                 sizeof(_nist_p_256_sqr)/sizeof(_nist_p_256_sqr[0]),
 648                 0,BN_FLG_STATIC_DATA };
 649
 650         field = &_bignum_nist_p_256; /* just to make sure */
 651
 652         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_256_sqr)>=0)
 653                 return BN_nnmod(r, a, field, ctx);
 654
 655         i = BN_ucmp(field, a);
 656         if (i == 0)
 657                 {
 658                 BN_zero(r);
 659                 return 1;
 660                 }
 661         else if (i > 0)
 662                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 663
 664         if (r != a)
 665                 {
 666                 if (!bn_wexpand(r, BN_NIST_256_TOP))
 667                         return 0;
 668                 r_d = r->d;
 669                 nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
 670                 }
 671         else
 672                 r_d = a_d;
 673
 674         nist_cp_bn_0(buf.bn, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
 675
 676 #if defined(NIST_INT64)
 677         {
 678         NIST_INT64              acc;    /* accumulator */
 679         unsigned int            *rp=(unsigned int *)r_d;
 680         const unsigned int      *bp=(const unsigned int *)buf.ui;
 681
 682         acc = rp[0];    acc += bp[8-8];
 683                         acc += bp[9-8];
 684                         acc -= bp[11-8];
 685                         acc -= bp[12-8];
 686                         acc -= bp[13-8];
 687                         acc -= bp[14-8]; rp[0] = (unsigned int)acc; acc >>= 32;
 688
 689         acc += rp[1];   acc += bp[9-8];
 690                         acc += bp[10-8];
 691                         acc -= bp[12-8];
 692                         acc -= bp[13-8];
 693                         acc -= bp[14-8];
 694                         acc -= bp[15-8]; rp[1] = (unsigned int)acc; acc >>= 32;
 695
 696         acc += rp[2];   acc += bp[10-8];
 697                         acc += bp[11-8];
 698                         acc -= bp[13-8];
 699                         acc -= bp[14-8];
 700                         acc -= bp[15-8]; rp[2] = (unsigned int)acc; acc >>= 32;
 701
 702         acc += rp[3];   acc += bp[11-8];
 703                         acc += bp[11-8];
 704                         acc += bp[12-8];
 705                         acc += bp[12-8];
 706                         acc += bp[13-8];
 707                         acc -= bp[15-8];
 708                         acc -= bp[8-8];
 709                         acc -= bp[9-8];  rp[3] = (unsigned int)acc; acc >>= 32;
 710
 711         acc += rp[4];   acc += bp[12-8];
 712                         acc += bp[12-8];
 713                         acc += bp[13-8];
 714                         acc += bp[13-8];
 715                         acc += bp[14-8];
 716                         acc -= bp[9-8];
 717                         acc -= bp[10-8]; rp[4] = (unsigned int)acc; acc >>= 32;
 718
 719         acc += rp[5];   acc += bp[13-8];
 720                         acc += bp[13-8];
 721                         acc += bp[14-8];
 722                         acc += bp[14-8];
 723                         acc += bp[15-8];
 724                         acc -= bp[10-8];
 725                         acc -= bp[11-8]; rp[5] = (unsigned int)acc; acc >>= 32;
 726
 727         acc += rp[6];   acc += bp[14-8];
 728                         acc += bp[14-8];
 729                         acc += bp[15-8];
 730                         acc += bp[15-8];
 731                         acc += bp[14-8];
 732                         acc += bp[13-8];
 733                         acc -= bp[8-8];
 734                         acc -= bp[9-8];  rp[6] = (unsigned int)acc; acc >>= 32;
 735
 736         acc += rp[7];   acc += bp[15-8];
 737                         acc += bp[15-8];
 738                         acc += bp[15-8];
 739                         acc += bp[8 -8];
 740                         acc -= bp[10-8];
 741                         acc -= bp[11-8];
 742                         acc -= bp[12-8];
 743                         acc -= bp[13-8]; rp[7] = (unsigned int)acc;
 744
 745         carry = (int)(acc>>32);
 746         }
 747 #else
 748         {
 749         BN_ULONG t_d[BN_NIST_256_TOP];
 750
 751         /*S1*/
 752         nist_set_256(t_d, buf.bn, 15, 14, 13, 12, 11, 0, 0, 0);
 753         /*S2*/
 754         nist_set_256(c_d, buf.bn, 0, 15, 14, 13, 12, 0, 0, 0);
 755         carry = (int)bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
 756         /* left shift */
 757                 {
 758                 register BN_ULONG *ap,t,c;
 759                 ap = t_d;
 760                 c=0;
 761                 for (i = BN_NIST_256_TOP; i != 0; --i)
 762                         {
 763                         t= *ap;
 764                         *(ap++)=((t<<1)|c)&BN_MASK2;
 765                         c=(t & BN_TBIT)?1:0;
 766                         }
 767                 carry <<= 1;
 768                 carry  |= c;
 769                 }
 770         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 771         /*S3*/
 772         nist_set_256(t_d, buf.bn, 15, 14, 0, 0, 0, 10, 9, 8);
 773         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 774         /*S4*/
 775         nist_set_256(t_d, buf.bn, 8, 13, 15, 14, 13, 11, 10, 9);
 776         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 777         /*D1*/
 778         nist_set_256(t_d, buf.bn, 10, 8, 0, 0, 0, 13, 12, 11);
 779         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 780         /*D2*/
 781         nist_set_256(t_d, buf.bn, 11, 9, 0, 0, 15, 14, 13, 12);
 782         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 783         /*D3*/
 784         nist_set_256(t_d, buf.bn, 12, 0, 10, 9, 8, 15, 14, 13);
 785         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 786         /*D4*/
 787         nist_set_256(t_d, buf.bn, 13, 0, 11, 10, 9, 0, 15, 14);
 788         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
 789
 790         }
 791 #endif
 792         /* see BN_nist_mod_224 for explanation */
 793         u.f = bn_sub_words;
 794         if (carry > 0)
 795                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_256[carry-1],BN_NIST_256_TOP);
 796         else if (carry < 0)
 797                 {
 798                 carry = (int)bn_add_words(r_d,r_d,_nist_p_256[-carry-1],BN_NIST_256_TOP);
 799                 mask = 0-(PTR_SIZE_INT)carry;
 800                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
 801                  ((PTR_SIZE_INT)bn_add_words&~mask);
 802                 }
 803         else
 804                 carry = 1;
 805
 806         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_256[0],BN_NIST_256_TOP);
 807         mask &= 0-(PTR_SIZE_INT)carry;
 808         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
 809          ((PTR_SIZE_INT)r_d&mask));
 810         nist_cp_bn(r_d, res, BN_NIST_256_TOP);
 811         r->top = BN_NIST_256_TOP;
 812         bn_correct_top(r);
 813
 814         return 1;
 815         }
 816
 817 #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
 818         { \
 819         bn_cp_32(to, 0, from,  (a12) - 12) \
 820         bn_cp_32(to, 1, from,  (a11) - 12) \
 821         bn_cp_32(to, 2, from,  (a10) - 12) \
 822         bn_cp_32(to, 3, from,  (a9) - 12)  \
 823         bn_cp_32(to, 4, from,  (a8) - 12)  \
 824         bn_cp_32(to, 5, from,  (a7) - 12)  \
 825         bn_cp_32(to, 6, from,  (a6) - 12)  \
 826         bn_cp_32(to, 7, from,  (a5) - 12)  \
 827         bn_cp_32(to, 8, from,  (a4) - 12)  \
 828         bn_cp_32(to, 9, from,  (a3) - 12)  \
 829         bn_cp_32(to, 10, from, (a2) - 12)  \
 830         bn_cp_32(to, 11, from, (a1) - 12)  \
 831         }
 832
 833 int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
 834         BN_CTX *ctx)
 835         {
 836         int     i, top = a->top;
 837         int     carry = 0;
 838         register BN_ULONG *r_d, *a_d = a->d;
 839         union   {
 840                 BN_ULONG bn[BN_NIST_384_TOP];
 841                 unsigned int ui[BN_NIST_384_TOP*sizeof(BN_ULONG)/sizeof(unsigned int)];
 842                 } buf;
 843         BN_ULONG c_d[BN_NIST_384_TOP],
 844                 *res;
 845         PTR_SIZE_INT mask;
 846         union { bn_addsub_f f; PTR_SIZE_INT p; } u;
 847         static const BIGNUM _bignum_nist_p_384_sqr = {
 848                 (BN_ULONG *)_nist_p_384_sqr,
 849                 sizeof(_nist_p_384_sqr)/sizeof(_nist_p_384_sqr[0]),
 850                 sizeof(_nist_p_384_sqr)/sizeof(_nist_p_384_sqr[0]),
 851                 0,BN_FLG_STATIC_DATA };
 852
 853
 854         field = &_bignum_nist_p_384; /* just to make sure */
 855
 856         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_384_sqr)>=0)
 857                 return BN_nnmod(r, a, field, ctx);
 858
 859         i = BN_ucmp(field, a);
 860         if (i == 0)
 861                 {
 862                 BN_zero(r);
 863                 return 1;
 864                 }
 865         else if (i > 0)
 866                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
 867
 868         if (r != a)
 869                 {
 870                 if (!bn_wexpand(r, BN_NIST_384_TOP))
 871                         return 0;
 872                 r_d = r->d;
 873                 nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
 874                 }
 875         else
 876                 r_d = a_d;
 877
 878         nist_cp_bn_0(buf.bn, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
 879
 880 #if defined(NIST_INT64)
 881         {
 882         NIST_INT64              acc;    /* accumulator */
 883         unsigned int            *rp=(unsigned int *)r_d;
 884         const unsigned int      *bp=(const unsigned int *)buf.ui;
 885
 886         acc = rp[0];    acc += bp[12-12];
 887                         acc += bp[21-12];
 888                         acc += bp[20-12];
 889                         acc -= bp[23-12]; rp[0] = (unsigned int)acc; acc >>= 32;
 890
 891         acc += rp[1];   acc += bp[13-12];
 892                         acc += bp[22-12];
 893                         acc += bp[23-12];
 894                         acc -= bp[12-12];
 895                         acc -= bp[20-12]; rp[1] = (unsigned int)acc; acc >>= 32;
 896
 897         acc += rp[2];   acc += bp[14-12];
 898                         acc += bp[23-12];
 899                         acc -= bp[13-12];
 900                         acc -= bp[21-12]; rp[2] = (unsigned int)acc; acc >>= 32;
 901
 902         acc += rp[3];   acc += bp[15-12];
 903                         acc += bp[12-12];
 904                         acc += bp[20-12];
 905                         acc += bp[21-12];
 906                         acc -= bp[14-12];
 907                         acc -= bp[22-12];
 908                         acc -= bp[23-12]; rp[3] = (unsigned int)acc; acc >>= 32;
 909
 910         acc += rp[4];   acc += bp[21-12];
 911                         acc += bp[21-12];
 912                         acc += bp[16-12];
 913                         acc += bp[13-12];
 914                         acc += bp[12-12];
 915                         acc += bp[20-12];
 916                         acc += bp[22-12];
 917                         acc -= bp[15-12];
 918                         acc -= bp[23-12];
 919                         acc -= bp[23-12]; rp[4] = (unsigned int)acc; acc >>= 32;
 920
 921         acc += rp[5];   acc += bp[22-12];
 922                         acc += bp[22-12];
 923                         acc += bp[17-12];
 924                         acc += bp[14-12];
 925                         acc += bp[13-12];
 926                         acc += bp[21-12];
 927                         acc += bp[23-12];
 928                         acc -= bp[16-12]; rp[5] = (unsigned int)acc; acc >>= 32;
 929
 930         acc += rp[6];   acc += bp[23-12];
 931                         acc += bp[23-12];
 932                         acc += bp[18-12];
 933                         acc += bp[15-12];
 934                         acc += bp[14-12];
 935                         acc += bp[22-12];
 936                         acc -= bp[17-12]; rp[6] = (unsigned int)acc; acc >>= 32;
 937
 938         acc += rp[7];   acc += bp[19-12];
 939                         acc += bp[16-12];
 940                         acc += bp[15-12];
 941                         acc += bp[23-12];
 942                         acc -= bp[18-12]; rp[7] = (unsigned int)acc; acc >>= 32;
 943
 944         acc += rp[8];   acc += bp[20-12];
 945                         acc += bp[17-12];
 946                         acc += bp[16-12];
 947                         acc -= bp[19-12]; rp[8] = (unsigned int)acc; acc >>= 32;
 948
 949         acc += rp[9];   acc += bp[21-12];
 950                         acc += bp[18-12];
 951                         acc += bp[17-12];
 952                         acc -= bp[20-12]; rp[9] = (unsigned int)acc; acc >>= 32;
 953
 954         acc += rp[10];  acc += bp[22-12];
 955                         acc += bp[19-12];
 956                         acc += bp[18-12];
 957                         acc -= bp[21-12]; rp[10] = (unsigned int)acc; acc >>= 32;
 958
 959         acc += rp[11];  acc += bp[23-12];
 960                         acc += bp[20-12];
 961                         acc += bp[19-12];
 962                         acc -= bp[22-12]; rp[11] = (unsigned int)acc;
 963
 964         carry = (int)(acc>>32);
 965         }
 966 #else
 967         {
 968         BN_ULONG t_d[BN_NIST_384_TOP];
 969
 970         /*S1*/
 971         nist_set_256(t_d, buf.bn, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
 972                 /* left shift */
 973                 {
 974                 register BN_ULONG *ap,t,c;
 975                 ap = t_d;
 976                 c=0;
 977                 for (i = 3; i != 0; --i)
 978                         {
 979                         t= *ap;
 980                         *(ap++)=((t<<1)|c)&BN_MASK2;
 981                         c=(t & BN_TBIT)?1:0;
 982                         }
 983                 *ap=c;
 984                 }
 985         carry = (int)bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
 986                 t_d, BN_NIST_256_TOP);
 987         /*S2 */
 988         carry += (int)bn_add_words(r_d, r_d, buf.bn, BN_NIST_384_TOP);
 989         /*S3*/
 990         nist_set_384(t_d,buf.bn,20,19,18,17,16,15,14,13,12,23,22,21);
 991         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 992         /*S4*/
 993         nist_set_384(t_d,buf.bn,19,18,17,16,15,14,13,12,20,0,23,0);
 994         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 995         /*S5*/
 996         nist_set_384(t_d, buf.bn,0,0,0,0,23,22,21,20,0,0,0,0);
 997         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
 998         /*S6*/
 999         nist_set_384(t_d,buf.bn,0,0,0,0,0,0,23,22,21,0,0,20);
1000         carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
1001         /*D1*/
1002         nist_set_384(t_d,buf.bn,22,21,20,19,18,17,16,15,14,13,12,23);
1003         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
1004         /*D2*/
1005         nist_set_384(t_d,buf.bn,0,0,0,0,0,0,0,23,22,21,20,0);
1006         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
1007         /*D3*/
1008         nist_set_384(t_d,buf.bn,0,0,0,0,0,0,0,23,23,0,0,0);
1009         carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
1010
1011         }
1012 #endif
1013         /* see BN_nist_mod_224 for explanation */
1014         u.f = bn_sub_words;
1015         if (carry > 0)
1016                 carry = (int)bn_sub_words(r_d,r_d,_nist_p_384[carry-1],BN_NIST_384_TOP);
1017         else if (carry < 0)
1018                 {
1019                 carry = (int)bn_add_words(r_d,r_d,_nist_p_384[-carry-1],BN_NIST_384_TOP);
1020                 mask = 0-(PTR_SIZE_INT)carry;
1021                 u.p = ((PTR_SIZE_INT)bn_sub_words&mask) |
1022                  ((PTR_SIZE_INT)bn_add_words&~mask);
1023                 }
1024         else
1025                 carry = 1;
1026
1027         mask  = 0-(PTR_SIZE_INT)(*u.f)(c_d,r_d,_nist_p_384[0],BN_NIST_384_TOP);
1028         mask &= 0-(PTR_SIZE_INT)carry;
1029         res   = (BN_ULONG *)(((PTR_SIZE_INT)c_d&~mask) |
1030          ((PTR_SIZE_INT)r_d&mask));
1031         nist_cp_bn(r_d, res, BN_NIST_384_TOP);
1032         r->top = BN_NIST_384_TOP;
1033         bn_correct_top(r);
1034
1035         return 1;
1036         }
1037
1038 #define BN_NIST_521_RSHIFT      (521%BN_BITS2)
1039 #define BN_NIST_521_LSHIFT      (BN_BITS2-BN_NIST_521_RSHIFT)
1040 #define BN_NIST_521_TOP_MASK    ((BN_ULONG)BN_MASK2>>BN_NIST_521_LSHIFT)
1041
1042 int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
1043         BN_CTX *ctx)
1044         {
1045         int     top = a->top, i;
1046         BN_ULONG *r_d, *a_d = a->d,
1047                  t_d[BN_NIST_521_TOP],
1048                  val,tmp,*res;
1049         PTR_SIZE_INT mask;
1050         static const BIGNUM _bignum_nist_p_521_sqr = {
1051                 (BN_ULONG *)_nist_p_521_sqr,
1052                 sizeof(_nist_p_521_sqr)/sizeof(_nist_p_521_sqr[0]),
1053                 sizeof(_nist_p_521_sqr)/sizeof(_nist_p_521_sqr[0]),
1054                 0,BN_FLG_STATIC_DATA };
1055
1056         field = &_bignum_nist_p_521; /* just to make sure */
1057
1058         if (BN_is_negative(a) || BN_ucmp(a,&_bignum_nist_p_521_sqr)>=0)
1059                 return BN_nnmod(r, a, field, ctx);
1060
1061         i = BN_ucmp(field, a);
1062         if (i == 0)
1063                 {
1064                 BN_zero(r);
1065                 return 1;
1066                 }
1067         else if (i > 0)
1068                 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
1069
1070         if (r != a)
1071                 {
1072                 if (!bn_wexpand(r,BN_NIST_521_TOP))
1073                         return 0;
1074                 r_d = r->d;
1075                 nist_cp_bn(r_d,a_d, BN_NIST_521_TOP);
1076                 }
1077         else
1078                 r_d = a_d;
1079
1080         /* upper 521 bits, copy ... */
1081         nist_cp_bn_0(t_d,a_d + (BN_NIST_521_TOP-1), top - (BN_NIST_521_TOP-1),BN_NIST_521_TOP);
1082         /* ... and right shift */
1083         for (val=t_d[0],i=0; i<BN_NIST_521_TOP-1; i++)
1084                 {
1085                 tmp = val>>BN_NIST_521_RSHIFT;
1086                 val = t_d[i+1];
1087                 t_d[i] = (tmp | val<<BN_NIST_521_LSHIFT) & BN_MASK2;
1088                 }
1089         t_d[i] = val>>BN_NIST_521_RSHIFT;
1090         /* lower 521 bits */
1091         r_d[i] &= BN_NIST_521_TOP_MASK;
1092
1093         bn_add_words(r_d,r_d,t_d,BN_NIST_521_TOP);
1094         mask = 0-(PTR_SIZE_INT)bn_sub_words(t_d,r_d,_nist_p_521,BN_NIST_521_TOP);
1095         res  = (BN_ULONG *)(((PTR_SIZE_INT)t_d&~mask) |
1096          ((PTR_SIZE_INT)r_d&mask));
1097         nist_cp_bn(r_d,res,BN_NIST_521_TOP);
1098         r->top = BN_NIST_521_TOP;
1099         bn_correct_top(r);
1100
1101         return 1;
1102         }