/* crypto/bn/bn_nist.c */
/*
* Written by Nils Larsch for the OpenSSL project
*/
/* ====================================================================
* Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#include "bn_lcl.h"
#include "cryptlib.h"
#define BN_NIST_192_TOP (192+BN_BITS2-1)/BN_BITS2
#define BN_NIST_224_TOP (224+BN_BITS2-1)/BN_BITS2
#define BN_NIST_256_TOP (256+BN_BITS2-1)/BN_BITS2
#define BN_NIST_384_TOP (384+BN_BITS2-1)/BN_BITS2
#define BN_NIST_521_TOP (521+BN_BITS2-1)/BN_BITS2
#if BN_BITS2 == 64
static const BN_ULONG _nist_p_192[] =
{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,
0xFFFFFFFFFFFFFFFFULL};
static const BN_ULONG _nist_p_224[] =
{0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL};
static const BN_ULONG _nist_p_256[] =
{0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFF00000001ULL};
static const BN_ULONG _nist_p_384[] =
{0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,
0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL};
static const BN_ULONG _nist_p_521[] =
{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
0x00000000000001FFULL};
#elif BN_BITS2 == 32
static const BN_ULONG _nist_p_192[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
static const BN_ULONG _nist_p_224[] = {0x00000001,0x00000000,0x00000000,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
static const BN_ULONG _nist_p_256[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0x00000000,0x00000000,0x00000000,0x00000001,0xFFFFFFFF};
static const BN_ULONG _nist_p_384[] = {0xFFFFFFFF,0x00000000,0x00000000,
0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0x000001FF};
#endif
const BIGNUM *BN_get0_nist_prime_192(void)
{
static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,
BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_192;
}
const BIGNUM *BN_get0_nist_prime_224(void)
{
static BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224,
BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_224;
}
const BIGNUM *BN_get0_nist_prime_256(void)
{
static BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256,
BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_256;
}
const BIGNUM *BN_get0_nist_prime_384(void)
{
static BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384,
BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_384;
}
const BIGNUM *BN_get0_nist_prime_521(void)
{
static BIGNUM const_nist_521 = { (BN_ULONG *)_nist_p_521,
BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_521;
}
#define BN_NIST_ADD_ONE(a) while (!(*(a)=(*(a)+1)&BN_MASK2)) ++(a);
static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)
{
int i;
BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
for (i = (top); i != 0; i--)
*_tmp1++ = *_tmp2++;
for (i = (max) - (top); i != 0; i--)
*_tmp1++ = (BN_ULONG) 0;
}
static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
{
int i;
BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
for (i = (top); i != 0; i--)
*_tmp1++ = *_tmp2++;
}
#if BN_BITS2 == 64
#define bn_cp_64(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
#define bn_64_set_0(to, n) (to)[n] = (BN_ULONG)0;
/* TBD */
#define bn_cp_32(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
#define bn_32_set_0(to, n) (to)[n] = (BN_ULONG)0;
#else
#define bn_cp_64(to, n, from, m) \
{ \
bn_cp_32(to, (n)*2, from, (m)*2); \
bn_cp_32(to, (n)*2+1, from, (m)*2+1); \
}
#define bn_64_set_0(to, n) \
{ \
bn_32_set_0(to, (n)*2); \
bn_32_set_0(to, (n)*2+1); \
}
#if BN_BITS2 == 32
#define bn_cp_32(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
#define bn_32_set_0(to, n) (to)[n] = (BN_ULONG)0;
#endif
#endif /* BN_BITS2 != 64 */
#define nist_set_192(to, from, a1, a2, a3) \
{ \
if (a3 != 0) bn_cp_64(to, 0, from, (a3) - 3) else bn_64_set_0(to, 0)\
bn_cp_64(to, 1, from, (a2) - 3) \
if (a1 != 0) bn_cp_64(to, 2, from, (a1) - 3) else bn_64_set_0(to, 2)\
}
int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
int top = a->top, i;
int carry;
register BN_ULONG *r_d, *a_d = a->d;
BN_ULONG t_d[BN_NIST_192_TOP],
buf[BN_NIST_192_TOP],
c_d[BN_NIST_192_TOP],
*res;
size_t mask;
i = BN_ucmp(field, a);
if (i == 0)
{
BN_zero(r);
return 1;
}
else if (i > 0)
return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
if (top == BN_NIST_192_TOP)
return BN_usub(r, a, field);
if (r != a)
{
if (!bn_wexpand(r, BN_NIST_192_TOP))
return 0;
r_d = r->d;
nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
}
else
r_d = a_d;
nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
nist_set_192(t_d, buf, 0, 3, 3);
carry = bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_set_192(t_d, buf, 4, 4, 0);
carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_set_192(t_d, buf, 5, 5, 5)
carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_cp_bn(r_d, res, BN_NIST_192_TOP);
r->top = BN_NIST_192_TOP;
bn_correct_top(r);
return 1;
}
#define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
{ \
if (a7 != 0) bn_cp_32(to, 0, from, (a7) - 7) else bn_32_set_0(to, 0)\
if (a6 != 0) bn_cp_32(to, 1, from, (a6) - 7) else bn_32_set_0(to, 1)\
if (a5 != 0) bn_cp_32(to, 2, from, (a5) - 7) else bn_32_set_0(to, 2)\
if (a4 != 0) bn_cp_32(to, 3, from, (a4) - 7) else bn_32_set_0(to, 3)\
if (a3 != 0) bn_cp_32(to, 4, from, (a3) - 7) else bn_32_set_0(to, 4)\
if (a2 != 0) bn_cp_32(to, 5, from, (a2) - 7) else bn_32_set_0(to, 5)\
if (a1 != 0) bn_cp_32(to, 6, from, (a1) - 7) else bn_32_set_0(to, 6)\
}
int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
#if BN_BITS2 == 32
int top = a->top, i;
int carry;
BN_ULONG *r_d, *a_d = a->d;
BN_ULONG t_d[BN_NIST_224_TOP],
buf[BN_NIST_224_TOP],
c_d[BN_NIST_224_TOP],
*res;
size_t mask;
i = BN_ucmp(field, a);
if (i == 0)
{
BN_zero(r);
return 1;
}
else if (i > 0)
return (r == a)? 1 : (BN_copy(r ,a) != NULL);
if (top == BN_NIST_224_TOP)
return BN_usub(r, a, field);
if (r != a)
{
if (!bn_wexpand(r, BN_NIST_224_TOP))
return 0;
r_d = r->d;
nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
}
else
r_d = a_d;
nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);
carry = bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);
carry = bn_add_words(r_d, res, t_d, BN_NIST_224_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP))
bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
#endif
nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_cp_bn(r_d, res, BN_NIST_224_TOP);
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP))
bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
#endif
r->top = BN_NIST_224_TOP;
bn_correct_top(r);
return 1;
#else /* BN_BITS!=32 */
return 0;
#endif
}
#define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
{ \
if (a8 != 0) bn_cp_32(to, 0, from, (a8) - 8) else bn_32_set_0(to, 0)\
if (a7 != 0) bn_cp_32(to, 1, from, (a7) - 8) else bn_32_set_0(to, 1)\
if (a6 != 0) bn_cp_32(to, 2, from, (a6) - 8) else bn_32_set_0(to, 2)\
if (a5 != 0) bn_cp_32(to, 3, from, (a5) - 8) else bn_32_set_0(to, 3)\
if (a4 != 0) bn_cp_32(to, 4, from, (a4) - 8) else bn_32_set_0(to, 4)\
if (a3 != 0) bn_cp_32(to, 5, from, (a3) - 8) else bn_32_set_0(to, 5)\
if (a2 != 0) bn_cp_32(to, 6, from, (a2) - 8) else bn_32_set_0(to, 6)\
if (a1 != 0) bn_cp_32(to, 7, from, (a1) - 8) else bn_32_set_0(to, 7)\
}
int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
#if BN_BITS2 == 32
int i, top = a->top;
int carry = 0;
register BN_ULONG *a_d = a->d, *r_d;
BN_ULONG t_d[BN_NIST_256_TOP],
buf[BN_NIST_256_TOP],
c_d[BN_NIST_256_TOP],
*res;
size_t mask;
i = BN_ucmp(field, a);
if (i == 0)
{
BN_zero(r);
return 1;
}
else if (i > 0)
return (r == a)? 1 : (BN_copy(r ,a) != NULL);
if (top == BN_NIST_256_TOP)
return BN_usub(r, a, field);
if (r != a)
{
if (!bn_wexpand(r, BN_NIST_256_TOP))
return 0;
r_d = r->d;
nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
}
else
r_d = a_d;
nist_cp_bn_0(buf, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
/*S1*/
nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0);
/*S2*/
nist_set_256(c_d,buf, 0, 15, 14, 13, 12, 0, 0, 0);
carry = bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
carry = bn_add_words(t_d, res, res, BN_NIST_256_TOP);
mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
carry = bn_add_words(r_d, r_d, res, BN_NIST_256_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S3*/
nist_set_256(t_d, buf, 15, 14, 0, 0, 0, 10, 9, 8);
carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S4*/
nist_set_256(t_d, buf, 8, 13, 15, 14, 13, 11, 10, 9);
carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*D1*/
nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP))
bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
#endif
/*D2*/
nist_set_256(t_d, buf, 11, 9, 0, 0, 15, 14, 13, 12);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
#endif
/*D3*/
nist_set_256(t_d, buf, 12, 0, 10, 9, 8, 15, 14, 13);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
#endif
/*D4*/
nist_set_256(t_d, buf, 13, 0, 11, 10, 9, 0, 15, 14);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_cp_bn(r_d, res, BN_NIST_384_TOP);
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
#endif
r->top = BN_NIST_256_TOP;
bn_correct_top(r);
return 1;
#else /* BN_BITS!=32 */
return 0;
#endif
}
#define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
{ \
if (a12 != 0) bn_cp_32(to, 0, from, (a12) - 12) else bn_32_set_0(to, 0)\
if (a11 != 0) bn_cp_32(to, 1, from, (a11) - 12) else bn_32_set_0(to, 1)\
if (a10 != 0) bn_cp_32(to, 2, from, (a10) - 12) else bn_32_set_0(to, 2)\
if (a9 != 0) bn_cp_32(to, 3, from, (a9) - 12) else bn_32_set_0(to, 3)\
if (a8 != 0) bn_cp_32(to, 4, from, (a8) - 12) else bn_32_set_0(to, 4)\
if (a7 != 0) bn_cp_32(to, 5, from, (a7) - 12) else bn_32_set_0(to, 5)\
if (a6 != 0) bn_cp_32(to, 6, from, (a6) - 12) else bn_32_set_0(to, 6)\
if (a5 != 0) bn_cp_32(to, 7, from, (a5) - 12) else bn_32_set_0(to, 7)\
if (a4 != 0) bn_cp_32(to, 8, from, (a4) - 12) else bn_32_set_0(to, 8)\
if (a3 != 0) bn_cp_32(to, 9, from, (a3) - 12) else bn_32_set_0(to, 9)\
if (a2 != 0) bn_cp_32(to, 10, from, (a2) - 12) else bn_32_set_0(to, 10)\
if (a1 != 0) bn_cp_32(to, 11, from, (a1) - 12) else bn_32_set_0(to, 11)\
}
int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
#if BN_BITS2 == 32
int i, top = a->top;
int carry = 0;
register BN_ULONG *r_d, *a_d = a->d;
BN_ULONG t_d[BN_NIST_384_TOP],
buf[BN_NIST_384_TOP],
c_d[BN_NIST_384_TOP],
*res;
size_t mask;
i = BN_ucmp(field, a);
if (i == 0)
{
BN_zero(r);
return 1;
}
else if (i > 0)
return (r == a)? 1 : (BN_copy(r ,a) != NULL);
if (top == BN_NIST_384_TOP)
return BN_usub(r, a, field);
if (r != a)
{
if (!bn_wexpand(r, BN_NIST_384_TOP))
return 0;
r_d = r->d;
nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
}
else
r_d = a_d;
nist_cp_bn_0(buf, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
/*S1*/
nist_set_256(t_d, buf, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
/* left shift */
{
register BN_ULONG *ap,t,c;
ap = t_d;
c=0;
for (i = 3; i != 0; --i)
{
t= *ap;
*(ap++)=((t<<1)|c)&BN_MASK2;
c=(t & BN_TBIT)?1:0;
}
*ap=c;
}
carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
t_d, BN_NIST_256_TOP);
/*
* we need if (result>=modulus) subtract(result,modulus);
* in n-bit space this can be expressed as
* if (carry || result>=modulus) subtract(result,modulus);
* the catch is that comparison implies subtraction and
* therefore one can write tmp=subtract(result,modulus);
* and then if(carry || !borrow) result=tmp; this's what
* happens below, but without explicit if:-) a.
*/
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S2 */
carry = bn_add_words(r_d, res, buf, BN_NIST_384_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S3*/
nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21);
carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S4*/
nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0);
carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S5*/
nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0);
carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*S6*/
nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20);
carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = ~mask | (0-(size_t)carry);
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
/*D1*/
nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP))
bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
#endif
/*D2*/
nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
#endif
/*D3*/
nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0);
#if BRANCH_FREE
carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
mask = 0-(size_t)carry;
res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
nist_cp_bn(r_d, res, BN_NIST_384_TOP);
#else
if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
#endif
r->top = BN_NIST_384_TOP;
bn_correct_top(r);
return 1;
#else /* BN_BITS!=32 */
return 0;
#endif
}
int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
#if BN_BITS2 == 64
#define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
#elif BN_BITS2 == 32
#define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
#endif
int top, ret = 0;
BN_ULONG *r_d;
BIGNUM *tmp;
/* check whether a reduction is necessary */
top = a->top;
if (top < BN_NIST_521_TOP || ( top == BN_NIST_521_TOP &&
(!(a->d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))))
return (r == a)? 1 : (BN_copy(r ,a) != NULL);
BN_CTX_start(ctx);
tmp = BN_CTX_get(ctx);
if (!tmp)
goto err;
if (!bn_wexpand(tmp, BN_NIST_521_TOP))
goto err;
nist_cp_bn(tmp->d, a->d, BN_NIST_521_TOP);
tmp->top = BN_NIST_521_TOP;
tmp->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;
bn_correct_top(tmp);
if (!BN_rshift(r, a, 521))
goto err;
if (!BN_uadd(r, tmp, r))
goto err;
top = r->top;
r_d = r->d;
if (top == BN_NIST_521_TOP &&
(r_d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))
{
BN_NIST_ADD_ONE(r_d)
r->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;
}
bn_correct_top(r);
ret = 1;
err:
BN_CTX_end(ctx);
bn_check_top(r);
return ret;
}