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openssl/crypto/bn/bn_nist.c

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/*
* Copyright 2002-2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "bn_local.h"
#include "internal/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
/* pre-computed tables are "carry-less" values of modulus*(i+1) */
#if BN_BITS2 == 64
static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
{0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFEULL, 0xFFFFFFFFFFFFFFFFULL},
{0xFFFFFFFFFFFFFFFEULL, 0xFFFFFFFFFFFFFFFDULL, 0xFFFFFFFFFFFFFFFFULL},
{0xFFFFFFFFFFFFFFFDULL, 0xFFFFFFFFFFFFFFFCULL, 0xFFFFFFFFFFFFFFFFULL}
};
static const BN_ULONG _nist_p_192_sqr[] = {
0x0000000000000001ULL, 0x0000000000000002ULL, 0x0000000000000001ULL,
0xFFFFFFFFFFFFFFFEULL, 0xFFFFFFFFFFFFFFFDULL, 0xFFFFFFFFFFFFFFFFULL
};
static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
{0x0000000000000001ULL, 0xFFFFFFFF00000000ULL,
0xFFFFFFFFFFFFFFFFULL, 0x00000000FFFFFFFFULL},
{0x0000000000000002ULL, 0xFFFFFFFE00000000ULL,
0xFFFFFFFFFFFFFFFFULL, 0x00000001FFFFFFFFULL} /* this one is
* "carry-full" */
};
static const BN_ULONG _nist_p_224_sqr[] = {
0x0000000000000001ULL, 0xFFFFFFFE00000000ULL,
0xFFFFFFFFFFFFFFFFULL, 0x0000000200000000ULL,
0x0000000000000000ULL, 0xFFFFFFFFFFFFFFFEULL,
0xFFFFFFFFFFFFFFFFULL
};
static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
{0xFFFFFFFFFFFFFFFFULL, 0x00000000FFFFFFFFULL,
0x0000000000000000ULL, 0xFFFFFFFF00000001ULL},
{0xFFFFFFFFFFFFFFFEULL, 0x00000001FFFFFFFFULL,
0x0000000000000000ULL, 0xFFFFFFFE00000002ULL},
{0xFFFFFFFFFFFFFFFDULL, 0x00000002FFFFFFFFULL,
0x0000000000000000ULL, 0xFFFFFFFD00000003ULL},
{0xFFFFFFFFFFFFFFFCULL, 0x00000003FFFFFFFFULL,
0x0000000000000000ULL, 0xFFFFFFFC00000004ULL},
{0xFFFFFFFFFFFFFFFBULL, 0x00000004FFFFFFFFULL,
0x0000000000000000ULL, 0xFFFFFFFB00000005ULL},
};
static const BN_ULONG _nist_p_256_sqr[] = {
0x0000000000000001ULL, 0xFFFFFFFE00000000ULL,
0xFFFFFFFFFFFFFFFFULL, 0x00000001FFFFFFFEULL,
0x00000001FFFFFFFEULL, 0x00000001FFFFFFFEULL,
0xFFFFFFFE00000001ULL, 0xFFFFFFFE00000002ULL
};
static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
{0x00000000FFFFFFFFULL, 0xFFFFFFFF00000000ULL, 0xFFFFFFFFFFFFFFFEULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL},
{0x00000001FFFFFFFEULL, 0xFFFFFFFE00000000ULL, 0xFFFFFFFFFFFFFFFDULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL},
{0x00000002FFFFFFFDULL, 0xFFFFFFFD00000000ULL, 0xFFFFFFFFFFFFFFFCULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL},
{0x00000003FFFFFFFCULL, 0xFFFFFFFC00000000ULL, 0xFFFFFFFFFFFFFFFBULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL},
{0x00000004FFFFFFFBULL, 0xFFFFFFFB00000000ULL, 0xFFFFFFFFFFFFFFFAULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL},
};
static const BN_ULONG _nist_p_384_sqr[] = {
0xFFFFFFFE00000001ULL, 0x0000000200000000ULL, 0xFFFFFFFE00000000ULL,
0x0000000200000000ULL, 0x0000000000000001ULL, 0x0000000000000000ULL,
0x00000001FFFFFFFEULL, 0xFFFFFFFE00000000ULL, 0xFFFFFFFFFFFFFFFDULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL
};
static const BN_ULONG _nist_p_521[] =
{ 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0x00000000000001FFULL
};
static const BN_ULONG _nist_p_521_sqr[] = {
0x0000000000000001ULL, 0x0000000000000000ULL, 0x0000000000000000ULL,
0x0000000000000000ULL, 0x0000000000000000ULL, 0x0000000000000000ULL,
0x0000000000000000ULL, 0x0000000000000000ULL, 0xFFFFFFFFFFFFFC00ULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL, 0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL, 0x000000000003FFFFULL
};
#elif BN_BITS2 == 32
static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
{0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFC, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}
};
static const BN_ULONG _nist_p_192_sqr[] = {
0x00000001, 0x00000000, 0x00000002, 0x00000000, 0x00000001, 0x00000000,
0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF
};
static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
{0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0x00000002, 0x00000000, 0x00000000, 0xFFFFFFFE,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}
};
static const BN_ULONG _nist_p_224_sqr[] = {
0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE,
0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000002,
0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF
};
static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
{0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000,
0x00000000, 0x00000000, 0x00000001, 0xFFFFFFFF},
{0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000001,
0x00000000, 0x00000000, 0x00000002, 0xFFFFFFFE},
{0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000002,
0x00000000, 0x00000000, 0x00000003, 0xFFFFFFFD},
{0xFFFFFFFC, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000003,
0x00000000, 0x00000000, 0x00000004, 0xFFFFFFFC},
{0xFFFFFFFB, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000004,
0x00000000, 0x00000000, 0x00000005, 0xFFFFFFFB},
};
static const BN_ULONG _nist_p_256_sqr[] = {
0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0x00000001,
0xFFFFFFFE, 0x00000001, 0xFFFFFFFE, 0x00000001,
0x00000001, 0xFFFFFFFE, 0x00000002, 0xFFFFFFFE
};
static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
{0xFFFFFFFF, 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFE, 0x00000001, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFD, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFD, 0x00000002, 0x00000000, 0xFFFFFFFD, 0xFFFFFFFC, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFC, 0x00000003, 0x00000000, 0xFFFFFFFC, 0xFFFFFFFB, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
{0xFFFFFFFB, 0x00000004, 0x00000000, 0xFFFFFFFB, 0xFFFFFFFA, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF},
};
static const BN_ULONG _nist_p_384_sqr[] = {
0x00000001, 0xFFFFFFFE, 0x00000000, 0x00000002, 0x00000000, 0xFFFFFFFE,
0x00000000, 0x00000002, 0x00000001, 0x00000000, 0x00000000, 0x00000000,
0xFFFFFFFE, 0x00000001, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFD, 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
};
static const BN_ULONG _nist_p_521_sqr[] = {
0x00000001, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0xFFFFFC00, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF, 0x0003FFFF
};
#else
# error "unsupported BN_BITS2"
#endif
static const BIGNUM _bignum_nist_p_192 = {
(BN_ULONG *)_nist_p_192[0],
BN_NIST_192_TOP,
BN_NIST_192_TOP,
0,
BN_FLG_STATIC_DATA
};
static const BIGNUM _bignum_nist_p_224 = {
(BN_ULONG *)_nist_p_224[0],
BN_NIST_224_TOP,
BN_NIST_224_TOP,
0,
BN_FLG_STATIC_DATA
};
static const BIGNUM _bignum_nist_p_256 = {
(BN_ULONG *)_nist_p_256[0],
BN_NIST_256_TOP,
BN_NIST_256_TOP,
0,
BN_FLG_STATIC_DATA
};
static const BIGNUM _bignum_nist_p_384 = {
(BN_ULONG *)_nist_p_384[0],
BN_NIST_384_TOP,
BN_NIST_384_TOP,
0,
BN_FLG_STATIC_DATA
};
static const BIGNUM _bignum_nist_p_521 = {
(BN_ULONG *)_nist_p_521,
BN_NIST_521_TOP,
BN_NIST_521_TOP,
0,
BN_FLG_STATIC_DATA
};
const BIGNUM *BN_get0_nist_prime_192(void)
{
return &_bignum_nist_p_192;
}
const BIGNUM *BN_get0_nist_prime_224(void)
{
return &_bignum_nist_p_224;
}
const BIGNUM *BN_get0_nist_prime_256(void)
{
return &_bignum_nist_p_256;
}
const BIGNUM *BN_get0_nist_prime_384(void)
{
return &_bignum_nist_p_384;
}
const BIGNUM *BN_get0_nist_prime_521(void)
{
return &_bignum_nist_p_521;
}
/*
* To avoid more recent compilers (specifically clang-14) from treating this
* code as a violation of the strict aliasing conditions and omiting it, this
* cannot be declared as a function. Moreover, the dst parameter cannot be
* cached in a local since this no longer references the union and again falls
* foul of the strict aliasing criteria. Refer to #18225 for the initial
* diagnostics and llvm/llvm-project#55255 for the later discussions with the
* LLVM developers. The problem boils down to if an array in the union is
* converted to a pointer or if it is used directly.
*
* This function was inlined regardless, so there is no space cost to be
* paid for making it a macro.
*/
#define nist_cp_bn_0(dst, src_in, top, max) \
{ \
int ii; \
const BN_ULONG *src = src_in; \
\
for (ii = 0; ii < top; ii++) \
(dst)[ii] = src[ii]; \
for (; ii < max; ii++) \
(dst)[ii] = 0; \
}
static void nist_cp_bn(BN_ULONG *dst, const BN_ULONG *src, int top)
{
int i;
for (i = 0; i < top; i++)
dst[i] = src[i];
}
#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;
/*
* two following macros are implemented under assumption that they
* are called in a sequence with *ascending* n, i.e. as they are...
*/
# 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))\
:(to[(n)/2] =((m)&1)?(from[(m)/2]>>32):(from[(m)/2]&BN_MASK2l)))
# define bn_32_set_0(to, n) (((n)&1)?(to[(n)/2]&=BN_MASK2l):(to[(n)/2]=0));
# define bn_cp_32(to,n,from,m) ((m)>=0)?bn_cp_32_naked(to,n,from,m):bn_32_set_0(to,n)
# if defined(L_ENDIAN)
# if defined(__arch64__)
# define NIST_INT64 long
# else
# define NIST_INT64 long long
# endif
# endif
#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); \
}
# 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;
# if defined(_WIN32) && !defined(__GNUC__)
# define NIST_INT64 __int64
# elif defined(BN_LLONG)
# define NIST_INT64 long long
# endif
#endif /* BN_BITS2 != 64 */
#define nist_set_192(to, from, a1, a2, a3) \
{ \
bn_cp_64(to, 0, from, (a3) - 3) \
bn_cp_64(to, 1, from, (a2) - 3) \
bn_cp_64(to, 2, from, (a1) - 3) \
}
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;
union {
BN_ULONG bn[BN_NIST_192_TOP];
unsigned int ui[BN_NIST_192_TOP * sizeof(BN_ULONG) /
sizeof(unsigned int)];
} buf;
BN_ULONG c_d[BN_NIST_192_TOP], *res;
PTR_SIZE_INT mask;
static const BIGNUM _bignum_nist_p_192_sqr = {
(BN_ULONG *)_nist_p_192_sqr,
OSSL_NELEM(_nist_p_192_sqr),
OSSL_NELEM(_nist_p_192_sqr),
0, BN_FLG_STATIC_DATA
};
field = &_bignum_nist_p_192; /* just to make sure */
if (BN_is_negative(a) || BN_ucmp(a, &_bignum_nist_p_192_sqr) >= 0)
return BN_nnmod(r, a, field, ctx);
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 (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.bn, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP,
BN_NIST_192_TOP);
#if defined(NIST_INT64)
{
NIST_INT64 acc; /* accumulator */
unsigned int *rp = (unsigned int *)r_d;
const unsigned int *bp = (const unsigned int *)buf.ui;
acc = rp[0];
acc += bp[3 * 2 - 6];
acc += bp[5 * 2 - 6];
rp[0] = (unsigned int)acc;
acc >>= 32;
acc += rp[1];
acc += bp[3 * 2 - 5];
acc += bp[5 * 2 - 5];
rp[1] = (unsigned int)acc;
acc >>= 32;
acc += rp[2];
acc += bp[3 * 2 - 6];
acc += bp[4 * 2 - 6];
acc += bp[5 * 2 - 6];
rp[2] = (unsigned int)acc;
acc >>= 32;
acc += rp[3];
acc += bp[3 * 2 - 5];
acc += bp[4 * 2 - 5];
acc += bp[5 * 2 - 5];
rp[3] = (unsigned int)acc;
acc >>= 32;
acc += rp[4];
acc += bp[4 * 2 - 6];
acc += bp[5 * 2 - 6];
rp[4] = (unsigned int)acc;
acc >>= 32;
acc += rp[5];
acc += bp[4 * 2 - 5];
acc += bp[5 * 2 - 5];
rp[5] = (unsigned int)acc;
carry = (int)(acc >> 32);
}
#else
{
BN_ULONG t_d[BN_NIST_192_TOP];
nist_set_192(t_d, buf.bn, 0, 3, 3);
carry = (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
nist_set_192(t_d, buf.bn, 4, 4, 0);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
nist_set_192(t_d, buf.bn, 5, 5, 5)
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
}
#endif
if (carry > 0)
carry =
(int)bn_sub_words(r_d, r_d, _nist_p_192[carry - 1],
BN_NIST_192_TOP);
else
carry = 1;
/*
* we need 'if (carry==0 || result>=modulus) result-=modulus;'
* as comparison implies subtraction, we can write
* 'tmp=result-modulus; if (!carry || !borrow) result=tmp;'
* this is what happens below, but without explicit if:-) a.
*/
mask =
0 - (PTR_SIZE_INT) bn_sub_words(c_d, r_d, _nist_p_192[0],
BN_NIST_192_TOP);
mask &= 0 - (PTR_SIZE_INT) carry;
res = c_d;
res = (BN_ULONG *)
(((PTR_SIZE_INT) res & ~mask) | ((PTR_SIZE_INT) 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;
}
typedef BN_ULONG (*bn_addsub_f) (BN_ULONG *, const BN_ULONG *,
const BN_ULONG *, int);
#define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
{ \
bn_cp_32(to, 0, from, (a7) - 7) \
bn_cp_32(to, 1, from, (a6) - 7) \
bn_cp_32(to, 2, from, (a5) - 7) \
bn_cp_32(to, 3, from, (a4) - 7) \
bn_cp_32(to, 4, from, (a3) - 7) \
bn_cp_32(to, 5, from, (a2) - 7) \
bn_cp_32(to, 6, from, (a1) - 7) \
}
int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
int top = a->top, i;
int carry;
BN_ULONG *r_d, *a_d = a->d;
union {
BN_ULONG bn[BN_NIST_224_TOP];
unsigned int ui[BN_NIST_224_TOP * sizeof(BN_ULONG) /
sizeof(unsigned int)];
} buf;
BN_ULONG c_d[BN_NIST_224_TOP], *res;
PTR_SIZE_INT mask;
union {
bn_addsub_f f;
PTR_SIZE_INT p;
} u;
static const BIGNUM _bignum_nist_p_224_sqr = {
(BN_ULONG *)_nist_p_224_sqr,
OSSL_NELEM(_nist_p_224_sqr),
OSSL_NELEM(_nist_p_224_sqr),
0, BN_FLG_STATIC_DATA
};
field = &_bignum_nist_p_224; /* just to make sure */
if (BN_is_negative(a) || BN_ucmp(a, &_bignum_nist_p_224_sqr) >= 0)
return BN_nnmod(r, a, field, ctx);
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 (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;
#if BN_BITS2==64
/* copy upper 256 bits of 448 bit number ... */
nist_cp_bn_0(c_d, a_d + (BN_NIST_224_TOP - 1),
top - (BN_NIST_224_TOP - 1), BN_NIST_224_TOP);
/* ... and right shift by 32 to obtain upper 224 bits */
nist_set_224(buf.bn, c_d, 14, 13, 12, 11, 10, 9, 8);
/* truncate lower part to 224 bits too */
r_d[BN_NIST_224_TOP - 1] &= BN_MASK2l;
#else
nist_cp_bn_0(buf.bn, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP,
BN_NIST_224_TOP);
#endif
#if defined(NIST_INT64) && BN_BITS2!=64
{
NIST_INT64 acc; /* accumulator */
unsigned int *rp = (unsigned int *)r_d;
const unsigned int *bp = (const unsigned int *)buf.ui;
acc = rp[0];
acc -= bp[7 - 7];
acc -= bp[11 - 7];
rp[0] = (unsigned int)acc;
acc >>= 32;
acc += rp[1];
acc -= bp[8 - 7];
acc -= bp[12 - 7];
rp[1] = (unsigned int)acc;
acc >>= 32;
acc += rp[2];
acc -= bp[9 - 7];
acc -= bp[13 - 7];
rp[2] = (unsigned int)acc;
acc >>= 32;
acc += rp[3];
acc += bp[7 - 7];
acc += bp[11 - 7];
acc -= bp[10 - 7];
rp[3] = (unsigned int)acc;
acc >>= 32;
acc += rp[4];
acc += bp[8 - 7];
acc += bp[12 - 7];
acc -= bp[11 - 7];
rp[4] = (unsigned int)acc;
acc >>= 32;
acc += rp[5];
acc += bp[9 - 7];
acc += bp[13 - 7];
acc -= bp[12 - 7];
rp[5] = (unsigned int)acc;
acc >>= 32;
acc += rp[6];
acc += bp[10 - 7];
acc -= bp[13 - 7];
rp[6] = (unsigned int)acc;
carry = (int)(acc >> 32);
# if BN_BITS2==64
rp[7] = carry;
# endif
}
#else
{
BN_ULONG t_d[BN_NIST_224_TOP];
nist_set_224(t_d, buf.bn, 10, 9, 8, 7, 0, 0, 0);
carry = (int)bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
nist_set_224(t_d, buf.bn, 0, 13, 12, 11, 0, 0, 0);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
nist_set_224(t_d, buf.bn, 13, 12, 11, 10, 9, 8, 7);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
nist_set_224(t_d, buf.bn, 0, 0, 0, 0, 13, 12, 11);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
# if BN_BITS2==64
carry = (int)(r_d[BN_NIST_224_TOP - 1] >> 32);
# endif
}
#endif
u.f = bn_sub_words;
if (carry > 0) {
carry =
(int)bn_sub_words(r_d, r_d, _nist_p_224[carry - 1],
BN_NIST_224_TOP);
#if BN_BITS2==64
carry = (int)(~(r_d[BN_NIST_224_TOP - 1] >> 32)) & 1;
#endif
} else if (carry < 0) {
/*
* it's a bit more complicated logic in this case. if bn_add_words
* yields no carry, then result has to be adjusted by unconditionally
* *adding* the modulus. but if it does, then result has to be
* compared to the modulus and conditionally adjusted by
* *subtracting* the latter.
*/
carry =
(int)bn_add_words(r_d, r_d, _nist_p_224[-carry - 1],
BN_NIST_224_TOP);
mask = 0 - (PTR_SIZE_INT) carry;
u.p = ((PTR_SIZE_INT) bn_sub_words & mask) |
((PTR_SIZE_INT) bn_add_words & ~mask);
} else
carry = 1;
/* otherwise it's effectively same as in BN_nist_mod_192... */
mask =
0 - (PTR_SIZE_INT) (*u.f) (c_d, r_d, _nist_p_224[0], BN_NIST_224_TOP);
mask &= 0 - (PTR_SIZE_INT) carry;
res = c_d;
res = (BN_ULONG *)(((PTR_SIZE_INT) res & ~mask) |
((PTR_SIZE_INT) r_d & mask));
nist_cp_bn(r_d, res, BN_NIST_224_TOP);
r->top = BN_NIST_224_TOP;
bn_correct_top(r);
return 1;
}
#define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
{ \
bn_cp_32(to, 0, from, (a8) - 8) \
bn_cp_32(to, 1, from, (a7) - 8) \
bn_cp_32(to, 2, from, (a6) - 8) \
bn_cp_32(to, 3, from, (a5) - 8) \
bn_cp_32(to, 4, from, (a4) - 8) \
bn_cp_32(to, 5, from, (a3) - 8) \
bn_cp_32(to, 6, from, (a2) - 8) \
bn_cp_32(to, 7, from, (a1) - 8) \
}
int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
int i, top = a->top;
int carry = 0;
register BN_ULONG *a_d = a->d, *r_d;
union {
BN_ULONG bn[BN_NIST_256_TOP];
unsigned int ui[BN_NIST_256_TOP * sizeof(BN_ULONG) /
sizeof(unsigned int)];
} buf;
BN_ULONG c_d[BN_NIST_256_TOP], *res;
PTR_SIZE_INT mask;
union {
bn_addsub_f f;
PTR_SIZE_INT p;
} u;
static const BIGNUM _bignum_nist_p_256_sqr = {
(BN_ULONG *)_nist_p_256_sqr,
OSSL_NELEM(_nist_p_256_sqr),
OSSL_NELEM(_nist_p_256_sqr),
0, BN_FLG_STATIC_DATA
};
field = &_bignum_nist_p_256; /* just to make sure */
if (BN_is_negative(a) || BN_ucmp(a, &_bignum_nist_p_256_sqr) >= 0)
return BN_nnmod(r, a, field, ctx);
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 (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.bn, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP,
BN_NIST_256_TOP);
#if defined(NIST_INT64)
{
NIST_INT64 acc; /* accumulator */
unsigned int *rp = (unsigned int *)r_d;
const unsigned int *bp = (const unsigned int *)buf.ui;
acc = rp[0];
acc += bp[8 - 8];
acc += bp[9 - 8];
acc -= bp[11 - 8];
acc -= bp[12 - 8];
acc -= bp[13 - 8];
acc -= bp[14 - 8];
rp[0] = (unsigned int)acc;
acc >>= 32;
acc += rp[1];
acc += bp[9 - 8];
acc += bp[10 - 8];
acc -= bp[12 - 8];
acc -= bp[13 - 8];
acc -= bp[14 - 8];
acc -= bp[15 - 8];
rp[1] = (unsigned int)acc;
acc >>= 32;
acc += rp[2];
acc += bp[10 - 8];
acc += bp[11 - 8];
acc -= bp[13 - 8];
acc -= bp[14 - 8];
acc -= bp[15 - 8];
rp[2] = (unsigned int)acc;
acc >>= 32;
acc += rp[3];
acc += bp[11 - 8];
acc += bp[11 - 8];
acc += bp[12 - 8];
acc += bp[12 - 8];
acc += bp[13 - 8];
acc -= bp[15 - 8];
acc -= bp[8 - 8];
acc -= bp[9 - 8];
rp[3] = (unsigned int)acc;
acc >>= 32;
acc += rp[4];
acc += bp[12 - 8];
acc += bp[12 - 8];
acc += bp[13 - 8];
acc += bp[13 - 8];
acc += bp[14 - 8];
acc -= bp[9 - 8];
acc -= bp[10 - 8];
rp[4] = (unsigned int)acc;
acc >>= 32;
acc += rp[5];
acc += bp[13 - 8];
acc += bp[13 - 8];
acc += bp[14 - 8];
acc += bp[14 - 8];
acc += bp[15 - 8];
acc -= bp[10 - 8];
acc -= bp[11 - 8];
rp[5] = (unsigned int)acc;
acc >>= 32;
acc += rp[6];
acc += bp[14 - 8];
acc += bp[14 - 8];
acc += bp[15 - 8];
acc += bp[15 - 8];
acc += bp[14 - 8];
acc += bp[13 - 8];
acc -= bp[8 - 8];
acc -= bp[9 - 8];
rp[6] = (unsigned int)acc;
acc >>= 32;
acc += rp[7];
acc += bp[15 - 8];
acc += bp[15 - 8];
acc += bp[15 - 8];
acc += bp[8 - 8];
acc -= bp[10 - 8];
acc -= bp[11 - 8];
acc -= bp[12 - 8];
acc -= bp[13 - 8];
rp[7] = (unsigned int)acc;
carry = (int)(acc >> 32);
}
#else
{
BN_ULONG t_d[BN_NIST_256_TOP];
/*
* S1
*/
nist_set_256(t_d, buf.bn, 15, 14, 13, 12, 11, 0, 0, 0);
/*
* S2
*/
nist_set_256(c_d, buf.bn, 0, 15, 14, 13, 12, 0, 0, 0);
carry = (int)bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
/* left shift */
{
register BN_ULONG *ap, t, c;
ap = t_d;
c = 0;
for (i = BN_NIST_256_TOP; i != 0; --i) {
t = *ap;
*(ap++) = ((t << 1) | c) & BN_MASK2;
c = (t & BN_TBIT) ? 1 : 0;
}
carry <<= 1;
carry |= c;
}
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* S3
*/
nist_set_256(t_d, buf.bn, 15, 14, 0, 0, 0, 10, 9, 8);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* S4
*/
nist_set_256(t_d, buf.bn, 8, 13, 15, 14, 13, 11, 10, 9);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* D1
*/
nist_set_256(t_d, buf.bn, 10, 8, 0, 0, 0, 13, 12, 11);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* D2
*/
nist_set_256(t_d, buf.bn, 11, 9, 0, 0, 15, 14, 13, 12);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* D3
*/
nist_set_256(t_d, buf.bn, 12, 0, 10, 9, 8, 15, 14, 13);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*
* D4
*/
nist_set_256(t_d, buf.bn, 13, 0, 11, 10, 9, 0, 15, 14);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
}
#endif
/* see BN_nist_mod_224 for explanation */
u.f = bn_sub_words;
if (carry > 0)
carry =
(int)bn_sub_words(r_d, r_d, _nist_p_256[carry - 1],
BN_NIST_256_TOP);
else if (carry < 0) {
carry =
(int)bn_add_words(r_d, r_d, _nist_p_256[-carry - 1],
BN_NIST_256_TOP);
mask = 0 - (PTR_SIZE_INT) carry;
u.p = ((PTR_SIZE_INT) bn_sub_words & mask) |
((PTR_SIZE_INT) bn_add_words & ~mask);
} else
carry = 1;
mask =
0 - (PTR_SIZE_INT) (*u.f) (c_d, r_d, _nist_p_256[0], BN_NIST_256_TOP);
mask &= 0 - (PTR_SIZE_INT) carry;
res = c_d;
res = (BN_ULONG *)(((PTR_SIZE_INT) res & ~mask) |
((PTR_SIZE_INT) r_d & mask));
nist_cp_bn(r_d, res, BN_NIST_256_TOP);
r->top = BN_NIST_256_TOP;
bn_correct_top(r);
return 1;
}
#define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
{ \
bn_cp_32(to, 0, from, (a12) - 12) \
bn_cp_32(to, 1, from, (a11) - 12) \
bn_cp_32(to, 2, from, (a10) - 12) \
bn_cp_32(to, 3, from, (a9) - 12) \
bn_cp_32(to, 4, from, (a8) - 12) \
bn_cp_32(to, 5, from, (a7) - 12) \
bn_cp_32(to, 6, from, (a6) - 12) \
bn_cp_32(to, 7, from, (a5) - 12) \
bn_cp_32(to, 8, from, (a4) - 12) \
bn_cp_32(to, 9, from, (a3) - 12) \
bn_cp_32(to, 10, from, (a2) - 12) \
bn_cp_32(to, 11, from, (a1) - 12) \
}
int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
int i, top = a->top;
int carry = 0;
register BN_ULONG *r_d, *a_d = a->d;
union {
BN_ULONG bn[BN_NIST_384_TOP];
unsigned int ui[BN_NIST_384_TOP * sizeof(BN_ULONG) /
sizeof(unsigned int)];
} buf;
BN_ULONG c_d[BN_NIST_384_TOP], *res;
PTR_SIZE_INT mask;
union {
bn_addsub_f f;
PTR_SIZE_INT p;
} u;
static const BIGNUM _bignum_nist_p_384_sqr = {
(BN_ULONG *)_nist_p_384_sqr,
OSSL_NELEM(_nist_p_384_sqr),
OSSL_NELEM(_nist_p_384_sqr),
0, BN_FLG_STATIC_DATA
};
field = &_bignum_nist_p_384; /* just to make sure */
if (BN_is_negative(a) || BN_ucmp(a, &_bignum_nist_p_384_sqr) >= 0)
return BN_nnmod(r, a, field, ctx);
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 (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.bn, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP,
BN_NIST_384_TOP);
#if defined(NIST_INT64)
{
NIST_INT64 acc; /* accumulator */
unsigned int *rp = (unsigned int *)r_d;
const unsigned int *bp = (const unsigned int *)buf.ui;
acc = rp[0];
acc += bp[12 - 12];
acc += bp[21 - 12];
acc += bp[20 - 12];
acc -= bp[23 - 12];
rp[0] = (unsigned int)acc;
acc >>= 32;
acc += rp[1];
acc += bp[13 - 12];
acc += bp[22 - 12];
acc += bp[23 - 12];
acc -= bp[12 - 12];
acc -= bp[20 - 12];
rp[1] = (unsigned int)acc;
acc >>= 32;
acc += rp[2];
acc += bp[14 - 12];
acc += bp[23 - 12];
acc -= bp[13 - 12];
acc -= bp[21 - 12];
rp[2] = (unsigned int)acc;
acc >>= 32;
acc += rp[3];
acc += bp[15 - 12];
acc += bp[12 - 12];
acc += bp[20 - 12];
acc += bp[21 - 12];
acc -= bp[14 - 12];
acc -= bp[22 - 12];
acc -= bp[23 - 12];
rp[3] = (unsigned int)acc;
acc >>= 32;
acc += rp[4];
acc += bp[21 - 12];
acc += bp[21 - 12];
acc += bp[16 - 12];
acc += bp[13 - 12];
acc += bp[12 - 12];
acc += bp[20 - 12];
acc += bp[22 - 12];
acc -= bp[15 - 12];
acc -= bp[23 - 12];
acc -= bp[23 - 12];
rp[4] = (unsigned int)acc;
acc >>= 32;
acc += rp[5];
acc += bp[22 - 12];
acc += bp[22 - 12];
acc += bp[17 - 12];
acc += bp[14 - 12];
acc += bp[13 - 12];
acc += bp[21 - 12];
acc += bp[23 - 12];
acc -= bp[16 - 12];
rp[5] = (unsigned int)acc;
acc >>= 32;
acc += rp[6];
acc += bp[23 - 12];
acc += bp[23 - 12];
acc += bp[18 - 12];
acc += bp[15 - 12];
acc += bp[14 - 12];
acc += bp[22 - 12];
acc -= bp[17 - 12];
rp[6] = (unsigned int)acc;
acc >>= 32;
acc += rp[7];
acc += bp[19 - 12];
acc += bp[16 - 12];
acc += bp[15 - 12];
acc += bp[23 - 12];
acc -= bp[18 - 12];
rp[7] = (unsigned int)acc;
acc >>= 32;
acc += rp[8];
acc += bp[20 - 12];
acc += bp[17 - 12];
acc += bp[16 - 12];
acc -= bp[19 - 12];
rp[8] = (unsigned int)acc;
acc >>= 32;
acc += rp[9];
acc += bp[21 - 12];
acc += bp[18 - 12];
acc += bp[17 - 12];
acc -= bp[20 - 12];
rp[9] = (unsigned int)acc;
acc >>= 32;
acc += rp[10];
acc += bp[22 - 12];
acc += bp[19 - 12];
acc += bp[18 - 12];
acc -= bp[21 - 12];
rp[10] = (unsigned int)acc;
acc >>= 32;
acc += rp[11];
acc += bp[23 - 12];
acc += bp[20 - 12];
acc += bp[19 - 12];
acc -= bp[22 - 12];
rp[11] = (unsigned int)acc;
carry = (int)(acc >> 32);
}
#else
{
BN_ULONG t_d[BN_NIST_384_TOP];
/*
* S1
*/
nist_set_256(t_d, buf.bn, 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 =
(int)bn_add_words(r_d + (128 / BN_BITS2), r_d + (128 / BN_BITS2),
t_d, BN_NIST_256_TOP);
/*
* S2
*/
carry += (int)bn_add_words(r_d, r_d, buf.bn, BN_NIST_384_TOP);
/*
* S3
*/
nist_set_384(t_d, buf.bn, 20, 19, 18, 17, 16, 15, 14, 13, 12, 23, 22,
21);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* S4
*/
nist_set_384(t_d, buf.bn, 19, 18, 17, 16, 15, 14, 13, 12, 20, 0, 23,
0);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* S5
*/
nist_set_384(t_d, buf.bn, 0, 0, 0, 0, 23, 22, 21, 20, 0, 0, 0, 0);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* S6
*/
nist_set_384(t_d, buf.bn, 0, 0, 0, 0, 0, 0, 23, 22, 21, 0, 0, 20);
carry += (int)bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* D1
*/
nist_set_384(t_d, buf.bn, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12,
23);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* D2
*/
nist_set_384(t_d, buf.bn, 0, 0, 0, 0, 0, 0, 0, 23, 22, 21, 20, 0);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*
* D3
*/
nist_set_384(t_d, buf.bn, 0, 0, 0, 0, 0, 0, 0, 23, 23, 0, 0, 0);
carry -= (int)bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
}
#endif
/* see BN_nist_mod_224 for explanation */
u.f = bn_sub_words;
if (carry > 0)
carry =
(int)bn_sub_words(r_d, r_d, _nist_p_384[carry - 1],
BN_NIST_384_TOP);
else if (carry < 0) {
carry =
(int)bn_add_words(r_d, r_d, _nist_p_384[-carry - 1],
BN_NIST_384_TOP);
mask = 0 - (PTR_SIZE_INT) carry;
u.p = ((PTR_SIZE_INT) bn_sub_words & mask) |
((PTR_SIZE_INT) bn_add_words & ~mask);
} else
carry = 1;
mask =
0 - (PTR_SIZE_INT) (*u.f) (c_d, r_d, _nist_p_384[0], BN_NIST_384_TOP);
mask &= 0 - (PTR_SIZE_INT) carry;
res = c_d;
res = (BN_ULONG *)(((PTR_SIZE_INT) res & ~mask) |
((PTR_SIZE_INT) r_d & mask));
nist_cp_bn(r_d, res, BN_NIST_384_TOP);
r->top = BN_NIST_384_TOP;
bn_correct_top(r);
return 1;
}
#define BN_NIST_521_RSHIFT (521%BN_BITS2)
#define BN_NIST_521_LSHIFT (BN_BITS2-BN_NIST_521_RSHIFT)
#define BN_NIST_521_TOP_MASK ((BN_ULONG)BN_MASK2>>BN_NIST_521_LSHIFT)
int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
BN_CTX *ctx)
{
int top = a->top, i;
BN_ULONG *r_d, *a_d = a->d, t_d[BN_NIST_521_TOP], val, tmp, *res;
PTR_SIZE_INT mask;
static const BIGNUM _bignum_nist_p_521_sqr = {
(BN_ULONG *)_nist_p_521_sqr,
OSSL_NELEM(_nist_p_521_sqr),
OSSL_NELEM(_nist_p_521_sqr),
0, BN_FLG_STATIC_DATA
};
field = &_bignum_nist_p_521; /* just to make sure */
if (BN_is_negative(a) || BN_ucmp(a, &_bignum_nist_p_521_sqr) >= 0)
return BN_nnmod(r, a, field, ctx);
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 (r != a) {
if (!bn_wexpand(r, BN_NIST_521_TOP))
return 0;
r_d = r->d;
nist_cp_bn(r_d, a_d, BN_NIST_521_TOP);
} else
r_d = a_d;
/* upper 521 bits, copy ... */
nist_cp_bn_0(t_d, a_d + (BN_NIST_521_TOP - 1),
top - (BN_NIST_521_TOP - 1), BN_NIST_521_TOP);
/* ... and right shift */
for (val = t_d[0], i = 0; i < BN_NIST_521_TOP - 1; i++) {
#if 0
/*
* MSC ARM compiler [version 2013, presumably even earlier,
* much earlier] miscompiles this code, but not one in
* #else section. See RT#3541.
*/
tmp = val >> BN_NIST_521_RSHIFT;
val = t_d[i + 1];
t_d[i] = (tmp | val << BN_NIST_521_LSHIFT) & BN_MASK2;
#else
t_d[i] = (val >> BN_NIST_521_RSHIFT |
(tmp = t_d[i + 1]) << BN_NIST_521_LSHIFT) & BN_MASK2;
val = tmp;
#endif
}
t_d[i] = val >> BN_NIST_521_RSHIFT;
/* lower 521 bits */
r_d[i] &= BN_NIST_521_TOP_MASK;
bn_add_words(r_d, r_d, t_d, BN_NIST_521_TOP);
mask =
0 - (PTR_SIZE_INT) bn_sub_words(t_d, r_d, _nist_p_521,
BN_NIST_521_TOP);
res = t_d;
res = (BN_ULONG *)(((PTR_SIZE_INT) res & ~mask) |
((PTR_SIZE_INT) r_d & mask));
nist_cp_bn(r_d, res, BN_NIST_521_TOP);
r->top = BN_NIST_521_TOP;
bn_correct_top(r);
return 1;
}
int (*BN_nist_mod_func(const BIGNUM *p)) (BIGNUM *r, const BIGNUM *a,
const BIGNUM *field, BN_CTX *ctx) {
if (BN_ucmp(&_bignum_nist_p_192, p) == 0)
return BN_nist_mod_192;
if (BN_ucmp(&_bignum_nist_p_224, p) == 0)
return BN_nist_mod_224;
if (BN_ucmp(&_bignum_nist_p_256, p) == 0)
return BN_nist_mod_256;
if (BN_ucmp(&_bignum_nist_p_384, p) == 0)
return BN_nist_mod_384;
if (BN_ucmp(&_bignum_nist_p_521, p) == 0)
return BN_nist_mod_521;
return 0;
}
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