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提交 830b8877 编写于 作者: A Andy Polyakov
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Takanori Yanagisawa has shown how to correctly use pre-computed values. 

So in a sense this commit reverts few latest ones fixing bugs in original
code and improving it, most notably adding 64-bit support [though not in
BN_nist_mod_224 yet].
PR: 1593
上级 9912ab67
隐藏空白更改
内联 并排
Showing with 219 addition and 231 deletion
crypto/bn/bn_nist.c
浏览文件 @ 830b8877
......@@ -65,20 +65,43 @@
#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[] =
{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,
0xFFFFFFFFFFFFFFFFULL};
static const BN_ULONG _nist_p_224[] =
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_224[][BN_NIST_224_TOP] = {
{0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL};
static const BN_ULONG _nist_p_256[] =
0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL},
{0x0000000000000002ULL,0xFFFFFFFE00000000ULL,
0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL}
};
static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
{0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFF00000001ULL};
static const BN_ULONG _nist_p_384[] =
{0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,
0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL};
0x0000000000000000ULL,0xFFFFFFFF00000001ULL},
{0xFFFFFFFFFFFFFFFEULL,0x00000001FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFE00000002ULL},
{0xFFFFFFFFFFFFFFFDULL,0x00000002FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFD00000003ULL},
{0xFFFFFFFFFFFFFFFCULL,0x00000003FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFC00000004ULL},
{0xFFFFFFFFFFFFFFFBULL,0x00000004FFFFFFFFULL,
0x0000000000000000ULL,0xFFFFFFFB00000005ULL},
};
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_521[] =
{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
......@@ -86,15 +109,41 @@ static const BN_ULONG _nist_p_521[] =
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_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_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_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_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_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
......@@ -103,28 +152,28 @@ static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
const BIGNUM *BN_get0_nist_prime_192(void)
{
static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,
static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192[0],
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,
static BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224[0],
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,
static BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256[0],
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,
static BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384[0],
BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };
return &const_nist_384;
}
......@@ -159,9 +208,14 @@ static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
#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;
/*
* 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)
#else
#define bn_cp_64(to, n, from, m) \
{ \
......@@ -182,9 +236,9 @@ static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
#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, 0, from, (a3) - 3) \
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)\
bn_cp_64(to, 2, from, (a1) - 3) \
}
int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
......@@ -225,22 +279,25 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
if (carry > 0)
carry = 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-(size_t)bn_sub_words(c_d,r_d,_nist_p_192[0],BN_NIST_192_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_192_TOP);
r->top = BN_NIST_192_TOP;
bn_correct_top(r);
......@@ -248,15 +305,17 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
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) \
{ \
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)\
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,
......@@ -271,6 +330,7 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
c_d[BN_NIST_224_TOP],
*res;
size_t mask;
union { bn_addsub_f f; size_t p; } u;
i = BN_ucmp(field, a);
if (i == 0)
......@@ -298,38 +358,36 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
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));
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
u.f = bn_sub_words;
if (carry > 0)
carry = bn_sub_words(r_d,r_d,_nist_p_224[carry-1],BN_NIST_224_TOP);
else if (carry < 0)
{
/* it's a bit more comlicated 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 = bn_add_words(r_d,r_d,_nist_p_224[-carry-1],BN_NIST_224_TOP);
mask = 0-(size_t)carry;
u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
}
else
carry = 1;
/* otherwise it's effectively same as in BN_nist_mod_192... */
mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_224[0],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);
......@@ -341,20 +399,19 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
#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)\
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)
{
#if BN_BITS2 == 32
int i, top = a->top;
int carry = 0;
register BN_ULONG *a_d = a->d, *r_d;
......@@ -363,6 +420,7 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
c_d[BN_NIST_256_TOP],
*res;
size_t mask;
union { bn_addsub_f f; size_t p; } u;
i = BN_ucmp(field, a);
if (i == 0)
......@@ -391,111 +449,84 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
/*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);
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));
/* 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 += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
/*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));
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
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
/* see BN_nist_mod_224 for explanation */
u.f = bn_sub_words;
if (carry > 0)
carry = bn_sub_words(r_d,r_d,_nist_p_256[carry-1],BN_NIST_256_TOP);
else if (carry < 0)
{
carry = bn_add_words(r_d,r_d,_nist_p_256[-carry-1],BN_NIST_256_TOP);
mask = 0-(size_t)carry;
u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
}
else
carry = 1;
mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_256[0],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_256_TOP);
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)\
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)
{
#if BN_BITS2 == 32
int i, top = a->top;
int carry = 0;
register BN_ULONG *r_d, *a_d = a->d;
......@@ -504,6 +535,7 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
c_d[BN_NIST_384_TOP],
*res;
size_t mask;
union { bn_addsub_f f; size_t p; } u;
i = BN_ucmp(field, a);
if (i == 0)
......@@ -546,95 +578,51 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
}
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));
carry += bn_add_words(r_d, r_d, buf, BN_NIST_384_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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));
carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/*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));
carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
/* see BN_nist_mod_224 for explanation */
u.f = bn_sub_words;
if (carry > 0)
carry = bn_sub_words(r_d,r_d,_nist_p_384[carry-1],BN_NIST_384_TOP);
else if (carry < 0)
{
carry = bn_add_words(r_d,r_d,_nist_p_384[-carry-1],BN_NIST_384_TOP);
mask = 0-(size_t)carry;
u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
}
else
carry = 1;
mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_384[0],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,
......
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