From 830b8877ba69c70c49869d296df2568e3c8441b7 Mon Sep 17 00:00:00 2001 From: Andy Polyakov Date: Wed, 23 Apr 2008 08:10:25 +0000 Subject: [PATCH] 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 --- crypto/bn/bn_nist.c | 450 +++++++++++++++++++++----------------------- 1 file changed, 219 insertions(+), 231 deletions(-) diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c index e14232fdbb..d8b443c562 100644 --- a/crypto/bn/bn_nist.c +++ b/crypto/bn/bn_nist.c @@ -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, -- 2.25.1