From e4bc9d9ef674a632419ec0f0eeb2735138683da8 Mon Sep 17 00:00:00 2001 From: Andy Polyakov Date: Tue, 1 Apr 2008 08:42:08 +0000 Subject: [PATCH] Fix fast reduction on NIST curves [from HEAD]. PR: 1593 --- crypto/bn/bn_nist.c | 148 ++++++++++++++++---------------------------- 1 file changed, 52 insertions(+), 96 deletions(-) diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c index f8e306bb82..fd15c28777 100644 --- a/crypto/bn/bn_nist.c +++ b/crypto/bn/bn_nist.c @@ -182,7 +182,7 @@ static int _is_set_384_data = 0; static void _init_384_data(void); #endif -#define BN_NIST_ADD_ONE(a) while (!(++(*(a)))) ++(a); +#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) { @@ -255,7 +255,6 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, BN_CTX *ctx) { int top = a->top, i; - BN_ULONG carry = 0; register BN_ULONG *r_d, *a_d = a->d; BN_ULONG t_d[BN_NIST_192_TOP], buf[BN_NIST_192_TOP]; @@ -291,11 +290,11 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, nist_set_192(t_d, buf, 0, 3, 3); if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP)) - ++carry; + bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP); nist_set_192(t_d, buf, 4, 4, 0); if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP)) - ++carry; + bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP); #if defined(OPENSSL_SYS_VMS) && defined(__DECC) # pragma message restore @@ -303,13 +302,8 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, nist_set_192(t_d, buf, 5, 5, 5) if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP)) - ++carry; + bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP); - while (carry) - { - if (bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP)) - --carry; - } r->top = BN_NIST_192_TOP; bn_correct_top(r); if (BN_ucmp(r, field) >= 0) @@ -336,9 +330,8 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, BN_CTX *ctx) { -#if BN_BITS2 != 64 +#if BN_BITS2 == 32 int top = a->top, i; - int carry = 0; BN_ULONG *r_d, *a_d = a->d; BN_ULONG t_d[BN_NIST_224_TOP], buf[BN_NIST_224_TOP]; @@ -369,29 +362,16 @@ 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); if (bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP)) - ++carry; + bn_sub_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP); nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0); if (bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP)) - ++carry; + bn_sub_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP); nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7); if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP)) - --carry; + bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP); nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11); if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP)) - --carry; - - if (carry > 0) - while (carry) - { - if (bn_sub_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP)) - --carry; - } - else if (carry < 0) - while (carry) - { - if (bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP)) - ++carry; - } + bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP); r->top = BN_NIST_224_TOP; bn_correct_top(r); @@ -407,7 +387,7 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, #endif } -#if BN_BITS2 != 64 +#if BN_BITS2 == 32 static void _init_256_data(void) { int i; @@ -442,7 +422,7 @@ static void _init_256_data(void) int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, BN_CTX *ctx) { -#if BN_BITS2 != 64 +#if BN_BITS2 == 32 int i, top = a->top; int carry = 0; register BN_ULONG *a_d = a->d, *r_d; @@ -488,8 +468,7 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0); /*S2*/ nist_set_256(t_d2,buf, 0, 15, 14, 13, 12, 0, 0, 0); - if (bn_add_words(t_d, t_d, t_d2, BN_NIST_256_TOP)) - carry = 2; + carry = bn_add_words(t_d, t_d, t_d2, BN_NIST_256_TOP); /* left shift */ { register BN_ULONG *ap,t,c; @@ -501,49 +480,38 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, *(ap++)=((t<<1)|c)&BN_MASK2; c=(t & BN_TBIT)?1:0; } - if (c) - ++carry; + carry <<= 1; + carry |= c; } - if (bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - ++carry; + 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); - if (bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - ++carry; + 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); - if (bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - ++carry; + carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP); + + if (carry) + bn_sub_words(r_d, r_d, _256_data + BN_NIST_256_TOP * + (carry-1), BN_NIST_256_TOP); + /*D1*/ nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11); - if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - --carry; + 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 (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - --carry; + 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 (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - --carry; + 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 (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP)) - --carry; + carry += bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP); if (carry) - { - if (carry > 0) - bn_sub_words(r_d, r_d, _256_data + BN_NIST_256_TOP * - --carry, BN_NIST_256_TOP); - else - { - carry = -carry; - bn_add_words(r_d, r_d, _256_data + BN_NIST_256_TOP * - --carry, BN_NIST_256_TOP); - } - } + bn_add_words(r_d, r_d, _256_data + BN_NIST_256_TOP * + (carry-1), BN_NIST_256_TOP); r->top = BN_NIST_256_TOP; bn_correct_top(r); @@ -559,7 +527,7 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, #endif } -#if BN_BITS2 != 64 +#if BN_BITS2 == 32 static void _init_384_data(void) { int i; @@ -598,7 +566,7 @@ static void _init_384_data(void) int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, BN_CTX *ctx) { -#if BN_BITS2 != 64 +#if BN_BITS2 == 32 int i, top = a->top; int carry = 0; register BN_ULONG *r_d, *a_d = a->d; @@ -646,61 +614,49 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, register BN_ULONG *ap,t,c; ap = t_d; c=0; - for (i = BN_NIST_256_TOP; i != 0; --i) + for (i = 3; i != 0; --i) { t= *ap; *(ap++)=((t<<1)|c)&BN_MASK2; c=(t & BN_TBIT)?1:0; } + *ap=c; } - if (bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), - t_d, BN_NIST_256_TOP)) - ++carry; + carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), + t_d, BN_NIST_256_TOP); /*S2 */ - if (bn_add_words(r_d, r_d, buf, BN_NIST_384_TOP)) - ++carry; + 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); - if (bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - ++carry; + 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); - if (bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - ++carry; + carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP); /*S5*/ nist_set_256(t_d, buf, 0, 0, 0, 0, 23-4, 22-4, 21-4, 20-4); - if (bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), - t_d, BN_NIST_256_TOP)) - ++carry; + carry += bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), + t_d, BN_NIST_256_TOP); /*S6*/ nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20); - if (bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - ++carry; + carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP); + + if (carry) + bn_sub_words(r_d, r_d, _384_data + BN_NIST_384_TOP * + (carry-1), BN_NIST_384_TOP); + /*D1*/ nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23); - if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - --carry; + 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 (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - --carry; + 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 (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP)) - --carry; - + carry += bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP); + if (carry) - { - if (carry > 0) - bn_sub_words(r_d, r_d, _384_data + BN_NIST_384_TOP * - --carry, BN_NIST_384_TOP); - else - { - carry = -carry; - bn_add_words(r_d, r_d, _384_data + BN_NIST_384_TOP * - --carry, BN_NIST_384_TOP); - } - } + bn_add_words(r_d, r_d, _384_data + BN_NIST_384_TOP * + (carry-1), BN_NIST_384_TOP); r->top = BN_NIST_384_TOP; bn_correct_top(r); @@ -762,7 +718,7 @@ int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, (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; + r->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK; } bn_correct_top(r); -- 2.40.0