Commit 2819ffb5 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

Fix fast reduction on NIST curves (as well BN_NIST_ADD_ONE macro). 

PR: 1593
parent 964c7e8f

crypto/bn/bn_nist.c

+52 −96
Original line number Diff line number Diff line
@@ -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);

			}

		}

				(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);

			}

		}

				(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);