[thirdparty/openssl.git] / crypto / bn / bn_prime.c

/* crypto/bn/bn_prime.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include <time.h>
#include "cryptlib.h"
#include "bn_lcl.h"
#include <openssl/rand.h>

/* The quick seive algorithm approach to weeding out primes is
 * Philip Zimmermann's, as implemented in PGP.  I have had a read of
 * his comments and implemented my own version.
 */
#include "bn_prime.h"

static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx,BN_CTX *ctx2,
	BN_MONT_CTX *mont);
static int probable_prime(BIGNUM *rnd, int bits);
static int probable_prime_dh(BIGNUM *rnd, int bits,
	BIGNUM *add, BIGNUM *rem, BN_CTX *ctx);
static int probable_prime_dh_safe(BIGNUM *rnd, int bits,
	BIGNUM *add, BIGNUM *rem, BN_CTX *ctx);

BIGNUM *BN_generate_prime(BIGNUM *ret, int bits, int safe, BIGNUM *add,
	     BIGNUM *rem, void (*callback)(int,int,void *), void *cb_arg)
	{
	BIGNUM *rnd=NULL;
	BIGNUM t;
	int i,j,c1=0;
	BN_CTX *ctx;
	int checks = BN_prime_checks(bits);

	ctx=BN_CTX_new();
	if (ctx == NULL) goto err;
	if (ret == NULL)
		{
		if ((rnd=BN_new()) == NULL) goto err;
		}
	else
		rnd=ret;
	BN_init(&t);
loop: 
	/* make a random number and set the top and bottom bits */
	if (add == NULL)
		{
		if (!probable_prime(rnd,bits)) goto err;
		}
	else
		{
		if (safe)
			{
			if (!probable_prime_dh_safe(rnd,bits,add,rem,ctx))
				 goto err;
			}
		else
			{
			if (!probable_prime_dh(rnd,bits,add,rem,ctx))
				goto err;
			}
		}
	/* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */
	if (callback != NULL) callback(0,c1++,cb_arg);

	if (!safe)
		{
		i=BN_is_prime(rnd,checks,callback,ctx,cb_arg);
		if (i == -1) goto err;
		if (i == 0) goto loop;
		}
	else
		{
		/* for "safe prime" generation,
		 * check that (p-1)/2 is prime.
		 * Since a prime is odd, We just
		 * need to divide by 2 */
		if (!BN_rshift1(&t,rnd)) goto err;

		for (i=0; i<checks; i++)
			{
			j=BN_is_prime(rnd,1,callback,ctx,cb_arg);
			if (j == -1) goto err;
			if (j == 0) goto loop;

			j=BN_is_prime(&t,1,callback,ctx,cb_arg);
			if (j == -1) goto err;
			if (j == 0) goto loop;

			if (callback != NULL) callback(2,c1-1,cb_arg);
			/* We have a safe prime test pass */
			}
		}
	/* we have a prime :-) */
	ret=rnd;
err:
	if ((ret == NULL) && (rnd != NULL)) BN_free(rnd);
	BN_free(&t);
	if (ctx != NULL) BN_CTX_free(ctx);
	return(ret);
	}

int BN_is_prime(BIGNUM *a, int checks, void (*callback)(int,int,void *),
	     BN_CTX *ctx_passed, void *cb_arg)
	{
	int i,j,c2=0,ret= -1;
	BIGNUM *check;
	BN_CTX *ctx=NULL,*ctx2=NULL;
	BN_MONT_CTX *mont=NULL;

	if (!BN_is_odd(a))
		return(0);
	if (ctx_passed != NULL)
		ctx=ctx_passed;
	else
		if ((ctx=BN_CTX_new()) == NULL) goto err;

	if ((ctx2=BN_CTX_new()) == NULL) goto err;
	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;

	check= &(ctx->bn[ctx->tos++]);

	/* Setup the montgomery structure */
	if (!BN_MONT_CTX_set(mont,a,ctx2)) goto err;

	for (i=0; i<checks; i++)
		{
		if (!BN_rand(check,BN_num_bits(a)-1,0,0)) goto err;
		j=witness(check,a,ctx,ctx2,mont);
		if (j == -1) goto err;
		if (j)
			{
			ret=0;
			goto err;
			}
		if (callback != NULL) callback(1,c2++,cb_arg);
		}
	ret=1;
err:
	ctx->tos--;
	if ((ctx_passed == NULL) && (ctx != NULL))
		BN_CTX_free(ctx);
	if (ctx2 != NULL)
		BN_CTX_free(ctx2);
	if (mont != NULL) BN_MONT_CTX_free(mont);
		
	return(ret);
	}

#define RECP_MUL_MOD

static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx, BN_CTX *ctx2,
	     BN_MONT_CTX *mont)
	{
	int k,i,ret= -1,good;
	BIGNUM *d,*dd,*tmp,*d1,*d2,*n1;
	BIGNUM *mont_one,*mont_n1,*mont_a;

	d1= &(ctx->bn[ctx->tos]);
	d2= &(ctx->bn[ctx->tos+1]);
	n1= &(ctx->bn[ctx->tos+2]);
	ctx->tos+=3;

	mont_one= &(ctx2->bn[ctx2->tos]);
	mont_n1= &(ctx2->bn[ctx2->tos+1]);
	mont_a= &(ctx2->bn[ctx2->tos+2]);
	ctx2->tos+=3;

	d=d1;
	dd=d2;
	if (!BN_one(d)) goto err;
	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	k=BN_num_bits(n1);

	if (!BN_to_montgomery(mont_one,BN_value_one(),mont,ctx2)) goto err;
	if (!BN_to_montgomery(mont_n1,n1,mont,ctx2)) goto err;
	if (!BN_to_montgomery(mont_a,a,mont,ctx2)) goto err;

	BN_copy(d,mont_one);
	for (i=k-1; i>=0; i--)
		{
		if (	(BN_cmp(d,mont_one) != 0) &&
			(BN_cmp(d,mont_n1) != 0))
			good=1;
		else
			good=0;

		BN_mod_mul_montgomery(dd,d,d,mont,ctx2);

		if (good && (BN_cmp(dd,mont_one) == 0))
			{
			ret=1;
			goto err;
			}
		if (BN_is_bit_set(n1,i))
			{
			BN_mod_mul_montgomery(d,dd,mont_a,mont,ctx2);
			}
		else
			{
			tmp=d;
			d=dd;
			dd=tmp;
			}
		}
	if (BN_cmp(d,mont_one) == 0)
		i=0;
	else	i=1;
	ret=i;
err:
	ctx->tos-=3;
	ctx2->tos-=3;
	return(ret);
	}

static int probable_prime(BIGNUM *rnd, int bits)
	{
	int i;
	MS_STATIC BN_ULONG mods[NUMPRIMES];
	BN_ULONG delta,d;

again:
	if (!BN_rand(rnd,bits,1,1)) return(0);
	/* we now have a random number 'rand' to test. */
	for (i=1; i<NUMPRIMES; i++)
		mods[i]=BN_mod_word(rnd,(BN_ULONG)primes[i]);
	delta=0;
	loop: for (i=1; i<NUMPRIMES; i++)
		{
		/* check that rnd is not a prime and also
		 * that gcd(rnd-1,primes) == 1 (except for 2) */
		if (((mods[i]+delta)%primes[i]) <= 1)
			{
			d=delta;
			delta+=2;
			/* perhaps need to check for overflow of
			 * delta (but delta can be upto 2^32)
			 * 21-May-98 eay - added overflow check */
			if (delta < d) goto again;
			goto loop;
			}
		}
	if (!BN_add_word(rnd,delta)) return(0);
	return(1);
	}

static int probable_prime_dh(BIGNUM *rnd, int bits, BIGNUM *add, BIGNUM *rem,
	     BN_CTX *ctx)
	{
	int i,ret=0;
	BIGNUM *t1;

	t1= &(ctx->bn[ctx->tos++]);

	if (!BN_rand(rnd,bits,0,1)) goto err;

	/* we need ((rnd-rem) % add) == 0 */

	if (!BN_mod(t1,rnd,add,ctx)) goto err;
	if (!BN_sub(rnd,rnd,t1)) goto err;
	if (rem == NULL)
		{ if (!BN_add_word(rnd,1)) goto err; }
	else
		{ if (!BN_add(rnd,rnd,rem)) goto err; }

	/* we now have a random number 'rand' to test. */

	loop: for (i=1; i<NUMPRIMES; i++)
		{
		/* check that rnd is a prime */
		if (BN_mod_word(rnd,(BN_ULONG)primes[i]) <= 1)
			{
			if (!BN_add(rnd,rnd,add)) goto err;
			goto loop;
			}
		}
	ret=1;
err:
	ctx->tos--;
	return(ret);
	}

static int probable_prime_dh_safe(BIGNUM *p, int bits, BIGNUM *padd,
	     BIGNUM *rem, BN_CTX *ctx)
	{
	int i,ret=0;
	BIGNUM *t1,*qadd=NULL,*q=NULL;

	bits--;
	t1= &(ctx->bn[ctx->tos++]);
	q= &(ctx->bn[ctx->tos++]);
	qadd= &(ctx->bn[ctx->tos++]);

	if (!BN_rshift1(qadd,padd)) goto err;
		
	if (!BN_rand(q,bits,0,1)) goto err;

	/* we need ((rnd-rem) % add) == 0 */
	if (!BN_mod(t1,q,qadd,ctx)) goto err;
	if (!BN_sub(q,q,t1)) goto err;
	if (rem == NULL)
		{ if (!BN_add_word(q,1)) goto err; }
	else
		{
		if (!BN_rshift1(t1,rem)) goto err;
		if (!BN_add(q,q,t1)) goto err;
		}

	/* we now have a random number 'rand' to test. */
	if (!BN_lshift1(p,q)) goto err;
	if (!BN_add_word(p,1)) goto err;

	loop: for (i=1; i<NUMPRIMES; i++)
		{
		/* check that p and q are prime */
		/* check that for p and q
		 * gcd(p-1,primes) == 1 (except for 2) */
		if (	(BN_mod_word(p,(BN_ULONG)primes[i]) == 0) ||
			(BN_mod_word(q,(BN_ULONG)primes[i]) == 0))
			{
			if (!BN_add(p,p,padd)) goto err;
			if (!BN_add(q,q,qadd)) goto err;
			goto loop;
			}
		}
	ret=1;
err:
	ctx->tos-=3;
	return(ret);
	}

#if 0
static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx)
	{
	int k,i,nb,ret= -1;
	BIGNUM *d,*dd,*tmp;
	BIGNUM *d1,*d2,*x,*n1,*inv;

	d1= &(ctx->bn[ctx->tos]);
	d2= &(ctx->bn[ctx->tos+1]);
	x=  &(ctx->bn[ctx->tos+2]);
	n1= &(ctx->bn[ctx->tos+3]);
	inv=&(ctx->bn[ctx->tos+4]);
	ctx->tos+=5;

	d=d1;
	dd=d2;
	if (!BN_one(d)) goto err;
	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	k=BN_num_bits(n1);

	/* i=BN_num_bits(n); */
#ifdef RECP_MUL_MOD
	nb=BN_reciprocal(inv,n,ctx); /**/
	if (nb == -1) goto err;
#endif

	for (i=k-1; i>=0; i--)
		{
		if (BN_copy(x,d) == NULL) goto err;
#ifndef RECP_MUL_MOD
		if (!BN_mod_mul(dd,d,d,n,ctx)) goto err;
#else
		if (!BN_mod_mul_reciprocal(dd,d,d,n,inv,nb,ctx)) goto err;
#endif
		if (	BN_is_one(dd) &&
			!BN_is_one(x) &&
			(BN_cmp(x,n1) != 0))
			{
			ret=1;
			goto err;
			}
		if (BN_is_bit_set(n1,i))
			{
#ifndef RECP_MUL_MOD
			if (!BN_mod_mul(d,dd,a,n,ctx)) goto err;
#else
			if (!BN_mod_mul_reciprocal(d,dd,a,n,inv,nb,ctx)) goto err; 
#endif
			}
		else
			{
			tmp=d;
			d=dd;
			dd=tmp;
			}
		}
	if (BN_is_one(d))
		i=0;
	else	i=1;
	ret=i;
err:
	ctx->tos-=5;
	return(ret);
	}
#endif
Commit	Line	Data
d02b48c6	1	/* crypto/bn/bn_prime.c */
58964a49	2	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
d02b48c6 RE	3	* All rights reserved.
	4	*
	5	* This package is an SSL implementation written
	6	* by Eric Young (eay@cryptsoft.com).
	7	* The implementation was written so as to conform with Netscapes SSL.
	8	*
	9	* This library is free for commercial and non-commercial use as long as
	10	* the following conditions are aheared to. The following conditions
	11	* apply to all code found in this distribution, be it the RC4, RSA,
	12	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
	13	* included with this distribution is covered by the same copyright terms
	14	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
	15	*
	16	* Copyright remains Eric Young's, and as such any Copyright notices in
	17	* the code are not to be removed.
	18	* If this package is used in a product, Eric Young should be given attribution
	19	* as the author of the parts of the library used.
	20	* This can be in the form of a textual message at program startup or
	21	* in documentation (online or textual) provided with the package.
	22	*
	23	* Redistribution and use in source and binary forms, with or without
	24	* modification, are permitted provided that the following conditions
	25	* are met:
	26	* 1. Redistributions of source code must retain the copyright
	27	* notice, this list of conditions and the following disclaimer.
	28	* 2. Redistributions in binary form must reproduce the above copyright
	29	* notice, this list of conditions and the following disclaimer in the
	30	* documentation and/or other materials provided with the distribution.
	31	* 3. All advertising materials mentioning features or use of this software
	32	* must display the following acknowledgement:
	33	* "This product includes cryptographic software written by
	34	* Eric Young (eay@cryptsoft.com)"
	35	* The word 'cryptographic' can be left out if the rouines from the library
	36	* being used are not cryptographic related :-).
	37	* 4. If you include any Windows specific code (or a derivative thereof) from
	38	* the apps directory (application code) you must include an acknowledgement:
	39	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
	40	*
	41	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
	42	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	44	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	45	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	46	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	47	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	48	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	49	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	50	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	51	* SUCH DAMAGE.
	52	*
	53	* The licence and distribution terms for any publically available version or
	54	* derivative of this code cannot be changed. i.e. this code cannot simply be
	55	* copied and put under another distribution licence
	56	* [including the GNU Public Licence.]
	57	*/
	58
	59	#include <stdio.h>
	60	#include <time.h>
	61	#include "cryptlib.h"
	62	#include "bn_lcl.h"
ec577822	63	#include <openssl/rand.h>
d02b48c6 RE	64
	65	/* The quick seive algorithm approach to weeding out primes is
	66	* Philip Zimmermann's, as implemented in PGP. I have had a read of
	67	* his comments and implemented my own version.
	68	*/
	69	#include "bn_prime.h"
	70
58964a49 RE	71	static int witness(BIGNUM a, BIGNUM n, BN_CTX ctx,BN_CTX ctx2,
58964a49 RE	72	BN_MONT_CTX *mont);
d02b48c6 RE	73	static int probable_prime(BIGNUM *rnd, int bits);
	74	static int probable_prime_dh(BIGNUM *rnd, int bits,
	75	BIGNUM add, BIGNUM rem, BN_CTX *ctx);
76aa0ddc	76	static int probable_prime_dh_safe(BIGNUM *rnd, int bits,
d02b48c6	77	BIGNUM add, BIGNUM rem, BN_CTX *ctx);
eb952088	78
76aa0ddc	79	BIGNUM BN_generate_prime(BIGNUM ret, int bits, int safe, BIGNUM *add,
b4f76582	80	BIGNUM rem, void (callback)(int,int,void ), void cb_arg)
d02b48c6 RE	81	{
d02b48c6 RE	82	BIGNUM *rnd=NULL;
dfeab068	83	BIGNUM t;
d02b48c6 RE	84	int i,j,c1=0;
d02b48c6 RE	85	BN_CTX *ctx;
76aa0ddc	86	int checks = BN_prime_checks(bits);
d02b48c6 RE	87
	88	ctx=BN_CTX_new();
	89	if (ctx == NULL) goto err;
dfeab068 RE	90	if (ret == NULL)
	91	{
	92	if ((rnd=BN_new()) == NULL) goto err;
	93	}
	94	else
	95	rnd=ret;
	96	BN_init(&t);
d02b48c6 RE	97	loop:
	98	/* make a random number and set the top and bottom bits */
	99	if (add == NULL)
	100	{
	101	if (!probable_prime(rnd,bits)) goto err;
	102	}
	103	else
	104	{
76aa0ddc	105	if (safe)
d02b48c6	106	{
76aa0ddc	107	if (!probable_prime_dh_safe(rnd,bits,add,rem,ctx))
d02b48c6 RE	108	goto err;
	109	}
	110	else
	111	{
	112	if (!probable_prime_dh(rnd,bits,add,rem,ctx))
	113	goto err;
	114	}
	115	}
	116	/* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */
58964a49	117	if (callback != NULL) callback(0,c1++,cb_arg);
d02b48c6	118
76aa0ddc	119	if (!safe)
d02b48c6	120	{
76aa0ddc	121	i=BN_is_prime(rnd,checks,callback,ctx,cb_arg);
d02b48c6 RE	122	if (i == -1) goto err;
	123	if (i == 0) goto loop;
	124	}
	125	else
	126	{
76aa0ddc	127	/* for "safe prime" generation,
d02b48c6 RE	128	* check that (p-1)/2 is prime.
	129	* Since a prime is odd, We just
	130	* need to divide by 2 */
dfeab068	131	if (!BN_rshift1(&t,rnd)) goto err;
d02b48c6	132
76aa0ddc	133	for (i=0; i<checks; i++)
d02b48c6	134	{
58964a49	135	j=BN_is_prime(rnd,1,callback,ctx,cb_arg);
d02b48c6 RE	136	if (j == -1) goto err;
	137	if (j == 0) goto loop;
	138
dfeab068	139	j=BN_is_prime(&t,1,callback,ctx,cb_arg);
d02b48c6 RE	140	if (j == -1) goto err;
	141	if (j == 0) goto loop;
	142
58964a49	143	if (callback != NULL) callback(2,c1-1,cb_arg);
76aa0ddc	144	/* We have a safe prime test pass */
d02b48c6 RE	145	}
	146	}
	147	/* we have a prime :-) */
	148	ret=rnd;
	149	err:
	150	if ((ret == NULL) && (rnd != NULL)) BN_free(rnd);
dfeab068	151	BN_free(&t);
d02b48c6 RE	152	if (ctx != NULL) BN_CTX_free(ctx);
	153	return(ret);
	154	}
	155
b4f76582 BL	156	int BN_is_prime(BIGNUM a, int checks, void (callback)(int,int,void *),
b4f76582 BL	157	BN_CTX ctx_passed, void cb_arg)
d02b48c6 RE	158	{
	159	int i,j,c2=0,ret= -1;
	160	BIGNUM *check;
58964a49 RE	161	BN_CTX ctx=NULL,ctx2=NULL;
58964a49 RE	162	BN_MONT_CTX *mont=NULL;
d02b48c6	163
58964a49 RE	164	if (!BN_is_odd(a))
58964a49 RE	165	return(0);
d02b48c6 RE	166	if (ctx_passed != NULL)
	167	ctx=ctx_passed;
	168	else
	169	if ((ctx=BN_CTX_new()) == NULL) goto err;
	170
58964a49 RE	171	if ((ctx2=BN_CTX_new()) == NULL) goto err;
	172	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
	173
dfeab068	174	check= &(ctx->bn[ctx->tos++]);
58964a49 RE	175
	176	/* Setup the montgomery structure */
	177	if (!BN_MONT_CTX_set(mont,a,ctx2)) goto err;
	178
d02b48c6 RE	179	for (i=0; i<checks; i++)
	180	{
	181	if (!BN_rand(check,BN_num_bits(a)-1,0,0)) goto err;
58964a49	182	j=witness(check,a,ctx,ctx2,mont);
d02b48c6 RE	183	if (j == -1) goto err;
	184	if (j)
	185	{
	186	ret=0;
	187	goto err;
	188	}
58964a49	189	if (callback != NULL) callback(1,c2++,cb_arg);
d02b48c6 RE	190	}
	191	ret=1;
	192	err:
	193	ctx->tos--;
	194	if ((ctx_passed == NULL) && (ctx != NULL))
	195	BN_CTX_free(ctx);
58964a49 RE	196	if (ctx2 != NULL)
	197	BN_CTX_free(ctx2);
	198	if (mont != NULL) BN_MONT_CTX_free(mont);
d02b48c6 RE	199
	200	return(ret);
	201	}
	202
	203	#define RECP_MUL_MOD
	204
6b691a5c UM	205	static int witness(BIGNUM a, BIGNUM n, BN_CTX ctx, BN_CTX ctx2,
6b691a5c UM	206	BN_MONT_CTX *mont)
d02b48c6	207	{
58964a49 RE	208	int k,i,ret= -1,good;
	209	BIGNUM d,dd,tmp,d1,d2,n1;
	210	BIGNUM mont_one,mont_n1,*mont_a;
d02b48c6	211
dfeab068 RE	212	d1= &(ctx->bn[ctx->tos]);
	213	d2= &(ctx->bn[ctx->tos+1]);
	214	n1= &(ctx->bn[ctx->tos+2]);
58964a49 RE	215	ctx->tos+=3;
58964a49 RE	216
dfeab068 RE	217	mont_one= &(ctx2->bn[ctx2->tos]);
	218	mont_n1= &(ctx2->bn[ctx2->tos+1]);
	219	mont_a= &(ctx2->bn[ctx2->tos+2]);
58964a49	220	ctx2->tos+=3;
d02b48c6 RE	221
	222	d=d1;
	223	dd=d2;
	224	if (!BN_one(d)) goto err;
	225	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	226	k=BN_num_bits(n1);
	227
58964a49 RE	228	if (!BN_to_montgomery(mont_one,BN_value_one(),mont,ctx2)) goto err;
	229	if (!BN_to_montgomery(mont_n1,n1,mont,ctx2)) goto err;
	230	if (!BN_to_montgomery(mont_a,a,mont,ctx2)) goto err;
d02b48c6	231
58964a49	232	BN_copy(d,mont_one);
d02b48c6 RE	233	for (i=k-1; i>=0; i--)
d02b48c6 RE	234	{
58964a49 RE	235	if ( (BN_cmp(d,mont_one) != 0) &&
	236	(BN_cmp(d,mont_n1) != 0))
	237	good=1;
	238	else
	239	good=0;
	240
	241	BN_mod_mul_montgomery(dd,d,d,mont,ctx2);
4f9b306c	242
58964a49	243	if (good && (BN_cmp(dd,mont_one) == 0))
d02b48c6 RE	244	{
	245	ret=1;
	246	goto err;
	247	}
	248	if (BN_is_bit_set(n1,i))
	249	{
58964a49	250	BN_mod_mul_montgomery(d,dd,mont_a,mont,ctx2);
d02b48c6 RE	251	}
	252	else
	253	{
	254	tmp=d;
	255	d=dd;
	256	dd=tmp;
	257	}
	258	}
58964a49	259	if (BN_cmp(d,mont_one) == 0)
d02b48c6 RE	260	i=0;
	261	else i=1;
	262	ret=i;
	263	err:
58964a49 RE	264	ctx->tos-=3;
58964a49 RE	265	ctx2->tos-=3;
d02b48c6 RE	266	return(ret);
	267	}
	268
6b691a5c	269	static int probable_prime(BIGNUM *rnd, int bits)
d02b48c6 RE	270	{
	271	int i;
	272	MS_STATIC BN_ULONG mods[NUMPRIMES];
dfeab068	273	BN_ULONG delta,d;
d02b48c6	274
dfeab068	275	again:
d02b48c6 RE	276	if (!BN_rand(rnd,bits,1,1)) return(0);
	277	/* we now have a random number 'rand' to test. */
	278	for (i=1; i<NUMPRIMES; i++)
	279	mods[i]=BN_mod_word(rnd,(BN_ULONG)primes[i]);
	280	delta=0;
	281	loop: for (i=1; i<NUMPRIMES; i++)
	282	{
	283	/* check that rnd is not a prime and also
	284	* that gcd(rnd-1,primes) == 1 (except for 2) */
	285	if (((mods[i]+delta)%primes[i]) <= 1)
	286	{
dfeab068	287	d=delta;
d02b48c6 RE	288	delta+=2;
d02b48c6 RE	289	/* perhaps need to check for overflow of
dfeab068 RE	290	* delta (but delta can be upto 2^32)
	291	* 21-May-98 eay - added overflow check */
	292	if (delta < d) goto again;
d02b48c6 RE	293	goto loop;
	294	}
	295	}
	296	if (!BN_add_word(rnd,delta)) return(0);
	297	return(1);
	298	}
	299
6b691a5c UM	300	static int probable_prime_dh(BIGNUM rnd, int bits, BIGNUM add, BIGNUM *rem,
6b691a5c UM	301	BN_CTX *ctx)
d02b48c6 RE	302	{
	303	int i,ret=0;
	304	BIGNUM *t1;
	305
dfeab068	306	t1= &(ctx->bn[ctx->tos++]);
d02b48c6 RE	307
	308	if (!BN_rand(rnd,bits,0,1)) goto err;
	309
	310	/* we need ((rnd-rem) % add) == 0 */
	311
	312	if (!BN_mod(t1,rnd,add,ctx)) goto err;
	313	if (!BN_sub(rnd,rnd,t1)) goto err;
	314	if (rem == NULL)
	315	{ if (!BN_add_word(rnd,1)) goto err; }
	316	else
	317	{ if (!BN_add(rnd,rnd,rem)) goto err; }
	318
	319	/* we now have a random number 'rand' to test. */
	320
	321	loop: for (i=1; i<NUMPRIMES; i++)
	322	{
	323	/* check that rnd is a prime */
e14d4443	324	if (BN_mod_word(rnd,(BN_ULONG)primes[i]) <= 1)
d02b48c6 RE	325	{
	326	if (!BN_add(rnd,rnd,add)) goto err;
	327	goto loop;
	328	}
	329	}
	330	ret=1;
	331	err:
	332	ctx->tos--;
	333	return(ret);
	334	}
	335
76aa0ddc	336	static int probable_prime_dh_safe(BIGNUM p, int bits, BIGNUM padd,
6b691a5c	337	BIGNUM rem, BN_CTX ctx)
d02b48c6 RE	338	{
	339	int i,ret=0;
	340	BIGNUM t1,qadd=NULL,*q=NULL;
	341
	342	bits--;
dfeab068 RE	343	t1= &(ctx->bn[ctx->tos++]);
	344	q= &(ctx->bn[ctx->tos++]);
	345	qadd= &(ctx->bn[ctx->tos++]);
d02b48c6 RE	346
	347	if (!BN_rshift1(qadd,padd)) goto err;
	348
	349	if (!BN_rand(q,bits,0,1)) goto err;
	350
	351	/* we need ((rnd-rem) % add) == 0 */
	352	if (!BN_mod(t1,q,qadd,ctx)) goto err;
	353	if (!BN_sub(q,q,t1)) goto err;
	354	if (rem == NULL)
	355	{ if (!BN_add_word(q,1)) goto err; }
	356	else
	357	{
	358	if (!BN_rshift1(t1,rem)) goto err;
	359	if (!BN_add(q,q,t1)) goto err;
	360	}
	361
	362	/* we now have a random number 'rand' to test. */
	363	if (!BN_lshift1(p,q)) goto err;
	364	if (!BN_add_word(p,1)) goto err;
	365
	366	loop: for (i=1; i<NUMPRIMES; i++)
	367	{
	368	/* check that p and q are prime */
	369	/* check that for p and q
	370	* gcd(p-1,primes) == 1 (except for 2) */
e14d4443 UM	371	if ( (BN_mod_word(p,(BN_ULONG)primes[i]) == 0) \|\|
e14d4443 UM	372	(BN_mod_word(q,(BN_ULONG)primes[i]) == 0))
d02b48c6 RE	373	{
	374	if (!BN_add(p,p,padd)) goto err;
	375	if (!BN_add(q,q,qadd)) goto err;
	376	goto loop;
	377	}
	378	}
	379	ret=1;
	380	err:
	381	ctx->tos-=3;
	382	return(ret);
	383	}
	384
58964a49	385	#if 0
6b691a5c	386	static int witness(BIGNUM a, BIGNUM n, BN_CTX *ctx)
58964a49 RE	387	{
	388	int k,i,nb,ret= -1;
	389	BIGNUM d,dd,*tmp;
	390	BIGNUM d1,d2,x,n1,*inv;
	391
dfeab068 RE	392	d1= &(ctx->bn[ctx->tos]);
	393	d2= &(ctx->bn[ctx->tos+1]);
	394	x= &(ctx->bn[ctx->tos+2]);
	395	n1= &(ctx->bn[ctx->tos+3]);
	396	inv=&(ctx->bn[ctx->tos+4]);
58964a49 RE	397	ctx->tos+=5;
	398
	399	d=d1;
	400	dd=d2;
	401	if (!BN_one(d)) goto err;
	402	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	403	k=BN_num_bits(n1);
	404
	405	/* i=BN_num_bits(n); */
	406	#ifdef RECP_MUL_MOD
	407	nb=BN_reciprocal(inv,n,ctx); /**/
	408	if (nb == -1) goto err;
	409	#endif
	410
	411	for (i=k-1; i>=0; i--)
	412	{
	413	if (BN_copy(x,d) == NULL) goto err;
	414	#ifndef RECP_MUL_MOD
	415	if (!BN_mod_mul(dd,d,d,n,ctx)) goto err;
	416	#else
	417	if (!BN_mod_mul_reciprocal(dd,d,d,n,inv,nb,ctx)) goto err;
	418	#endif
	419	if ( BN_is_one(dd) &&
	420	!BN_is_one(x) &&
	421	(BN_cmp(x,n1) != 0))
	422	{
	423	ret=1;
	424	goto err;
	425	}
	426	if (BN_is_bit_set(n1,i))
	427	{
	428	#ifndef RECP_MUL_MOD
	429	if (!BN_mod_mul(d,dd,a,n,ctx)) goto err;
	430	#else
	431	if (!BN_mod_mul_reciprocal(d,dd,a,n,inv,nb,ctx)) goto err;
	432	#endif
	433	}
	434	else
	435	{
	436	tmp=d;
	437	d=dd;
	438	dd=tmp;
	439	}
	440	}
	441	if (BN_is_one(d))
	442	i=0;
	443	else i=1;
	444	ret=i;
	445	err:
	446	ctx->tos-=5;
	447	return(ret);
	448	}
	449	#endif