[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 sieve 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 found=0;
	int i,j,c1=0;
	BN_CTX *ctx,*ctx2=NULL;
	int checks = BN_prime_checks_for_size(bits);

	ctx=BN_CTX_new();
	if (ctx == NULL) goto err;
	ctx2=BN_CTX_new();
	if (ctx2 == 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_fasttest(rnd,checks,callback,ctx,ctx2,cb_arg,0);
		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_fasttest(rnd,1,callback,ctx,ctx2,cb_arg,0);
			if (j == -1) goto err;
			if (j == 0) goto loop;

			j=BN_is_prime_fasttest(&t,1,callback,ctx,ctx2,cb_arg,0);
			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 :-) */
	found = 1;
err:
	if (!found && (ret == NULL) && (rnd != NULL)) BN_free(rnd);
	BN_free(&t);
	if (ctx != NULL) BN_CTX_free(ctx);
	if (ctx2 != NULL) BN_CTX_free(ctx2);
	return(found ? rnd : NULL);
	}

int BN_is_prime_fasttest(BIGNUM *a, int checks,
		void (*callback)(int,int,void *),
		BN_CTX *ctx_passed, BN_CTX *ctx2_passed, void *cb_arg,
		int do_trial_division)
	{
	int i,j,ret= -1;
	BIGNUM *check;
	BN_CTX *ctx=NULL,*ctx2=NULL;
	BN_MONT_CTX *mont=NULL;

	if (checks == BN_prime_checks)
		{
		int bits = BN_num_bits(a);
		checks = BN_prime_checks_for_size(bits);
		}

	if (!BN_is_odd(a))
		return(0);
	if (do_trial_division)
		{
		for (i = 1; i < NUMPRIMES; i++)
			if (BN_mod_word(a, primes[i]) == 0) 
				return 0;
		if (callback != NULL) callback(1,-1,cb_arg);
		}

	if (ctx_passed != NULL)
		ctx=ctx_passed;
	else
		if ((ctx=BN_CTX_new()) == NULL) goto err;
	if (ctx2_passed != NULL)
		ctx2=ctx2_passed;
	else
		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_pseudo_rand(check,BN_num_bits(a),0,0)) goto err;
		if (BN_cmp(check, a) >= 0)
			BN_sub(check, check, a);
		if (BN_is_zero(check)) BN_one(check);
		j=witness(check,a,ctx,ctx2,mont);
		if (j == -1) goto err;
		if (j)
			{
			ret=0;
			goto err;
			}
		if (callback != NULL) callback(1,i,cb_arg);
		}
	ret=1;
err:
	ctx->tos--;
	if ((ctx_passed == NULL) && (ctx != NULL))
		BN_CTX_free(ctx);
	if ((ctx2_passed == NULL) && (ctx2 != NULL))
		BN_CTX_free(ctx2);
	if (mont != NULL) BN_MONT_CTX_free(mont);
		
	return(ret);
	}

int BN_is_prime(BIGNUM *a, int checks, void (*callback)(int,int,void *),
	BN_CTX *ctx_passed, void *cb_arg)
	{
	return BN_is_prime_fasttest(a, checks, callback, ctx_passed, NULL, cb_arg, 0);
	}

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;
	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

#define RECP_MUL_MOD

static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx,
		   BN_CTX *unused, BN_MONT_CTX *unused2)
	{
	int k,i,ret= -1;
	BIGNUM *d,*dd,*tmp;
	BIGNUM *d1,*d2,*x,*n1;
	BN_RECP_CTX recp;

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

	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
	BN_RECP_CTX_init(&recp);
	if (BN_RECP_CTX_set(&recp,n,ctx) <= 0) 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,&recp,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,&recp,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-=4;
#ifdef RECP_MUL_MOD
	BN_RECP_CTX_free(&recp);
#endif
	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	64
4486d0cd	65	/* The quick sieve algorithm approach to weeding out primes is
d02b48c6 RE	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;
4486d0cd	84	int found=0;
d02b48c6	85	int i,j,c1=0;
51ca375e	86	BN_CTX ctx,ctx2=NULL;
a87030a1	87	int checks = BN_prime_checks_for_size(bits);
d02b48c6 RE	88
	89	ctx=BN_CTX_new();
	90	if (ctx == NULL) goto err;
51ca375e UM	91	ctx2=BN_CTX_new();
51ca375e UM	92	if (ctx2 == NULL) goto err;
dfeab068 RE	93	if (ret == NULL)
	94	{
	95	if ((rnd=BN_new()) == NULL) goto err;
	96	}
	97	else
	98	rnd=ret;
	99	BN_init(&t);
d02b48c6 RE	100	loop:
	101	/* make a random number and set the top and bottom bits */
	102	if (add == NULL)
	103	{
	104	if (!probable_prime(rnd,bits)) goto err;
	105	}
	106	else
	107	{
76aa0ddc	108	if (safe)
d02b48c6	109	{
76aa0ddc	110	if (!probable_prime_dh_safe(rnd,bits,add,rem,ctx))
d02b48c6 RE	111	goto err;
	112	}
	113	else
	114	{
	115	if (!probable_prime_dh(rnd,bits,add,rem,ctx))
	116	goto err;
	117	}
	118	}
	119	/* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */
58964a49	120	if (callback != NULL) callback(0,c1++,cb_arg);
d02b48c6	121
76aa0ddc	122	if (!safe)
d02b48c6	123	{
51ca375e	124	i=BN_is_prime_fasttest(rnd,checks,callback,ctx,ctx2,cb_arg,0);
d02b48c6 RE	125	if (i == -1) goto err;
	126	if (i == 0) goto loop;
	127	}
	128	else
	129	{
76aa0ddc	130	/* for "safe prime" generation,
d02b48c6 RE	131	* check that (p-1)/2 is prime.
	132	* Since a prime is odd, We just
	133	* need to divide by 2 */
dfeab068	134	if (!BN_rshift1(&t,rnd)) goto err;
d02b48c6	135
76aa0ddc	136	for (i=0; i<checks; i++)
d02b48c6	137	{
51ca375e	138	j=BN_is_prime_fasttest(rnd,1,callback,ctx,ctx2,cb_arg,0);
d02b48c6 RE	139	if (j == -1) goto err;
	140	if (j == 0) goto loop;
	141
51ca375e	142	j=BN_is_prime_fasttest(&t,1,callback,ctx,ctx2,cb_arg,0);
d02b48c6 RE	143	if (j == -1) goto err;
	144	if (j == 0) goto loop;
	145
58964a49	146	if (callback != NULL) callback(2,c1-1,cb_arg);
76aa0ddc	147	/* We have a safe prime test pass */
d02b48c6 RE	148	}
	149	}
	150	/* we have a prime :-) */
4486d0cd	151	found = 1;
d02b48c6	152	err:
4486d0cd	153	if (!found && (ret == NULL) && (rnd != NULL)) BN_free(rnd);
dfeab068	154	BN_free(&t);
d02b48c6	155	if (ctx != NULL) BN_CTX_free(ctx);
51ca375e	156	if (ctx2 != NULL) BN_CTX_free(ctx2);
4486d0cd	157	return(found ? rnd : NULL);
d02b48c6 RE	158	}
d02b48c6 RE	159
a87030a1 BM	160	int BN_is_prime_fasttest(BIGNUM *a, int checks,
	161	void (callback)(int,int,void ),
	162	BN_CTX ctx_passed, BN_CTX ctx2_passed, void *cb_arg,
	163	int do_trial_division)
d02b48c6	164	{
a87030a1	165	int i,j,ret= -1;
d02b48c6	166	BIGNUM *check;
58964a49 RE	167	BN_CTX ctx=NULL,ctx2=NULL;
58964a49 RE	168	BN_MONT_CTX *mont=NULL;
d02b48c6	169
4486d0cd UM	170	if (checks == BN_prime_checks)
	171	{
	172	int bits = BN_num_bits(a);
a87030a1	173	checks = BN_prime_checks_for_size(bits);
4486d0cd UM	174	}
4486d0cd UM	175
58964a49 RE	176	if (!BN_is_odd(a))
58964a49 RE	177	return(0);
a87030a1	178	if (do_trial_division)
1baa9490	179	{
a87030a1 BM	180	for (i = 1; i < NUMPRIMES; i++)
	181	if (BN_mod_word(a, primes[i]) == 0)
	182	return 0;
1baa9490 BM	183	if (callback != NULL) callback(1,-1,cb_arg);
1baa9490 BM	184	}
a87030a1	185
d02b48c6 RE	186	if (ctx_passed != NULL)
	187	ctx=ctx_passed;
	188	else
	189	if ((ctx=BN_CTX_new()) == NULL) goto err;
a87030a1 BM	190	if (ctx2_passed != NULL)
	191	ctx2=ctx2_passed;
	192	else
	193	if ((ctx2=BN_CTX_new()) == NULL) goto err;
d02b48c6	194
58964a49 RE	195	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
58964a49 RE	196
dfeab068	197	check= &(ctx->bn[ctx->tos++]);
58964a49 RE	198
	199	/* Setup the montgomery structure */
	200	if (!BN_MONT_CTX_set(mont,a,ctx2)) goto err;
	201
d02b48c6 RE	202	for (i=0; i<checks; i++)
d02b48c6 RE	203	{
a87030a1 BM	204	if (!BN_pseudo_rand(check,BN_num_bits(a),0,0)) goto err;
	205	if (BN_cmp(check, a) >= 0)
	206	BN_sub(check, check, a);
1399f17a	207	if (BN_is_zero(check)) BN_one(check);
58964a49	208	j=witness(check,a,ctx,ctx2,mont);
d02b48c6 RE	209	if (j == -1) goto err;
	210	if (j)
	211	{
	212	ret=0;
	213	goto err;
	214	}
a87030a1	215	if (callback != NULL) callback(1,i,cb_arg);
d02b48c6 RE	216	}
	217	ret=1;
	218	err:
	219	ctx->tos--;
	220	if ((ctx_passed == NULL) && (ctx != NULL))
	221	BN_CTX_free(ctx);
a87030a1	222	if ((ctx2_passed == NULL) && (ctx2 != NULL))
58964a49 RE	223	BN_CTX_free(ctx2);
58964a49 RE	224	if (mont != NULL) BN_MONT_CTX_free(mont);
d02b48c6 RE	225
	226	return(ret);
	227	}
	228
a87030a1 BM	229	int BN_is_prime(BIGNUM a, int checks, void (callback)(int,int,void *),
	230	BN_CTX ctx_passed, void cb_arg)
	231	{
	232	return BN_is_prime_fasttest(a, checks, callback, ctx_passed, NULL, cb_arg, 0);
	233	}
	234
6b691a5c UM	235	static int witness(BIGNUM a, BIGNUM n, BN_CTX ctx, BN_CTX ctx2,
6b691a5c UM	236	BN_MONT_CTX *mont)
d02b48c6	237	{
58964a49 RE	238	int k,i,ret= -1,good;
	239	BIGNUM d,dd,tmp,d1,d2,n1;
	240	BIGNUM mont_one,mont_n1,*mont_a;
d02b48c6	241
dfeab068 RE	242	d1= &(ctx->bn[ctx->tos]);
	243	d2= &(ctx->bn[ctx->tos+1]);
	244	n1= &(ctx->bn[ctx->tos+2]);
58964a49 RE	245	ctx->tos+=3;
58964a49 RE	246
dfeab068 RE	247	mont_one= &(ctx2->bn[ctx2->tos]);
	248	mont_n1= &(ctx2->bn[ctx2->tos+1]);
	249	mont_a= &(ctx2->bn[ctx2->tos+2]);
58964a49	250	ctx2->tos+=3;
d02b48c6 RE	251
	252	d=d1;
	253	dd=d2;
	254	if (!BN_one(d)) goto err;
	255	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	256	k=BN_num_bits(n1);
	257
58964a49 RE	258	if (!BN_to_montgomery(mont_one,BN_value_one(),mont,ctx2)) goto err;
	259	if (!BN_to_montgomery(mont_n1,n1,mont,ctx2)) goto err;
	260	if (!BN_to_montgomery(mont_a,a,mont,ctx2)) goto err;
d02b48c6	261
58964a49	262	BN_copy(d,mont_one);
d02b48c6 RE	263	for (i=k-1; i>=0; i--)
d02b48c6 RE	264	{
58964a49 RE	265	if ( (BN_cmp(d,mont_one) != 0) &&
	266	(BN_cmp(d,mont_n1) != 0))
	267	good=1;
	268	else
	269	good=0;
	270
	271	BN_mod_mul_montgomery(dd,d,d,mont,ctx2);
4f9b306c	272
58964a49	273	if (good && (BN_cmp(dd,mont_one) == 0))
d02b48c6 RE	274	{
	275	ret=1;
	276	goto err;
	277	}
	278	if (BN_is_bit_set(n1,i))
	279	{
58964a49	280	BN_mod_mul_montgomery(d,dd,mont_a,mont,ctx2);
d02b48c6 RE	281	}
	282	else
	283	{
	284	tmp=d;
	285	d=dd;
	286	dd=tmp;
	287	}
	288	}
58964a49	289	if (BN_cmp(d,mont_one) == 0)
d02b48c6 RE	290	i=0;
	291	else i=1;
	292	ret=i;
	293	err:
58964a49 RE	294	ctx->tos-=3;
58964a49 RE	295	ctx2->tos-=3;
d02b48c6 RE	296	return(ret);
	297	}
	298
6b691a5c	299	static int probable_prime(BIGNUM *rnd, int bits)
d02b48c6 RE	300	{
d02b48c6 RE	301	int i;
a87030a1	302	BN_ULONG mods[NUMPRIMES];
dfeab068	303	BN_ULONG delta,d;
d02b48c6	304
dfeab068	305	again:
d02b48c6 RE	306	if (!BN_rand(rnd,bits,1,1)) return(0);
	307	/* we now have a random number 'rand' to test. */
	308	for (i=1; i<NUMPRIMES; i++)
	309	mods[i]=BN_mod_word(rnd,(BN_ULONG)primes[i]);
	310	delta=0;
	311	loop: for (i=1; i<NUMPRIMES; i++)
	312	{
	313	/* check that rnd is not a prime and also
	314	* that gcd(rnd-1,primes) == 1 (except for 2) */
	315	if (((mods[i]+delta)%primes[i]) <= 1)
	316	{
dfeab068	317	d=delta;
d02b48c6 RE	318	delta+=2;
d02b48c6 RE	319	/* perhaps need to check for overflow of
dfeab068 RE	320	* delta (but delta can be upto 2^32)
	321	* 21-May-98 eay - added overflow check */
	322	if (delta < d) goto again;
d02b48c6 RE	323	goto loop;
	324	}
	325	}
	326	if (!BN_add_word(rnd,delta)) return(0);
	327	return(1);
	328	}
	329
6b691a5c UM	330	static int probable_prime_dh(BIGNUM rnd, int bits, BIGNUM add, BIGNUM *rem,
6b691a5c UM	331	BN_CTX *ctx)
d02b48c6 RE	332	{
	333	int i,ret=0;
	334	BIGNUM *t1;
	335
dfeab068	336	t1= &(ctx->bn[ctx->tos++]);
d02b48c6 RE	337
	338	if (!BN_rand(rnd,bits,0,1)) goto err;
	339
	340	/* we need ((rnd-rem) % add) == 0 */
	341
	342	if (!BN_mod(t1,rnd,add,ctx)) goto err;
	343	if (!BN_sub(rnd,rnd,t1)) goto err;
	344	if (rem == NULL)
	345	{ if (!BN_add_word(rnd,1)) goto err; }
	346	else
	347	{ if (!BN_add(rnd,rnd,rem)) goto err; }
	348
	349	/* we now have a random number 'rand' to test. */
	350
	351	loop: for (i=1; i<NUMPRIMES; i++)
	352	{
	353	/* check that rnd is a prime */
e14d4443	354	if (BN_mod_word(rnd,(BN_ULONG)primes[i]) <= 1)
d02b48c6 RE	355	{
	356	if (!BN_add(rnd,rnd,add)) goto err;
	357	goto loop;
	358	}
	359	}
	360	ret=1;
	361	err:
	362	ctx->tos--;
	363	return(ret);
	364	}
	365
76aa0ddc	366	static int probable_prime_dh_safe(BIGNUM p, int bits, BIGNUM padd,
6b691a5c	367	BIGNUM rem, BN_CTX ctx)
d02b48c6 RE	368	{
	369	int i,ret=0;
	370	BIGNUM t1,qadd=NULL,*q=NULL;
	371
	372	bits--;
dfeab068 RE	373	t1= &(ctx->bn[ctx->tos++]);
	374	q= &(ctx->bn[ctx->tos++]);
	375	qadd= &(ctx->bn[ctx->tos++]);
d02b48c6 RE	376
	377	if (!BN_rshift1(qadd,padd)) goto err;
	378
	379	if (!BN_rand(q,bits,0,1)) goto err;
	380
	381	/* we need ((rnd-rem) % add) == 0 */
	382	if (!BN_mod(t1,q,qadd,ctx)) goto err;
	383	if (!BN_sub(q,q,t1)) goto err;
	384	if (rem == NULL)
	385	{ if (!BN_add_word(q,1)) goto err; }
	386	else
	387	{
	388	if (!BN_rshift1(t1,rem)) goto err;
	389	if (!BN_add(q,q,t1)) goto err;
	390	}
	391
	392	/* we now have a random number 'rand' to test. */
	393	if (!BN_lshift1(p,q)) goto err;
	394	if (!BN_add_word(p,1)) goto err;
	395
	396	loop: for (i=1; i<NUMPRIMES; i++)
	397	{
	398	/* check that p and q are prime */
	399	/* check that for p and q
	400	* gcd(p-1,primes) == 1 (except for 2) */
e14d4443 UM	401	if ( (BN_mod_word(p,(BN_ULONG)primes[i]) == 0) \|\|
e14d4443 UM	402	(BN_mod_word(q,(BN_ULONG)primes[i]) == 0))
d02b48c6 RE	403	{
	404	if (!BN_add(p,p,padd)) goto err;
	405	if (!BN_add(q,q,qadd)) goto err;
	406	goto loop;
	407	}
	408	}
	409	ret=1;
	410	err:
	411	ctx->tos-=3;
	412	return(ret);
	413	}
	414
58964a49	415	#if 0
dd8dec69 UM	416
	417	#define RECP_MUL_MOD
	418
	419	static int witness(BIGNUM a, BIGNUM n, BN_CTX *ctx,
	420	BN_CTX unused, BN_MONT_CTX unused2)
58964a49	421	{
dd8dec69	422	int k,i,ret= -1;
58964a49	423	BIGNUM d,dd,*tmp;
dd8dec69 UM	424	BIGNUM d1,d2,x,n1;
dd8dec69 UM	425	BN_RECP_CTX recp;
58964a49	426
dfeab068 RE	427	d1= &(ctx->bn[ctx->tos]);
	428	d2= &(ctx->bn[ctx->tos+1]);
	429	x= &(ctx->bn[ctx->tos+2]);
	430	n1= &(ctx->bn[ctx->tos+3]);
dd8dec69	431	ctx->tos+=4;
58964a49 RE	432
	433	d=d1;
	434	dd=d2;
	435	if (!BN_one(d)) goto err;
	436	if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */
	437	k=BN_num_bits(n1);
	438
	439	/* i=BN_num_bits(n); */
	440	#ifdef RECP_MUL_MOD
dd8dec69 UM	441	BN_RECP_CTX_init(&recp);
dd8dec69 UM	442	if (BN_RECP_CTX_set(&recp,n,ctx) <= 0) goto err;
58964a49 RE	443	#endif
	444
	445	for (i=k-1; i>=0; i--)
	446	{
	447	if (BN_copy(x,d) == NULL) goto err;
	448	#ifndef RECP_MUL_MOD
	449	if (!BN_mod_mul(dd,d,d,n,ctx)) goto err;
	450	#else
dd8dec69	451	if (!BN_mod_mul_reciprocal(dd,d,d,&recp,ctx)) goto err;
58964a49 RE	452	#endif
	453	if ( BN_is_one(dd) &&
	454	!BN_is_one(x) &&
	455	(BN_cmp(x,n1) != 0))
	456	{
	457	ret=1;
	458	goto err;
	459	}
	460	if (BN_is_bit_set(n1,i))
	461	{
	462	#ifndef RECP_MUL_MOD
	463	if (!BN_mod_mul(d,dd,a,n,ctx)) goto err;
	464	#else
dd8dec69	465	if (!BN_mod_mul_reciprocal(d,dd,a,&recp,ctx)) goto err;
58964a49 RE	466	#endif
	467	}
	468	else
	469	{
	470	tmp=d;
	471	d=dd;
	472	dd=tmp;
	473	}
	474	}
	475	if (BN_is_one(d))
	476	i=0;
	477	else i=1;
	478	ret=i;
	479	err:
dd8dec69 UM	480	ctx->tos-=4;
	481	#ifdef RECP_MUL_MOD
	482	BN_RECP_CTX_free(&recp);
	483	#endif
58964a49 RE	484	return(ret);
	485	}
	486	#endif