[thirdparty/openssl.git] / crypto / dsa / dsa_gen.c

/* crypto/dsa/dsa_gen.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.]
 */

#undef GENUINE_DSA

#ifdef GENUINE_DSA
#define HASH    SHA
#else
#define HASH    SHA1
#endif 

#include <stdio.h>
#include <time.h>
#include "cryptlib.h"
#include "sha.h"
#include "bn.h"
#include "dsa.h"
#include "rand.h"

DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
	     int *counter_ret, unsigned long *h_ret, void (*callback)(),
	     char *cb_arg)
	{
	int ok=0;
	unsigned char seed[SHA_DIGEST_LENGTH];
	unsigned char md[SHA_DIGEST_LENGTH];
	unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
	BIGNUM *r0,*W,*X,*c,*test;
	BIGNUM *g=NULL,*q=NULL,*p=NULL;
	BN_MONT_CTX *mont=NULL;
	int k,n=0,i,b,m=0;
	int counter=0;
	BN_CTX *ctx=NULL,*ctx2=NULL;
	unsigned int h=2;
	DSA *ret=NULL;

	if (bits < 512) bits=512;
	bits=(bits+63)/64*64;

	if ((seed_in != NULL) && (seed_len == 20))
		memcpy(seed,seed_in,seed_len);

	if ((ctx=BN_CTX_new()) == NULL) goto err;
	if ((ctx2=BN_CTX_new()) == NULL) goto err;
	if ((ret=DSA_new()) == NULL) goto err;

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

	r0= &(ctx2->bn[0]);
	g= &(ctx2->bn[1]);
	W= &(ctx2->bn[2]);
	q= &(ctx2->bn[3]);
	X= &(ctx2->bn[4]);
	c= &(ctx2->bn[5]);
	p= &(ctx2->bn[6]);
	test= &(ctx2->bn[7]);

	BN_lshift(test,BN_value_one(),bits-1);

	for (;;)
		{
		for (;;)
			{
			/* step 1 */
			if (callback != NULL) callback(0,m++,cb_arg);

			if (!seed_len)
				RAND_bytes(seed,SHA_DIGEST_LENGTH);
			else
				seed_len=0;

			memcpy(buf,seed,SHA_DIGEST_LENGTH);
			memcpy(buf2,seed,SHA_DIGEST_LENGTH);
			for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
				{
				buf[i]++;
				if (buf[i] != 0) break;
				}

			/* step 2 */
			HASH(seed,SHA_DIGEST_LENGTH,md);
			HASH(buf,SHA_DIGEST_LENGTH,buf2);
			for (i=0; i<SHA_DIGEST_LENGTH; i++)
				md[i]^=buf2[i];

			/* step 3 */
			md[0]|=0x80;
			md[SHA_DIGEST_LENGTH-1]|=0x01;
			if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort();

			/* step 4 */
			if (DSA_is_prime(q,callback,cb_arg) > 0) break;
			/* do a callback call */
			/* step 5 */
			}

		if (callback != NULL) callback(2,0,cb_arg);
		if (callback != NULL) callback(3,0,cb_arg);

		/* step 6 */
		counter=0;

		n=(bits-1)/160;
		b=(bits-1)-n*160;

		for (;;)
			{
			/* step 7 */
			BN_zero(W);
			for (k=0; k<=n; k++)
				{
				for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
					{
					buf[i]++;
					if (buf[i] != 0) break;
					}

				HASH(buf,SHA_DIGEST_LENGTH,md);

				/* step 8 */
				if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
				BN_lshift(r0,r0,160*k);
				BN_add(W,W,r0);
				}

			/* more of step 8 */
			BN_mask_bits(W,bits-1);
			BN_copy(X,W); /* this should be ok */
			BN_add(X,X,test); /* this should be ok */

			/* step 9 */
			BN_lshift1(r0,q);
			BN_mod(c,X,r0,ctx);
			BN_sub(r0,c,BN_value_one());
			BN_sub(p,X,r0);

			/* step 10 */
			if (BN_cmp(p,test) >= 0)
				{
				/* step 11 */
				if (DSA_is_prime(p,callback,cb_arg) > 0)
					goto end;
				}

			/* step 13 */
			counter++;

			/* step 14 */
			if (counter >= 4096) break;

			if (callback != NULL) callback(0,counter,cb_arg);
			}
		}
end:
	if (callback != NULL) callback(2,1,cb_arg);

	/* We now need to gernerate g */
	/* Set r0=(p-1)/q */
        BN_sub(test,p,BN_value_one());
        BN_div(r0,NULL,test,q,ctx);

	BN_set_word(test,h);
	BN_MONT_CTX_set(mont,p,ctx);

	for (;;)
		{
		/* g=test^r0%p */
		BN_mod_exp_mont(g,test,r0,p,ctx,mont);
		if (!BN_is_one(g)) break;
		BN_add(test,test,BN_value_one());
		h++;
		}

	if (callback != NULL) callback(3,1,cb_arg);

	ok=1;
err:
	if (!ok)
		{
		if (ret != NULL) DSA_free(ret);
		}
	else
		{
		ret->p=BN_dup(p);
		ret->q=BN_dup(q);
		ret->g=BN_dup(g);
		if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
		if (counter_ret != NULL) *counter_ret=counter;
		if (h_ret != NULL) *h_ret=h;
		}
	if (ctx != NULL) BN_CTX_free(ctx);
	if (ctx != NULL) BN_CTX_free(ctx2);
	if (mont != NULL) BN_MONT_CTX_free(mont);
	return(ok?ret:NULL);
	}

int DSA_is_prime(BIGNUM *w, void (*callback)(), char *cb_arg)
	{
	int ok= -1,j,i,n;
	BN_CTX *ctx=NULL,*ctx2=NULL;
	BIGNUM *w_1,*b,*m,*z,*tmp,*mont_1;
	int a;
	BN_MONT_CTX *mont=NULL;

	if (!BN_is_bit_set(w,0)) return(0);

	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;

	m=   &(ctx2->bn[2]);
	b=   &(ctx2->bn[3]);
	z=   &(ctx2->bn[4]);
	w_1= &(ctx2->bn[5]);
	tmp= &(ctx2->bn[6]);
	mont_1= &(ctx2->bn[7]);

	/* step 1 */
	n=50;

	/* step 2 */
	if (!BN_sub(w_1,w,BN_value_one())) goto err;
	for (a=1; !BN_is_bit_set(w_1,a); a++)
		;
	if (!BN_rshift(m,w_1,a)) goto err;

	BN_MONT_CTX_set(mont,w,ctx);
	BN_to_montgomery(mont_1,BN_value_one(),mont,ctx);
	BN_to_montgomery(w_1,w_1,mont,ctx);
	for (i=1; i < n; i++)
		{
		/* step 3 */
		BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0);
		/* BN_set_word(b,0x10001L); */

		/* step 4 */
		j=0;
		if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err;

		if (!BN_to_montgomery(z,z,mont,ctx)) goto err;

		/* step 5 */
		for (;;)
			{
			if (((j == 0) && (BN_cmp(z,mont_1) == 0)) ||
				(BN_cmp(z,w_1) == 0))
				break;

			/* step 6 */
			if ((j > 0) && (BN_cmp(z,mont_1) == 0))
				{
				ok=0;
				goto err;
				}

			j++;
			if (j >= a)
				{
				ok=0;
				goto err;
				}

			if (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err;
			if (callback != NULL) callback(1,j,cb_arg);
			}
		}

	ok=1;
err:
	if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);
	BN_CTX_free(ctx);
	BN_CTX_free(ctx2);
	
	return(ok);
	}
Commit	Line	Data
d02b48c6	1	/* crypto/dsa/dsa_gen.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	#undef GENUINE_DSA
	60
	61	#ifdef GENUINE_DSA
	62	#define HASH SHA
	63	#else
	64	#define HASH SHA1
	65	#endif
	66
67	#include <stdio.h>
68	#include <time.h>
69	#include "cryptlib.h"
70	#include "sha.h"
71	#include "bn.h"
72	#include "dsa.h"
73	#include "rand.h"
74
6b691a5c UM	75	DSA DSA_generate_parameters(int bits, unsigned char seed_in, int seed_len,
	76	int counter_ret, unsigned long h_ret, void (*callback)(),
	77	char *cb_arg)
d02b48c6 RE	78	{
	79	int ok=0;
	80	unsigned char seed[SHA_DIGEST_LENGTH];
	81	unsigned char md[SHA_DIGEST_LENGTH];
	82	unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
	83	BIGNUM r0,W,X,c,*test;
	84	BIGNUM g=NULL,q=NULL,*p=NULL;
dfeab068	85	BN_MONT_CTX *mont=NULL;
d02b48c6 RE	86	int k,n=0,i,b,m=0;
	87	int counter=0;
	88	BN_CTX ctx=NULL,ctx2=NULL;
	89	unsigned int h=2;
	90	DSA *ret=NULL;
	91
	92	if (bits < 512) bits=512;
	93	bits=(bits+63)/64*64;
	94
	95	if ((seed_in != NULL) && (seed_len == 20))
	96	memcpy(seed,seed_in,seed_len);
	97
dfeab068 RE	98	if ((ctx=BN_CTX_new()) == NULL) goto err;
	99	if ((ctx2=BN_CTX_new()) == NULL) goto err;
	100	if ((ret=DSA_new()) == NULL) goto err;
	101
	102	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
	103
	104	r0= &(ctx2->bn[0]);
	105	g= &(ctx2->bn[1]);
	106	W= &(ctx2->bn[2]);
	107	q= &(ctx2->bn[3]);
	108	X= &(ctx2->bn[4]);
	109	c= &(ctx2->bn[5]);
	110	p= &(ctx2->bn[6]);
	111	test= &(ctx2->bn[7]);
d02b48c6 RE	112
	113	BN_lshift(test,BN_value_one(),bits-1);
	114
	115	for (;;)
	116	{
	117	for (;;)
	118	{
	119	/* step 1 */
58964a49	120	if (callback != NULL) callback(0,m++,cb_arg);
d02b48c6 RE	121
	122	if (!seed_len)
	123	RAND_bytes(seed,SHA_DIGEST_LENGTH);
	124	else
	125	seed_len=0;
	126
	127	memcpy(buf,seed,SHA_DIGEST_LENGTH);
	128	memcpy(buf2,seed,SHA_DIGEST_LENGTH);
	129	for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
	130	{
	131	buf[i]++;
	132	if (buf[i] != 0) break;
	133	}
	134
	135	/* step 2 */
	136	HASH(seed,SHA_DIGEST_LENGTH,md);
	137	HASH(buf,SHA_DIGEST_LENGTH,buf2);
	138	for (i=0; i<SHA_DIGEST_LENGTH; i++)
	139	md[i]^=buf2[i];
	140
	141	/* step 3 */
	142	md[0]\|=0x80;
	143	md[SHA_DIGEST_LENGTH-1]\|=0x01;
	144	if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort();
	145
	146	/* step 4 */
58964a49	147	if (DSA_is_prime(q,callback,cb_arg) > 0) break;
d02b48c6 RE	148	/* do a callback call */
	149	/* step 5 */
	150	}
	151
58964a49 RE	152	if (callback != NULL) callback(2,0,cb_arg);
58964a49 RE	153	if (callback != NULL) callback(3,0,cb_arg);
d02b48c6 RE	154
	155	/* step 6 */
	156	counter=0;
	157
	158	n=(bits-1)/160;
	159	b=(bits-1)-n*160;
	160
	161	for (;;)
	162	{
	163	/* step 7 */
	164	BN_zero(W);
	165	for (k=0; k<=n; k++)
	166	{
	167	for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
	168	{
	169	buf[i]++;
	170	if (buf[i] != 0) break;
	171	}
	172
	173	HASH(buf,SHA_DIGEST_LENGTH,md);
	174
	175	/* step 8 */
	176	if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
	177	BN_lshift(r0,r0,160*k);
	178	BN_add(W,W,r0);
	179	}
	180
	181	/* more of step 8 */
	182	BN_mask_bits(W,bits-1);
	183	BN_copy(X,W); /* this should be ok */
	184	BN_add(X,X,test); /* this should be ok */
	185
	186	/* step 9 */
	187	BN_lshift1(r0,q);
	188	BN_mod(c,X,r0,ctx);
	189	BN_sub(r0,c,BN_value_one());
	190	BN_sub(p,X,r0);
	191
	192	/* step 10 */
	193	if (BN_cmp(p,test) >= 0)
	194	{
	195	/* step 11 */
58964a49	196	if (DSA_is_prime(p,callback,cb_arg) > 0)
d02b48c6 RE	197	goto end;
	198	}
	199
	200	/* step 13 */
	201	counter++;
	202
	203	/* step 14 */
	204	if (counter >= 4096) break;
	205
58964a49	206	if (callback != NULL) callback(0,counter,cb_arg);
d02b48c6 RE	207	}
	208	}
	209	end:
58964a49	210	if (callback != NULL) callback(2,1,cb_arg);
d02b48c6 RE	211
	212	/* We now need to gernerate g */
	213	/* Set r0=(p-1)/q */
	214	BN_sub(test,p,BN_value_one());
	215	BN_div(r0,NULL,test,q,ctx);
	216
	217	BN_set_word(test,h);
dfeab068 RE	218	BN_MONT_CTX_set(mont,p,ctx);
dfeab068 RE	219
d02b48c6 RE	220	for (;;)
	221	{
	222	/* g=test^r0%p */
dfeab068	223	BN_mod_exp_mont(g,test,r0,p,ctx,mont);
d02b48c6 RE	224	if (!BN_is_one(g)) break;
	225	BN_add(test,test,BN_value_one());
	226	h++;
	227	}
	228
58964a49	229	if (callback != NULL) callback(3,1,cb_arg);
d02b48c6 RE	230
	231	ok=1;
	232	err:
	233	if (!ok)
	234	{
	235	if (ret != NULL) DSA_free(ret);
	236	}
	237	else
	238	{
	239	ret->p=BN_dup(p);
	240	ret->q=BN_dup(q);
	241	ret->g=BN_dup(g);
	242	if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
	243	if (counter_ret != NULL) *counter_ret=counter;
	244	if (h_ret != NULL) *h_ret=h;
	245	}
dfeab068 RE	246	if (ctx != NULL) BN_CTX_free(ctx);
	247	if (ctx != NULL) BN_CTX_free(ctx2);
	248	if (mont != NULL) BN_MONT_CTX_free(mont);
d02b48c6 RE	249	return(ok?ret:NULL);
	250	}
	251
6b691a5c	252	int DSA_is_prime(BIGNUM w, void (callback)(), char *cb_arg)
d02b48c6 RE	253	{
	254	int ok= -1,j,i,n;
	255	BN_CTX ctx=NULL,ctx2=NULL;
dfeab068	256	BIGNUM w_1,b,m,z,tmp,mont_1;
d02b48c6	257	int a;
dfeab068	258	BN_MONT_CTX *mont=NULL;
d02b48c6 RE	259
	260	if (!BN_is_bit_set(w,0)) return(0);
	261
dfeab068 RE	262	if ((ctx=BN_CTX_new()) == NULL) goto err;
	263	if ((ctx2=BN_CTX_new()) == NULL) goto err;
	264	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
d02b48c6	265
dfeab068 RE	266	m= &(ctx2->bn[2]);
	267	b= &(ctx2->bn[3]);
	268	z= &(ctx2->bn[4]);
	269	w_1= &(ctx2->bn[5]);
	270	tmp= &(ctx2->bn[6]);
	271	mont_1= &(ctx2->bn[7]);
d02b48c6 RE	272
	273	/* step 1 */
	274	n=50;
	275
	276	/* step 2 */
	277	if (!BN_sub(w_1,w,BN_value_one())) goto err;
	278	for (a=1; !BN_is_bit_set(w_1,a); a++)
	279	;
	280	if (!BN_rshift(m,w_1,a)) goto err;
	281
dfeab068 RE	282	BN_MONT_CTX_set(mont,w,ctx);
	283	BN_to_montgomery(mont_1,BN_value_one(),mont,ctx);
	284	BN_to_montgomery(w_1,w_1,mont,ctx);
d02b48c6 RE	285	for (i=1; i < n; i++)
	286	{
	287	/* step 3 */
	288	BN_rand(b,BN_num_bits(w)-2/-1/,0,0);
dfeab068	289	/* BN_set_word(b,0x10001L); */
d02b48c6 RE	290
	291	/* step 4 */
	292	j=0;
dfeab068 RE	293	if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err;
	294
	295	if (!BN_to_montgomery(z,z,mont,ctx)) goto err;
d02b48c6 RE	296
	297	/* step 5 */
	298	for (;;)
	299	{
dfeab068 RE	300	if (((j == 0) && (BN_cmp(z,mont_1) == 0)) \|\|
dfeab068 RE	301	(BN_cmp(z,w_1) == 0))
d02b48c6 RE	302	break;
	303
	304	/* step 6 */
dfeab068	305	if ((j > 0) && (BN_cmp(z,mont_1) == 0))
d02b48c6 RE	306	{
	307	ok=0;
	308	goto err;
	309	}
	310
	311	j++;
	312	if (j >= a)
	313	{
	314	ok=0;
	315	goto err;
	316	}
	317
dfeab068	318	if (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err;
58964a49	319	if (callback != NULL) callback(1,j,cb_arg);
d02b48c6 RE	320	}
	321	}
	322
	323	ok=1;
	324	err:
	325	if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);
	326	BN_CTX_free(ctx);
	327	BN_CTX_free(ctx2);
	328
	329	return(ok);
	330	}
	331