[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
/* Parameter generation follows the original release of FIPS PUB 186,
 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
#define HASH    EVP_sha()
#else
/* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
 * FIPS PUB 180-1) */
#define HASH    EVP_sha1()
#endif 

#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */

#ifndef OPENSSL_NO_SHA

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include "dsa_locl.h"

int DSA_generate_parameters_ex(DSA *ret, int bits,
		const unsigned char *seed_in, int seed_len,
		int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
	{
	if(ret->meth->dsa_paramgen)
		return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
				counter_ret, h_ret, cb);
	else
		{
		const EVP_MD *evpmd;
		size_t qbits = bits >= 2048 ? 256 : 160;

		if (bits >= 2048)
			{
			qbits = 256;
			evpmd = EVP_sha256();
			}
		else
			{
			qbits = 160;
			evpmd = EVP_sha1();
			}

		return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
				seed_in, seed_len, counter_ret, h_ret, cb);
		}
	}

int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
	const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
	int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
	{
	int ok=0;
	unsigned char seed[SHA256_DIGEST_LENGTH];
	unsigned char md[SHA256_DIGEST_LENGTH];
	unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
	BIGNUM *r0,*W,*X,*c,*test;
	BIGNUM *g=NULL,*q=NULL,*p=NULL;
	BN_MONT_CTX *mont=NULL;
	int i, k,n=0,b,m=0, qsize = qbits >> 3;
	int counter=0;
	int r=0;
	BN_CTX *ctx=NULL;
	unsigned int h=2;

	if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
	    qsize != SHA256_DIGEST_LENGTH)
		/* invalid q size */
		return 0;

	if (evpmd == NULL)
		/* use SHA1 as default */
		evpmd = EVP_sha1();

	if (bits < 512)
		bits = 512;

	bits = (bits+63)/64*64;

	/* NB: seed_len == 0 is special case: copy generated seed to
 	 * seed_in if it is not NULL.
 	 */
	if (seed_len && (seed_len < (size_t)qsize))
		seed_in = NULL;		/* seed buffer too small -- ignore */
	if (seed_len > (size_t)qsize) 
		seed_len = qsize;	/* App. 2.2 of FIPS PUB 186 allows larger SEED,
					 * but our internal buffers are restricted to 160 bits*/
	if (seed_in != NULL)
		memcpy(seed, seed_in, seed_len);

	if ((ctx=BN_CTX_new()) == NULL)
		goto err;

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

	BN_CTX_start(ctx);
	r0 = BN_CTX_get(ctx);
	g = BN_CTX_get(ctx);
	W = BN_CTX_get(ctx);
	q = BN_CTX_get(ctx);
	X = BN_CTX_get(ctx);
	c = BN_CTX_get(ctx);
	p = BN_CTX_get(ctx);
	test = BN_CTX_get(ctx);

	if (!BN_lshift(test,BN_value_one(),bits-1))
		goto err;

	for (;;)
		{
		for (;;) /* find q */
			{
			int seed_is_random;

			/* step 1 */
			if(!BN_GENCB_call(cb, 0, m++))
				goto err;

			if (!seed_len)
				{
				RAND_pseudo_bytes(seed, qsize);
				seed_is_random = 1;
				}
			else
				{
				seed_is_random = 0;
				seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
				}
			memcpy(buf , seed, qsize);
			memcpy(buf2, seed, qsize);
			/* precompute "SEED + 1" for step 7: */
			for (i = qsize-1; i >= 0; i--)
				{
				buf[i]++;
				if (buf[i] != 0)
					break;
				}

			/* step 2 */
			if (!EVP_Digest(seed, qsize, md,   NULL, evpmd, NULL))
				goto err;
			if (!EVP_Digest(buf,  qsize, buf2, NULL, evpmd, NULL))
				goto err;
			for (i = 0; i < qsize; i++)
				md[i]^=buf2[i];

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

			/* step 4 */
			r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
					seed_is_random, cb);
			if (r > 0)
				break;
			if (r != 0)
				goto err;

			/* do a callback call */
			/* step 5 */
			}

		if(!BN_GENCB_call(cb, 2, 0)) goto err;
		if(!BN_GENCB_call(cb, 3, 0)) goto err;

		/* step 6 */
		counter=0;
		/* "offset = 2" */

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

		for (;;)
			{
			if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
				goto err;

			/* step 7 */
			BN_zero(W);
			/* now 'buf' contains "SEED + offset - 1" */
			for (k=0; k<=n; k++)
				{
				/* obtain "SEED + offset + k" by incrementing: */
				for (i = qsize-1; i >= 0; i--)
					{
					buf[i]++;
					if (buf[i] != 0)
						break;
					}

				if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
									NULL))
					goto err;

				/* step 8 */
				if (!BN_bin2bn(md, qsize, r0))
					goto err;
				if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
				if (!BN_add(W,W,r0)) goto err;
				}

			/* more of step 8 */
			if (!BN_mask_bits(W,bits-1)) goto err;
			if (!BN_copy(X,W)) goto err;
			if (!BN_add(X,X,test)) goto err;

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

			/* step 10 */
			if (BN_cmp(p,test) >= 0)
				{
				/* step 11 */
				r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
						ctx, 1, cb);
				if (r > 0)
						goto end; /* found it */
				if (r != 0)
					goto err;
				}

			/* step 13 */
			counter++;
			/* "offset = offset + n + 1" */

			/* step 14 */
			if (counter >= 4096) break;
			}
		}
end:
	if(!BN_GENCB_call(cb, 2, 1))
		goto err;

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

	if (!BN_set_word(test,h)) goto err;
	if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;

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

	if(!BN_GENCB_call(cb, 3, 1))
		goto err;

	ok=1;
err:
	if (ok)
		{
		if(ret->p) BN_free(ret->p);
		if(ret->q) BN_free(ret->q);
		if(ret->g) BN_free(ret->g);
		ret->p=BN_dup(p);
		ret->q=BN_dup(q);
		ret->g=BN_dup(g);
		if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
			{
			ok=0;
			goto err;
			}
		if (counter_ret != NULL) *counter_ret=counter;
		if (h_ret != NULL) *h_ret=h;
		}
	if(ctx)
		{
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
		}
	if (mont != NULL) BN_MONT_CTX_free(mont);
	return ok;
	}
#endif
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
a87030a1 BM	62	/* Parameter generation follows the original release of FIPS PUB 186,
a87030a1 BM	63	* Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
323f289c	64	#define HASH EVP_sha()
d02b48c6	65	#else
a87030a1 BM	66	/* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
	67	* also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
	68	* FIPS PUB 180-1) */
323f289c	69	#define HASH EVP_sha1()
d02b48c6 RE	70	#endif
d02b48c6 RE	71
751ff1d3 RL	72	#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
751ff1d3 RL	73
cf1b7d96	74	#ifndef OPENSSL_NO_SHA
a87030a1	75
d02b48c6	76	#include <stdio.h>
d02b48c6	77	#include "cryptlib.h"
323f289c	78	#include <openssl/evp.h>
ec577822	79	#include <openssl/bn.h>
ec577822	80	#include <openssl/rand.h>
dbad1690	81	#include <openssl/sha.h>
357d5de5	82	#include "dsa_locl.h"
0e4aa0d2	83
e9224c71	84	int DSA_generate_parameters_ex(DSA *ret, int bits,
1457619e	85	const unsigned char *seed_in, int seed_len,
e9224c71	86	int counter_ret, unsigned long h_ret, BN_GENCB *cb)
d02b48c6	87	{
0e4aa0d2 GT	88	if(ret->meth->dsa_paramgen)
	89	return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
	90	counter_ret, h_ret, cb);
357d5de5 NL	91	else
	92	{
	93	const EVP_MD *evpmd;
	94	size_t qbits = bits >= 2048 ? 256 : 160;
	95
	96	if (bits >= 2048)
	97	{
	98	qbits = 256;
	99	evpmd = EVP_sha256();
	100	}
	101	else
	102	{
	103	qbits = 160;
	104	evpmd = EVP_sha1();
	105	}
	106
	107	return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
	108	seed_in, seed_len, counter_ret, h_ret, cb);
	109	}
0e4aa0d2 GT	110	}
0e4aa0d2 GT	111
357d5de5	112	int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
1457619e	113	const EVP_MD evpmd, const unsigned char seed_in, size_t seed_len,
357d5de5	114	int counter_ret, unsigned long h_ret, BN_GENCB *cb)
0e4aa0d2	115	{
d02b48c6	116	int ok=0;
357d5de5 NL	117	unsigned char seed[SHA256_DIGEST_LENGTH];
	118	unsigned char md[SHA256_DIGEST_LENGTH];
	119	unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
d02b48c6 RE	120	BIGNUM r0,W,X,c,*test;
d02b48c6 RE	121	BIGNUM g=NULL,q=NULL,*p=NULL;
dfeab068	122	BN_MONT_CTX *mont=NULL;
ebb01b84	123	int i, k,n=0,b,m=0, qsize = qbits >> 3;
d02b48c6	124	int counter=0;
a87030a1	125	int r=0;
08e1cbc6	126	BN_CTX *ctx=NULL;
d02b48c6	127	unsigned int h=2;
d02b48c6	128
357d5de5 NL	129	if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
	130	qsize != SHA256_DIGEST_LENGTH)
	131	/* invalid q size */
	132	return 0;
d02b48c6	133
357d5de5 NL	134	if (evpmd == NULL)
	135	/* use SHA1 as default */
	136	evpmd = EVP_sha1();
d02b48c6	137
357d5de5 NL	138	if (bits < 512)
357d5de5 NL	139	bits = 512;
dfeab068	140
357d5de5 NL	141	bits = (bits+63)/64*64;
357d5de5 NL	142
fcd1cb66 DSH	143	/* NB: seed_len == 0 is special case: copy generated seed to
	144	* seed_in if it is not NULL.
	145	*/
	146	if (seed_len && (seed_len < (size_t)qsize))
357d5de5	147	seed_in = NULL; /* seed buffer too small -- ignore */
3627fedb	148	if (seed_len > (size_t)qsize)
357d5de5 NL	149	seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
	150	* but our internal buffers are restricted to 160 bits*/
	151	if (seed_in != NULL)
	152	memcpy(seed, seed_in, seed_len);
	153
	154	if ((ctx=BN_CTX_new()) == NULL)
	155	goto err;
	156
	157	if ((mont=BN_MONT_CTX_new()) == NULL)
	158	goto err;
dfeab068	159
08e1cbc6 GT	160	BN_CTX_start(ctx);
	161	r0 = BN_CTX_get(ctx);
	162	g = BN_CTX_get(ctx);
	163	W = BN_CTX_get(ctx);
	164	q = BN_CTX_get(ctx);
	165	X = BN_CTX_get(ctx);
	166	c = BN_CTX_get(ctx);
	167	p = BN_CTX_get(ctx);
	168	test = BN_CTX_get(ctx);
d02b48c6	169
41c70d47 DSH	170	if (!BN_lshift(test,BN_value_one(),bits-1))
41c70d47 DSH	171	goto err;
d02b48c6 RE	172
	173	for (;;)
	174	{
a87030a1	175	for (;;) /* find q */
d02b48c6	176	{
7865b871	177	int seed_is_random;
a87030a1	178
d02b48c6	179	/* step 1 */
e9224c71 GT	180	if(!BN_GENCB_call(cb, 0, m++))
e9224c71 GT	181	goto err;
d02b48c6 RE	182
d02b48c6 RE	183	if (!seed_len)
a87030a1	184	{
357d5de5	185	RAND_pseudo_bytes(seed, qsize);
a87030a1 BM	186	seed_is_random = 1;
a87030a1 BM	187	}
d02b48c6	188	else
7865b871 BM	189	{
	190	seed_is_random = 0;
	191	seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
	192	}
357d5de5 NL	193	memcpy(buf , seed, qsize);
357d5de5 NL	194	memcpy(buf2, seed, qsize);
a87030a1	195	/* precompute "SEED + 1" for step 7: */
357d5de5	196	for (i = qsize-1; i >= 0; i--)
d02b48c6 RE	197	{
d02b48c6 RE	198	buf[i]++;
357d5de5 NL	199	if (buf[i] != 0)
357d5de5 NL	200	break;
d02b48c6 RE	201	}
	202
	203	/* step 2 */
b6dcdbfc DSH	204	if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
	205	goto err;
	206	if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
	207	goto err;
357d5de5	208	for (i = 0; i < qsize; i++)
d02b48c6 RE	209	md[i]^=buf2[i];
	210
	211	/* step 3 */
357d5de5 NL	212	md[0] \|= 0x80;
	213	md[qsize-1] \|= 0x01;
	214	if (!BN_bin2bn(md, qsize, q))
	215	goto err;
d02b48c6 RE	216
d02b48c6 RE	217	/* step 4 */
08e1cbc6	218	r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
e9224c71	219	seed_is_random, cb);
a87030a1	220	if (r > 0)
aff0825c	221	break;
a87030a1	222	if (r != 0)
aff0825c	223	goto err;
a87030a1	224
d02b48c6 RE	225	/* do a callback call */
	226	/* step 5 */
	227	}
	228
e9224c71 GT	229	if(!BN_GENCB_call(cb, 2, 0)) goto err;
e9224c71 GT	230	if(!BN_GENCB_call(cb, 3, 0)) goto err;
d02b48c6 RE	231
	232	/* step 6 */
	233	counter=0;
a87030a1	234	/* "offset = 2" */
d02b48c6 RE	235
	236	n=(bits-1)/160;
	237	b=(bits-1)-n*160;
	238
	239	for (;;)
	240	{
e9224c71 GT	241	if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
e9224c71 GT	242	goto err;
a87030a1	243
d02b48c6	244	/* step 7 */
c01d2b97	245	BN_zero(W);
a87030a1	246	/* now 'buf' contains "SEED + offset - 1" */
d02b48c6 RE	247	for (k=0; k<=n; k++)
d02b48c6 RE	248	{
a87030a1	249	/* obtain "SEED + offset + k" by incrementing: */
357d5de5	250	for (i = qsize-1; i >= 0; i--)
d02b48c6 RE	251	{
d02b48c6 RE	252	buf[i]++;
357d5de5 NL	253	if (buf[i] != 0)
357d5de5 NL	254	break;
d02b48c6 RE	255	}
d02b48c6 RE	256
b6dcdbfc DSH	257	if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
	258	NULL))
	259	goto err;
d02b48c6 RE	260
d02b48c6 RE	261	/* step 8 */
357d5de5	262	if (!BN_bin2bn(md, qsize, r0))
38e33cef	263	goto err;
357d5de5	264	if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
41c70d47	265	if (!BN_add(W,W,r0)) goto err;
d02b48c6 RE	266	}
	267
	268	/* more of step 8 */
41c70d47 DSH	269	if (!BN_mask_bits(W,bits-1)) goto err;
	270	if (!BN_copy(X,W)) goto err;
	271	if (!BN_add(X,X,test)) goto err;
d02b48c6 RE	272
d02b48c6 RE	273	/* step 9 */
41c70d47 DSH	274	if (!BN_lshift1(r0,q)) goto err;
	275	if (!BN_mod(c,X,r0,ctx)) goto err;
	276	if (!BN_sub(r0,c,BN_value_one())) goto err;
	277	if (!BN_sub(p,X,r0)) goto err;
d02b48c6 RE	278
	279	/* step 10 */
	280	if (BN_cmp(p,test) >= 0)
	281	{
	282	/* step 11 */
e9224c71	283	r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
08e1cbc6	284	ctx, 1, cb);
a87030a1 BM	285	if (r > 0)
	286	goto end; /* found it */
	287	if (r != 0)
	288	goto err;
d02b48c6 RE	289	}
	290
	291	/* step 13 */
	292	counter++;
a87030a1	293	/* "offset = offset + n + 1" */
d02b48c6 RE	294
	295	/* step 14 */
	296	if (counter >= 4096) break;
d02b48c6 RE	297	}
	298	}
	299	end:
e9224c71 GT	300	if(!BN_GENCB_call(cb, 2, 1))
e9224c71 GT	301	goto err;
d02b48c6	302
38e33cef	303	/* We now need to generate g */
d02b48c6	304	/* Set r0=(p-1)/q */
41c70d47 DSH	305	if (!BN_sub(test,p,BN_value_one())) goto err;
41c70d47 DSH	306	if (!BN_div(r0,NULL,test,q,ctx)) goto err;
d02b48c6	307
41c70d47 DSH	308	if (!BN_set_word(test,h)) goto err;
41c70d47 DSH	309	if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
dfeab068	310
d02b48c6 RE	311	for (;;)
	312	{
	313	/* g=test^r0%p */
41c70d47	314	if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
d02b48c6	315	if (!BN_is_one(g)) break;
41c70d47	316	if (!BN_add(test,test,BN_value_one())) goto err;
d02b48c6 RE	317	h++;
	318	}
	319
e9224c71 GT	320	if(!BN_GENCB_call(cb, 3, 1))
e9224c71 GT	321	goto err;
d02b48c6 RE	322
	323	ok=1;
	324	err:
e9224c71	325	if (ok)
d02b48c6	326	{
e9224c71 GT	327	if(ret->p) BN_free(ret->p);
	328	if(ret->q) BN_free(ret->q);
	329	if(ret->g) BN_free(ret->g);
d02b48c6 RE	330	ret->p=BN_dup(p);
	331	ret->q=BN_dup(q);
	332	ret->g=BN_dup(g);
41c70d47 DSH	333	if (ret->p == NULL \|\| ret->q == NULL \|\| ret->g == NULL)
	334	{
	335	ok=0;
	336	goto err;
	337	}
d02b48c6 RE	338	if (counter_ret != NULL) *counter_ret=counter;
	339	if (h_ret != NULL) *h_ret=h;
	340	}
08e1cbc6	341	if(ctx)
9b141126	342	{
08e1cbc6 GT	343	BN_CTX_end(ctx);
08e1cbc6 GT	344	BN_CTX_free(ctx);
9b141126	345	}
dfeab068	346	if (mont != NULL) BN_MONT_CTX_free(mont);
e9224c71	347	return ok;
d02b48c6	348	}
d02f751c	349	#endif