315 lines
8.9 KiB
C
315 lines
8.9 KiB
C
/* crypto/dsa/dsa_gen.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#undef GENUINE_DSA
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#ifdef GENUINE_DSA
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/* Parameter generation follows the original release of FIPS PUB 186,
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* Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
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#define HASH EVP_sha()
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#else
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/* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
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* also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
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* FIPS PUB 180-1) */
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#define HASH EVP_sha1()
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#endif
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#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
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#ifndef OPENSSL_NO_SHA
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#include <stdio.h>
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#include <time.h>
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#include "cryptlib.h"
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#include <openssl/evp.h>
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#include <openssl/bn.h>
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#include <openssl/dsa.h>
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#include <openssl/rand.h>
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#include <openssl/sha.h>
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static int dsa_builtin_paramgen(DSA *ret, int bits,
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unsigned char *seed_in, int seed_len,
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
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int DSA_generate_parameters_ex(DSA *ret, int bits,
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unsigned char *seed_in, int seed_len,
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
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{
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if(ret->meth->dsa_paramgen)
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return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
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counter_ret, h_ret, cb);
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return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
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counter_ret, h_ret, cb);
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}
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static int dsa_builtin_paramgen(DSA *ret, int bits,
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unsigned char *seed_in, int seed_len,
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
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{
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int ok=0;
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unsigned char seed[SHA_DIGEST_LENGTH];
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unsigned char md[SHA_DIGEST_LENGTH];
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unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
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BIGNUM *r0,*W,*X,*c,*test;
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BIGNUM *g=NULL,*q=NULL,*p=NULL;
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BN_MONT_CTX *mont=NULL;
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int k,n=0,i,b,m=0;
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int counter=0;
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int r=0;
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BN_CTX *ctx=NULL;
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unsigned int h=2;
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if (bits < 512) bits=512;
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bits=(bits+63)/64*64;
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if (seed_len < 20)
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seed_in = NULL; /* seed buffer too small -- ignore */
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if (seed_len > 20)
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seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
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* but our internal buffers are restricted to 160 bits*/
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if ((seed_in != NULL) && (seed_len == 20))
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memcpy(seed,seed_in,seed_len);
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if ((ctx=BN_CTX_new()) == NULL) goto err;
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if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
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BN_CTX_start(ctx);
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r0 = BN_CTX_get(ctx);
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g = BN_CTX_get(ctx);
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W = BN_CTX_get(ctx);
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q = BN_CTX_get(ctx);
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X = BN_CTX_get(ctx);
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c = BN_CTX_get(ctx);
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p = BN_CTX_get(ctx);
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test = BN_CTX_get(ctx);
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if (!BN_lshift(test,BN_value_one(),bits-1))
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goto err;
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for (;;)
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{
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for (;;) /* find q */
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{
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int seed_is_random;
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/* step 1 */
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if(!BN_GENCB_call(cb, 0, m++))
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goto err;
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if (!seed_len)
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{
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RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
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seed_is_random = 1;
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}
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else
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{
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seed_is_random = 0;
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seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
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}
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memcpy(buf,seed,SHA_DIGEST_LENGTH);
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memcpy(buf2,seed,SHA_DIGEST_LENGTH);
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/* precompute "SEED + 1" for step 7: */
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for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
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{
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buf[i]++;
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if (buf[i] != 0) break;
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}
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/* step 2 */
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EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
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EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
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for (i=0; i<SHA_DIGEST_LENGTH; i++)
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md[i]^=buf2[i];
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/* step 3 */
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md[0]|=0x80;
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md[SHA_DIGEST_LENGTH-1]|=0x01;
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if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
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/* step 4 */
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r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
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seed_is_random, cb);
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if (r > 0)
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break;
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if (r != 0)
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goto err;
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/* do a callback call */
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/* step 5 */
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}
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if(!BN_GENCB_call(cb, 2, 0)) goto err;
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if(!BN_GENCB_call(cb, 3, 0)) goto err;
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/* step 6 */
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counter=0;
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/* "offset = 2" */
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n=(bits-1)/160;
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b=(bits-1)-n*160;
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for (;;)
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{
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if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
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goto err;
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/* step 7 */
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BN_zero(W);
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/* now 'buf' contains "SEED + offset - 1" */
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for (k=0; k<=n; k++)
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{
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/* obtain "SEED + offset + k" by incrementing: */
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for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
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{
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buf[i]++;
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if (buf[i] != 0) break;
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}
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EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
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/* step 8 */
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if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
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goto err;
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if (!BN_lshift(r0,r0,160*k)) goto err;
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if (!BN_add(W,W,r0)) goto err;
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}
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/* more of step 8 */
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if (!BN_mask_bits(W,bits-1)) goto err;
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if (!BN_copy(X,W)) goto err;
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if (!BN_add(X,X,test)) goto err;
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/* step 9 */
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if (!BN_lshift1(r0,q)) goto err;
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if (!BN_mod(c,X,r0,ctx)) goto err;
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if (!BN_sub(r0,c,BN_value_one())) goto err;
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if (!BN_sub(p,X,r0)) goto err;
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/* step 10 */
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if (BN_cmp(p,test) >= 0)
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{
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/* step 11 */
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r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
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ctx, 1, cb);
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if (r > 0)
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goto end; /* found it */
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if (r != 0)
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goto err;
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}
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/* step 13 */
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counter++;
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/* "offset = offset + n + 1" */
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/* step 14 */
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if (counter >= 4096) break;
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}
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}
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end:
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if(!BN_GENCB_call(cb, 2, 1))
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goto err;
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/* We now need to generate g */
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/* Set r0=(p-1)/q */
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if (!BN_sub(test,p,BN_value_one())) goto err;
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if (!BN_div(r0,NULL,test,q,ctx)) goto err;
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if (!BN_set_word(test,h)) goto err;
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if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
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for (;;)
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{
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/* g=test^r0%p */
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if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
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if (!BN_is_one(g)) break;
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if (!BN_add(test,test,BN_value_one())) goto err;
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h++;
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}
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if(!BN_GENCB_call(cb, 3, 1))
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goto err;
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ok=1;
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err:
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if (ok)
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{
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if(ret->p) BN_free(ret->p);
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if(ret->q) BN_free(ret->q);
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if(ret->g) BN_free(ret->g);
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ret->p=BN_dup(p);
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ret->q=BN_dup(q);
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ret->g=BN_dup(g);
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if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
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{
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ok=0;
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goto err;
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}
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if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
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if (counter_ret != NULL) *counter_ret=counter;
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if (h_ret != NULL) *h_ret=h;
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}
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if(ctx)
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{
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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}
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if (mont != NULL) BN_MONT_CTX_free(mont);
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return ok;
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}
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#endif
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