0e4aa0d2d2
override key-generation implementations by placing handlers in the methods for DSA and DH. Also, parameter generation for DSA and DH is possible by another new handler for each method.
311 lines
8.7 KiB
C
311 lines
8.7 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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#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,*ctx2=NULL,*ctx3=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 ((ctx2=BN_CTX_new()) == NULL) goto err;
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if ((ctx3=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(ctx2);
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r0 = BN_CTX_get(ctx2);
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g = BN_CTX_get(ctx2);
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W = BN_CTX_get(ctx2);
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q = BN_CTX_get(ctx2);
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X = BN_CTX_get(ctx2);
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c = BN_CTX_get(ctx2);
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p = BN_CTX_get(ctx2);
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test = BN_CTX_get(ctx2);
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BN_lshift(test,BN_value_one(),bits-1);
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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, ctx3,
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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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BN_lshift(r0,r0,160*k);
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BN_add(W,W,r0);
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}
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/* more of step 8 */
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BN_mask_bits(W,bits-1);
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BN_copy(X,W); /* this should be ok */
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BN_add(X,X,test); /* this should be ok */
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/* step 9 */
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BN_lshift1(r0,q);
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BN_mod(c,X,r0,ctx);
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BN_sub(r0,c,BN_value_one());
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BN_sub(p,X,r0);
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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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ctx3, 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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BN_sub(test,p,BN_value_one());
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BN_div(r0,NULL,test,q,ctx);
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BN_set_word(test,h);
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BN_MONT_CTX_set(mont,p,ctx);
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for (;;)
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{
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/* g=test^r0%p */
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BN_mod_exp_mont(g,test,r0,p,ctx,mont);
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if (!BN_is_one(g)) break;
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BN_add(test,test,BN_value_one());
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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 ((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 != NULL) BN_CTX_free(ctx);
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if (ctx2 != NULL)
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{
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BN_CTX_end(ctx2);
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BN_CTX_free(ctx2);
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}
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if (ctx3 != NULL) BN_CTX_free(ctx3);
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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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