340 lines
8.5 KiB
C
340 lines
8.5 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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#define HASH SHA
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#else
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#define HASH SHA1
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#endif
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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 "sha.h"
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#include "bn.h"
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#include "dsa.h"
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#include "rand.h"
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DSA *DSA_generate_parameters(bits,seed_in,seed_len,counter_ret,h_ret,callback,
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cb_arg)
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int bits;
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unsigned char *seed_in;
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int seed_len;
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int *counter_ret;
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unsigned long *h_ret;
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void (*callback)();
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char *cb_arg;
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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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BN_CTX *ctx=NULL,*ctx2=NULL;
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unsigned int h=2;
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DSA *ret=NULL;
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if (bits < 512) bits=512;
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bits=(bits+63)/64*64;
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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 ((ret=DSA_new()) == NULL) goto err;
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if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
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r0= &(ctx2->bn[0]);
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g= &(ctx2->bn[1]);
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W= &(ctx2->bn[2]);
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q= &(ctx2->bn[3]);
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X= &(ctx2->bn[4]);
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c= &(ctx2->bn[5]);
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p= &(ctx2->bn[6]);
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test= &(ctx2->bn[7]);
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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 (;;)
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{
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/* step 1 */
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if (callback != NULL) callback(0,m++,cb_arg);
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if (!seed_len)
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RAND_bytes(seed,SHA_DIGEST_LENGTH);
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else
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seed_len=0;
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memcpy(buf,seed,SHA_DIGEST_LENGTH);
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memcpy(buf2,seed,SHA_DIGEST_LENGTH);
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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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HASH(seed,SHA_DIGEST_LENGTH,md);
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HASH(buf,SHA_DIGEST_LENGTH,buf2);
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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)) abort();
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/* step 4 */
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if (DSA_is_prime(q,callback,cb_arg) > 0) break;
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/* do a callback call */
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/* step 5 */
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}
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if (callback != NULL) callback(2,0,cb_arg);
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if (callback != NULL) callback(3,0,cb_arg);
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/* step 6 */
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counter=0;
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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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/* step 7 */
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BN_zero(W);
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for (k=0; k<=n; k++)
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{
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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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HASH(buf,SHA_DIGEST_LENGTH,md);
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/* step 8 */
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if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
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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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if (DSA_is_prime(p,callback,cb_arg) > 0)
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goto end;
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}
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/* step 13 */
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counter++;
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/* step 14 */
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if (counter >= 4096) break;
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if (callback != NULL) callback(0,counter,cb_arg);
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}
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}
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end:
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if (callback != NULL) callback(2,1,cb_arg);
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/* We now need to gernerate 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 (callback != NULL) callback(3,1,cb_arg);
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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 != NULL) DSA_free(ret);
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}
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else
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{
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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 (ctx != NULL) BN_CTX_free(ctx2);
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if (mont != NULL) BN_MONT_CTX_free(mont);
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return(ok?ret:NULL);
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}
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int DSA_is_prime(w, callback,cb_arg)
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BIGNUM *w;
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void (*callback)();
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char *cb_arg;
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{
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int ok= -1,j,i,n;
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BN_CTX *ctx=NULL,*ctx2=NULL;
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BIGNUM *w_1,*b,*m,*z,*tmp,*mont_1;
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int a;
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BN_MONT_CTX *mont=NULL;
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if (!BN_is_bit_set(w,0)) return(0);
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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 ((mont=BN_MONT_CTX_new()) == NULL) goto err;
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m= &(ctx2->bn[2]);
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b= &(ctx2->bn[3]);
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z= &(ctx2->bn[4]);
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w_1= &(ctx2->bn[5]);
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tmp= &(ctx2->bn[6]);
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mont_1= &(ctx2->bn[7]);
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/* step 1 */
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n=50;
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/* step 2 */
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if (!BN_sub(w_1,w,BN_value_one())) goto err;
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for (a=1; !BN_is_bit_set(w_1,a); a++)
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;
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if (!BN_rshift(m,w_1,a)) goto err;
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BN_MONT_CTX_set(mont,w,ctx);
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BN_to_montgomery(mont_1,BN_value_one(),mont,ctx);
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BN_to_montgomery(w_1,w_1,mont,ctx);
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for (i=1; i < n; i++)
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{
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/* step 3 */
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BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0);
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/* BN_set_word(b,0x10001L); */
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/* step 4 */
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j=0;
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if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err;
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if (!BN_to_montgomery(z,z,mont,ctx)) goto err;
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/* step 5 */
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for (;;)
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{
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if (((j == 0) && (BN_cmp(z,mont_1) == 0)) ||
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(BN_cmp(z,w_1) == 0))
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break;
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/* step 6 */
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if ((j > 0) && (BN_cmp(z,mont_1) == 0))
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{
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ok=0;
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goto err;
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}
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j++;
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if (j >= a)
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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 (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err;
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if (callback != NULL) callback(1,j,cb_arg);
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}
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}
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ok=1;
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err:
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if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);
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BN_CTX_free(ctx);
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BN_CTX_free(ctx2);
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return(ok);
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}
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