dsa_gen.c
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- /* 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 <time.h>
- #include "cryptlib.h"
- #include <openssl/evp.h>
- #include <openssl/bn.h>
- #include <openssl/dsa.h>
- #include <openssl/rand.h>
- #include <openssl/sha.h>
- static int dsa_builtin_paramgen(DSA *ret, int bits,
- unsigned char *seed_in, int seed_len,
- int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
- int DSA_generate_parameters_ex(DSA *ret, int bits,
- 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);
- return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
- counter_ret, h_ret, cb);
- }
- static int dsa_builtin_paramgen(DSA *ret, int bits,
- unsigned char *seed_in, int seed_len,
- int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
- {
- 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;
- int r=0;
- BN_CTX *ctx=NULL;
- unsigned int h=2;
- if (bits < 512) bits=512;
- bits=(bits+63)/64*64;
- if (seed_len < 20)
- seed_in = NULL; /* seed buffer too small -- ignore */
- if (seed_len > 20)
- seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
- * but our internal buffers are restricted to 160 bits*/
- if ((seed_in != NULL) && (seed_len == 20))
- 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,SHA_DIGEST_LENGTH);
- 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,SHA_DIGEST_LENGTH);
- memcpy(buf2,seed,SHA_DIGEST_LENGTH);
- /* precompute "SEED + 1" for step 7: */
- for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
- {
- buf[i]++;
- if (buf[i] != 0) break;
- }
- /* step 2 */
- EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
- EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
- 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)) 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=SHA_DIGEST_LENGTH-1; i >= 0; i--)
- {
- buf[i]++;
- if (buf[i] != 0) break;
- }
- EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
- /* step 8 */
- if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
- goto err;
- if (!BN_lshift(r0,r0,160*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 ((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)
- {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
- if (mont != NULL) BN_MONT_CTX_free(mont);
- return ok;
- }
- #endif