1 /* crypto/dsa/dsa_gen.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
62 /* Parameter generation follows the original release of FIPS PUB 186,
63 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
64 #define HASH EVP_sha()
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
69 #define HASH EVP_sha1()
72 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
74 #ifndef OPENSSL_NO_SHA
79 #include <openssl/evp.h>
80 #include <openssl/bn.h>
81 #include <openssl/dsa.h>
82 #include <openssl/rand.h>
83 #include <openssl/sha.h>
84 #include <openssl/err.h>
88 static int dsa_builtin_paramgen(DSA *ret, int bits,
89 unsigned char *seed_in, int seed_len,
90 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
92 int DSA_generate_parameters_ex(DSA *ret, int bits,
93 unsigned char *seed_in, int seed_len,
94 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
96 if(ret->meth->dsa_paramgen)
97 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
98 counter_ret, h_ret, cb);
99 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
100 counter_ret, h_ret, cb);
103 static int dsa_builtin_paramgen(DSA *ret, int bits,
104 unsigned char *seed_in, int seed_len,
105 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
108 unsigned char seed[SHA_DIGEST_LENGTH];
109 unsigned char md[SHA_DIGEST_LENGTH];
110 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
111 BIGNUM *r0,*W,*X,*c,*test;
112 BIGNUM *g=NULL,*q=NULL,*p=NULL;
113 BN_MONT_CTX *mont=NULL;
120 if(FIPS_selftest_failed())
122 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN,
123 FIPS_R_FIPS_SELFTEST_FAILED);
127 if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
129 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
133 if (bits < 512) bits=512;
134 bits=(bits+63)/64*64;
136 /* NB: seed_len == 0 is special case: copy generated seed to
137 * seed_in if it is not NULL.
139 if (seed_len && (seed_len < 20))
140 seed_in = NULL; /* seed buffer too small -- ignore */
142 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
143 * but our internal buffers are restricted to 160 bits*/
144 if ((seed_in != NULL) && (seed_len == 20))
146 memcpy(seed,seed_in,seed_len);
147 /* set seed_in to NULL to avoid it being copied back */
151 if ((ctx=BN_CTX_new()) == NULL) goto err;
153 if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
156 r0 = BN_CTX_get(ctx);
163 test = BN_CTX_get(ctx);
165 if (!BN_lshift(test,BN_value_one(),bits-1))
170 for (;;) /* find q */
175 if(!BN_GENCB_call(cb, 0, m++))
180 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
186 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
188 memcpy(buf,seed,SHA_DIGEST_LENGTH);
189 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
190 /* precompute "SEED + 1" for step 7: */
191 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
194 if (buf[i] != 0) break;
198 EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
199 EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
200 for (i=0; i<SHA_DIGEST_LENGTH; i++)
205 md[SHA_DIGEST_LENGTH-1]|=0x01;
206 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
209 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
216 /* do a callback call */
220 if(!BN_GENCB_call(cb, 2, 0)) goto err;
221 if(!BN_GENCB_call(cb, 3, 0)) goto err;
232 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
237 /* now 'buf' contains "SEED + offset - 1" */
240 /* obtain "SEED + offset + k" by incrementing: */
241 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
244 if (buf[i] != 0) break;
247 EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
250 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
252 if (!BN_lshift(r0,r0,160*k)) goto err;
253 if (!BN_add(W,W,r0)) goto err;
257 if (!BN_mask_bits(W,bits-1)) goto err;
258 if (!BN_copy(X,W)) goto err;
259 if (!BN_add(X,X,test)) goto err;
262 if (!BN_lshift1(r0,q)) goto err;
263 if (!BN_mod(c,X,r0,ctx)) goto err;
264 if (!BN_sub(r0,c,BN_value_one())) goto err;
265 if (!BN_sub(p,X,r0)) goto err;
268 if (BN_cmp(p,test) >= 0)
271 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
274 goto end; /* found it */
281 /* "offset = offset + n + 1" */
284 if (counter >= 4096) break;
288 if(!BN_GENCB_call(cb, 2, 1))
291 /* We now need to generate g */
293 if (!BN_sub(test,p,BN_value_one())) goto err;
294 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
296 if (!BN_set_word(test,h)) goto err;
297 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
302 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
303 if (!BN_is_one(g)) break;
304 if (!BN_add(test,test,BN_value_one())) goto err;
308 if(!BN_GENCB_call(cb, 3, 1))
315 if(ret->p) BN_free(ret->p);
316 if(ret->q) BN_free(ret->q);
317 if(ret->g) BN_free(ret->g);
321 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
326 if (seed_in != NULL) memcpy(seed_in,seed,20);
327 if (counter_ret != NULL) *counter_ret=counter;
328 if (h_ret != NULL) *h_ret=h;
335 if (mont != NULL) BN_MONT_CTX_free(mont);