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
80 #include <openssl/evp.h>
81 #include <openssl/bn.h>
82 #include <openssl/rand.h>
83 #include <openssl/sha.h>
87 int DSA_generate_parameters_ex(DSA *ret, int bits,
88 const unsigned char *seed_in, int seed_len,
89 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
91 if(ret->meth->dsa_paramgen)
92 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
93 counter_ret, h_ret, cb);
97 size_t qbits = bits >= 2048 ? 256 : 160;
102 evpmd = EVP_sha256();
110 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
111 seed_in, seed_len, NULL, counter_ret, h_ret, cb);
115 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
116 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
117 unsigned char *seed_out,
118 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
121 unsigned char seed[SHA256_DIGEST_LENGTH];
122 unsigned char md[SHA256_DIGEST_LENGTH];
123 unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
124 BIGNUM *r0,*W,*X,*c,*test;
125 BIGNUM *g=NULL,*q=NULL,*p=NULL;
126 BN_MONT_CTX *mont=NULL;
127 int i, k, n=0, m=0, qsize = qbits >> 3;
133 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
134 qsize != SHA256_DIGEST_LENGTH)
139 /* use SHA1 as default */
145 bits = (bits+63)/64*64;
147 /* NB: seed_len == 0 is special case: copy generated seed to
148 * seed_in if it is not NULL.
150 if (seed_len && (seed_len < (size_t)qsize))
151 seed_in = NULL; /* seed buffer too small -- ignore */
152 if (seed_len > (size_t)qsize)
153 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
154 * but our internal buffers are restricted to 160 bits*/
156 memcpy(seed, seed_in, seed_len);
158 if ((ctx=BN_CTX_new()) == NULL)
161 if ((mont=BN_MONT_CTX_new()) == NULL)
165 r0 = BN_CTX_get(ctx);
172 test = BN_CTX_get(ctx);
174 if (!BN_lshift(test,BN_value_one(),bits-1))
179 for (;;) /* find q */
184 if(!BN_GENCB_call(cb, 0, m++))
189 if (RAND_pseudo_bytes(seed, qsize) < 0)
196 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
198 memcpy(buf , seed, qsize);
199 memcpy(buf2, seed, qsize);
200 /* precompute "SEED + 1" for step 7: */
201 for (i = qsize-1; i >= 0; i--)
209 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
211 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
213 for (i = 0; i < qsize; i++)
219 if (!BN_bin2bn(md, qsize, q))
223 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
230 /* do a callback call */
234 if(!BN_GENCB_call(cb, 2, 0)) goto err;
235 if(!BN_GENCB_call(cb, 3, 0)) goto err;
245 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
250 /* now 'buf' contains "SEED + offset - 1" */
253 /* obtain "SEED + offset + k" by incrementing: */
254 for (i = qsize-1; i >= 0; i--)
261 if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
266 if (!BN_bin2bn(md, qsize, r0))
268 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
269 if (!BN_add(W,W,r0)) goto err;
273 if (!BN_mask_bits(W,bits-1)) goto err;
274 if (!BN_copy(X,W)) goto err;
275 if (!BN_add(X,X,test)) goto err;
278 if (!BN_lshift1(r0,q)) goto err;
279 if (!BN_mod(c,X,r0,ctx)) goto err;
280 if (!BN_sub(r0,c,BN_value_one())) goto err;
281 if (!BN_sub(p,X,r0)) goto err;
284 if (BN_cmp(p,test) >= 0)
287 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
290 goto end; /* found it */
297 /* "offset = offset + n + 1" */
300 if (counter >= 4096) break;
304 if(!BN_GENCB_call(cb, 2, 1))
307 /* We now need to generate g */
309 if (!BN_sub(test,p,BN_value_one())) goto err;
310 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
312 if (!BN_set_word(test,h)) goto err;
313 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
318 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
319 if (!BN_is_one(g)) break;
320 if (!BN_add(test,test,BN_value_one())) goto err;
324 if(!BN_GENCB_call(cb, 3, 1))
331 if(ret->p) BN_free(ret->p);
332 if(ret->q) BN_free(ret->q);
333 if(ret->g) BN_free(ret->g);
337 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
342 if (counter_ret != NULL) *counter_ret=counter;
343 if (h_ret != NULL) *h_ret=h;
345 memcpy(seed_out, seed, qsize);
352 if (mont != NULL) BN_MONT_CTX_free(mont);
356 /* This is a parameter generation algorithm for the DSA2 algorithm as
357 * described in FIPS 186-3.
360 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
361 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
362 int idx, unsigned char *seed_out,
363 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
366 unsigned char *seed = NULL, *seed_tmp = NULL;
367 unsigned char md[EVP_MAX_MD_SIZE];
369 BIGNUM *r0,*W,*X,*c,*test;
370 BIGNUM *g=NULL,*q=NULL,*p=NULL;
371 BN_MONT_CTX *mont=NULL;
372 int i, k, n=0, m=0, qsize = N >> 3;
379 EVP_MD_CTX_init(&mctx);
386 evpmd = EVP_sha224();
388 evpmd = EVP_sha256();
391 mdsize = M_EVP_MD_size(evpmd);
392 /* If unverificable g generation only don't need seed */
393 if (!ret->p || !ret->q || idx >= 0)
398 seed = OPENSSL_malloc(seed_len);
403 seed_tmp = OPENSSL_malloc(seed_len);
405 if (!seed || !seed_tmp)
409 memcpy(seed, seed_in, seed_len);
413 if ((ctx=BN_CTX_new()) == NULL)
416 if ((mont=BN_MONT_CTX_new()) == NULL)
420 r0 = BN_CTX_get(ctx);
425 test = BN_CTX_get(ctx);
427 /* if p, q already supplied generate g only */
428 if (ret->p && ret->q)
433 memcpy(seed_tmp, seed, seed_len);
442 if (!BN_lshift(test,BN_value_one(),L-1))
446 for (;;) /* find q */
450 if(!BN_GENCB_call(cb, 0, m++))
455 if (RAND_pseudo_bytes(seed, seed_len) < 0)
459 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
461 /* Take least significant bits of md */
463 pmd = md + mdsize - qsize;
468 memset(md + mdsize, 0, qsize - mdsize);
472 pmd[qsize-1] |= 0x01;
473 if (!BN_bin2bn(pmd, qsize, q))
477 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
478 seed_in ? 1 : 0, cb);
483 /* Provided seed didn't produce a prime: error */
487 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
491 /* do a callback call */
494 /* Copy seed to seed_out before we mess with it */
496 memcpy(seed_out, seed, seed_len);
498 if(!BN_GENCB_call(cb, 2, 0)) goto err;
499 if(!BN_GENCB_call(cb, 3, 0)) goto err;
505 n=(L-1)/(mdsize << 3);
509 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
514 /* now 'buf' contains "SEED + offset - 1" */
517 /* obtain "SEED + offset + k" by incrementing: */
518 for (i = seed_len-1; i >= 0; i--)
525 if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
530 if (!BN_bin2bn(md, mdsize, r0))
532 if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
533 if (!BN_add(W,W,r0)) goto err;
537 if (!BN_mask_bits(W,L-1)) goto err;
538 if (!BN_copy(X,W)) goto err;
539 if (!BN_add(X,X,test)) goto err;
542 if (!BN_lshift1(r0,q)) goto err;
543 if (!BN_mod(c,X,r0,ctx)) goto err;
544 if (!BN_sub(r0,c,BN_value_one())) goto err;
545 if (!BN_sub(p,X,r0)) goto err;
548 if (BN_cmp(p,test) >= 0)
551 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
554 goto end; /* found it */
561 /* "offset = offset + n + 1" */
564 if (counter >= (int)(4 * L)) break;
569 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
574 if(!BN_GENCB_call(cb, 2, 1))
579 /* We now need to generate g */
581 if (!BN_sub(test,p,BN_value_one())) goto err;
582 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
586 if (!BN_set_word(test,h))
591 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
595 static const unsigned char ggen[4] = {0x67,0x67,0x65,0x6e};
599 md[1] = (h >> 8) & 0xff;
601 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
603 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
605 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
607 if (!EVP_DigestUpdate(&mctx, md, 3))
609 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
611 if (!BN_bin2bn(md, mdsize, test))
615 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
616 if (!BN_is_one(g)) break;
617 if (idx < 0 && !BN_add(test,test,BN_value_one())) goto err;
619 if ( idx >= 0 && h > 0xffff)
623 if(!BN_GENCB_call(cb, 3, 1))
632 if(ret->p) BN_free(ret->p);
637 if(ret->q) BN_free(ret->q);
640 if(ret->g) BN_free(ret->g);
642 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
647 if (counter_ret != NULL) *counter_ret=counter;
648 if (h_ret != NULL) *h_ret=h;
652 if (seed_out != seed_tmp)
653 OPENSSL_free(seed_tmp);
659 if (mont != NULL) BN_MONT_CTX_free(mont);
660 EVP_MD_CTX_cleanup(&mctx);
664 int dsa_paramgen_check_g(DSA *dsa)
668 BN_MONT_CTX *mont = NULL;
674 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
676 if (BN_cmp(dsa->g, dsa->p) >= 0)
678 tmp = BN_CTX_get(ctx);
681 if ((mont=BN_MONT_CTX_new()) == NULL)
683 if (!BN_MONT_CTX_set(mont,dsa->p,ctx))
685 /* Work out g^q mod p */
686 if (!BN_mod_exp_mont(tmp,dsa->g,dsa->q, dsa->p, ctx, mont))
688 if (!BN_cmp(tmp, BN_value_one()))
695 BN_MONT_CTX_free(mont);