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
76 #define OPENSSL_FIPSAPI
80 #include <openssl/evp.h>
81 #include <openssl/bn.h>
82 #include <openssl/rand.h>
83 #include <openssl/sha.h>
85 #include <openssl/fips.h>
90 int DSA_generate_parameters_ex(DSA *ret, int bits,
91 const unsigned char *seed_in, int seed_len,
92 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
94 if(ret->meth->dsa_paramgen)
95 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
96 counter_ret, h_ret, cb);
100 size_t qbits = bits >= 2048 ? 256 : 160;
105 evpmd = EVP_sha256();
113 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
114 seed_in, seed_len, NULL, counter_ret, h_ret, cb);
118 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
119 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
120 unsigned char *seed_out,
121 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
124 unsigned char seed[SHA256_DIGEST_LENGTH];
125 unsigned char md[SHA256_DIGEST_LENGTH];
126 unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
127 BIGNUM *r0,*W,*X,*c,*test;
128 BIGNUM *g=NULL,*q=NULL,*p=NULL;
129 BN_MONT_CTX *mont=NULL;
130 int i, k, n=0, m=0, qsize = qbits >> 3;
137 if(FIPS_selftest_failed())
139 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED);
143 if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
145 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
150 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
151 qsize != SHA256_DIGEST_LENGTH)
156 /* use SHA1 as default */
162 bits = (bits+63)/64*64;
164 /* NB: seed_len == 0 is special case: copy generated seed to
165 * seed_in if it is not NULL.
167 if (seed_len && (seed_len < (size_t)qsize))
168 seed_in = NULL; /* seed buffer too small -- ignore */
169 if (seed_len > (size_t)qsize)
170 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
171 * but our internal buffers are restricted to 160 bits*/
173 memcpy(seed, seed_in, seed_len);
175 if ((ctx=BN_CTX_new()) == NULL)
178 if ((mont=BN_MONT_CTX_new()) == NULL)
182 r0 = BN_CTX_get(ctx);
189 test = BN_CTX_get(ctx);
191 if (!BN_lshift(test,BN_value_one(),bits-1))
196 for (;;) /* find q */
201 if(!BN_GENCB_call(cb, 0, m++))
206 if (RAND_pseudo_bytes(seed, qsize) < 0)
213 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
215 memcpy(buf , seed, qsize);
216 memcpy(buf2, seed, qsize);
217 /* precompute "SEED + 1" for step 7: */
218 for (i = qsize-1; i >= 0; i--)
226 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
228 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
230 for (i = 0; i < qsize; i++)
236 if (!BN_bin2bn(md, qsize, q))
240 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
247 /* do a callback call */
251 if(!BN_GENCB_call(cb, 2, 0)) goto err;
252 if(!BN_GENCB_call(cb, 3, 0)) goto err;
262 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
267 /* now 'buf' contains "SEED + offset - 1" */
270 /* obtain "SEED + offset + k" by incrementing: */
271 for (i = qsize-1; i >= 0; i--)
278 if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
283 if (!BN_bin2bn(md, qsize, r0))
285 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
286 if (!BN_add(W,W,r0)) goto err;
290 if (!BN_mask_bits(W,bits-1)) goto err;
291 if (!BN_copy(X,W)) goto err;
292 if (!BN_add(X,X,test)) goto err;
295 if (!BN_lshift1(r0,q)) goto err;
296 if (!BN_mod(c,X,r0,ctx)) goto err;
297 if (!BN_sub(r0,c,BN_value_one())) goto err;
298 if (!BN_sub(p,X,r0)) goto err;
301 if (BN_cmp(p,test) >= 0)
304 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
307 goto end; /* found it */
314 /* "offset = offset + n + 1" */
317 if (counter >= 4096) break;
321 if(!BN_GENCB_call(cb, 2, 1))
324 /* We now need to generate g */
326 if (!BN_sub(test,p,BN_value_one())) goto err;
327 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
329 if (!BN_set_word(test,h)) goto err;
330 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
335 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
336 if (!BN_is_one(g)) break;
337 if (!BN_add(test,test,BN_value_one())) goto err;
341 if(!BN_GENCB_call(cb, 3, 1))
348 if(ret->p) BN_free(ret->p);
349 if(ret->q) BN_free(ret->q);
350 if(ret->g) BN_free(ret->g);
354 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
359 if (counter_ret != NULL) *counter_ret=counter;
360 if (h_ret != NULL) *h_ret=h;
362 memcpy(seed_out, seed, qsize);
369 if (mont != NULL) BN_MONT_CTX_free(mont);
373 /* Security strength of parameter values for (L,N): see FIPS186-3 4.2
378 static int dsa2_security_strength(size_t L, size_t N)
380 if (L == 1024 && N == 160)
382 if (L == 2048 && N == 224)
384 if (L == 2048 && N == 256)
386 if (L == 3072 && N == 256)
391 /* This is a parameter generation algorithm for the DSA2 algorithm as
392 * described in FIPS 186-3.
395 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
396 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
397 unsigned char *seed_out,
398 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
401 unsigned char *seed = NULL;
402 unsigned char md[EVP_MAX_MD_SIZE];
404 BIGNUM *r0,*W,*X,*c,*test;
405 BIGNUM *g=NULL,*q=NULL,*p=NULL;
406 BN_MONT_CTX *mont=NULL;
407 int i, k, n=0, m=0, qsize = N >> 3;
414 if(FIPS_selftest_failed())
416 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
417 FIPS_R_FIPS_SELFTEST_FAILED);
421 if (!dsa2_security_strength(L, N))
423 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
433 evpmd = EVP_sha224();
435 evpmd = EVP_sha256();
438 mdsize = M_EVP_MD_size(evpmd);
443 seed = OPENSSL_malloc(seed_len);
449 memcpy(seed, seed_in, seed_len);
451 if ((ctx=BN_CTX_new()) == NULL)
454 if ((mont=BN_MONT_CTX_new()) == NULL)
458 r0 = BN_CTX_get(ctx);
465 test = BN_CTX_get(ctx);
467 if (!BN_lshift(test,BN_value_one(),L-1))
471 for (;;) /* find q */
475 if(!BN_GENCB_call(cb, 0, m++))
480 if (RAND_pseudo_bytes(seed, seed_len) < 0)
484 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
486 /* Take least significant bits of md */
488 pmd = md + mdsize - qsize;
493 memset(md + mdsize, 0, qsize - mdsize);
497 pmd[qsize-1] |= 0x01;
498 if (!BN_bin2bn(pmd, qsize, q))
502 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
503 seed_in ? 1 : 0, cb);
508 /* Provided seed didn't produce a prime: error */
512 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
516 /* do a callback call */
519 /* Copy seed to seed_out before we mess with it */
521 memcpy(seed_out, seed, seed_len);
523 if(!BN_GENCB_call(cb, 2, 0)) goto err;
524 if(!BN_GENCB_call(cb, 3, 0)) goto err;
530 n=(L-1)/(mdsize << 3);
534 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
539 /* now 'buf' contains "SEED + offset - 1" */
542 /* obtain "SEED + offset + k" by incrementing: */
543 for (i = seed_len-1; i >= 0; i--)
550 if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
555 if (!BN_bin2bn(md, mdsize, r0))
557 if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
558 if (!BN_add(W,W,r0)) goto err;
562 if (!BN_mask_bits(W,L-1)) goto err;
563 if (!BN_copy(X,W)) goto err;
564 if (!BN_add(X,X,test)) goto err;
567 if (!BN_lshift1(r0,q)) goto err;
568 if (!BN_mod(c,X,r0,ctx)) goto err;
569 if (!BN_sub(r0,c,BN_value_one())) goto err;
570 if (!BN_sub(p,X,r0)) goto err;
573 if (BN_cmp(p,test) >= 0)
576 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
579 goto end; /* found it */
586 /* "offset = offset + n + 1" */
589 if (counter >= 4096) break;
593 if(!BN_GENCB_call(cb, 2, 1))
596 /* We now need to generate g */
598 if (!BN_sub(test,p,BN_value_one())) goto err;
599 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
601 if (!BN_set_word(test,h)) goto err;
602 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
607 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
608 if (!BN_is_one(g)) break;
609 if (!BN_add(test,test,BN_value_one())) goto err;
613 if(!BN_GENCB_call(cb, 3, 1))
620 if(ret->p) BN_free(ret->p);
621 if(ret->q) BN_free(ret->q);
622 if(ret->g) BN_free(ret->g);
626 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
631 if (counter_ret != NULL) *counter_ret=counter;
632 if (h_ret != NULL) *h_ret=h;
641 if (mont != NULL) BN_MONT_CTX_free(mont);