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>
86 #include <openssl/fips_rand.h>
91 int DSA_generate_parameters_ex(DSA *ret, int bits,
92 const unsigned char *seed_in, int seed_len,
93 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
95 if(ret->meth->dsa_paramgen)
96 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
97 counter_ret, h_ret, cb);
101 size_t qbits = bits >= 2048 ? 256 : 160;
106 evpmd = EVP_sha256();
114 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
115 seed_in, seed_len, NULL, counter_ret, h_ret, cb);
119 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
120 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
121 unsigned char *seed_out,
122 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
125 unsigned char seed[SHA256_DIGEST_LENGTH];
126 unsigned char md[SHA256_DIGEST_LENGTH];
127 unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
128 BIGNUM *r0,*W,*X,*c,*test;
129 BIGNUM *g=NULL,*q=NULL,*p=NULL;
130 BN_MONT_CTX *mont=NULL;
131 int i, k, n=0, m=0, qsize = qbits >> 3;
138 if(FIPS_selftest_failed())
140 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED);
144 if (FIPS_module_mode() && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)
145 && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
147 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
152 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
153 qsize != SHA256_DIGEST_LENGTH)
158 /* use SHA1 as default */
164 bits = (bits+63)/64*64;
166 /* NB: seed_len == 0 is special case: copy generated seed to
167 * seed_in if it is not NULL.
169 if (seed_len && (seed_len < (size_t)qsize))
170 seed_in = NULL; /* seed buffer too small -- ignore */
171 if (seed_len > (size_t)qsize)
172 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
173 * but our internal buffers are restricted to 160 bits*/
175 memcpy(seed, seed_in, seed_len);
177 if ((ctx=BN_CTX_new()) == NULL)
180 if ((mont=BN_MONT_CTX_new()) == NULL)
184 r0 = BN_CTX_get(ctx);
191 test = BN_CTX_get(ctx);
193 if (!BN_lshift(test,BN_value_one(),bits-1))
198 for (;;) /* find q */
203 if(!BN_GENCB_call(cb, 0, m++))
208 if (RAND_pseudo_bytes(seed, qsize) < 0)
215 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
217 memcpy(buf , seed, qsize);
218 memcpy(buf2, seed, qsize);
219 /* precompute "SEED + 1" for step 7: */
220 for (i = qsize-1; i >= 0; i--)
228 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
230 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
232 for (i = 0; i < qsize; i++)
238 if (!BN_bin2bn(md, qsize, q))
242 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
249 /* do a callback call */
253 if(!BN_GENCB_call(cb, 2, 0)) goto err;
254 if(!BN_GENCB_call(cb, 3, 0)) goto err;
264 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
269 /* now 'buf' contains "SEED + offset - 1" */
272 /* obtain "SEED + offset + k" by incrementing: */
273 for (i = qsize-1; i >= 0; i--)
280 if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
285 if (!BN_bin2bn(md, qsize, r0))
287 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
288 if (!BN_add(W,W,r0)) goto err;
292 if (!BN_mask_bits(W,bits-1)) goto err;
293 if (!BN_copy(X,W)) goto err;
294 if (!BN_add(X,X,test)) goto err;
297 if (!BN_lshift1(r0,q)) goto err;
298 if (!BN_mod(c,X,r0,ctx)) goto err;
299 if (!BN_sub(r0,c,BN_value_one())) goto err;
300 if (!BN_sub(p,X,r0)) goto err;
303 if (BN_cmp(p,test) >= 0)
306 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
309 goto end; /* found it */
316 /* "offset = offset + n + 1" */
319 if (counter >= 4096) break;
323 if(!BN_GENCB_call(cb, 2, 1))
326 /* We now need to generate g */
328 if (!BN_sub(test,p,BN_value_one())) goto err;
329 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
331 if (!BN_set_word(test,h)) goto err;
332 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
337 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
338 if (!BN_is_one(g)) break;
339 if (!BN_add(test,test,BN_value_one())) goto err;
343 if(!BN_GENCB_call(cb, 3, 1))
350 if(ret->p) BN_free(ret->p);
351 if(ret->q) BN_free(ret->q);
352 if(ret->g) BN_free(ret->g);
356 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
361 if (counter_ret != NULL) *counter_ret=counter;
362 if (h_ret != NULL) *h_ret=h;
364 memcpy(seed_out, seed, qsize);
371 if (mont != NULL) BN_MONT_CTX_free(mont);
377 /* Security strength of parameter values for (L,N): see FIPS186-3 4.2
382 static int fips_ffc_strength(size_t L, size_t N)
384 if (L >= 15360 && N >= 512)
386 if (L >= 7680 && N >= 384)
388 if (L >= 3072 && N >= 256)
390 if (L >= 2048 && N >= 224)
392 if (L >= 1024 && N >= 160)
397 /* Valid DSA2 parameters from FIPS 186-3 */
399 static int dsa2_valid_parameters(size_t L, size_t N)
401 if (L == 1024 && N == 160)
403 if (L == 2048 && N == 224)
405 if (L == 2048 && N == 256)
407 if (L == 3072 && N == 256)
412 int fips_check_dsa_prng(DSA *dsa, size_t L, size_t N)
415 if (!FIPS_module_mode())
418 if (dsa->flags & (DSA_FLAG_NON_FIPS_ALLOW|DSA_FLAG_FIPS_CHECKED))
423 L = BN_num_bits(dsa->p);
424 N = BN_num_bits(dsa->q);
426 if (!dsa2_valid_parameters(L, N))
428 FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG, FIPS_R_INVALID_PARAMETERS);
432 strength = fips_ffc_strength(L, N);
436 FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_KEY_TOO_SHORT);
440 if (FIPS_rand_strength() >= strength)
443 FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_PRNG_STRENGTH_TOO_LOW);
447 #endif /* OPENSSL_FIPS */
449 /* This is a parameter generation algorithm for the DSA2 algorithm as
450 * described in FIPS 186-3.
453 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
454 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
455 int idx, unsigned char *seed_out,
456 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
459 unsigned char *seed = NULL, *seed_tmp = NULL;
460 unsigned char md[EVP_MAX_MD_SIZE];
462 BIGNUM *r0,*W,*X,*c,*test;
463 BIGNUM *g=NULL,*q=NULL,*p=NULL;
464 BN_MONT_CTX *mont=NULL;
465 int i, k, n=0, m=0, qsize = N >> 3;
472 EVP_MD_CTX_init(&mctx);
475 if(FIPS_selftest_failed())
477 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
478 FIPS_R_FIPS_SELFTEST_FAILED);
482 if (!fips_check_dsa_prng(ret, L, N))
491 evpmd = EVP_sha224();
493 evpmd = EVP_sha256();
496 mdsize = M_EVP_MD_size(evpmd);
497 /* If unverificable g generation only don't need seed */
498 if (!ret->p || !ret->q || idx >= 0)
503 seed = OPENSSL_malloc(seed_len);
508 seed_tmp = OPENSSL_malloc(seed_len);
510 if (!seed || !seed_tmp)
514 memcpy(seed, seed_in, seed_len);
518 if ((ctx=BN_CTX_new()) == NULL)
521 if ((mont=BN_MONT_CTX_new()) == NULL)
525 r0 = BN_CTX_get(ctx);
530 test = BN_CTX_get(ctx);
532 /* if p, q already supplied generate g only */
533 if (ret->p && ret->q)
538 memcpy(seed_tmp, seed, seed_len);
547 if (!BN_lshift(test,BN_value_one(),L-1))
551 for (;;) /* find q */
555 if(!BN_GENCB_call(cb, 0, m++))
560 if (RAND_pseudo_bytes(seed, seed_len) < 0)
564 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
566 /* Take least significant bits of md */
568 pmd = md + mdsize - qsize;
573 memset(md + mdsize, 0, qsize - mdsize);
577 pmd[qsize-1] |= 0x01;
578 if (!BN_bin2bn(pmd, qsize, q))
582 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
583 seed_in ? 1 : 0, cb);
588 /* Provided seed didn't produce a prime: error */
592 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
596 /* do a callback call */
599 /* Copy seed to seed_out before we mess with it */
601 memcpy(seed_out, seed, seed_len);
603 if(!BN_GENCB_call(cb, 2, 0)) goto err;
604 if(!BN_GENCB_call(cb, 3, 0)) goto err;
610 n=(L-1)/(mdsize << 3);
614 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
619 /* now 'buf' contains "SEED + offset - 1" */
622 /* obtain "SEED + offset + k" by incrementing: */
623 for (i = seed_len-1; i >= 0; i--)
630 if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
635 if (!BN_bin2bn(md, mdsize, r0))
637 if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
638 if (!BN_add(W,W,r0)) goto err;
642 if (!BN_mask_bits(W,L-1)) goto err;
643 if (!BN_copy(X,W)) goto err;
644 if (!BN_add(X,X,test)) goto err;
647 if (!BN_lshift1(r0,q)) goto err;
648 if (!BN_mod(c,X,r0,ctx)) goto err;
649 if (!BN_sub(r0,c,BN_value_one())) goto err;
650 if (!BN_sub(p,X,r0)) goto err;
653 if (BN_cmp(p,test) >= 0)
656 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
659 goto end; /* found it */
666 /* "offset = offset + n + 1" */
669 if (counter >= 4096) break;
673 if(!BN_GENCB_call(cb, 2, 1))
678 /* We now need to generate g */
680 if (!BN_sub(test,p,BN_value_one())) goto err;
681 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
685 if (!BN_set_word(test,h))
690 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
695 static const unsigned char ggen[4] = {0x67,0x67,0x65,0x6e};
699 md[1] = (h >> 8) & 0xff;
701 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
703 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
705 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
707 if (!EVP_DigestUpdate(&mctx, md, 3))
709 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
711 if (!BN_bin2bn(md, mdsize, test))
715 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
716 if (!BN_is_one(g)) break;
717 if (idx < 0 && !BN_add(test,test,BN_value_one())) goto err;
719 if ( idx >= 0 && h > 0xffff)
723 if(!BN_GENCB_call(cb, 3, 1))
732 if(ret->p) BN_free(ret->p);
737 if(ret->q) BN_free(ret->q);
740 if(ret->g) BN_free(ret->g);
742 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
747 if (counter_ret != NULL) *counter_ret=counter;
748 if (h_ret != NULL) *h_ret=h;
752 if (seed_out != seed_tmp)
753 OPENSSL_free(seed_tmp);
759 if (mont != NULL) BN_MONT_CTX_free(mont);
760 EVP_MD_CTX_cleanup(&mctx);
764 int dsa_paramgen_check_g(DSA *dsa)
768 BN_MONT_CTX *mont = NULL;
774 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
776 if (BN_cmp(dsa->g, dsa->p) >= 0)
778 tmp = BN_CTX_get(ctx);
781 if ((mont=BN_MONT_CTX_new()) == NULL)
783 if (!BN_MONT_CTX_set(mont,dsa->p,ctx))
785 /* Work out g^q mod p */
786 if (!BN_mod_exp_mont(tmp,dsa->g,dsa->q, dsa->p, ctx, mont))
788 if (!BN_cmp(tmp, BN_value_one()))
795 BN_MONT_CTX_free(mont);