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>
85 static int dsa_builtin_paramgen(DSA
*ret
, int bits
,
86 unsigned char *seed_in
, int seed_len
,
87 int *counter_ret
, unsigned long *h_ret
, BN_GENCB
*cb
);
89 int DSA_generate_parameters_ex(DSA
*ret
, int bits
,
90 unsigned char *seed_in
, int seed_len
,
91 int *counter_ret
, unsigned long *h_ret
, BN_GENCB
*cb
)
93 if(ret
->meth
->dsa_paramgen
)
94 return ret
->meth
->dsa_paramgen(ret
, bits
, seed_in
, seed_len
,
95 counter_ret
, h_ret
, cb
);
96 return dsa_builtin_paramgen(ret
, bits
, seed_in
, seed_len
,
97 counter_ret
, h_ret
, cb
);
100 static int dsa_builtin_paramgen(DSA
*ret
, int bits
,
101 unsigned char *seed_in
, int seed_len
,
102 int *counter_ret
, unsigned long *h_ret
, BN_GENCB
*cb
)
105 unsigned char seed
[SHA_DIGEST_LENGTH
];
106 unsigned char md
[SHA_DIGEST_LENGTH
];
107 unsigned char buf
[SHA_DIGEST_LENGTH
],buf2
[SHA_DIGEST_LENGTH
];
108 BIGNUM
*r0
,*W
,*X
,*c
,*test
;
109 BIGNUM
*g
=NULL
,*q
=NULL
,*p
=NULL
;
110 BN_MONT_CTX
*mont
=NULL
;
117 if (bits
< 512) bits
=512;
118 bits
=(bits
+63)/64*64;
120 /* NB: seed_len == 0 is special case: copy generated seed to
121 * seed_in if it is not NULL.
123 if (seed_len
&& (seed_len
< 20))
124 seed_in
= NULL
; /* seed buffer too small -- ignore */
126 seed_len
= 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
127 * but our internal buffers are restricted to 160 bits*/
128 if ((seed_in
!= NULL
) && (seed_len
== 20))
130 memcpy(seed
,seed_in
,seed_len
);
131 /* set seed_in to NULL to avoid it being copied back */
135 if ((ctx
=BN_CTX_new()) == NULL
) goto err
;
137 if ((mont
=BN_MONT_CTX_new()) == NULL
) goto err
;
140 r0
= BN_CTX_get(ctx
);
147 test
= BN_CTX_get(ctx
);
149 if (!BN_lshift(test
,BN_value_one(),bits
-1))
154 for (;;) /* find q */
159 if(!BN_GENCB_call(cb
, 0, m
++))
164 RAND_pseudo_bytes(seed
,SHA_DIGEST_LENGTH
);
170 seed_len
=0; /* use random seed if 'seed_in' turns out to be bad*/
172 memcpy(buf
,seed
,SHA_DIGEST_LENGTH
);
173 memcpy(buf2
,seed
,SHA_DIGEST_LENGTH
);
174 /* precompute "SEED + 1" for step 7: */
175 for (i
=SHA_DIGEST_LENGTH
-1; i
>= 0; i
--)
178 if (buf
[i
] != 0) break;
182 EVP_Digest(seed
,SHA_DIGEST_LENGTH
,md
,NULL
,HASH
, NULL
);
183 EVP_Digest(buf
,SHA_DIGEST_LENGTH
,buf2
,NULL
,HASH
, NULL
);
184 for (i
=0; i
<SHA_DIGEST_LENGTH
; i
++)
189 md
[SHA_DIGEST_LENGTH
-1]|=0x01;
190 if (!BN_bin2bn(md
,SHA_DIGEST_LENGTH
,q
)) goto err
;
193 r
= BN_is_prime_fasttest_ex(q
, DSS_prime_checks
, ctx
,
200 /* do a callback call */
204 if(!BN_GENCB_call(cb
, 2, 0)) goto err
;
205 if(!BN_GENCB_call(cb
, 3, 0)) goto err
;
216 if ((counter
!= 0) && !BN_GENCB_call(cb
, 0, counter
))
221 /* now 'buf' contains "SEED + offset - 1" */
224 /* obtain "SEED + offset + k" by incrementing: */
225 for (i
=SHA_DIGEST_LENGTH
-1; i
>= 0; i
--)
228 if (buf
[i
] != 0) break;
231 EVP_Digest(buf
,SHA_DIGEST_LENGTH
,md
,NULL
,HASH
, NULL
);
234 if (!BN_bin2bn(md
,SHA_DIGEST_LENGTH
,r0
))
236 if (!BN_lshift(r0
,r0
,160*k
)) goto err
;
237 if (!BN_add(W
,W
,r0
)) goto err
;
241 if (!BN_mask_bits(W
,bits
-1)) goto err
;
242 if (!BN_copy(X
,W
)) goto err
;
243 if (!BN_add(X
,X
,test
)) goto err
;
246 if (!BN_lshift1(r0
,q
)) goto err
;
247 if (!BN_mod(c
,X
,r0
,ctx
)) goto err
;
248 if (!BN_sub(r0
,c
,BN_value_one())) goto err
;
249 if (!BN_sub(p
,X
,r0
)) goto err
;
252 if (BN_cmp(p
,test
) >= 0)
255 r
= BN_is_prime_fasttest_ex(p
, DSS_prime_checks
,
258 goto end
; /* found it */
265 /* "offset = offset + n + 1" */
268 if (counter
>= 4096) break;
272 if(!BN_GENCB_call(cb
, 2, 1))
275 /* We now need to generate g */
277 if (!BN_sub(test
,p
,BN_value_one())) goto err
;
278 if (!BN_div(r0
,NULL
,test
,q
,ctx
)) goto err
;
280 if (!BN_set_word(test
,h
)) goto err
;
281 if (!BN_MONT_CTX_set(mont
,p
,ctx
)) goto err
;
286 if (!BN_mod_exp_mont(g
,test
,r0
,p
,ctx
,mont
)) goto err
;
287 if (!BN_is_one(g
)) break;
288 if (!BN_add(test
,test
,BN_value_one())) goto err
;
292 if(!BN_GENCB_call(cb
, 3, 1))
299 if(ret
->p
) BN_free(ret
->p
);
300 if(ret
->q
) BN_free(ret
->q
);
301 if(ret
->g
) BN_free(ret
->g
);
305 if (ret
->p
== NULL
|| ret
->q
== NULL
|| ret
->g
== NULL
)
310 if (seed_in
!= NULL
) memcpy(seed_in
,seed
,20);
311 if (counter_ret
!= NULL
) *counter_ret
=counter
;
312 if (h_ret
!= NULL
) *h_ret
=h
;
319 if (mont
!= NULL
) BN_MONT_CTX_free(mont
);