1 /*-
2  * Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 /*
11  * Example showing how to generate an DSA key pair.
12  */
13 
14 #include <openssl/evp.h>
15 #include "dsa.inc"
16 
17 /*
18  * Generate dsa params using default values.
19  * See the EVP_PKEY_DSA_param_fromdata demo if you need
20  * to load DSA params from raw values.
21  * See the EVP_PKEY_DSA_paramgen demo if you need to
22  * use non default parameters.
23  */
24 EVP_PKEY *dsa_genparams(OSSL_LIB_CTX *libctx, const char *propq)
25 {
26     EVP_PKEY *dsaparamkey = NULL;
27     EVP_PKEY_CTX *ctx = NULL;
28 
29     /* Use the dsa params in a EVP_PKEY ctx */
30     ctx = EVP_PKEY_CTX_new_from_name(libctx, "DSA", propq);
31     if (ctx == NULL) {
32         fprintf(stderr, "EVP_PKEY_CTX_new_from_name() failed\n");
33         return NULL;
34     }
35 
36     if (EVP_PKEY_paramgen_init(ctx) <= 0
37             || EVP_PKEY_paramgen(ctx, &dsaparamkey) <= 0) {
38         fprintf(stderr, "DSA paramgen failed\n");
39         goto cleanup;
40     }
41 cleanup:
42     EVP_PKEY_CTX_free(ctx);
43     return dsaparamkey;
44 }
45 
46 int main(int argc, char **argv)
47 {
48     int rv = EXIT_FAILURE;
49     OSSL_LIB_CTX *libctx = NULL;
50     const char *propq = NULL;
51     EVP_PKEY *dsaparamskey = NULL;
52     EVP_PKEY *dsakey = NULL;
53     EVP_PKEY_CTX *ctx = NULL;
54 
55     /* Generate random dsa params */
56     dsaparamskey = dsa_genparams(libctx, propq);
57     if (dsaparamskey == NULL)
58         goto cleanup;
59 
60     /* Use the dsa params in a EVP_PKEY ctx */
61     ctx = EVP_PKEY_CTX_new_from_pkey(libctx, dsaparamskey, propq);
62     if (ctx == NULL) {
63         fprintf(stderr, "EVP_PKEY_CTX_new_from_pkey() failed\n");
64         goto cleanup;
65     }
66 
67     /* Generate a key using the dsa params */
68     if (EVP_PKEY_keygen_init(ctx) <= 0
69             || EVP_PKEY_keygen(ctx, &dsakey) <= 0) {
70         fprintf(stderr, "DSA keygen failed\n");
71         goto cleanup;
72     }
73 
74     if (!dsa_print_key(dsakey, 1, libctx, propq))
75         goto cleanup;
76 
77     rv = EXIT_SUCCESS;
78 cleanup:
79     EVP_PKEY_free(dsakey);
80     EVP_PKEY_free(dsaparamskey);
81     EVP_PKEY_CTX_free(ctx);
82     return rv;
83 }
84