5 DSA_generate_parameters - Generate DSA parameters
9 #include <openssl/dsa.h>
11 DSA * DSA_generate_parameters(int bits, unsigned char *seed,
12 int seed_len, int *counter_ret, unsigned long *h_ret,
13 void (*callback)(), void *cb_arg);
17 DSA_generate_parameters() generates primes p and q and a generator g
20 B<bits> is the length of the prime to be generated; the DSS allows a
23 If B<seed> is NULL or B<seed_len> E<lt> 20, the primes will be
24 generated at random. Otherwise, the seed is used to generate
25 them. If the given seed does not yield a prime q, a new random
26 seed is chosen and placed at B<seed>.
28 DSA_generate_parameters() places the iteration count in
29 *B<counter_ret> and a counter used for finding a generator in
30 *B<h_ret>, unless these are NULL.
32 A callback function may be used to provide feedback about the progress
33 of the key generation. If B<callback> is not B<NULL>, it will be
40 When the the m-th candidate for q is generated, B<callback(0, m,
45 B<callback(1, j++, cb_arg)> is called in the inner loop of the
46 Miller-Rabin primality test.
50 When a prime q has been found, B<callback(2, 0, cb_arg)> and
51 B<callback(3, 0, cb_arg)> are called.
55 While candidates for p are being tested, B<callback(1, j++, cb_arg)>
56 is called in the inner loop of the Miller-Rabin primality test, then
57 B<callback(0, counter, cb_arg)> is called when the next candidate
62 When p has been found, B<callback(2, 1, cb_arg)> is called.
66 When the generator has been found, B<callback(3, 1, cb_arg)> is called.
72 DSA_generate_parameters() returns a pointer to the DSA structure, or
73 NULL if the parameter generation fails. The error codes can be
74 obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
78 The deterministic generation of p does not follow the NIST algorithm:
79 r0 is SHA1(s+k+1), but should be SHA1(s+j+k) with j_0=2,
80 j_counter=j_counter-1 + n + 1.
82 Seed lengths E<gt> 20 are not supported.
86 L<dsa(3)|dsa(3)>, L<err(3)|err(3)>, L<rand(3)|rand(3)>,
87 L<DSA_free(3)|DSA_free(3)>
91 DSA_generate_parameters() appeared in SSLeay 0.8. The B<cb_arg>
92 argument was added in SSLeay 0.9.0.