=pod =head1 NAME DSA_generate_parameters - generate DSA parameters =head1 SYNOPSIS #include DSA *DSA_generate_parameters(int bits, unsigned char *seed, int seed_len, int *counter_ret, unsigned long *h_ret, void (*callback)(int, int, void *), void *cb_arg); =head1 DESCRIPTION DSA_generate_parameters() generates primes p and q and a generator g for use in the DSA. B is the length of the prime to be generated; the DSS allows a maximum of 1024 bits. If B is B or B E 20, the primes will be generated at random. Otherwise, the seed is used to generate them. If the given seed does not yield a prime q, a new random seed is chosen and placed at B. DSA_generate_parameters() places the iteration count in *B and a counter used for finding a generator in *B, unless these are B. A callback function may be used to provide feedback about the progress of the key generation. If B is not B, it will be called as follows: =over 4 =item * When a candidate for q is generated, B is called (m is 0 for the first candidate). =item * When a candidate for q has passed a test by trial division, B is called. While a candidate for q is tested by Miller-Rabin primality tests, B is called in the outer loop (once for each witness that confirms that the candidate may be prime); i is the loop counter (starting at 0). =item * When a prime q has been found, B and B are called. =item * Before a candidate for p (other than the first) is generated and tested, B is called. =item * When a candidate for p has passed the test by trial division, B is called. While it is tested by the Miller-Rabin primality test, B is called in the outer loop (once for each witness that confirms that the candidate may be prime). i is the loop counter (starting at 0). =item * When p has been found, B is called. =item * When the generator has been found, B is called. =back =head1 RETURN VALUE DSA_generate_parameters() returns a pointer to the DSA structure, or B if the parameter generation fails. The error codes can be obtained by L. =head1 BUGS Seed lengths E 20 are not supported. =head1 SEE ALSO L, L, L, L =head1 HISTORY DSA_generate_parameters() appeared in SSLeay 0.8. The B argument was added in SSLeay 0.9.0. In versions up to OpenSSL 0.9.4, B was called in the inner loop of the Miller-Rabin test whenever it reached the squaring step (the parameters to B did not reveal how many witnesses had been tested); since OpenSSL 0.9.5, B is called as in BN_is_prime(3), i.e. once for each witness. =cut