1=pod 2 3=head1 NAME 4 5DSA_generate_parameters_ex, DSA_generate_parameters - generate DSA parameters 6 7=head1 SYNOPSIS 8 9 #include <openssl/dsa.h> 10 11 int DSA_generate_parameters_ex(DSA *dsa, int bits, 12 const unsigned char *seed, int seed_len, 13 int *counter_ret, unsigned long *h_ret, 14 BN_GENCB *cb); 15 16Deprecated: 17 18 #if OPENSSL_API_COMPAT < 0x00908000L 19 DSA *DSA_generate_parameters(int bits, unsigned char *seed, int seed_len, 20 int *counter_ret, unsigned long *h_ret, 21 void (*callback)(int, int, void *), void *cb_arg); 22 #endif 23 24=head1 DESCRIPTION 25 26DSA_generate_parameters_ex() generates primes p and q and a generator g 27for use in the DSA and stores the result in B<dsa>. 28 29B<bits> is the length of the prime p to be generated. 30For lengths under 2048 bits, the length of q is 160 bits; for lengths 31greater than or equal to 2048 bits, the length of q is set to 256 bits. 32 33If B<seed> is NULL, the primes will be generated at random. 34If B<seed_len> is less than the length of q, an error is returned. 35 36DSA_generate_parameters_ex() places the iteration count in 37*B<counter_ret> and a counter used for finding a generator in 38*B<h_ret>, unless these are B<NULL>. 39 40A callback function may be used to provide feedback about the progress 41of the key generation. If B<cb> is not B<NULL>, it will be 42called as shown below. For information on the BN_GENCB structure and the 43BN_GENCB_call function discussed below, refer to 44L<BN_generate_prime(3)>. 45 46DSA_generate_prime() is similar to DSA_generate_prime_ex() but 47expects an old-style callback function; see 48L<BN_generate_prime(3)> for information on the old-style callback. 49 50=over 2 51 52=item * 53 54When a candidate for q is generated, B<BN_GENCB_call(cb, 0, m++)> is called 55(m is 0 for the first candidate). 56 57=item * 58 59When a candidate for q has passed a test by trial division, 60B<BN_GENCB_call(cb, 1, -1)> is called. 61While a candidate for q is tested by Miller-Rabin primality tests, 62B<BN_GENCB_call(cb, 1, i)> is called in the outer loop 63(once for each witness that confirms that the candidate may be prime); 64i is the loop counter (starting at 0). 65 66=item * 67 68When a prime q has been found, B<BN_GENCB_call(cb, 2, 0)> and 69B<BN_GENCB_call(cb, 3, 0)> are called. 70 71=item * 72 73Before a candidate for p (other than the first) is generated and tested, 74B<BN_GENCB_call(cb, 0, counter)> is called. 75 76=item * 77 78When a candidate for p has passed the test by trial division, 79B<BN_GENCB_call(cb, 1, -1)> is called. 80While it is tested by the Miller-Rabin primality test, 81B<BN_GENCB_call(cb, 1, i)> is called in the outer loop 82(once for each witness that confirms that the candidate may be prime). 83i is the loop counter (starting at 0). 84 85=item * 86 87When p has been found, B<BN_GENCB_call(cb, 2, 1)> is called. 88 89=item * 90 91When the generator has been found, B<BN_GENCB_call(cb, 3, 1)> is called. 92 93=back 94 95=head1 RETURN VALUES 96 97DSA_generate_parameters_ex() returns a 1 on success, or 0 otherwise. 98The error codes can be obtained by L<ERR_get_error(3)>. 99 100DSA_generate_parameters() returns a pointer to the DSA structure or 101B<NULL> if the parameter generation fails. 102 103=head1 BUGS 104 105Seed lengths greater than 20 are not supported. 106 107=head1 SEE ALSO 108 109L<DSA_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, 110L<DSA_free(3)>, L<BN_generate_prime(3)> 111 112=head1 HISTORY 113 114DSA_generate_parameters() was deprecated in OpenSSL 0.9.8; use 115DSA_generate_parameters_ex() instead. 116 117=head1 COPYRIGHT 118 119Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. 120 121Licensed under the OpenSSL license (the "License"). You may not use 122this file except in compliance with the License. You can obtain a copy 123in the file LICENSE in the source distribution or at 124L<https://www.openssl.org/source/license.html>. 125 126=cut 127