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 11The following functions have been deprecated since OpenSSL 3.0, and can be 12hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 13see L<openssl_user_macros(7)>: 14 15 int DSA_generate_parameters_ex(DSA *dsa, int bits, 16 const unsigned char *seed, int seed_len, 17 int *counter_ret, unsigned long *h_ret, 18 BN_GENCB *cb); 19 20The following functions have been deprecated since OpenSSL 0.9.8, and can be 21hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 22see L<openssl_user_macros(7)>: 23 24 DSA *DSA_generate_parameters(int bits, unsigned char *seed, int seed_len, 25 int *counter_ret, unsigned long *h_ret, 26 void (*callback)(int, int, void *), void *cb_arg); 27 28=head1 DESCRIPTION 29 30All of the functions described on this page are deprecated. 31Applications should instead use L<EVP_PKEY_paramgen_init(3)> and 32L<EVP_PKEY_keygen(3)> as described in L<EVP_PKEY-DSA(7)>. 33 34DSA_generate_parameters_ex() generates primes p and q and a generator g 35for use in the DSA and stores the result in B<dsa>. 36 37B<bits> is the length of the prime p to be generated. 38For lengths under 2048 bits, the length of q is 160 bits; for lengths 39greater than or equal to 2048 bits, the length of q is set to 256 bits. 40 41If B<seed> is NULL, the primes will be generated at random. 42If B<seed_len> is less than the length of q, an error is returned. 43 44DSA_generate_parameters_ex() places the iteration count in 45*B<counter_ret> and a counter used for finding a generator in 46*B<h_ret>, unless these are B<NULL>. 47 48A callback function may be used to provide feedback about the progress 49of the key generation. If B<cb> is not B<NULL>, it will be 50called as shown below. For information on the BN_GENCB structure and the 51BN_GENCB_call function discussed below, refer to 52L<BN_generate_prime(3)>. 53 54DSA_generate_parameters() is similar to DSA_generate_parameters_ex() but 55expects an old-style callback function; see 56L<BN_generate_prime(3)> for information on the old-style callback. 57 58=over 2 59 60=item * 61 62When a candidate for q is generated, B<BN_GENCB_call(cb, 0, m++)> is called 63(m is 0 for the first candidate). 64 65=item * 66 67When a candidate for q has passed a test by trial division, 68B<BN_GENCB_call(cb, 1, -1)> is called. 69While a candidate for q is tested by Miller-Rabin primality tests, 70B<BN_GENCB_call(cb, 1, i)> is called in the outer loop 71(once for each witness that confirms that the candidate may be prime); 72i is the loop counter (starting at 0). 73 74=item * 75 76When a prime q has been found, B<BN_GENCB_call(cb, 2, 0)> and 77B<BN_GENCB_call(cb, 3, 0)> are called. 78 79=item * 80 81Before a candidate for p (other than the first) is generated and tested, 82B<BN_GENCB_call(cb, 0, counter)> is called. 83 84=item * 85 86When a candidate for p has passed the test by trial division, 87B<BN_GENCB_call(cb, 1, -1)> is called. 88While it is tested by the Miller-Rabin primality test, 89B<BN_GENCB_call(cb, 1, i)> is called in the outer loop 90(once for each witness that confirms that the candidate may be prime). 91i is the loop counter (starting at 0). 92 93=item * 94 95When p has been found, B<BN_GENCB_call(cb, 2, 1)> is called. 96 97=item * 98 99When the generator has been found, B<BN_GENCB_call(cb, 3, 1)> is called. 100 101=back 102 103=head1 RETURN VALUES 104 105DSA_generate_parameters_ex() returns a 1 on success, or 0 otherwise. 106The error codes can be obtained by L<ERR_get_error(3)>. 107 108DSA_generate_parameters() returns a pointer to the DSA structure or 109B<NULL> if the parameter generation fails. 110 111=head1 BUGS 112 113Seed lengths greater than 20 are not supported. 114 115=head1 SEE ALSO 116 117L<DSA_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, 118L<DSA_free(3)>, L<BN_generate_prime(3)> 119 120=head1 HISTORY 121 122DSA_generate_parameters_ex() was deprecated in OpenSSL 3.0. 123 124DSA_generate_parameters() was deprecated in OpenSSL 0.9.8; use 125DSA_generate_parameters_ex() instead. 126 127=head1 COPYRIGHT 128 129Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. 130 131Licensed under the Apache License 2.0 (the "License"). You may not use 132this file except in compliance with the License. You can obtain a copy 133in the file LICENSE in the source distribution or at 134L<https://www.openssl.org/source/license.html>. 135 136=cut 137