a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
111 lines
3.3 KiB
Text
111 lines
3.3 KiB
Text
=pod
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=head1 NAME
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DSA_generate_parameters_ex, DSA_generate_parameters - generate DSA parameters
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=head1 SYNOPSIS
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#include <openssl/dsa.h>
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int DSA_generate_parameters_ex(DSA *dsa, int bits,
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const unsigned char *seed,int seed_len,
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
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Deprecated:
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DSA *DSA_generate_parameters(int bits, unsigned char *seed,
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int seed_len, int *counter_ret, unsigned long *h_ret,
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void (*callback)(int, int, void *), void *cb_arg);
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=head1 DESCRIPTION
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DSA_generate_parameters_ex() generates primes p and q and a generator g
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for use in the DSA and stores the result in B<dsa>.
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B<bits> is the length of the prime p to be generated.
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For lengths under 2048 bits, the length of q is 160 bits; for lengths
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greater than or equal to 2048 bits, the length of q is set to 256 bits.
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If B<seed> is NULL, the primes will be generated at random.
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If B<seed_len> is less than the length of q, an error is returned.
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DSA_generate_parameters_ex() places the iteration count in
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*B<counter_ret> and a counter used for finding a generator in
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*B<h_ret>, unless these are B<NULL>.
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A callback function may be used to provide feedback about the progress
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of the key generation. If B<cb> is not B<NULL>, it will be
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called as shown below. For information on the BN_GENCB structure and the
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BN_GENCB_call function discussed below, refer to
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L<BN_generate_prime(3)>.
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=over 4
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=item *
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When a candidate for q is generated, B<BN_GENCB_call(cb, 0, m++)> is called
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(m is 0 for the first candidate).
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=item *
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When a candidate for q has passed a test by trial division,
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B<BN_GENCB_call(cb, 1, -1)> is called.
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While a candidate for q is tested by Miller-Rabin primality tests,
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B<BN_GENCB_call(cb, 1, i)> is called in the outer loop
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(once for each witness that confirms that the candidate may be prime);
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i is the loop counter (starting at 0).
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=item *
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When a prime q has been found, B<BN_GENCB_call(cb, 2, 0)> and
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B<BN_GENCB_call(cb, 3, 0)> are called.
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=item *
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Before a candidate for p (other than the first) is generated and tested,
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B<BN_GENCB_call(cb, 0, counter)> is called.
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=item *
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When a candidate for p has passed the test by trial division,
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B<BN_GENCB_call(cb, 1, -1)> is called.
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While it is tested by the Miller-Rabin primality test,
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B<BN_GENCB_call(cb, 1, i)> is called in the outer loop
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(once for each witness that confirms that the candidate may be prime).
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i is the loop counter (starting at 0).
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=item *
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When p has been found, B<BN_GENCB_call(cb, 2, 1)> is called.
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=item *
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When the generator has been found, B<BN_GENCB_call(cb, 3, 1)> is called.
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=back
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DSA_generate_parameters() (deprecated) works in much the same way as for DSA_generate_parameters_ex, except that no B<dsa> parameter is passed and
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instead a newly allocated B<DSA> structure is returned. Additionally "old
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style" callbacks are used instead of the newer BN_GENCB based approach.
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Refer to L<BN_generate_prime(3)> for further information.
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=head1 RETURN VALUE
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DSA_generate_parameters_ex() returns a 1 on success, or 0 otherwise.
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DSA_generate_parameters() returns a pointer to the DSA structure, or
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B<NULL> if the parameter generation fails.
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The error codes can be obtained by L<ERR_get_error(3)>.
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=head1 BUGS
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Seed lengths E<gt> 20 are not supported.
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=head1 SEE ALSO
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L<dsa(3)>, L<ERR_get_error(3)>, L<rand(3)>,
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L<DSA_free(3)>, L<BN_generate_prime(3)>
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=cut
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