diff options
Diffstat (limited to 'doc')
-rw-r--r-- | doc/crypto/DSA_generate_parameters.pod | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/doc/crypto/DSA_generate_parameters.pod b/doc/crypto/DSA_generate_parameters.pod index 1058c5eb44..bae4e1b560 100644 --- a/doc/crypto/DSA_generate_parameters.pod +++ b/doc/crypto/DSA_generate_parameters.pod @@ -20,14 +20,14 @@ for use in the DSA. B<bits> is the length of the prime to be generated; the DSS allows a maximum of 1024 bits. -If B<seed> is NULL or B<seed_len> E<lt> 20, the primes will be +If B<seed> is B<NULL> or B<seed_len> E<lt> 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<seed>. DSA_generate_parameters() places the iteration count in *B<counter_ret> and a counter used for finding a generator in -*B<h_ret>, unless these are NULL. +*B<h_ret>, unless these are B<NULL>. A callback function may be used to provide feedback about the progress of the key generation. If B<callback> is not B<NULL>, it will be @@ -37,13 +37,15 @@ called as follows: =item * -When the the m-th candidate for q is generated, B<callback(0, m, -cb_arg)> is called. +When a candidate for q is generated, B<callback(0, m++, cb_arg)> is called +(m is 0 for the first candidate). =item * -B<callback(1, j++, cb_arg)> is called in the inner loop of the -Miller-Rabin primality test. +While a candidate for q is tested, B<callback(1, i, cb_arg)> +is called in the outer loop of the Miller-Rabin primality tests +(once for each witness that confirms that the candidate may be prime). +i is the loop counter (starting at 0). =item * @@ -52,10 +54,15 @@ B<callback(3, 0, cb_arg)> are called. =item * -While candidates for p are being tested, B<callback(1, j++, cb_arg)> -is called in the inner loop of the Miller-Rabin primality test, then -B<callback(0, counter, cb_arg)> is called when the next candidate -is chosen. +Before a candidate for p (other than the first) is generated and tested, +B<callback(0, counter, cb_arg)> is called. + +=item * + +While a candidate for p is tested, B<callback(1, j++, cb_arg)> +is called in the outer loop of the Miller-Rabin primality test +(once for each witness that confirms that the candidate may be prime). +i is the loop counter (starting at 0). =item * @@ -70,15 +77,11 @@ When the generator has been found, B<callback(3, 1, cb_arg)> is called. =head1 RETURN VALUE DSA_generate_parameters() returns a pointer to the DSA structure, or -NULL if the parameter generation fails. The error codes can be +B<NULL> if the parameter generation fails. The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. =head1 BUGS -The deterministic generation of p does not follow the NIST algorithm: -r0 is SHA1(s+k+1), but should be SHA1(s+j+k) with j_0=2, -j_counter=j_counter-1 + n + 1. - Seed lengths E<gt> 20 are not supported. =head1 SEE ALSO @@ -90,5 +93,9 @@ L<DSA_free(3)|DSA_free(3)> DSA_generate_parameters() appeared in SSLeay 0.8. The B<cb_arg> argument was added in SSLeay 0.9.0. - +In versions up to OpenSSL 0.9.4, B<callback(1, ...)> was called +in the inner loop of the Miller-Rabin test whenever it reached the +squaring step (the parameters to B<callback> did not reveal how many +witnesses had been tested); since OpenSSL 0.9.5, B<callback(1, ...)> +is called as in BN_is_prime(3), i.e. once for each witness. =cut |