diff options
Diffstat (limited to 'src/lib/libcrypto/doc/DSA_generate_parameters.pod')
| -rw-r--r-- | src/lib/libcrypto/doc/DSA_generate_parameters.pod | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/src/lib/libcrypto/doc/DSA_generate_parameters.pod b/src/lib/libcrypto/doc/DSA_generate_parameters.pod new file mode 100644 index 0000000000..be7c924ff8 --- /dev/null +++ b/src/lib/libcrypto/doc/DSA_generate_parameters.pod | |||
| @@ -0,0 +1,105 @@ | |||
| 1 | =pod | ||
| 2 | |||
| 3 | =head1 NAME | ||
| 4 | |||
| 5 | DSA_generate_parameters - generate DSA parameters | ||
| 6 | |||
| 7 | =head1 SYNOPSIS | ||
| 8 | |||
| 9 | #include <openssl/dsa.h> | ||
| 10 | |||
| 11 | DSA *DSA_generate_parameters(int bits, unsigned char *seed, | ||
| 12 | int seed_len, int *counter_ret, unsigned long *h_ret, | ||
| 13 | void (*callback)(int, int, void *), void *cb_arg); | ||
| 14 | |||
| 15 | =head1 DESCRIPTION | ||
| 16 | |||
| 17 | DSA_generate_parameters() generates primes p and q and a generator g | ||
| 18 | for use in the DSA. | ||
| 19 | |||
| 20 | B<bits> is the length of the prime to be generated; the DSS allows a | ||
| 21 | maximum of 1024 bits. | ||
| 22 | |||
| 23 | If B<seed> is B<NULL> or B<seed_len> E<lt> 20, the primes will be | ||
| 24 | generated at random. Otherwise, the seed is used to generate | ||
| 25 | them. If the given seed does not yield a prime q, a new random | ||
| 26 | seed is chosen and placed at B<seed>. | ||
| 27 | |||
| 28 | DSA_generate_parameters() places the iteration count in | ||
| 29 | *B<counter_ret> and a counter used for finding a generator in | ||
| 30 | *B<h_ret>, unless these are B<NULL>. | ||
| 31 | |||
| 32 | A callback function may be used to provide feedback about the progress | ||
| 33 | of the key generation. If B<callback> is not B<NULL>, it will be | ||
| 34 | called as follows: | ||
| 35 | |||
| 36 | =over 4 | ||
| 37 | |||
| 38 | =item * | ||
| 39 | |||
| 40 | When a candidate for q is generated, B<callback(0, m++, cb_arg)> is called | ||
| 41 | (m is 0 for the first candidate). | ||
| 42 | |||
| 43 | =item * | ||
| 44 | |||
| 45 | When a candidate for q has passed a test by trial division, | ||
| 46 | B<callback(1, -1, cb_arg)> is called. | ||
| 47 | While a candidate for q is tested by Miller-Rabin primality tests, | ||
| 48 | B<callback(1, i, cb_arg)> is called in the outer loop | ||
| 49 | (once for each witness that confirms that the candidate may be prime); | ||
| 50 | i is the loop counter (starting at 0). | ||
| 51 | |||
| 52 | =item * | ||
| 53 | |||
| 54 | When a prime q has been found, B<callback(2, 0, cb_arg)> and | ||
| 55 | B<callback(3, 0, cb_arg)> are called. | ||
| 56 | |||
| 57 | =item * | ||
| 58 | |||
| 59 | Before a candidate for p (other than the first) is generated and tested, | ||
| 60 | B<callback(0, counter, cb_arg)> is called. | ||
| 61 | |||
| 62 | =item * | ||
| 63 | |||
| 64 | When a candidate for p has passed the test by trial division, | ||
| 65 | B<callback(1, -1, cb_arg)> is called. | ||
| 66 | While it is tested by the Miller-Rabin primality test, | ||
| 67 | B<callback(1, i, cb_arg)> is called in the outer loop | ||
| 68 | (once for each witness that confirms that the candidate may be prime). | ||
| 69 | i is the loop counter (starting at 0). | ||
| 70 | |||
| 71 | =item * | ||
| 72 | |||
| 73 | When p has been found, B<callback(2, 1, cb_arg)> is called. | ||
| 74 | |||
| 75 | =item * | ||
| 76 | |||
| 77 | When the generator has been found, B<callback(3, 1, cb_arg)> is called. | ||
| 78 | |||
| 79 | =back | ||
| 80 | |||
| 81 | =head1 RETURN VALUE | ||
| 82 | |||
| 83 | DSA_generate_parameters() returns a pointer to the DSA structure, or | ||
| 84 | B<NULL> if the parameter generation fails. The error codes can be | ||
| 85 | obtained by L<ERR_get_error(3)|ERR_get_error(3)>. | ||
| 86 | |||
| 87 | =head1 BUGS | ||
| 88 | |||
| 89 | Seed lengths E<gt> 20 are not supported. | ||
| 90 | |||
| 91 | =head1 SEE ALSO | ||
| 92 | |||
| 93 | L<dsa(3)|dsa(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, | ||
| 94 | L<DSA_free(3)|DSA_free(3)> | ||
| 95 | |||
| 96 | =head1 HISTORY | ||
| 97 | |||
| 98 | DSA_generate_parameters() appeared in SSLeay 0.8. The B<cb_arg> | ||
| 99 | argument was added in SSLeay 0.9.0. | ||
| 100 | In versions up to OpenSSL 0.9.4, B<callback(1, ...)> was called | ||
| 101 | in the inner loop of the Miller-Rabin test whenever it reached the | ||
| 102 | squaring step (the parameters to B<callback> did not reveal how many | ||
| 103 | witnesses had been tested); since OpenSSL 0.9.5, B<callback(1, ...)> | ||
| 104 | is called as in BN_is_prime(3), i.e. once for each witness. | ||
| 105 | =cut | ||
