DSA_generate_parameters_ex, DSA_generate_parameters - generate DSA parameters
#include <openssl/dsa.h>
The following functions have been deprecated since OpenSSL 3.0, and can be
hidden entirely by defining
OPENSSL_API_COMPAT with a suitable version
value, see
openssl_user_macros(7):
int DSA_generate_parameters_ex(DSA *dsa, int bits,
const unsigned char *seed, int seed_len,
int *counter_ret, unsigned long *h_ret,
BN_GENCB *cb);
The following functions have been deprecated since OpenSSL 0.9.8, and can be
hidden entirely by defining
OPENSSL_API_COMPAT with a suitable version
value, see
openssl_user_macros(7):
DSA *DSA_generate_parameters(int bits, unsigned char *seed, int seed_len,
int *counter_ret, unsigned long *h_ret,
void (*callback)(int, int, void *), void *cb_arg);
All of the functions described on this page are deprecated. Applications should
instead use
EVP_PKEY_paramgen_init(3) and
EVP_PKEY_keygen(3) as
described in
EVP_PKEY-DSA(7).
DSA_generate_parameters_ex() generates primes p and q and a generator g
for use in the DSA and stores the result in
dsa.
bits is the length of the prime p to be generated. For lengths under 2048
bits, the length of q is 160 bits; for lengths greater than or equal to 2048
bits, the length of q is set to 256 bits.
If
seed is NULL, the primes will be generated at random. If
seed_len is less than the length of q, an error is returned.
DSA_generate_parameters_ex() places the iteration count in *
counter_ret and a counter used for finding a generator in *
h_ret, unless these are
NULL.
A callback function may be used to provide feedback about the progress of the
key generation. If
cb is not
NULL, it will be called as shown
below. For information on the BN_GENCB structure and the BN_GENCB_call
function discussed below, refer to
BN_generate_prime(3).
DSA_generate_parameters() is similar to
DSA_generate_parameters_ex() but expects an old-style callback
function; see
BN_generate_prime(3) for information on the old-style
callback.
- •
- When a candidate for q is generated, BN_GENCB_call(cb,
0, m++) is called (m is 0 for the first candidate).
- •
- When a candidate for q has passed a test by trial division,
BN_GENCB_call(cb, 1, -1) is called. While a candidate for q is
tested by Miller-Rabin primality tests, BN_GENCB_call(cb, 1, i) is
called in the outer loop (once for each witness that confirms that the
candidate may be prime); i is the loop counter (starting at 0).
- •
- When a prime q has been found, BN_GENCB_call(cb, 2,
0) and BN_GENCB_call(cb, 3, 0) are called.
- •
- Before a candidate for p (other than the first) is
generated and tested, BN_GENCB_call(cb, 0, counter) is called.
- •
- When a candidate for p has passed the test by trial
division, BN_GENCB_call(cb, 1, -1) is called. While it is tested by
the Miller-Rabin primality test, BN_GENCB_call(cb, 1, i) is called
in the outer loop (once for each witness that confirms that the candidate
may be prime). i is the loop counter (starting at 0).
- •
- When p has been found, BN_GENCB_call(cb, 2, 1) is
called.
- •
- When the generator has been found, BN_GENCB_call(cb, 3,
1) is called.
DSA_generate_parameters_ex() returns a 1 on success, or 0 otherwise. The
error codes can be obtained by
ERR_get_error(3).
DSA_generate_parameters() returns a pointer to the DSA structure or
NULL if the parameter generation fails.
Seed lengths greater than 20 are not supported.
DSA_new(3),
ERR_get_error(3),
RAND_bytes(3),
DSA_free(3),
BN_generate_prime(3)
DSA_generate_parameters_ex() was deprecated in OpenSSL 3.0.
DSA_generate_parameters() was deprecated in OpenSSL 0.9.8; use
DSA_generate_parameters_ex() instead.
Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy in the
file LICENSE in the source distribution or at
<
https://www.openssl.org/source/license.html>.