DH_generate_parameters_ex, DH_generate_parameters, DH_check, DH_check_params, DH_check_ex, DH_check_params_ex, DH_check_pub_key_ex - generate and check Diffie-Hellman parameters
#include <openssl/dh.h>
int DH_generate_parameters_ex(DH *dh, int prime_len, int generator, BN_GENCB *cb);
int DH_check(DH *dh, int *codes); int DH_check_params(DH *dh, int *codes);
int DH_check_ex(const DH *dh); int DH_check_params_ex(const DH *dh); int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key);
Deprecated:
#if OPENSSL_API_COMPAT < 0x00908000L DH *DH_generate_parameters(int prime_len, int generator, void (*callback)(int, int, void *), void *cb_arg); #endif
DH_generate_parameters_ex()
generates Diffie-Hellman parameters that can
be shared among a group of users, and stores them in the provided DH
structure. The pseudo-random number generator must be
seeded before calling it.
The parameters generated by DH_generate_parameters_ex()
should not be used in
signature schemes.
prime_len is the length in bits of the safe prime to be generated. generator is a small number > 1, typically 2 or 5.
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 described in BN_generate_prime(3) while a random prime
number is generated, and when a prime has been found, BN_GENCB_call(cb, 3, 0)
is called. See BN_generate_prime_ex(3) for information on
the BN_GENCB_call()
function.
DH_generate_parameters()
is similar to DH_generate_prime_ex()
but
expects an old-style callback function; see
BN_generate_prime(3) for information on the old-style callback.
DH_check_params()
confirms that the p and g are likely enough to
be valid.
This is a lightweight check, if a more thorough check is needed, use
DH_check()
.
The value of *codes is updated with any problems found.
If *codes is zero then no problems were found, otherwise the
following bits may be set:
The parameter p has been determined to not being an odd prime. Note that the lack of this bit doesn't guarantee that p is a prime.
The generator g is not suitable. Note that the lack of this bit doesn't guarantee that g is suitable, unless p is known to be a strong prime.
DH_check()
confirms that the Diffie-Hellman parameters dh are valid. The
value of *codes is updated with any problems found. If *codes is zero then
no problems were found, otherwise the following bits may be set:
The parameter p is not prime.
The parameter p is not a safe prime and no q value is present.
The generator g cannot be checked for suitability.
The generator g is not suitable.
The parameter q is not prime.
The parameter q is invalid.
The parameter j is invalid.
DH_check_ex()
, DH_check_params()
and DH_check_pub_key_ex()
are similar to
DH_check()
and DH_check_params()
respectively, but the error reasons are added
to the thread's error queue instead of provided as return values from the
function.
DH_generate_parameters_ex()
, DH_check()
and DH_check_params()
return 1
if the check could be performed, 0 otherwise.
DH_generate_parameters()
returns a pointer to the DH structure or NULL if
the parameter generation fails.
DH_check_ex()
, DH_check_params()
and DH_check_pub_key_ex()
return 1 if the
check is successful, 0 for failed.
The error codes can be obtained by ERR_get_error(3).
DH_new(3), ERR_get_error(3), RAND_bytes(3), DH_free(3)
DH_generate_parameters()
was deprecated in OpenSSL 0.9.8; use
DH_generate_parameters_ex()
instead.
Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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.