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 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:
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.
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.