1=pod 2 3=head1 NAME 4 5DH_get0_pqg, DH_set0_pqg, DH_get0_key, DH_set0_key, 6DH_get0_p, DH_get0_q, DH_get0_g, 7DH_get0_priv_key, DH_get0_pub_key, 8DH_clear_flags, DH_test_flags, DH_set_flags, DH_get0_engine, 9DH_get_length, DH_set_length - Routines for getting and setting data in a DH object 10 11=head1 SYNOPSIS 12 13 #include <openssl/dh.h> 14 15 void DH_get0_pqg(const DH *dh, 16 const BIGNUM **p, const BIGNUM **q, const BIGNUM **g); 17 int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g); 18 void DH_get0_key(const DH *dh, 19 const BIGNUM **pub_key, const BIGNUM **priv_key); 20 int DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key); 21 const BIGNUM *DH_get0_p(const DH *dh); 22 const BIGNUM *DH_get0_q(const DH *dh); 23 const BIGNUM *DH_get0_g(const DH *dh); 24 const BIGNUM *DH_get0_priv_key(const DH *dh); 25 const BIGNUM *DH_get0_pub_key(const DH *dh); 26 void DH_clear_flags(DH *dh, int flags); 27 int DH_test_flags(const DH *dh, int flags); 28 void DH_set_flags(DH *dh, int flags); 29 ENGINE *DH_get0_engine(DH *d); 30 long DH_get_length(const DH *dh); 31 int DH_set_length(DH *dh, long length); 32 33=head1 DESCRIPTION 34 35A DH object contains the parameters B<p>, B<q> and B<g>. Note that the B<q> 36parameter is optional. It also contains a public key (B<pub_key>) and 37(optionally) a private key (B<priv_key>). 38 39The B<p>, B<q> and B<g> parameters can be obtained by calling DH_get0_pqg(). 40If the parameters have not yet been set then B<*p>, B<*q> and B<*g> will be set 41to NULL. Otherwise they are set to pointers to their respective values. These 42point directly to the internal representations of the values and therefore 43should not be freed directly. 44Any of the out parameters B<p>, B<q>, and B<g> can be NULL, in which case no 45value will be returned for that parameter. 46 47The B<p>, B<q> and B<g> values can be set by calling DH_set0_pqg() and passing 48the new values for B<p>, B<q> and B<g> as parameters to the function. Calling 49this function transfers the memory management of the values to the DH object, 50and therefore the values that have been passed in should not be freed directly 51after this function has been called. The B<q> parameter may be NULL. 52 53To get the public and private key values use the DH_get0_key() function. A 54pointer to the public key will be stored in B<*pub_key>, and a pointer to the 55private key will be stored in B<*priv_key>. Either may be NULL if they have not 56been set yet, although if the private key has been set then the public key must 57be. The values point to the internal representation of the public key and 58private key values. This memory should not be freed directly. 59Any of the out parameters B<pub_key> and B<priv_key> can be NULL, in which case 60no value will be returned for that parameter. 61 62The public and private key values can be set using DH_set0_key(). Either 63parameter may be NULL, which means the corresponding DH field is left 64untouched. As with DH_set0_pqg() this function transfers the memory management 65of the key values to the DH object, and therefore they should not be freed 66directly after this function has been called. 67 68Any of the values B<p>, B<q>, B<g>, B<priv_key>, and B<pub_key> can also be 69retrieved separately by the corresponding function DH_get0_p(), DH_get0_q(), 70DH_get0_g(), DH_get0_priv_key(), and DH_get0_pub_key(), respectively. 71 72DH_set_flags() sets the flags in the B<flags> parameter on the DH object. 73Multiple flags can be passed in one go (bitwise ORed together). Any flags that 74are already set are left set. DH_test_flags() tests to see whether the flags 75passed in the B<flags> parameter are currently set in the DH object. Multiple 76flags can be tested in one go. All flags that are currently set are returned, or 77zero if none of the flags are set. DH_clear_flags() clears the specified flags 78within the DH object. 79 80DH_get0_engine() returns a handle to the ENGINE that has been set for this DH 81object, or NULL if no such ENGINE has been set. 82 83The DH_get_length() and DH_set_length() functions get and set the optional 84length parameter associated with this DH object. If the length is nonzero then 85it is used, otherwise it is ignored. The B<length> parameter indicates the 86length of the secret exponent (private key) in bits. 87 88=head1 NOTES 89 90Values retrieved with DH_get0_key() are owned by the DH object used 91in the call and may therefore I<not> be passed to DH_set0_key(). If 92needed, duplicate the received value using BN_dup() and pass the 93duplicate. The same applies to DH_get0_pqg() and DH_set0_pqg(). 94 95=head1 RETURN VALUES 96 97DH_set0_pqg() and DH_set0_key() return 1 on success or 0 on failure. 98 99DH_get0_p(), DH_get0_q(), DH_get0_g(), DH_get0_priv_key(), and DH_get0_pub_key() 100return the respective value, or NULL if it is unset. 101 102DH_test_flags() returns the current state of the flags in the DH object. 103 104DH_get0_engine() returns the ENGINE set for the DH object or NULL if no ENGINE 105has been set. 106 107DH_get_length() returns the length of the secret exponent (private key) in bits, 108or zero if no such length has been explicitly set. 109 110=head1 SEE ALSO 111 112L<DH_new(3)>, L<DH_new(3)>, L<DH_generate_parameters(3)>, L<DH_generate_key(3)>, 113L<DH_set_method(3)>, L<DH_size(3)>, L<DH_meth_new(3)> 114 115=head1 HISTORY 116 117The functions described here were added in OpenSSL 1.1.0. 118 119=head1 COPYRIGHT 120 121Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved. 122 123Licensed under the OpenSSL license (the "License"). You may not use 124this file except in compliance with the License. You can obtain a copy 125in the file LICENSE in the source distribution or at 126L<https://www.openssl.org/source/license.html>. 127 128=cut 129