1=pod 2 3=head1 NAME 4 5DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange 6 7=head1 SYNOPSIS 8 9 #include <openssl/dh.h> 10 11 int DH_generate_key(DH *dh); 12 13 int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh); 14 15=head1 DESCRIPTION 16 17DH_generate_key() performs the first step of a Diffie-Hellman key 18exchange by generating private and public DH values. By calling 19DH_compute_key(), these are combined with the other party's public 20value to compute the shared key. 21 22DH_generate_key() expects B<dh> to contain the shared parameters 23B<dh-E<gt>p> and B<dh-E<gt>g>. It generates a random private DH value 24unless B<dh-E<gt>priv_key> is already set, and computes the 25corresponding public value B<dh-E<gt>pub_key>, which can then be 26published. 27 28DH_compute_key() computes the shared secret from the private DH value 29in B<dh> and the other party's public value in B<pub_key> and stores 30it in B<key>. B<key> must point to B<DH_size(dh)> bytes of memory. 31 32=head1 RETURN VALUES 33 34DH_generate_key() returns 1 on success, 0 otherwise. 35 36DH_compute_key() returns the size of the shared secret on success, -1 37on error. 38 39The error codes can be obtained by L<ERR_get_error(3)>. 40 41=head1 SEE ALSO 42 43L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, L<DH_size(3)> 44 45=head1 COPYRIGHT 46 47Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. 48 49Licensed under the OpenSSL license (the "License"). You may not use 50this file except in compliance with the License. You can obtain a copy 51in the file LICENSE in the source distribution or at 52L<https://www.openssl.org/source/license.html>. 53 54=cut 55