Updated: 2021/Apr/14


DH_generate_key(3)                  OpenSSL                 DH_generate_key(3)



NAME
       DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/dh.h>

        int DH_generate_key(DH *dh);

        int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);

DESCRIPTION
       DH_generate_key() performs the first step of a Diffie-Hellman key
       exchange by generating private and public DH values. By calling
       DH_compute_key(), these are combined with the other party's public
       value to compute the shared key.

       DH_generate_key() expects dh to contain the shared parameters dh->p and
       dh->g. It generates a random private DH value unless dh->priv_key is
       already set, and computes the corresponding public value dh->pub_key,
       which can then be published.

       DH_compute_key() computes the shared secret from the private DH value
       in dh and the other party's public value in pub_key and stores it in
       key. key must point to DH_size(dh) bytes of memory.

RETURN VALUES
       DH_generate_key() returns 1 on success, 0 otherwise.

       DH_compute_key() returns the size of the shared secret on success, -1
       on error.

       The error codes can be obtained by ERR_get_error(3).

SEE ALSO
       DH_new(3), ERR_get_error(3), RAND_bytes(3), DH_size(3)

COPYRIGHT
       Copyright 2000-2016 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>.



1.1.1i                            2018-09-23                DH_generate_key(3)