freebsd man page for dh_generate_key

DH_generate_key(3SSL)						      OpenSSL						     DH_generate_key(3SSL)

NAME

       DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange

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(3), ERR_get_error(3), rand(3), DH_size(3)

HISTORY

       DH_generate_key() and DH_compute_key() are available in all versions of SSLeay and OpenSSL.

1.0.1e								    2013-02-11						     DH_generate_key(3SSL)