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.