DH_generate_key(3)DH_generate_key(3)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
The DH_generate_key() function 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.
The DH_generate_key() function expects dh to contain the shared parame‐
ters 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.
The DH_compute_key() function computes the shared secret from the pri‐
vate DH value in dh and the other party's public value in pub_key and
stores it in key. The key must point to DH_size(dh) bytes of memory.
RETURN VALUES
The DH_generate_key() function returns 1 on success, 0 otherwise.
The DH_compute_key() function returns the size of the shared secret on
success, -1 on error.
The error codes can be obtained from ERR_get_error().
HISTORY
The DH_generate_key() and DH_compute_key() functions are available in
all versions of SSLeay and OpenSSL.
SEE ALSO
Functions: dh(3), err(3), rand(3), DH_size(3)DH_generate_key(3)