/usr/man/cat.3/DH_compute_key.3

DH_generate_key(3)           OpenSSL           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

     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.

1.0.2t               Last change: 2019-09-10                    1

See also DH_generate_key(3)