NAME    [Toc]    [Back]

       DH_generate_key,  DH_compute_key  - Perform Diffie-Hellman
       key exchange

SYNOPSIS    [Toc]    [Back]

       #include <openssl/dh.h>

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

DESCRIPTION    [Toc]    [Back]

       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  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.

       The DH_compute_key() function 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.  The  key  must
       point to DH_size(dh) bytes of memory.

RETURN VALUES    [Toc]    [Back]

       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    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

       Functions: dh(3), err(3), rand(3), DH_size(3)



                                               DH_generate_key(3)