=pod =head1 NAME DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange =head1 SYNOPSIS #include int DH_generate_key(DH *dh); int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh); =head1 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 B to contain the shared parameters Bp> and Bg>. It generates a random private DH value unless Bpriv_key> is already set, and computes the corresponding public value Bpub_key>, which can then be published. DH_compute_key() computes the shared secret from the private DH value in B and the other party's public value in B and stores it in B. B must point to B bytes of memory. =head1 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 L. =head1 SEE ALSO L, L, L, L =head1 HISTORY DH_generate_key() and DH_compute_key() are available in all versions of SSLeay and OpenSSL. =cut