CTX_set_post_handshake_auth() and SSL_set_post_handshake_auth() enable the Post-Handshake Authentication extension to be added to the ClientHello such that post-handshake authentication can be requested by the server. If <b>val</b> is 0 then the extension is not sent, otherwise it is. By default the extension is not sent. A certificate callback will need to be set via SSL_CTX_set_client_cert_cb() if no certificate is provided at initialization.</p>

<p>SSL_verify_client_post_handshake() causes a Certificate