Hi, My name is Pietro Di Primo and I work on the INFN Grid project (http://grid.infn.it/). I'm trying to develop an application based on stunnel. Everything works well when I use user certificates (signed by our CA), but i need to use (on the client side) a particular proxy. This proxy contains a public and a private key, and the public key of the user that generated it (I atteched a file with a such proxy). On the server side I have the CA certificate but not the user's one, so I can't verify the client (unable to get local issuer certificate). I tried to get the user certificate using the SSL_get_peer_cert_chain function on the server, but it returns NULL. On the client side I tried SSL_CTX_use_certificate_chain_file, Also I tried to get a STACK_OF(X509) and use SSL_CTX_use_certificate (for proxy certificate), and SSL_CTX_add_extra_chain_cert (to include the user's certificate), but it still doesn't work. Can you help me please? Best Regards -- --- Ing. Pietro Di Primo INFN - Istituto Nazionale di Fisica Nucleare Grid Computing Research Area Via S. Sofia 78 95123 CATANIA (Italy) Voice : +39 095 378-5446/5517 Fax. : +39 095 378 5518 Mobile : +39 320 8591527 E-mail : pietro.diprimo@ct.infn.it Skype : pietrodiprimo