I have recently wrote a small client-server python code for illustration of the one time password creation and verification, creation of certificate authority, using digital certificates for authentication, signing and timestamp, and SSL proxy for communication security, my work is still under evaluation by the university so I can not publicate the source code for public now but you can find private link under the Source code section of my proposal page on Melange.

Such work can be started by the establishment of a system of logging decisions concerning the placing of trust in a particular certificate and certificate chain verification, refine the control of the trust and seek alternative solutions to build the trust as the use of PGP instead of x.509.