PKI Trust Models: Whom do you trust?

There has been a substantial amount of attention in the media recently regarding Public Key Infrastructures (PKI). Most often, secure web server exploits and signed malware have generated this attention and have led to the erosion of trust in PKI. Despite this negative media attention, there has been very little detailed discussion of the topic of PKI Trust proliferation and control. PKI is an integral part of our daily lives even though, for the most part, we never notice it. Europe is several years ahead of North America in the ubiquitous deployment of PKI to its citizens, but North America has begun to catch up. This paper covers four major areas including the definition of trust and trust models, implementation of trust, auditing of trust, and managing trust. The paper provides proof of concept tools to allow administrators to understand their current level of PKI trust and techniques manage trust.