Using Cryptography in Trust Computing for Networked Communications

We highlight some major difficulties encountered by current approaches that try to model trust computing in a realistic networked communications system. We characterize these approaches as top-down since they assume that trust is universal and readily quantifiable. Our main concern with these approaches is that their quest to define a universal trust often ends up with a loose, context-dependent definition of trust value. Based on this shortcoming of the top-down approaches, we propose another consideration of trust for networked communications. Namely, we underline the fact that trust is first and foremost a security constraint that exists in each specific network's security operation (i.e., attack and defense). Hence, its definition depends on the attack and defense being involved. We call this approach bottom-up and discuss the close relationship between trust and cryptography through some examples of network’s attack and defense.