Formal Analysis of Trust Chain

In this paper, we propose a formal model of trust chain from the view of measurement structure and remote attestation. Trust chain is an important technology in Trusted Computing and has received considerable attention. However, related researches on trust chain have some deficiencies such as the coarse granularity, single measurement function and ignorance of influence from run-environment when report. The goal of this paper is to analyze these problems and give a formal model to guide practice. To achieve the goal, we propose following improvements: 1. Design a measurement tree by refining coarse-grained entities and enriching measurement functions. 2. Improve the tree structure by introducing measurement agent to simplify the role of entities that is approach to engineering practice. 3. Construct the trust support group as the influence on trust of entities from the system environment. 4. Develop a remote verification process between two arbitrary end-points in Internet such as client and server. This paper offers a prototype toward establishing, reporting and verifying a trust chain in communication, which is applicable in pervasive circumstance.