The Research On Trust Management In Peer-to-Peer Networks Based On Public Key Infrastructure

The applications of security aspects in digital society heavily rely on the Public Key Infrastructure (PKI),a powerful tool to represent and manage trust relationships among entities so that the transactions based on these kinds of relations can be achieved practically. Definitely the mechanism of PKI is restricted to propagate the trust relationships instead of bringing any trust forth by itself.Aiming the applications of PKI at Peer-to-Peer networks (P2P),we provide an elegant composite model for trust and authorization to solve trust management problem efficiently. The idea to build up such a model originates from that of "Web of Trust" model of PGP mixed up with that of the delegation model of SPKI,as well as its resulted access control strategy by the combinations of trust and delegation policies. More details as follows:1. The composite model defined above adopts the nice features from that of PGP and SPKI. It can be viewed as a remedy of deficiencies in the respective model due to its reality to reflect one to one property and equivalent actions of each entity. Also one is benefit for its agile,easy implementation mechanism and suitable for extensions of various applications in the distributed network environment.2. A comprehensive framework is developed for the above model. Those include functional modules,related data structure,frames of message encoding,certificate management database,ring of keys,concrete information flows for access control and so on.3. Based on the pioneer works of Rahman and Hailies [72],we study an approach computing the trust value among entities special for P2P environment. The approach focuses on well defined update attributions of trust relationship controlled by any entity dynamically and tries to simplify trust chain model in cross delegations setting by the treatment of its associated definitions and related data computations.4. We provide an efficient trust relationship query protocol by applying new notion called recommendation certificate. It has several advantages such as efficiency,low computational and communication complexity compared with available results due to our associated processing strategy indicated by the protocol.5. We solve the discovery problem by developing a complete authorization certificate query protocol for distributed environment based on Clarke's discovery algorithm [132] for local certificate databases. This query protocol enjoys easy implementation,high efficiency and low computational complexity. Furthermore,it reduces the query numbersof public keys to...