Dynamic Bridge Model Based On The Pki Trust Mechanism

With the rapid development of computer network technology around the world applications of computer network brought great convenience to people. It improved the efficiency of work, changed the way of study and enriched our life of culture and entertainment. However, at a cost of convenience, computer network also results in security problems because of its open and sharing characteristics. People have to devote their attention to various solutions to Internet and Intranet.In 1976 American scientists proposed that the encryption system of public key could solve the problem of digital signature by cracking the hard nut of key management of network information system. The encryption system of public key can also be used in verifying identification and ensuring data integrity. Hereafter Public Key Infrastructure (PKI) based on Public Key(PK)became an attractive research field in network securityWith an introduction to the definition of PKI and its service and applications several traditional trust models. e.g. Strict Hierarchical Trust Model, Cross-certified Mesh Trust Model, Hybrid Trust Model, were intensively and extensively studied. Comparative studies of these traditional models were carried out from different points of view, including the selection of trust anchor PK, inter—corporation support, path construction directory dependency and growth model. The primary characteristics of the alternative trust models were summarized and their application scopes were analyzed.With the research of kinds of trust models, aiming at the deficiency of the bridge CAs trust model, this paper proposes the dynamic bridge trust model. To sum up, our work has approximately two innovation as follow: The first one is the import of the conception of "dynamic bridge", which is an automatically created transformation of a cross certificate topology, designed to reflect the same trust arrangements and constraints, but in a simplified structure., reduces the number of possible routesdrastically. At one time, this paper gives the flow chart of path construction of dynamic bridge trust models and Comparison of capability and analyses of feasibility. The second innovation in this paper is amelioration of the method of modeling PKI which is from the point of view of consumer, and proposing the method that uses the condition predication logic to the formalize modeling PKI, and presenting correlative reasoning rules. We use the four predications that Maurer proposed and adds a new predication Cross, the Cross-certified predication. Maurer thinks all the entity are capable of issuing certificate and recommending statement, while we strictly distinguish consumer entity from CA and just only CA has capability of issuing certificate and recommending statement. Lastly we combine the graphics and condition predication to gave a particular description of the framework and the trust relationship.The trust model proposed here has the advantage of convenience, flexibility and cheapness compared with the traditional trust models although it can not absolutely avoid mistakes. We wish our trust model be a source of the more sophisticated, stable and secure trust models.