The Research Of Subjective Trust Model Based On Fuzzy Comprehensive Evaluation

The security of P2P (Peer-to-Peer) network is an important research field of information security. Credibility assessment of trust model is a critical problem in this field, and building trust evaluation model is the basis of trust evaluation system. Due to complexity and uncertainty of trust, so how to measure the reliability of nodes by trust level, and how to construct a more practical trust evaluation model is still a challenging task. From the analysis of existing trust evaluation methods, we can find that the evaluation functions in most of methods are simplex. In the existing evaluation method, which is based on fuzzy comprehensive evaluation, weight small factors in the assessment process are almost ignored, and trust evaluation results are simplex. This is against the fuzziness and dynamic of trust models.In view of the above problems, this paper gives three subjective trust models, and the concrete contents are as follows.Firstly, we presented a subject trust model based on twice fuzzy comprehensive evaluation. Since the trust relationships among subjects are complex, so the influence of different factors for the same subject and the influence of the same factor for different subjects are various. The second chapter would confirm the weights of evaluation factors dynamically by means of Analytical Hierarchy Process(AHP), and draw into the weights that expert had made for evaluation functions, to make a twice comprehensively evaluation for the first consequence. Through a variety of different evaluation functions on the same subject comprehensive evaluation, unitary problem was effectively solved in the trust evaluation method.Secondly, according to the uncertainty of each factor weight in the trust evaluation and fuzzy decision theory, a subjective trust evaluation model was proposed, which weight changed with value assessment dynamically. We describe the trust of fuzziness by the degree of membership in fuzzy decision theory. And the trust hierarchy mechanism and comprehensive evaluation mechanism were given. Furthermore, according to the dynamic of the assessment value, the weights of subjective trust evaluation can be allocated dynamically by variable weight method. This can effectively highlight the role of factors that have smaller weights in evaluation.Thirdly, aiming at the fuzziness and dynamic of the trust, we put forward a subjective trust model based on interval. According to the"convex"curve of the interpersonal trust relationship in the sociology, and learning from weights of expert evaluation and weighted average of the evaluation on the subject, a model on the subject by scoring method is established. By using the trust interval to show the trust degree and evaluate the trust, the fuzziness and dynamic of the model were achieved in a certain extent.