答案:【计分规则】: For users, trust management systems lack incentives to encourage users to provide their feedback, personal interests and profiles. And the data provided by users could reveal sensitive information of providers. For reputation and trust management systems, they may face unfair ratings, and are vulnerable to a number of potential attacks, such as Sybil attack, on-off attack, independent/collaborative bad-mouthing attack and conflict behavior attack. In many trust management systems, due to users’ concern of privacy, pseudonyms make it hard to trace malicious behaviors that will influence the accuracy of reputation. Besides, there are not general and uniform user rating criteria to evaluate subjective behavior.