There is a common security issues in both cloud computing environment and P2P application, and this is also one of the security issues that the P2P applications need to address in cloud computing environment, and that is the establishment of a trust relationship. Each node including user node and cloud computing service provider node interacting with one another, needs communication and conveying the message, then it needs to be built on a basis of mutual trust. With a trusted relationship, more security details would be considered. The trust relationship is a very complex relationship, not only because it is quite vague, unstable but also very difficult to calculate and manage. Research areas in cloud computing has yet to put forward a quite fit model for trusted cloud computing. However, in a distributed system, P2P network, trust relationship was more in-depth research. This paper on the basis of in-depth study of these trust model, proposed a new trust model based on P2P technology in the cloud computing environment. The model takes into account more than one cloud computing platform, that is, considering the different cloud computing service provider provide the service of a cross-cloud platform. Such cross-platform cloud (Cross Cloud) can be called the composite cloud computing platform or cloud associated cloud computing platform. The nodes in the cloud computing environment are divided into two categories: customers and providers. According to the different roles of these two nodes, we designed a different trust mechanism, to divide the trust domain with independent single cloud, considered node independence and manageability of domain to process trust choice and trust update, and proposed a new kind of cloud computing service - trust recommendation service.
