Abstract: To solve the problems of the computational complexity and uncertainty of trust in P2P trust model, this paper proposed a new trust model for P2P network. The proposed model evaluates the peer's trust degree from the idea that absolute priority is given to human's direct experience in human psychological cognitive habits to judge,which reduces the computational complexity and the risk of accepting false recommendation information. Further, two characteristic parameters of cloud model, entropy and hyper entropy, are used to introduce positive and negative reward factors to en- courage good peers and punish malicious peers respectively. Experiments show that the proposed model can resist chcat- ing behaviors of strategic malicious peers and also distinguish complex malicious peers which behave badly with small probabilities.

Key words: P2P, Cloud model, I}rust, Cognition