Abstract: The security of Social Networks is an important field of research about SNs and has attracted a lot of attentions nowadays. Up to now, many security protocols have been proposed but most of them focus on the authentication. Although, these methods have addressed many conventional problems in the Social Networks but many novel malicious actors encountered in SNs could not be solved by authentication. Reputation based trust systems represent soft security mechanisms that complement traditional information security. Nowadays, the research of security mechanism based on reputation and trust has become a hot research issue in social networks. In this study, we propose a new security protocol RARRM to construct trustworthy social networks. This protocol not only can distinguish different applications but also can rank trust values. The objective of this protocol is not only to encourage actors to provide good services consecutively to establish a security environment of network but also to punish strictly those malicious actors that are trying to take advantage of reputation system to launch malicious attacks. Through intensive simulation, we will verify the correctness and efficiency of the proposed defense techniques.