Research And Implementation Of Tor Routing Algorithm Based On User Trust Relationship Of IM Communication System

With the rapid development of the Internet,people enjoy the convenience brought by Instant Messaging(IM),and pay more attention to personal data and privacy security in communication.Nowadays,most of the instant messaging software on the market has its own private communication protocol,which is not conducive to the expansion and interconnection of the system.In this context,it is particularly important to research and implement an IM system with good anonymity and heterogeneity.Firstly,aiming at the problem of privacy protection in communication,the system uses the Second Generation Onion Router(Tor)as the implementation scheme of anonymous communication.The users of the system form an anonymous social network transparent to third parties.Secondly,aiming at the problem of poor scalability and interoperability of instant messaging software,this system adopts XMPP(the Extensible Messaging and Presence Protocol)protocol as communication protocol,and realizes a multi-dimensional heterogeneous IM system by utilizing the flexibility and scalability of the XMPP protocol.The tests show that the system provides anonymous communication services for Android clients while meeting the basic IM functional requirements,and has the advantages of cross-platform and cross-domain servers.In order to further improve the anonymous security of the IM system,aiming at the problem that Tor routing algorithm lacks the credibility management of the routing nodes,so that it can't control the selection of malicious nodes with deceptive characteristics.After studying the routing scheme based on node credibility in recent years,we propose a trust diffusion model based on social network.Based on the user social network of IM system,the model proposes a scheme that combines direct trust,group trust,and indirect trust based on the first two,which is derived by the trust diffusion algorithm named SLTP(Social Link-based Trust Propagate),to evaluate the credibility of the user node.Based on the trust equivalence relationship between the user node and the Tor routing node guaranteed by the IM system architecture,an improved trust degree-based Tor routing algorithm named TDRS(Trust Degree-based Routing Selection)is proposed based on the trust diffusion model.We also give the realization scheme of combining the TDRS routing algorithm with the system based on the friend interaction relationship.The subsequent experimental results on the simulation platform TorPS show that the TDRS algorithm can effectively eliminate malicious nodes in the circuit and improve Tor's anonymity security on the premise of judging the identity of nodes based on credibility.