A Tor Anonymous Communication System with Security Enhancements

The improvement of network users’ awareness of protecting private information promotes the wide application of anonymous communications systems, such as Tor, Crowds, Anoymizer, which can secure users’ information. Studies have offered the evidence that security vulnerability existes in the Tor anonymous communications system. Thus, in order to improve its security, an enhanced system is proposed to improve the security of directory server and ensure the credibility of users and anonymous link through the trusted computing technology. Based on the trusted anonymous authentication protocol, the directory server of the enhanced system realizes mutual authentication between users and the server, and implements the credibility evaluation of the server on user platforms. Therefore, the bad effects of malicious forwarding nodes on the security and anonymity of anonymous link can be prevented; meanwhile, session key agreement reinforces its anti-attacking ability, because the anonymous communications link of the enhanced system is completely constructed by credible nodes. Compared with the original system, the enhanced one not only ensures credibility, but also has higher security and better anti-attack capability, thus the security risks are eliminated. Furthermore the simulation analysis proves that the proposed scheme can meet users’ need of anonymity.