A Bidirectional Anonymous Secret Communication Protocol Based On Onion Routing

With the continuous development and wide application of the Internet,people pay more and more attention to network security and privacy protection,identity privacy is an important part of privacy protection.Some agencies,such as national intelligence agencies and military agencies,have placed higher demands on cyber security,requiring that the identity information of agency communicators must not be obtained by attackers.Anonymous communication technology can protect the identity of users in the communication system and has important research value.The related researchers are devoted to the study of this technology.Anonymous communication technology has become an important research direction.At present,there are more researches on the anonymous communication which can realize the anonymity of the sender,compared with the research of the bidirectional anonymous communication which can realize the anonymity of the sender and the receiver.In this thesis,the onion routing protocol is modified,and a new bidirectional anonymous communication protocol is proposed,which is called the bidirectional anonymous secret communication protocol based on onion routing,and the protocol is described and discussed in detail.Firstly,in this thesis,the research status of anonymous communication technology is summarized.The basic concepts of anonymous communication,the types of anonymous communication and the types of attacks in anonymous communication system are introduced.And the thesis classifies anonymous technologies and anonymous communication systems.Secondly,this thesis proposes a new bidirectional anonymous secret communication protocol-onion routing-based bidirectional anonymous secret communication protocol,which is based on onion routing mechanism and has modified onion routing mechanism significantly.The onion routing protocol adopts the idea of source routing,the message is forwarded according to the constructedonion route and the protocol has sender anonymity.In this thesis,the protocol constructs the routing path in random order which contains all nodes in the system,and the message is forwarded according to the routing path.Each time the node receives a message,it firstly determines whether the user on the node is the recipient.If so,the recipient user receives the message and terminates forwarding message;if not,the node continues to forward the message according to the routing path.The identity of the sender or receiver will not be obtained by the other party or any other user.For another,only the two parties of communication know the message,and other nodes,users or attackers can not obtain the message.Third,the message must be eventually received by the recipient user.To sum up,this protocol can realize bidirectional anonymous secret communication.Finally,the protocol is analyzed and compared,the bidirectional anonymity of the protocol and the message security are proved,the security analysis and the anonymity analysis of the protocol are carried out,and the protocol and other anonymous communication protocols are compared.The bidirectional anonymous protocol in this thesis is only based on onion routing mechanism and is simple to implement.Compared with using multicast to realize bidirectional anonymity,it produces less traffic and smaller burden of system.The protocol is simulated experimentally and evaluated with an experimental scheme.The experimental results show that with the increase of the number of nodes in the system,the average response time increases approximately linearly,which shows that the system has good robustness and has been running steadily with the change of the number of users.