Design And Implementation Of An Anonymous E-Mail System Based On RG-Mix Strategy

As the quick development of Internet in the worldwide, the share of information within the whole society has come true, while, the problem regarding information security and privacy protection has been brought up at the same time. Anonymity which means hiding the identities of Internet users has become the basic requirement of a few internet applications. Anonymous communication technique on internet as a way to protect the privacy of internet users has been paid more and more attention to in academia and industry; however, after several years of study on it, the internet status of lacking in privacy protection has not been improved fundamentally. This is ascribed to the security problems lying in basic anonymous scheme and operational problems in real anonymous systems.The (N-1) attack is one of the most powerful active attacks against Mix which is the building block of many anonymous systems. This paper is organized in two parts. In the first part, we summarized the preconditions of the (N-1) attack, analyzed the weakness of current countermeasures against (N-1) attack, and proposed a new countermeasure named Regroup-And-Go MIX (we just call it RGMIX for short). RGMIX detects the (N-1) attack by examining the relative delay among the arriving time of packets in the same logical group at the MIX node. In this part we realized the random packets-grouping algorithm, and gave the theoretical analyses that prove the low probability of an attacker mounting a (N-1) attack without detection. Compared with the previous countermeasures against the (N-1) attack, RGMIX has the advantage of easy implementation and low overhead, is suitable to practical application and resistant to both inner and outer attackers.The anonymous technique applied in email is most mature. In the second part of this paper, the RGMIX strategy was combined in the design of an anonymous system for e-mail and experiments and simulations were carried out on the prototype system based on RGMIX to verify the effect of RGMIX in the detection of (N-1) attack. During the design and implementation of the prototype system, we discussed the concrete use of RGMIX, the compatibility with other measures countering other attack and the parameter in the system design. The result indicate RGmix strategy can be well combined in anonymous system for e-mail, and provide more secure service.The original idea of this paper is that a new strategy named RGmix for thwarting the (N-1) attack was proposed, an anonymous e-mail system based on RGmix was designed and implemented, which has shown the applicable and valid of RGMIX in the detection of (N-1) attack.