Security and design issues of regroup-and-go mix

(N - 1) attack is one of the most powerful active attacks against mix, which is the basic building block of many modern anonymous systems. RG mix is an effective scheme to protect against (n - 1) attack. However it has some security and design weaknesses. This paper investigates these problems and gives solutions. Information dispersal algorithm is imported to prevent the security and robustness vulnerabilities. An add-on heartbeat traffic policy and a multi-way routing scheme are proposed to improve the security of RG mix under low traffic levels. Also, an extensible return path scheme is proposed to support bi-directional anonymous communication in RG mix network. Analysis shows that these solutions can improve the security and robustness of RG mix.