A CCA-secure Verifiable Mix-Net

Abstract

A mix-net is an important cryptographic tool in schemes requiring anonymity of messages, such as in secure e-voting and e-auction schemes. In this paper, we present a novel mix-net protocol which achieves stronger security and satisfies both public verifiability and sender verifiability. Our mix-net is constructed based on Wikström's scheme and strengthens its se-curity by introducing an improved key generation procedure and proposing a new method for constructing zero knowledge proof of secret shuffle. It is proved to be CCA-secure under the assumption of random oracle. Compared with previous mix-net schemes which are CCA-secure, the proposed protocol does not require any trusted center, and incurs fewer inter-actions between servers which resulting in a lower computation and communication complexity.