Proof of a Shuffle for Lattice-Based Cryptography

In this paper we present the first proof of a shuffle for latticebased cryptography which can be used to build a universally verifiable mix-net capable of mixing votes encrypted with a post-quantum algorithm, thus achieving long-term privacy. Universal verifiability is achieved by means of the publication of a non-interactive zero knowledge proof of a shuffle generated by each mix-node which can be verified by any observer. This published data guarantees long-term privacy since its security is based on perfectly hiding commitments and also on the hardness of solving the Ring Learning With Errors (RLWE) problem, that is widely believed to be quantum resistant.