Abstract

Mixnet (Mix Network) was proposed by David Chaum [3] for anonymous communication in 1981. A mixnet is a multistage system that accepts encrypted messages under the public keys of all intermediate mixnet nodes and outputs randomly permuted corresponding plaintexts. In 2004, Golle et al [10] presented a new primitive called universal re-encryption based on the Elgamal public key cryptosystem. Universal mixnet based on universal re-encryption takes the input as encrypted messages under the public key of the recipients not the public key of the universal mixnet so it dispenses with the complexities of the key generation, key distribution and key maintenance. In Eurocrypt 2010 Gentry, Halevi and Vaikunthanathan [9] presented a cryptosystem which is an additive homomorphic and a multiplicative homomorphic for only one multiple. In this paper we present universal re-encryption scheme under learning with error (LWE) assumption based on [9].