A mix-net from any CCA2 secure cryptosystem

Abstract

We construct a provably secure mix-net from any CCA2 secure cryptosystem. The mix-net is secure against active adversaries that statically corrupt less than λ out of k mix-servers, where λ is a threshold parameter, and it is robust provided that at most min(λ - 1, k - λ) mix-servers are corrupted. The main component of our construction is a mix-net that outputs the correct result if all mix-servers behaved honestly, and aborts with probability 1 - O(H-(t-1)) otherwise (without disclosing anything about the inputs), where t is an auxiliary security parameter and H is the number of honest parties. The running time of this protocol for long messages is roughly 3tc, where c is the running time of Chaum's mix-net (1981). © International Association for Cryptologic Research 2012.