Randomized Partial Checking Revisited
The authors study mix-nets with Randomized Partial Checking (RPC) as proposed by Jakobsson, Juels, and Rivest. RPC is a technique to verify the correctness of an execution both for Chaumian and homomorphic mix-nets. The idea is to relax the correctness and privacy requirements to achieve a more efficient mix-net. They identify serious issues in the original description of mix-nets with RPC and show how to exploit these to break both correctness and privacy, both for Chaumian and homomorphic mix-nets. Their attacks are practical and applicable to real world mix-net implementations, e.g., the Civitas and the Scantegrity voting systems.