Security analysis of an identity-based mix net

One of the most important systems for providing anonymous communication is the Mix nets which should provide correctness and privacy as security requirements against active adversaries. In 2009, Zhong proposed a new mix net scheme which uses identity-based cryptographic techniques and proved that it has “correctness” and “privacy” properties in the semi-honest model. Since the semi-honest model is a very strong assumption for practical application, we show that if a user or the last mix server is corrupted, Zhong scheme does not provide privacy against an active adversary.