Cryptanalysis on Improved Chou et al.´s ID-Based Deniable Authentication Protocol

A deniable authentication protocol enables the protocol participants to authenticate their respective peers, while able to deny their participation after the protocol execution. This protocol can be extremely useful in some practical applications such as online negotiation, online shopping and electronic voting. Recently, we have improved a deniable authentication scheme proposed by Chou et al. due to its vulnerability to the key compromise impersonation attack in our previous report. However, we have later discovered that our previous enhanced protocol is vulnerable to the insider key compromise impersonation attack and key replicating attack. In this paper, we will again secure this protocol against these attacks and demonstrate its heuristic security analysis.