Analysis Two ID-Based Deniable Authentication Protocols on Pairings

In order to prevent the malicious attack, two new ID-based deniable authentication protocols based on pairings are proposed by Chou et al. and Cao et al., respectively. Both of them proposes some lemmas to prove their scheme can not only attain the desired deniable property but also can prevent malicious attacks. However, the security of these two ID-based deniable authentication protocols are not as strong as they claimed. In this article, we will show that their scheme are also vulnerable to the malicious attacks.