Security upgrade for a K-resilient identity-based identification scheme in the standard model

In 2010, Heng and Chin (2010) proposed an identity-based identification (IBI) scheme in the standard model which was resilient to a coalition of attackers conspiring together to break the scheme. They argued that the scheme was desirable due to its proof in the standard model, which is still rare in existing literature. Also desirable was that the proposed scheme was designed without bilinear pairings, which costs greatly in terms of operation costs, thereby allowingthe scheme to run more efficiently. However, the proof of security for the proposed scheme was only against impersonation under passive attacks, where the adversary is only allowed to eavesdrop on conversations between honest parties during the identification protocol. In this paper, we upgrade the security proof to prove that the scheme is also secure against impersonation under active and concurrent attacks, showing that the scheme is still secure even if the adversary is to interact with honest parties during the attack.