Paper 2021/414

Cryptanalysis of an Anonymous Identity-based Identification Scheme in Ad-Hoc Group without Pairings

Sook Yan Hue and Jason Chia and Ji-Jian Chin

Abstract

Anonymous identity-based identification scheme in the ad-hoc group is a multi-party cryptographic primitive that allows participants to form an ad-hoc group and prove membership anonymously in such a group. In this paper, we cryptanalyze an ad-hoc anonymous identity-based identification scheme proposed by Barapatre and Rangan and show that the scheme is not secure against key-only universal impersonation attack. We note that anyone can impersonate as a valid group member to convince the honest verifier successfully, even without knowing the group secret key. Moreover, we proposed a fix on the scheme and provide a security proof for our fixed scheme. The fixed scheme we proposed fulfills the security requirements of an ad-hoc anonymous identity-based identification scheme that are correctness, soundness, and anonymity.