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The Scientific World Journal
Volume 2015, Article ID 237514, 9 pages
Research Article

Twin-Schnorr: A Security Upgrade for the Schnorr Identity-Based Identification Scheme

1Faculty of Engineering, Multimedia University, 63000 Cyberjaya, Selangor, Malaysia
2Faculty of Information Science and Technology, Multimedia University, 75450 Melaka, Malaysia

Received 30 April 2014; Revised 9 September 2014; Accepted 10 September 2014

Academic Editor: Jong-Hyuk Park

Copyright © 2015 Ji-Jian Chin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Most identity-based identification (IBI) schemes proposed in recent literature are built using pairing operations. This decreases efficiency due to the high operation costs of pairings. Furthermore, most of these IBI schemes are proven to be secure against impersonation under active and concurrent attacks using interactive assumptions such as the one-more RSA inversion assumption or the one-more discrete logarithm assumption, translating to weaker security guarantees due to the interactive nature of these assumptions. The Schnorr-IBI scheme was first proposed through the Kurosawa-Heng transformation from the Schnorr signature. It remains one of the fastest yet most secure IBI schemes under impersonation against passive attacks due to its pairing-free design. However, when required to be secure against impersonators under active and concurrent attacks, it deteriorates greatly in terms of efficiency due to the protocol having to be repeated multiple times. In this paper, we upgrade the Schnorr-IBI scheme to be secure against impersonation under active and concurrent attacks using only the classical discrete logarithm assumption. This translates to a higher degree of security guarantee with only some minor increments in operational costs. Furthermore, because the scheme operates without pairings, it still retains its efficiency and superiority when compared to other pairing-based IBI schemes.