Key exposure free chameleon hash schemes based on discrete logarithm problem
Article first published online: 13 AUG 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Security and Communication Networks
Volume 6, Issue 7, pages 812–817, July 2013
How to Cite
Lim, S., Lee, J. and An, Y. (2013), Key exposure free chameleon hash schemes based on discrete logarithm problem. Security Comm. Networks, 6: 812–817. doi: 10.1002/sec.612
- Issue published online: 21 JUN 2013
- Article first published online: 13 AUG 2012
- key exposure free;
- chameleon hash;
- Schnorr signature;
- ElGamal encryption
A chameleon hash scheme is a trapdoor collision-resistant hash scheme, and it provides many interesting features in signature schemes with hash-and-sign construction. In this paper, we introduce the notion of key exposure threshold τ for a chameleon hash scheme for which a key exposure free chameleon hash scheme can be understood as the case with τ = ∞. We propose chameleon hash schemes CHτ with the key exposure threshold τ based on discrete logarithm problem (DLP). For τ < ∞, the proposed scheme is noninteractive and key exposure free as long as k ephemeral trapdoors are disclosed for k < τ. The proposed scheme CH∞ is a key exposure free chameleon hash scheme based on DLP, and it requires a label directory that can be managed by a third party. This improves the only known efficient key exposure free chameleon hash scheme based on DLP, which requires one interaction with the trapdoor holder. Copyright © 2012 John Wiley & Sons, Ltd.