On the Security of the Lee-Hwang Group-Oriented Undeniable Signature Schemes
Conference Proceeding Article
Undeniable signature is an intriguing concept introduced by Chaum and van Antwerpen at Crypto89. In 1999, Lee and Hwang presented two group-oriented undeniable signature schemes with a trusted center. Their schemes are natural generalizations of Chaums zero knowledge undeniable signature scheme proposed in 1990. However, we find that the Lee-Hwang schemes are insecure. In this paper, we demonstrate five effective attacks on their schemes: four of them are insider universal forgeries, in which one dishonest member (maybe colluding with a verifier) can get a valid signature on any chosen massage, and another attack allows a dishonest member to prevent honest members from generating valid signatures. We also suggest heuristic improvements to overcome some of the problems involved in these attacks.
Information Security and Trust
Trust and Privacy in Digital Business: First International Conference, TrustBus 2004, Zaragoza, Spain, August 30 - September 1: Proceedings
City or Country
WANG, Guilin; Zhou, J.; and DENG, Robert H..
On the Security of the Lee-Hwang Group-Oriented Undeniable Signature Schemes. (2004). Trust and Privacy in Digital Business: First International Conference, TrustBus 2004, Zaragoza, Spain, August 30 - September 1: Proceedings. 3184, 289-298. Research Collection School Of Information Systems.
Available at: http://ink.library.smu.edu.sg/sis_research/558