Interactive Bi-proof Systems and Undeniable Signature Schemes
Atsushi Fujioka, Tatsuaki Okamoto, Kazuo Ohta · Transactions of the Institute of Electronics, Information and Communication Engineers · 1992
This paper proposes a new construction of the minimum knowledge undeniable signature scheme which solves a problem inherent in Chaum's scheme. We formulate a new proof system, the minimum knowledge interactive bi-proof system, and a pair of languages, the common witness problem, based on the random self-reducible problem. And we show that any common witness problem has the minimum knowledge interactive bi-proof system. A practical construction for undeniable signature schemes is proposed based on such a proof system. These schemes assure signature confirmation and disavowal with the same protocol (or at the same time).