An Efficient ID-Based Verifiably Encrypted Signature Scheme Based on Hess's Scheme.

As many electronic items are exchanged over the Internet recently, the fair exchange problem becomes of a greater importance. When constructing fair exchange systems, verifiably encrypted signatures are usually used as a building block. Hence, we propose an efficient ID-based verifiably encrypted signature scheme based on Hess's signature scheme because it is known as a concise and secure signature scheme in ID-PKC. Our scheme does not need registrations between users and a trusted third party called an adjudicator, does not need zero-knowledge proof, and uses an optimized adjudicator who participates in the protocol only when problem occurs. Together with a formal model, we analyze security and efficiency of our scheme and show that it is more suitable for communication requirements than previous schemes of same kind. [ABSTRACT FROM AUTHOR]