An ID-based Transferable Off-line E-Cash System with Revokable Anonymity

In this paper, we first propose a new efficient ID-based restrictive partially blind signature. Then a new ID-based fair and transferable off-line electronic cash system with multiple banks based on the proposed ID-based restrictive partially blind signature and Tan-Liu´s ID-based group signature is proposed. Users withdraw electronic cash by performing ID-based restrictive partially blind signature protocol with the issuing banks. In order to implement transferability of electronic cash without any increase in size, all users (shops) are organized as a group, a trusted third authority act as group manager. The anonymity of the system can be revocable under certain conditions by an off-line trusted third authority, the system is untraceable (under normal cases), unlinkable and double-spending resistant.