Traceability of double spending in secure electronic cash system

With a widespread deployment of Internet and mobile communication skill, digital contents circulation has been in active. However, when people purchase multimedia contents such as multimedia books, online game, music, etc., by credit card, it has a problem that reveals card holder's private information. On the other hand, electronic cash provide user's anonymity and privacy, maintaining the value of paper money and its characteristics. In this paper, we propose an algorithm which uses the fair blind signature, supporting legitimate users' anonymity. It also has a function which can cancel the anonymity against double spending in electronic cash.