Cost-effective payment schemes with privacy regulation

In this paper, we introduce a new electronic money methodology: sub-contracting the blinding to a trustee and using an Identity-based piece of information to achieve provable privacy and security. This variation on the Brickel, Gemmel and Kravitz paradigm [2] offers protection against various attacks minimizing user's computational requirement. Furthermore, our scheme offers various complexity/privacy tradeoffs without endangering the issuer's overall security.