Digital Payment Systems with Passive Anonymity-Revoking Trustees
Jan Camenisch and Ueli Maurer and Markus Stadler
Anonymity of participants is an important requirement for some applications in electronic commerce. Because anonymity could be in conflict with law enforcement, it has been proposed to design systems in which a trustee or set of trustees can selectively revoke participants' anonymity. From an operational point of view, it can be an important requirement that such trustees are not involved in regular transactions. In this paper we investigate the design of anonymous digital payment systems satisfying this requirement. Several types of solutions are discussed and compared, and for each of these, a possible realization in terms of concrete protocols is proposed.