Cryptography and Information Security / Payment Systems

Anonymity of the participants is an important requirement for some applications in electronic commerce, in particular for payment systems. Because anonymity could be in conflict with law enforcement, for instance in cases of blackmailing or money laundering, we have proposed to design systems in which a trustee or a set of trustees can selectively revoke the anonymity of the participants involved in suspicious transactions. From an operational point of view, it can be an important requirement that such trustees be neither involved in payment transactions nor in the opening of an account, but only in case of a justified suspicion. In this project we have developed the first efficient anonymous digital payment systems satisfying this requirement. The described basic protocol for anonymity revocation can be used in on-line or off-line payment systems.

Research Highlights

Revocable anonymity in payments. A new paradigm in anonymous payment schemes (like e-cash), together with a concrete protocol, was proposed in [CMS97]. If necessary, the anonymity can be revoked by a trusted party. This is based on earlier work [SPC95] where the concept of fair blind signatures was introduced.

Publication Concerning This Topic

Lennart Meier
Special Aspects of Escrow-based E-Cash Systems
Master's thesis, Universit{ä}t des Saarlandes, Saarbr{ü}cken, 2000.
Available files: [ PS ] [ PDF ] [ Abstract ] [ BibTeX ]

Jan Camenisch
Group Signature Schemes and Payment Systems Based on the Discrete Logarithm Problem
PhD Thesis, {ETH Zurich}, 1998, Reprint as vol. 2 of ETH Series in Information Security and Cryptography}, {ISBN} 3-89649-286-1, {H}artung-{G}orre {V}erlag, {K}onstanz, 1998.
Available files: [ PDF ] [ Abstract ] [ BibTeX ]

Jan Camenisch, Ueli Maurer, and Markus Stadler
Digital Payment Systems with Passive Anonymity-Revoking Trustees
Journal of Computer Security, vol. 5, no. 1, pp. 69–89, 1997, Preliminary version: [CMS96].
Available files: [ PS ] [ PDF ] [ Abstract ] [ BibTeX ]

Jan Camenisch, Ueli Maurer, and Markus Stadler
Digital Payment Systems with Passive Anonymity-Revoking Trustees
European Symposium on Research in Computer Security — ESORICS '96, Lecture Notes in Computer Science, Springer-Verlag, vol. 1146, pp. 33–43, Sep 1996, Final version: [CMS97].
Available files: [ Abstract ] [ BibTeX ]

Jan Camenisch, Jean-Marc Piveteau, and Markus Stadler
An Efficient Fair Payment System
3rd ACM Conference on Computer and Communicatons Security — CCS '96, ACM, pp. 88–94, Mar 1996.
Available files: [ PS ] [ PDF ] [ Abstract ] [ BibTeX ]

Jan Camenisch, Jean-Marc Piveteau, and Markus Stadler
{F}aire {A}nonyme {Z}ahlungssysteme
{GISI} '95, {I}nformatik aktuell, Springer-Verlag, pp. 254–265, Sep 1995.
Available files: [ Abstract ] [ BibTeX ]

Jan Camenisch, Jean-Marc Piveteau, and Markus Stadler
An Efficient Electronic Payment System Protecting Privacy
European Symposium on Research in Computer Security — ESORICS '94, Lecture Notes in Computer Science, Springer-Verlag, vol. 875, pp. 207–215, Nov 1994.
Available files: [ PS ] [ PDF ] [ Abstract ] [ BibTeX ]

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