Fair tracing based on VSS and blind signature without Trustees

We propose a tracing scheme of e-cash which has not only fair tracing ability but also lower computational complexity for comparisons. Many other protocols allow optimistic fair tracing which means that illegal tracing can be found after tracing and depositing in bank. But in this scheme, illegal tracing done by bank alone is impossible. We propose a marking mechanism based on a variant of an Okamoto-Schnorr blind signature and Verifiable Secret Sharing scheme. And we put a merchant in this protocol instead of Trustees. This scheme is able to defend against blackmailing, kidnapping, bank robbery and money laundering.