Digital coin tracing using trustee tokens

US6446052B1 · kind B1 · utility

Assignee

• RSA Security LLC · US

Inventor

• Ari Juels · Brookline, US

Key dates

• Filing date: Nov 18, 1998
• Grant date: Sep 3, 2002
• Expiry date: Jan 28, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G06Q20/383
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

A system and method for obtaining traceable anonymous digital cash from a bank using a trustee as a trusted third-party. A user establishes her identity with the trustee using a secret known by the user. The user transmits to the trustee information describing a blinded traceable digital coin. The user receives from the trustee a trustee token including a signature by the trustee on the blinded coin. The user transmits the blinded coin and the trustee token to a bank. The user receives a signature from the bank certifying the blinded coin. The user can then unblind the coin, and spend the coin at a merchant. The system and method support both tracing of the identity of a user from a coin, referred to as coin tracing, and generation of a list of all coins belonging to a given user, referred to as owner tracing. Both of these operations require very little computation and database access. To determine the identity of the user, the trustee can generate the list of coins associated with a user. Alternatively, if presented with a coin, the trustee can determine the identity of the user who submitted the coin to the trustee for signature. This simple and highly efficient trustee-based tr…