Progress in Cryptology —INDOCRYPT 2000

Volume 1977 of the series Lecture Notes in Computer Science pp 93-103


An Online, Transferable E-Cash Payment System

  • R. Sai AnandAffiliated withDepartment of Computer Science & Automation, Indian Institute of Science
  • , C.E.Veni MadhavanAffiliated withDepartment of Computer Science & Automation, Indian Institute of Science

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Most electronic cash (e-cash) based payment systems that have been proposed do not possess the property of transferability. Transferability in an e-cash based system means that when a payee receives an electronic coin in a transaction he may spend it without depositing the coin first and getting a new coin issued from a bank. Usually electronic coins that are transferred in a transaction have a lifetime of the trans-action itself. In this paper, we propose a payment system where coins can be transferred over multiple hands, spread over various transactions, similar to physical cash. Detection or prevention of double spending of coins is a critical issue in online e-cash payment systems. In our system the verification is distributed across multiple entities as opposed to the case of a coin-issuing entity or a central bank alone being responsible for the verification. A resolution mechanism for handling disputes is also presented. The proposed system provides guarantees of anonymity, fairness and transferability.

Key words

E-cash Transferability Fairness Anonymity Double Spending.