Space efficient method of verifying electronic payments

United States Patent [w]

Demers et al.

[54] SPACE EFFICIENT METHOD OF

VERIFYING ELECTRONIC PAYMENTS

[75] Inventors: Alan J. Demers, Boulder Creek; Daniel H. Greene, Sunnyvale, both of Calif.; Bridget A. Spitznagel, Pittsburgh, Pa.; Roy Want, Los Altos, Calif.

[73] Assignee: Xerox Corporation, Stanford, Conn.

[21] Appl. No.: 08/758,136 [22] Filed: Nov. 25, 1996

[51] Int. CI.7 G06F 17/60

[52] U.S. CI 705/39; 705/41; 705/44;

380/24; 380/25; 235/379; 235/380

[58] Field of Search 705/309, 41, 44;

380/24, 25, 30; 235/379, 380

[56] References Cited

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4,812,628 3/1989 Boston et al 235/380

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4,914,698 4/1990 Chaum 380/30

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5,305,383 4/1994 Guillou et al 380/24

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OTHER PUBLICATIONS

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(List continued on next page.)

Primary Examiner—Emanuel Todd Voeltz
Assistant Examiner—George D. Morgan

[57] ABSTRACT

A method of verifying electronic payments generated using a key unknown to the verifier. In anticipation of accepting electronic payments, a seller requests and receives from a bank a conversation key and a first set of electronic verifiers for a first set of electronic payments from a customer. Each verifier allows authentication of an associated electronic payment without revealing the private key used by the customer to generate the electronic payments. Prior to initiating a transaction or series of transactions, the customer requests payment information from the seller for use, along with the master key, in generating electronic payments Afterward, when the customer pays with an electronic payment, the seller authenticates the electronic payment using one of the verifiers. The seller responds to the buyer's request if the electronic payment is authenticated.

8 Claims, 7 Drawing Sheets

OTHER PUBLICATIONS

Okamoto, T. et al., Universal Electronic Cash. Advances in Cryptology—CRYPTO '91 Proceedings, Berlin: Springer-Verlag, 1992, pp. 324-337.

Pedersen, T. P., Electronic Payments of Small Amounts. Computer Science Department Aarhus University, Aug. 1995, pp. 1-15.

Rivest, R. L. et al., Payword and Micromint: Two Simple Micropayment Schemes. May 7, 1996, pp. 1-18. Singleton, A., Cash on the Wirehead. BYTE, Jun. 1995, pp. 71-78.