Computer Security and Cryptography

19.12 LEON STAMBLER

Leon Stambler is an engineer who had been employed at RCA Laboratories; he is retired now and lives in Parkland, Florida. Mr. Stambler is also a prolific inventor and has been issued many patents. Mr. Stambler sued Diebold Incorporated, NCR Corporation, and Manufacturers Hanover Trust claiming infringement of U.S. Patent No. 5,793,302: “A Method for Securing Information Relevant to a Transaction”, filed November 12, 1996, issued August 11, 1998. Mr. Stambler claimed that the use of the PIN in ATM transactions by these defendants infringed the claims made in his '302 patent.

His suit was not successful; Hon. Judge Thomas C. Platt invoked the doctrine of estoppel in writing his opinion in the U.S. District Court for the Eastern District of New York. Equitable estoppel refers to a situation when a patent holder makes a misleading communication and subsequently a purported infringer relies on this to carry out his business practice. It appears that Mr. Stambler had been a member of an American National Standards Institutes (ANSI) Committee on ATM transactions and was surprisingly silent when the committee approved a standard involving ATM transactions. Judge Platt wrote that

The [trial] record contains some evidence of misleading conduct on the part of the plaintiff that may have led defendant to conclude that plaintiff did not intend to enforce his patent. Silence alone is not sufficient affirmative conduct to give rise to estoppel.

Mr. Stambler was not discouraged ...