s an electronics engineer, Leon Stambler spent a good portion of his life devising technology for identification verification and methods for encryption of information. Over the years, he has filed patents for what he has invented. He also has filed - and settled - lawsuits for patent infringement against some pretty large corporations, waging a kind of David-vs.-Goliath battle for the Information Age.

Two years ago, Stambler, 74 and a Florida resident, sued VeriSign, Inc. and RSA Security, Inc. for more than $20 million in damages in federal district court in Wilmington, Del. His suit alleged that the two companies incorporated his technology, without permission or compensation, into their systems for secure Internet transaction authentication.

This month, the jury on the case let VeriSign and RSA off the hook and decided that Stambler's patents had not been infringed.

Once the suit finally came to trial, it lasted two weeks. The jury reached its decision in three hours, based on argument that there was no patent infringement because Stambler's patents don't cover Internet transactions or message scrambling. Attorneys for VeriSign and RSA asserted that Stambler's technology uses different techniques and functions than the Secure Socket Layer (SSL) security standard used to scramble communications between Web sites and their customers. The SSL protocol was developed in 1994 and patented in 1997 by Netscape, now a part of AOL Time Warner.

Stambler was granted seven patents between 1993 and 1999; the last one, U.S. patent number 5,974,148, is for a "method for security information relevant to a transaction," which he and his attorney say includes SSL technology. Stambler testified he developed his technology in the early 1990s as a way to verify the identities of people involved in transactions after his son was prevented from cashing a check at a bank with only one form of ID.

Stambler has settled past claims with other companies, including First Data Corp., wireless software provider Openwave Systems, Inc. and wireless encryption software developer Certicom Corp. In the 1980s, Stambler's suit against NCR for ATM PIN technology netted him a $2.6 million licensing fee; he also unsuccessfully sued Diebold, Inc., which makes and services ATMs, for the same infringement issue.