"Encryption Flaw Rattles Comuter Security Industry" SAN FRANCISCO - The discovery of a vulvnerability has shaken the computer world's faith in the safe use of the data-security technologies on which most current and planned electronic banking, shopping and "digital cash" systems are based. The vulnerability has been found in a class of technologies known as public-key encryption - designed to provide electronic transactions by scrambling data so they can be read only by people with the proper mathematical keys to the code. The flaw was identified by Paul C. Kocher, a 22-year-old researcher, who demonstrated a way that an electronic eavesdropper who is able to monitor the repeated process of unscrambling the incoming messages could figure out the private key. It can be done by repeatedly keeping track of the precise length of time it takes to unscramble each message. --From TimesFax, Mon. Dec. 11 Internet Edition