Abstract

The traditional techniques for remote unauthorized access to private and confidential information—tapping communication links, code breaking, impersonation—become increasingly infeasible as the use of modern cryptographic protection techniques proliferates. Those in the business of obtaining information from other people’s computers without consent—criminals and spies, intelligence agency and law enforcement technicians, private detectives, market researchers—are therefore increasingly looking for alternative eavesdropping techniques. One class of alternatives utilises those unintentional information leaks caused by the physical/analogue underlying processes in computers and peripherals that can be sensed, amplified and decoded at a distance.

This talk provides an introduction, overview and demonstration of electromagnetic and optical passive eavesdropping techniques for personal computers, focusing in particular on video display units. It will present new techniques for eavesdropping liquid-crystal and cathode-ray tube displays and will discuss the information-security threat posed by these, along with simple new protective measures.