1. Electromagnetic Radiation from Video Display Units: An Eavesdropping Risk? Wim van Eck Computers & Security 4 ( 1985 ) Elsevier Science Publishers B.V. ( North-Holland) Two tires fly. Two wail. A bamboo grove, all chopped down From it, warring songs

2. Interception Using a Television or CRT and a small amount of custom hardware, it is possible to read the contents of a Screen from quite a distance. LCD’s are not as susceptible. This is my rifle There are many like it but This rifle is mine.

3. Electromagnetic Radiation All Electronic devices give of Electromagnetic Radiation ( EM ). The signal to the CRT is amplified to several hundred Volts, consequently it can be received significantly far away. Antenna searches Retriever’s nose in the wind Ether’s far secrets

4. Noise The EM from all the devices creates a lot of noise. But the video signal contains a distinctive pattern that makes it easy to extract from the rest of the noise. The leaves of Shanghai: Pale doorways in a steel sky. Winter has begun.

5. Electron Gun Scan Line Horizontal and Vertical `FlyBacks`

6. Video Signal Radiated signal is very similar to the video signal, but contains no synchronization information. Synchronization can be obtained from the ‘flyback’ gaps in the signal. Woman holds baby Eyes pale as a muzzle flash Band chimes frozen tears

7. Conclusion Obligatory thought provoking question: Should we worry about this kind of eavesdropping now that less susceptible technologies like LCD’s are in common use? Manila’s perfume Fanned by the coconut palms The thighs of Glory Haikus by Bobbie Shaftoe, from Neil Stevenson’s Cryptonomicon