Side Channel Attacks

2. A working CPU emits electromagnetic radiation that can be detected outside the computer, and even outside the building.
   A spy who knows the type of CPU being spied on can execute many programs on the same type of CPU, measure the radiation emitted, and thus associate certain patterns of radiation with certain types of computer operations, such as loops, idle, or input/output.
   Once such an association has been established, the spy can train a computer program to analyze radiation emitted by a spied computer and draw useful conclusions about the activity of the spied CPU at various times.
   A similar situation is possible also because CPUs emit sound.
   Controls:
   1. Surround computers with a conductive material to prevent any radiation from escaping.
   2. Generate random electromagnetic radiation and sound near the computer to mask the CPU's radiation and fool spies.