Worth Reading: Attacking from the side
Attacks on encryption frequently take devious routes. One common side channel attack scenario involves analysing a computer's power consumption. As part of a lecture, cryptography legend Adi Shamir presented two specific examples illustrating that this is not as far-fetched or exotic as many people believe.
In one case, one of his students reconstructed an RSA key using an ultrasound microphone originally designed for studying bats. In a second case, his team constructed a special USB device that was able to take extremely precise measurements of the power supply to the USB port.