Van Eck 2012 - Brain Sucking Cell Phone Spiders

The processors in smart phones and tablets leak radio signals that betray the encryption keys used to protect sensitive data. 

At the RSA computer security conference last week, Gary Kenworthy of Cryptography Research held up an iPod Touch on stage and looked over to a TV antenna three meters away. The signal picked up by the antenna, routed through an amplifier and computer software, revealed the secret key being used by an app running on the device to encrypt data. An attacker with access to this key could use it to perfectly impersonate the device he stole it from—to access e-mail on a company server, for example.

The antenna was detecting radio signals "leaking" from the transistors on the chip inside the phone performing the encryption calculations. Transistors leak those signals when they are active, so the pattern of signals from a chip provides an eavesdropper a representation of the work the chip is doing. When Kenworthy tuned his equipment to look in the right place, a clear, regular pattern of peaks and troughs appeared on his computer screen. They could be seen to come in two varieties, large and small, directly corresponding to the string of digital 1s and 0s that make up the encryption key.

"You could build an antenna into the side of a van to increase your gain—well, now you've gone from 10 feet to 300 feet." (more) (creepy computerized audio version) (Van Eck)