![]() ![]() ![]() An advanced adversary can probably very finely distinguish between active states."Įliott noted that she was carrying a very specific assortment of gadgets around DEF CON: an iPhone 4S, a Nexus 7, a Nintendo 3DS and a MacBook Air. "If you carefully study it, you can distinguish between different kinds of active states. "It's trivial to distinguish when one of these machines is idle and when it's active," she added. You can triangulate them in 3D space, almost like they're radio transmitters that you're carrying - because they are." "Different types of devices can be profiled for their activity, and then after you know exactly what they do, you can detect them," Elliott said. She could also see that her iPhone was downloading data over Verizon's 3G network. ![]() "You can pick up everything to some extent," Elliott said as she projected a screen shot of a neat grid generated by RAM memory chips. It's not just screens that emit radio signals, Elliott said keyboards, LED lights, wired and wireless microphones, computer memory and hard drives all put out signals. MORE: Can You Hide Anything From the NSA? But again, I have a $10 radio."Įlliott said an engineer co-worker told her that the cable from the netbook's video processor to its screen was emitting the signals - which explained why the signals stayed active even after the screen went to sleep. Unfortunately, my radio sample rate is not very high. "Can you recover the screen from this?" Elliott wondered. "Those are between 32 and 33 kilohertz apart," she said, explaining that the signal came from the netbook's real-time clock running at a standard 32.768 kHz.įurther demonstrations showed that keyboard presses emitted different radio signals, as did changing screen colors and patterns, with a black-and-white checkerboard pattern even being somewhat visible on the radio-signal analysis screen. "Do you see all those little spikes that weren't there a minute ago?" she asked. After a minute, she powered on her cheap Chinese netbook, which was a few feet away. On another laptop, Elliott used her USB tuner and her software-defined radio application to dial into an FM radio station, and projected her output on the conference-hall screen. They'd have a conniption if they knew I imported it." ![]() "I'm pretty sure that this violates FCC from Rule 1 to the last. So Elliott found a website that sold USB tuners for $10, and found free software to tune and analyze the signals.Īt DEF CON, she demonstrated how much radio noise electronic devices emit by using a netbook she bought for $50 on a trip to China. "That is how much they had to shield things just so they could reheat their pizza at 2 a.m." "They have a microwave oven, which is a Faraday cage" - a structure enclosed by a wire mesh to prevent electricity from getting in or out - "inside another Faraday cage, inside another room, which is also a Faraday cage," she recalled. "Their biggest challenge to getting the science done is the very electronics that they need to measure and process the signal, because those same electronics blast the signal out at the sky," Elliott said. National Radio Quiet Zone on the Virginia-West Virginia border, site of the world's largest moveable radio-astronomy telescope, taught Elliott otherwise. "I managed to go most of my life not knowing that my electronics were all leaking all of the signals that detail what they're getting up in their private little electronic lives," Elliott said.īut a visit to the U.S. MORE: 13 Security and Privacy Tips for the Truly Paranoid Elliott, a researcher at Boston-based security company Veracode, showed that an inexpensive USB dongle TV tuner costing about $10 can pick up a broad range of signals, which can be "tuned" and interpreted by software-defined radio (SDR) applications running on a laptop computer. ![]()
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