This week researchers at the University of Illinois at Urbana-Champaign announced a troubling breakthrough in surveillance technology that will allow for intelligence agencies and law enforcement to make use of a mobile phone’s vibration motor to listen in on conversations in real time.
The "Vibraphone" research comes from associate professor Romit Roy Choudhury and PhD candidate Nirupam Roy, and is predicated on the notion that a vibration motor is like a tiny speaker, with past research showing that any speaker can be modified into a microphone.
The two detail in a paper to be presented next month at MobiSys in Singapore, that it is not "fundamentally surprising" that the vibration motor could be used to pick up sounds, but "the fidelity to which this is possible has been somewhat unexpected."
For those worried about the creeping demise of privacy in America, the method is not triggered through a software virus or patch, but requires a fundamental rewiring of the user’s cell phone. The intrusive nature of this surveillance methodology would seem to preclude its use for mass surveillance, although the rewiring only takes a minute, suggesting that cell phone manufacturers could easily make their devices more surveillance friendly.
The two researchers have, however, posited a workaround that may enable surveillance agents to trigger the recording capacity of phones remotely.
In an email to TechCruch, Nirupam Roy suggested that "it may be possible to exploit the power controller chip to collect the voltage fluctuation in the vibration motor, but we did not investigate this possibility." The researcher suggested that cellphone users concerned about their privacy may be better protected by older devices because their low-quality vibration motors cannot capture sound as well.
There is another solution to those seeking to evade the long arm of Big Brother, the vibration motor cannot detect sounds pitched above 2 kHz, well below the normal female speaking range, indicating that the technique would apparently only be effective when used to spy on males, or those who have lower-pitched voices.
Other targets exist beyond exploiting mobile phones, including fitness bands, which ordinary civilians would not expect to pose a security risk as they lack a microphone, but which contain Linear Resonant Actuator (LRA) vibration motors, comparable to smartphones and ideal for exploitation using the researcher’s method.
Revealingly, the technological advance lacks applications beyond its use by surveillance agencies, marking the latest step toward a privacy-free society.
