Eavesdropping protectionAre your phones really secure?

Published 25 February 2011

Breakthroughs in technology have enabled malicious actors to listen in on any conversation using your phone even when not in use; eavesdroppers have circumvented encrypted audio channels by relying on a relatively simple principle in physics — resonance; by tapping into an object’s natural resonance, spies have turned phones and phone cables into listening devices even when they are not in use; researchers at Teo, a manufacturer of secure telecommunications equipment, were able to capture human voices using standard phones, unplugged Ethernet cables, or even a rock; to address this security gap, Teo has designed its IP TSG-6 phones with special vibration dampening circuitry and materials that render them impervious to these types of listening devices

Government agencies and businesses may believe that they have secure communication lines, but breakthroughs in technology have enabled malicious actors to listen in on any conversation using your phone even when not in use.

According to Thomas Beck, business strategy executive at Teo, a manufacturer of secure telecommunications equipment, government agencies are largely unaware of the fact that their phones can be compromised when not in use and that most agencies and businesses are only focusing their efforts on securing lines when in use.

“We’re finding that so many people have no idea that when their phone is hung up it can actually be compromised and used as a spy device,” Beck said.

Eavesdroppers have circumvented encrypted audio channels by relying on a relatively simple principle in physics — resonance.

By tapping into an object’s natural resonance, spies have turned phones and phone cables into listening devices even when they are not in use. These objects vibrate at low frequencies in the course of normal conversation and can actually transmit electrical signals. Wiretapping technology has taken advantage of this and used every possible vibrating object including wires and circuit boards to listen in on conversations.

In tests Teo researchers were able to capture human voices using standard phones, unplugged category five (Cat 5) Ethernet cables, or even a rock.

“In the lab we can actually take a rock and connect it to a Cat-5 cable and there will be enough microphonic oscillation that you can pick up intelligible speech,” he said.

To address this security gap, Teo has designed its IP TSG-6 phones with special vibration dampening circuitry and materials that render them impervious to these types of listening devices.

Beck said, “What we’re stopping is resonance transmitting down the transmission path down a Cat-5 cable or what have you.”

He added, “You can actually take a wire not connected to anything and that will transmit audio, but if you plug that wire into a Teo IP TSG-6 phone the suppression circuitry prevents that from happening, so you’re completely protected.”

Teo currently supplies the Department of Defense with its IP TSG-6 phone system and is looking to help protect other government agencies and businesses.