Eye, they can spy through the walls of your house with a smartphone

Our life runs submerged in a sea of ​​radio signals that allow our connection to the world thanks to mobile coverage or WiFi networks. When moving, we interact with these signals, distorting them, reflecting and refracting these waves, as happens when we move in the water. Now, a group of researchers from the University of California have developed a system that allows these distortions to be detected remotely, so that someone could spy on what we do after the door of our house with a simple smartphone.

Related "Although the wireless signals greatly improve our daily lives, they also reveal, without our knowledge, information about ourselves and our actions, ”says Yanzi Zhu of the University of California.

The new technique developed by Zhu and his colleagues allows an unprecedented invasion of privacy.«With just a smartphone you can locate and track people in your home or office from external walls, taking advantage of the changes in WiFi transmissions of the environment, "they say.

Researchers have experimented with Nexus 5 and Nexus 6 smartphones to spy in 11 offices and apartments that had several WiFi transmitters, which increases the accuracy of your system.«We see that with more than 2 WiFi devices in a normal room, our system can detect more than 99% of the presence and movement of the user in each room we have tested», affirm the researchers.

spy on the other side of the door

Zhu's team has also shown how different movements change the signal in different ways.For example, opening a door changes the field in two adjacent rooms and is therefore easy to detect. Even one action As you write, it creates small changes that a WiFi receiver of a smartphone can capture.

In their work, these North American scientists have used fluctuations in the electromagnetic field to determine the position, actions and movement of individuals.There have been previous works in this line but, until now, they had many shortcomings or were too much complexes.

The first step in the researchers approach is to locate the WiFi transmitter.They do this by measuring the change in signal strength as they walk around the target building or room.In fact, they have created an application that uses the accelerometers incorporated in the smartphone to record this movement and then analyze the change in signal strength as they move.That way, it is possible to determine the position of the transmitter even if there are numerous distortions.

noise as a defense

It is even possible to calculate exactly where the transmitter is inside a house, since the floor plans of most homes and offices in the US can be downloaded from different websites related to the real estate market.

Zhu's team says that by walking from one place to another several times outside a room or building, they can locate the transmitter exactly.« We found that four rounds of measurements are sufficient to achieve localization to room level with an average accuracy of 92.6% », they say.

The researchers state that, although there are several defenses against this type of attack, are difficult to implement and have limited effectiveness, so they believe that the most effective form of defense may be the addition of noise to signals.