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Scientists have learned via Wi-Fi to intercept keystrokes on the keyboard

Scientists have learned via Wi-Fi to intercept keystrokes on the keyboard

by sigismund » 2016-08-28 10:14:49

Technology WiKey allows you to define keystrokes with an accuracy of 97.5%.

A group of researchers from the University of Michigan (USA) and Nanjing University (China) have discovered a new way to intercept keystrokes on the keyboard, being near the victim. For the successful implementation of the attack is enough to use ready-made computer hardware (i.e. anything not necessary to collect) and standard Wi-Fi connection.

Scientists developed the technology WiKey is not perfect, but allows you to define keystrokes with an accuracy of 97.5% in a controlled environment and to 77.5% in real terms. WiKey works like other technologies of recognition of movements and gestures, such as Intel RealSense. However, unlike them, she recognizes where smaller movements such as pressing buttons.

For the attack the researchers used low-cost equipment available (router TP-Link WR1043ND and the laptop is a Lenovo X200) and 802.11 n/ac Wi-Fi. Using the values of the status information and the channel State Information, CSI) they were able to capture the movement in a given environment.
Earlier, the CSI was used for the recognition of larger movements and allowed to determine the presence of a person in the room and capture the gestures. Based on this technology system was developed WiHear able to recognize the mouth movements, that is, to read lips. WiKey led WiHear on a completely different level – now you can not only read lips, but also to determine the movements of fingers, hands and keys.
To recognize the micromotion is quite difficult. In a controlled environment without extraneous movements, scientists were able to capture even the slightest changes in activity of the wireless channel. To receive data via Wi-Fi researchers have used MIMO channels. MIMO – a method of spatial signal coding, allowing to increase the channel bandwidth in which transmission and reception of data are performed by the systems of multiple antennas.

Qoute:"for Every MIMO channel between each pair of antennas of transmitter and receiver is composed of a plurality of carrier frequencies. These Wi-Fi devices monitor the state of the wireless channel for the efficient allocation of transmission capacity and adaptation speed for each stream MIMO in order to maximize use of available capacity of the wireless channel. These devices determine the channel state in the CSI values. Essentially, the values of CSI are the frequency response of the channel for each subcarrier frequency between each pair of antennas of transmitter and receiver", - the report says scientists.

Next, the researchers filtered out the extraneous radio noise and movement not associated with keystrokes.
After removal of interference, they determined the time spent pressing each button. Comparing the obtained values, the scientists tied to each key is a numeric value, as shown in the table below.

According to researchers, WiHear is not only potential attack vectors, but also provides great opportunities for human interaction with the computer.
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