Intercepting messages using the sounds of keystrokes
Xuehui Shao · Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University · 2008
In order to covertly obtain data from a user's keystrokes,a new concept allows the capture of information hidden in the sound of typing.Sound to be processed is collected by a microphone array.First,by using a highest spectrum component tracking filter,wideband typing signals are transformed into narrowband ones.Then a near-field 2D-MUSIC spatial location algorithm is applied to keyboard sound,and correcting measures used to calibrate the microphone array's gain and phase error.Research leading to the proposed method for transforming raw sound file is discussed in detail.Finally,a hardware-in-the-loop simulation was performed to test the ability of the system to intercept information from the sound of typing.The results of the simulation prove the effectiveness of the proposed approach and its potential engineering value.