Behavicker: Eavesdropping Computer-Usage Activities through Acoustic Side Channel

Figure 5

The results of event detection with modified CFAR performed on signal sequences of six basic events, namely, KS, CMW, CLM, CRM, SWU, and SWD.

(a) Signals of keystroke (KS, top) and clicking mouse wheel (CMW, bottom)

(b) Signals of clicking left (CLM, top) and right mouse buttons (CRM, bottom)

(c) Signals of scrolling mouse wheel up (SWU, top) and down (SWD, bottom)