Keep Others from Peeking at Your Mobile Device Screen!

People use their mobile devices anywhere and anytime to run various apps, and the information shown on their device screens can be seen by nearby (unauthorized) parties, called shoulder surfers. To mitigate this privacy threat, we have developed HideScreen by utilizing the human vision and optical system properties to hide the users' on-screen information from the shoulder surfers. Specifically, HideScreen discretizes the device screen into grid patterns to neutralize the low-frequency components so that the on-screen information will "blend into'' the background when viewed from the outside of the designed range. We have developed and evaluated several ways of hiding both on-screen texts and images from shoulder surfers. Our extensive experimental evaluation of HideScreen demonstrates its high protection rates (>96% for texts and >99% for images) while providing good user experience.