The security and privacy of a user is enhanced by monitoring the background environment in which the user is working for changes. In an embodiment, a first or reference image is acquired using a front-facing camera of the user's computing device. A second or target image is acquired using the front-facing camera. The images are compared and an alert is generated if there is a change in background that exceeds a threshold. The change may be a person who has entered the environment and is watching the computing device screen. The alert may include reducing the visibility of information shown on the screen.