Abstract: System and method embodiments are provided for camera-based user authentication for content on a user device. In an embodiment, an action by a user for displaying content on a screen of the user device is detected. A content file on the user device is then scanned to determine whether the content file is protected. An image of the user is also captured without input from the user and without notifying or prompting the user. The content file is displayed on the screen if the content file is not protected, or if the content file is protected and the captured image of the user matches a retrieved image from an allowed users list of the content file.