Authenticity of a new application being installed on a mobile device is evaluated to provide a result. The evaluation uses a plurality of inputs. In response to the result, an action is performed (e.g., on the mobile device itself and/or a server performing or assisting with the evaluation). For example, the evaluating may be done for an application that a user of the mobile device desires to install from an application marketplace. In another example, the action is sending of a notification to the mobile device, and the notification includes an assessment of authenticity of the new application.