Abstract: A method for verifying user participation includes generating a motion signature associated with an event. The motion signature is generated on a mobile device with a user during the event. The mobile device includes one or more sensors configured to detect motion. The method includes comparing the generated motion signature with a predefined motion signature associated with the event. The predefined motion signature is stored in an event library that includes a plurality of predefined motion signatures, where each predefined motion signature is associated with an event. The method includes verifying that the user participated in the event by verifying that the generated motion signature matches the predefined motion signature of the event.