Methods and systems for verifying whether a user requesting an online account is likely a human or an automated program are described. A request for an online account may be received from a mobile device. A human challenge-response test adapted for displaying on a mobile device is displayed on the mobile device. Upon viewing the human challenge-response test, the user enters the user's solution to the human challenge-response test on the mobile device. A response hash value is created based on the user's solution. The response hash value is sent to an account request server for verification.