A physical token operates together with an online server to test whether a user operating a user computer to access a service available at the online server is human. The physical token has two states: inactive and active. When in the inactive state the physical token displays interaction instructions for performing a physical action on the token. When the interaction instructions are satisfied, the physical token transitions to the active state and displays a response that may be used for satisfying a challenge issued by the online server to the user seeking to access the service.