1. A computer-implemented method, comprising: generating a set of security tasks for unlocking a mobile device based at least in part on interactions with applications executed on the mobile device; causing a security task of the set of security tasks to be displayed through a user interface enabling use of the mobile device; obtaining a response to the security task; determining a score associated with the response to the security task based at least in part on the response; as a result of the score reaching a value relative to a threshold, determining to modify at least a subset of security tasks of the set of security tasks; modifying the subset of security tasks; and unlocking the mobile device based at least in part on the score.