Methods, systems, and products authenticate users for access to devices, applications, and services. Skills of a user are learned over time, such that an electronic model of random subject matter may be generated. The user is prompted to interpret the random subject matter, such as with a drawing, physical arrangement, or performance. The user's interpretation is then compared to the electronic model of the random subject matter. If the user is truly who they purport to be, their interpretation will match the electronic model, thus authenticating the user. If interpretation fails to match the electronic model, authentication may be denied.