A communal computing device such as an interactive digital whiteboard can provide progressively more access to functionality and data on the device based on a level of certainty in the identity of a user. If a user is identified based on one or more low-fidelity identification signals such as an image of the user or a device identifier, the communal computing device may provide a first level of functionality that is limited. If the user requests greater access, the communal computing device can request that a trusted cloud-based provider authenticate the user by way of a personal device, such as a smartphone. The authentication may be a password or high-fidelity biometric identification. The cloud-based provider communicates successful authentication to the communal computing device and it, in turn, provides the user access to higher, second level of functionality.