Embodiments of the present invention provide an approach for memory protection at a level of granularity above a “page” level (e.g., enhancing the protection provided by a memory key-based system). The approach further provides such a level of protection at a process or task level by associating the physical page key with a virtual key that corresponds to a particular process/task. When access to the data is requested for a particular process or task, it is determined if a protection bit for the data is set, and if the physical page keys and/or virtual keys submitted pursuant to the request match that previously stored for the data and process/task. If so, access to the data is allowed for the particular process/task.