A computing environment maintains the integrity of data stored in system memory. The system has a memory management unit that maintains a plurality of real page numbers. The system also comprises an address bus in communication with the memory management unit. The address bus comprises a plurality of address lines, wherein a value of at least one address line is set by a real page number from the memory management unit. The system has an operating system that controls memory usage by controlling the real page numbers stored in said page table that is accessed by the memory management unit. At least one security feature such as data encryption is selectively applied to data stored in a page of said memory as enabled by a value of said address line set by said real page number.