The Multiprogram Research Facility (MRF, also known as Building 5300) is a facility at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. It is used by the U.S. National Security Agency (NSA) to design and build supercomputers for cryptanalysis and other classified projects. It houses the classified component program of the High Productivity Computing Systems (HPCS) project sponsored by the Defense Advanced Research Projects Agency (DARPA).