 The AN/PYQ-10 supports both the DS-101 and DS-102 interfaces, as well as the KSD-64 Crypto Ignition Key.The SKL is backward-compatible with existing End Cryptographic Units (ECU) and forward-compatible with future security equipment and systems, including NSA's Key Management Infrastructure.Between 2005 and 2007, the U.S. Army budget included funds for over 24,000 SKL units.