Check the listing for details. DEFENSE SECURITY SERVICE Challenge Coin. Condition: New. Listed at 14.89 USD. DEFENSE SECURITY SERVICE Challenge Coin. This is a great looking United States Defense Security Service (DSS) challenge coin. Coin has reeded edges and is about 1 9/16" in diameter. All details are raised lettering. Coin is contained in an acrylic air tight holder. The Defense Security Service (DSS) is a federal security service of the United States Department of Defense (DoD). Within areas of DoD responsibility, DSS is tasked with facilitating personnel security investigations, supervising industrial security, and performing security education and awareness training. DSS is an authorized Federal Security Agency. Industrial Security Representatives and Information System Security Professionals are credentialed government agents. Originally known as the Defense Investigative Service (DIS), DIS was established in 1972. DSS changed from DIS in 1999.