The United States Secret Service is an American federal law enforcement agency that is part of the U.S. Department of Homeland Security. Until March 1, 2003, the Secret Service was part of the U.S. Department of the Treasury. The Secret Service has two distinct areas of responsibility: Financial Crimes, covering missions such as prevention and investigation of counterfeiting of U.S. currency and U.S. treasury securities, and investigation of major fraud; Protection, which entails ensuring the safety of current and former national leaders and their families, such as the President, former presidents, vice presidents, presidential candidates, visiting heads of state and foreign embassies. Protecting national leaders, visiting heads of state and government, designated sites and National Special Security Events has become more complex with the evolution of conventional and non-conventional weapons and technology. In meeting new challenges, the Secret Service will continue to provide progressive training, devise and implement sound security plans, measures, equipment and systems to ensure the safety of individuals, sites and events under Secret Service protection. Th e Secret Service’s unique investigative and protective mission is sustained by a strong, multi-tiered infrastructure of science, technology and information systems; administrative, professional and technical expertise; and management systems and processes.