The National Counterintelligence and Security Center (NCSC) is the nation’s premier source for counterintelligence and security expertise and a trusted mission partner in protecting America against foreign and other adversarial threats. The mission of NCSC is to lead and support the counterintelligence and security activities of the U.S. Government, the U.S. Intelligence Community, and U.S. private sector entities at risk of intelligence collection, penetration or attack by foreign and other adversaries.
(From: https://www.dni.gov/index.php/ncsc-home)