The National Security Act in South Korea is a law designed to help keep South Korea safe and secure. This Act helps the government protect the people in South Korea from dangerous things like terrorists and war. It also helps the government stop any bad people from coming into South Korea. The National Security Act also makes it easier for the South Korean police to arrest and keep people who are trying to hurt the safety and security of the citizens in South Korea. Finally, this Act is used to help South Korea stay out of wars and fights with other countries.