Edward Joseph Snowden is an American and naturalized Russian citizen who was a computer contractor who leaked highly classified information from the National Security Agency (NSA) in 2013 when he was an employee and subcontractor who is currently under indictment for espionage. His disclosures revealed numerous global surveillance programs, many run by the NSA and the Five Eyes intelligence alliance with the cooperation of telecommunication companies and European governments and prompted a cultural discussion about national security and individual privacy.

National security, or national defence, is the security and defence of a sovereign state, including its citizens, economy, and institutions, which is regarded as a duty of government. Originally conceived as protection against military attack, national security is widely understood to include also non-military dimensions, such as the security from terrorism, minimization of crime, economic security, energy security, environmental security, food security, and cyber-security. Similarly, national security risks include, in addition to the actions of other nation states, action by violent non-state actors, by narcotic cartels, organized crime, by multinational corporations, and also the effects of natural disasters.