A set of legal memoranda known as the "Torture Memos" were drafted by John Yoo as Deputy Assistant Attorney General of the United States and signed in August 2002 by Assistant Attorney General Jay S. Bybee, head of the Office of Legal Counsel of the United States Department of Justice. They advised the Central Intelligence Agency, the United States Department of Defense, and the president on the use of enhanced interrogation techniques—mental and physical torment and coercion such as prolonged sleep deprivation, binding in stress positions, and waterboarding—and stated that such acts, widely regarded as torture, might be legally permissible under an expansive interpretation of presidential authority during the Global War on Terrorism.