Kryptos is a sculpture by American artist James Sanborn located on the grounds of the Central Intelligence Agency (CIA) in Langley, Virginia, USA. Since its dedication on November 3, 1990, there has been much speculation about the meaning of the encrypted messages it bears. It continues to provide a diversion for some employees of the CIA and other cryptanalysts attempting to decrypt the messages.
The main sculpture is made of red and green slate, white quartz, petrified wood, lodestone and copper, and is located in the northwest corner of the New Headquarters Building courtyard, outside of the Agency cafeteria. The name Kryptos comes from the Greek word for "hidden", and the theme of the sculpture is "intelligence gathering." The most prominent feature is a large vertical S-shaped copper screen resembling a scroll, or piece of paper emerging from a computer printer, covered with characters comprising encrypted text. The characters consist of the 26 letters of the standard Roman alphabet and question marks cut out of the copper.
This "inscription" contains four separate enigmatic messages, each apparently encrypted with a different cipher.[citation needed]