Kryptos is an encrypted

Cipher

In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...

 sculpture

Sculpture

Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer materials can also be used, such as clay, textiles, plastics, polymers and softer metals...

 by American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 artist Jim Sanborn located on the grounds of the Central Intelligence Agency

Central Intelligence Agency

The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

 (CIA) in Langley

Langley, Virginia

Langley is an unincorporated community in the census-designated place of McLean in Fairfax County, Virginia, United States.The community was essentially absorbed into McLean many years ago, although there is still a Langley High School...

, Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

. Since its dedication on November 3, 1990, there has been much speculation about the meaning of the encrypted

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

 messages it bears. Of the four messages, three have been solved, with the fourth remaining one of the most famous unsolved codes in the world. The sculpture continues to provide a diversion for cryptanalysts, both amateur and professional, who are attempting to decrypt the final section.
The main sculpture is located in the northwest corner of the New Headquarters Building courtyard, outside of the Agency cafeteria.