Kryptos is a sculpture by the American artist Jim Sanborn located on the grounds of the Central Intelligence Agency (CIA) headquarters, the George Bush Center for Intelligence in Langley, Virginia. Since its dedication on November 3, 1990, there has been much speculation about the meaning of the four encrypted messages (most using a vigenere cipher with key word Kryptos) it bears. Of these four messages, the first three have been solved, while the fourth message remains one of the most famous unsolved codes in the world. Artist Jim Sanborn has hinted that a fifth coded message will reveal itself after the first four are solved. The sculpture continues to be of interest to cryptanalysts, both amateur and professional, attempting to decode the fourth passage. The artist has so far given four clues to this passage.
Description
The sculpture comprises four large copper plates with other elements consisting of water, wood, plants, red and green granite, white quartz, and petrified wood. The most prominent feature of the entire piece is a large vertical S-shaped copper screen resembling a scroll or a piece of paper emerging from a computer printer, half of which consists of encrypted text, that is located in the northwest corner of the New Headquarters Building courtyard, outside of the agency's cafeteria. The characters are all found within the 26 letters of the Latin alphabet, along with question marks, and are cut out of the copper plates. The main sculpture contains four separate enigmatic messages, three of which have been deciphered. In addition to the main part of the sculpture, Sanborn also placed other pieces of art on the CIA grounds, such as several large granite slabs with sandwiched copper sheets outside the entrance to the New Headquarters Building. Several Morse code messages are found on these copper sheets, and one of the stone slabs has an engraving of a compass rose pointing to a lodestone. The ciphers' increasing "complexity" through the entrance into the courtyard is intended to be as if it "were a fossil". Other elements of Sanborn's installation include a landscaped garden area, a fish pond with opposing wooden benches, a reflecting pool, and other pieces of stone, including a triangle-shaped black stone slab. The name Kryptos comes from the ancient Greek word for "hidden", and the theme of the sculpture is "intelligence gathering". The cost of building the sculpture in 1988 was US$250,000 (worth ~US$660,000 in 2024).
Encrypted messages The ciphertext on the left-hand side (as seen from the courtyard) of the main sculpture contains 869 characters in total: 865 letters and 4 question marks. In April 2006, Sanborn released information stating that a letter was omitted from this side of Kryptos "for aesthetic reasons, to keep the sculpture visually balanced". There are also three misspelled words in the plaintext of the deciphered first three passages, which Sanborn has claimed was intentional, and three letters ("YAR") near the beginning of the bottom half of the left side are the only characters on the sculpture in superscript. The right-hand side of the sculpture comprises a keyed Vigenère encryption tableau, consisting of 867 letters. One of the lines of the Vigenère tableau has an extra character (L). Bauer, Link, and Molle suggest that this may be a reference to the Hill cipher as an encryption method for the fourth passage of the sculpture, as with that extra L, the letters HILL appear consecutively down the rightmost column. However, Sanborn omitted the extra letter from the small Kryptos models that he sold.
Sanborn worked with a retiring CIA employee named Edward Scheidt to come up with the cryptographic systems used on the sculpture. Edward Scheidt stated that the difficulty of the encryption was around nine out of ten. He said that his intention was for it to be solved in five to ten years. He also said that there was an intentional "change in the methodology" of the encryption. Sanborn also suggested in a 2005 interview that should he die before the entire sculpture is deciphered, he had put in place a method by which a correct solution could be confirmed. In 2020, Sanborn stated that he planned to put the secret to the solution up for auction once he died. In August 2025, Sanborn announced that the K4 solution as well as a prototype sculpture, encryption tables, and other related ephemera would be auctioned by the firm RR Auction later in the year. In October 2025, the Kryptos auction was formally posted by RR Auction as part of the sale titled "Decoding History: Kryptos, Enigma and the Rosetta Stone", running from 16 October to 20 November 2025. As part of the same collection, a signed first-edition set of Howard Carter’s The Tomb of Tut-ankh-Amen was listed as running from 16 October to 20 November 2025. Sanborn had stated that the sculpture contains a riddle within a riddle, which will be solvable only after the four encrypted passages have been deciphered. He has given conflicting information about the sculpture's answer, saying at one time that he gave the complete solution to the then-CIA director William Webster during the dedication ceremony, but later, he also said that he had not given Webster the entire solution. He did, however, confirm that a passage of the plaintext of the second message reads, "Who knows the exact location? Only WW."
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