It was 1990, and the CIA headquarters in Langley, Virginia, was just finishing their expansion of the New Headquarters Building. Submissions had come in from all over the nation for artwork to adorn the courtyard. The only qualification for this $250,000 commission was that it should inspire feelings of well being and hope (Clues to Stubborn Secret in C.I.A.’s Backyard). The winner, a modern sculptor named Jim Sanborn, was partnered with Edward Scheidt, a retired CIA cryptographer, in order to design an encoded sculpture. Over twenty years later, Kryptos has yet to be fully decoded.
To begin with, Kryptos is made of red granite, green granite, quartz, petrified wood, and four large copper panels, into which the encoded messages are engraved. The sculpture is curved, like the letter S, and lies in the Northwest corner of the New Headquarters Building. One half of the message is a ciphertext, a style of encryption which uses an algorithm to encode. This first part contains eight hundred sixty five letters and four question marks. Sanborn also intentionally incorrectly spelled a few words to make the decoding process more difficult. The second half of the code is encrypted with Caesar ciphers. This is a style of code where one letter will represent another. For example, if B represented A, C represented B, and so on the word DOG would become EPH. However Sanborn made it much more complicated than this by using different sets of Caesar Ciphers. This technique is called a Vigenere Cipher.
The Vigenere Cipher is a seemingly complicated form of encryption. This code is attributed to Blaise de Vigenere. It is categorized as a polyalphabetic cipher, in other words a cipher based on multiple different alphabet substitutions. The first documentation of a polyalphabetic cipher is from the Renaissance artist Alberti. Within an encoded document, Alberti would switch alphabetical substitutions. This was the first step towards the Vigenere Cipher. The second occurred in 1508 with Johannes Trithemius. He invented the Tablua Recta, which is necessary for encoding in the Vigenere Cipher and a labor saving tool for Caesar Ciphers. The Tablua Recta is a chart made of the alphabet; twenty six letters by twenty six letters (See last page). But with each row, the alphabet is spelled in a different order. Giovan Bellaso was the first person to describe the concept of the Vigenere Cipher. Bellaso took Trithemius’s Tablua Recta and added the concept of changing the Caesar Cipher by a keyword. Blaise de Vigenere later published a description of a very similar code. The Vigenere Cipher is named after him, but many say that Bellaso was the true inventor.
In order to create a Vigenere Cipher, there are two necessary parts: a keyword and a Tablua Recta. Here is the process of encoding the word MATH in a Vigenere Cipher if the keyword is DOG. First you rewrite MATH using the keyword, so MATH becomes DOGD. Then you find the row on the Vigenere Square beginning with D, and find the letter to replace M. But to encode the second letter, you use a different row on the Vigenere square, so the code for the second letter is completely different than the code for the first letter. So MATH encoded with a Vigenere Cipher if the keyword is DOG becomes POZK. The longer the keyword, the more difficult it is to crack the code. For example if the keyword is MATHEMATICS, then MRCHAMBLESS would become YRVOEYBEMUK. Try decoding that!
Getting back to Kryptos, the first two messages are encoded with Vigenere Ciphers, the third section with Ciphertext, and the last part with an unknown encryption. The first message reads, “Between subtle shading and the absence of light lies the nuance of illusion,” and is encoded with the keyword PALIMPSEST. The second message is much longer: “It was totally invisible, how’s that possible? They used the Earth’s magnetic field. The information was gathered and transmitted underground to an unknown location. Does Langley know about this? They should; it’s buried out there somewhere. Who knows the exact location? Only WW; this was his last message. ‘Thirty eight degrees, fifty seven minutes, six point five seconds north.'” The third message is encoded with a ciphertext, and is a quote about the opening of King Tut’s tomb. “Slowly, desperately slowly the remains of passage debris that encumbered the lower part of the doorway was removed with trembling hands. I made a tiny breach in the upper left hand corner, and then widening the hole a little, I inserted a candle and peered in. The hot air escaping from the chamber caused the flame to flicker, but presently the details of the room within emerged from the mist. ‘Can you see anything?'” This is a quote from The Tomb of Tutankhamen by Howard Carter. From these three messages alone, Kryptos already creates an aura of good feeling and hope.
But Kryptos is not necessarily famous for its characteristic good feeling and hope, but its aura of mystery. This atmosphere is created by the unsolved fourth message. Thousands have unsuccessfully tried to crack this code, but Sanborn proved each of them wrong. In 2003, a Yahoo! Group dedicated to solving the remaining portion of Kryptos was solved. It actively coordinates the work of over 2,000 members. Interest in the Sculpture drastically increased in 2010, when Sanborn decided o give the CIA a hint, that within the fourth part, the 64th through 69th letters encode the word Berlin. After this clue, Richard Gray, a former NSA and current CIA operative, claims to have identified the encryption of the fourth message. He believes that the last section is encoded with a Playfair system and a keyword, but he has yet to actually decode the message. He is not the first to believe he has solved it; some code breakers have begun accusing Sanborn of lying about the message. Yet with all of the current technology, it seems that a 20 year old code would be easy to crack. But Kryptos has proved everyone wrong.