Kryptos: The Cipher the CIA Can't Crack in Its Own Courtyard
In a courtyard at CIA headquarters in Langley, Virginia, stands a curved copper screen punched through with roughly 1,800 letters. The sculpture, called Kryptos, was created by American artist Jim Sanborn and dedicated in November 1990. It was designed as a challenge to the very people who walk past it every day: professional spies and cryptanalysts. Sanborn, who was not a cryptographer, learned the craft with help from Ed Scheidt, a retired chairman of the CIA's Cryptographic Center, and hid four encrypted messages in the metal.
The first three fell within a decade. In 1998, CIA analyst David Stein cracked them by hand, working through lunch breaks; a year later, computer scientist Jim Gillogly independently solved the same three sections by computer and went public. K1 is a poetic phrase about the lure of the unseen, K2 hints at something buried and gives coordinates near the Agency's grounds, and K3 paraphrases archaeologist Howard Carter's account of opening Tutankhamun's tomb in 1922.
Then there is K4 — just 97 characters, and a wall that has stood for 35 years. The NSA, the CIA, and a global community of thousands of amateur solvers have thrown everything at it: Vigenère variants, transposition schemes, statistical attacks. Nothing has produced a confirmed plaintext.
Sanborn, tired of waiting, began releasing clues. In 2010 he revealed that letters 64 through 69 of the solution spell BERLIN. In 2014 he added the next word: CLOCK. In 2020 came two more fragments — EAST and NORTHEAST. Solvers now know four islands of plaintext in a sea of cipher, yet the method that connects them remains unknown.
In 2025 the story took a turn no one predicted. Sanborn, approaching his 80s, decided to auction the solution rather than let it die with him. Weeks before the sale, two researchers, writer Jarett Kobek and Richard Byrne, told Sanborn they had found the plaintext — not by cryptanalysis, but among the artist's own papers deposited at the Smithsonian, which promptly sealed the archive. They pledged silence. On November 20, 2025, RR Auction in Boston sold Sanborn's private Kryptos archive, including the K4 solution, for $962,500 — nearly double the high estimate — to an anonymous buyer who agreed to keep the secret and act as the new keeper of the puzzle.
So today the answer to K4 exists in at least three sets of hands, and still no one can read it. The cipher itself remains unbroken, and Sanborn has hinted that even a solved K4 points to one final riddle hidden in the sculpture. The mystery was sold. It was not solved.