The complete archive containing the solution to decode the final unsolved message in the famous Kryptos sculpture at CIA headquarters in Virginia has been sold to an anonymous bidder for $963,000 at a Boston auction. The sale, conducted by RR Auction of Boston, includes all documents and coding charts created by artist Jim Sanborn, who designed the cryptographic artwork that was dedicated in 1990.

The 10-foot-tall sculpture, which resembles a piece of paper emerging from a fax machine, features an S-shaped copper screen with four encrypted messages. Three of these messages, known as K1, K2, and K3, have been successfully decoded over the years. However, the fourth message, K4, has remained an unsolved mystery that has frustrated both professional cryptographers and amateur code-breaking enthusiasts for more than three decades.

The artwork consists of two sides: one displaying a series of staggered alphabets that serve as the key to decoding the messages, and the other side containing the four encrypted texts. The challenge of solving K4 has attracted so much attention that the 80-year-old Sanborn began charging $50 per submission after receiving countless inquiries from would-be code breakers. One particularly dedicated individual has been in regular contact with Sanborn for the past two decades, attempting to crack the final code.

The winning bidder will receive more than just the archive materials. The purchase includes a private meeting with Sanborn himself, during which he will explain the codes, charts, and artistic intent behind both K4 and an alternate paragraph he calls K5. According to RR Auction, the purchaser is developing a long-term stewardship plan for the materials, and Sanborn hopes the new owner will continue his tradition of interacting with cryptography enthusiasts while keeping the solution's secrets safe.

The auction faced potential complications in September when two Kryptos researchers discovered Sanborn's original scrambled texts in the artist's papers housed at the Smithsonian Institution. This discovery prompted a change in the auction format, expanding it from offering only the K4 solution to selling Sanborn's entire archive. However, Sanborn emphasized the crucial distinction between discovery and decryption, stating to The Associated Press: "The important distinction is that they discovered it. They did not decipher it. They do not have the key. They don't have the method with which it's deciphered."

Sanborn, whose career spans approximately 50 public sculptures, has created works beyond the famous CIA puzzle, including a memorial commemorating the victims of a 2019 mass shooting in Odessa, Texas. The Kryptos sculpture has become one of the most famous unsolved puzzles in the world, attracting attention from professional cryptographers, intelligence agencies, and amateur sleuths who have formed communities dedicated to cracking its final secret. With the archive now in private hands, the future of K4's solution remains as mysterious as the code itself.