An anonymous bidder has won the solution to a 35-year-old puzzle for nearly $1 million. The top-secret code could be used to solve Kryptos, an infamously enigmatic sculpture containing four hidden messages that stands at the CIA headquarters in Virginia.
The work has gained a dedicated cult following thanks to ongoing efforts to solve its final puzzle. Since its debut in 1990, three of the four messages—known as K1, K2, and K3—have long since been solved. K4, however, has remained frustratingly elusive to even world-class cryptographers.
The artist behind the work, Jim Sanborn, has kept the solution to K4 under lock and key. He has been open about the stresses of this job, which include having his computer hacked and receiving threats. As he prepared to turn 80 earlier this month, Sanborn grew weary of gatekeeping this secret and decided to hand over the responsibility to the highest bidder.
Sanborn’s handwritten code for K4 was offered as part of a bundle of other unpublished items as well as a “proof-of-concept” prototype for Kryptos, in an online sale by R.R. Auction. The winning bid of $962,500 soared past the presale estimate of $300,000 to $500,000. A portion of the proceeds will go to programs for the disabled.
Photograph of Jim Sanborn with cut Kryptos copper plate, 1990. Image courtesy RR Auctions.
How Much Is the Last Key Worth?
The impressive result was a relief for Sanborn. In the months leading up to the sale, the value of his K4 solution was called into question when it was accidentally leaked to a pair of sleuths who tracked it down using information from the sale’s catalog notes.
On September 3, Sanborn received an email containing the full, decoded text of K4. The sender, Jarett Kobek, was a journalist who had spotted a reference to Sanborn’s original “coding charts” being kept at the Smithsonian in the detailed notes provided by R.R. Auction. He asked his friend Richard Byrne, a journalist based in Washington D.C., to request the Sanborn papers from the Smithsonian’s Archives of American Art. Inside, the pair found the entire, uncoded plaintext version of K4, identifiable thanks to clues that Sanborn released in 2010 and 2014.
The artist, who plans to use proceeds from the auction to pay for medical expenses, as well as to fund disability programs, asked both journalists to sign NDAs requiring them to guard the secrets of K4. In exchange, he was prepared to offer them a portion of the auction’s proceeds. This offer was refused, with Kobek and Byrne claiming that it could make them “party to fraud” in the auction.
In an email, Sanborn confirmed that Kobek and Bryne have promised not to release the K4 text. “I have to take them at their word,” he said. He added that, although the pair’s discovery was “unfortunate for a lot of reasons,” all bidders on his unpublished materials already know that “tens of thousands” are currently working to crack K4 and any one might succeed at any time.
Sanborn told the New York Times last month month that he included the solution to K4 in his files for the Smithsonian by mistake, while receiving cancer treatment about a decade ago. “I was not sure how long I would be around and I hastily gathered all of my papers together,” he said. The files have now been sealed until 2075.
What Is the Kryptos Sculpture?
Kryptos was installed on the grounds of the Central Intelligence Agency (CIA) in Langley, Virginia on November 3, 1990. It stands 12 feet tall and 20 feet long, curves in an S-shape, and is made of copper, petrified wood, water, and stones. It takes its name from the Greek word for “hidden.”
Into Kryptos‘s curved copper screen, Sanborn hand-cut almost 2,000 letters that can be divided into four messages, each using a new code. These cryptographic systems were not designed by the sculptor himself but by Edward Scheidt, who retired as chairman of the CIA’s Cryptographic Center in 1989. Three have already been solved by CIA employees but the fourth, known as K4, remains frustratingly elusive.
“Every artwork strives to hold your attention for as long as possible,” Sanborn told the YouTube channel Great Big Story. “If it’s an artwork that contains something that keeps your attention for even 10 minutes, much less 30 years, I get a great sense of satisfaction from that. It’s become part of many people’s lives.”
Public artworks by Sanborn made in a similar style include Ex Nexum (1994–97) in Little Rock, Arkansas, and Lux (2001) in Fort Myers, Florida. His work has also been exhibited at the Los Angeles County Museum of Art, the High Museum of Art in Atlanta, Georgia, and the Hirshhorn Museum and Sculpture Garden in Washington, D.C.
Attempts to Crack the Code
The mystery of K4 has gained international attention and inspired an army of dedicated sleuths. In the U.S., a group of experts and amateurs alike meets every year to discuss their theories.
The previously interpreted messages include K3, a paraphrasing of Howard Carter’s account of opening Tutankhamun’s tomb, and K1, which reads “between subtle shading and the absence of light lies the nuance of iqlusion.” The text contained an intentional misspelling of “illusion” as a red herring. These messages may aid in cracking K4, as Sanborn has teased that there is a link between all four messages.
Even seasoned cryptographers and intelligence experts have remained baffled by the cryptic text. So far, however, only minimal progress has been made. The few words “northeast” and “Berlin clock” have been revealed thanks to clues offered by Sanborn in 2010, 2014, and 2020.
Jim Sanborn’s copper maquette for Kryptos, submitted to the CIA in 1988. Photo courtesy RR Auctions.
Humans hoping they might one day be the one to solve the puzzle will be relieved to know that Sanborn has remained thoroughly unconvinced by A.I.’s efforts so far. He revealed to the New York Times that he has begun receiving solutions devised by ChatGPT, but described these efforts as “nothing short of fairly silly.”
The New Keeper of the Code
The transfer of ownership of the K4 code from Sanborn to the highest bidder was set to mark the first time that this top secret information would be shared. The artist hopes that its new owner will continue to protect the secret, which he said gives the work its power, and that they may even resume the responsibility of reviewing proposed solutions.
“The ideal outcome would be for the winner to become a guardian of the secret, not its revealer,” agreed Bobby Livingston, executive vice president of RR Auction, in a press statement announcing the auction. “Imagine the satisfaction of watching someone else crack it through pure intellectual effort, knowing you hold the key to confirm their success. That’s the true legacy of Kryptos.”
Sanborn has made no secret that he is “tired” of dealing with queries about K4 himself, and has begun charging a $50 fee for replies. He told the NYT that this earns him an estimate $40,000 each year. However, he is looking forward to being free from the responsibility of controlling the secrets of K4, allowing him time for new artistic ventures.
So what exactly will Kryptos‘s new owner receive? The lot is a veritable goodie bag for any Kryptos enthusiast. As well as the original handwritten K4 code, offered with a signed typed letter from cryptographer Ed Scheidt, they can expect to win the 12-by-18 inch copper maquette submitted as a sample to the CIA in 1988, archival photographs relating to the works’ creation, the original dedication pamphlet signed by the late CIA director William Webster, and copies of coding charts used to code Kryptos.
This story was updated on Monday, November 24, 2025 at 7:30 a.m. E.T. to reflect the auction result.