Kryptos Creator to Auction Final Cipher Solution as Decades-Long CIA Mystery Nears New Chapter

Kryptos Artist Jim Sanborn to Auction Unsolved Final Cipher as Public Art Icon Faces Its Next Era

For more than three decades, Kryptos has captivated codebreakers, artists, intelligence enthusiasts, and puzzle solvers around the world. Now, the creator of the CIA’s most famous sculpture says it is time for someone else to take responsibility for its last remaining secret. Jim Sanborn, the artist who designed Kryptos in 1990, has announced plans to auction the full solution to the sculpture’s final encrypted message—an unresolved code known as K4. The decision follows years of public fascination and a recent archival discovery that briefly threatened the sale.

The story of Kryptos has evolved from an artistic experiment in cryptography into one of the world’s most enduring cultural puzzles. Its creator hopes the next keeper will continue engaging with the global community that has spent decades attempting to solve its final unsolved passage.

The Origins of a Cultural Cipher

When Jim Sanborn was commissioned to create a sculpture for CIA headquarters in Langley, Virginia, he wanted to design a work that reflected the agency’s culture of secrecy, intelligence gathering, and coded communication. The result was Kryptos—a curved, copper, S-shaped screen resembling a sheet of paper emerging from a machine, with letters encrypted using classical cryptographic techniques.

Sanborn said his intention was to create a work that would engage viewers far longer than traditional public art. At the time, encryption was considered an obscure and highly technical field; he hoped to bring it into the public imagination. The sculpture includes four encrypted messages—K1, K2, K3, and K4. The first three were solved in the early 1990s, but the fourth has resisted every attempt.

Over the years, Kryptos has drawn thousands of enthusiasts, from professional cryptologists to hobbyist puzzle solvers. Sanborn regularly received messages from people trying to crack K4—sometimes multiple inquiries a week. To slow the surge of submissions, he eventually introduced a fee and charged $50 per attempt.

A Global Puzzle with One Remaining Secret

The unsolved K4 has remained at the center of a worldwide mystery. Sanborn revealed that one individual has contacted him every week for the past 20 years, hoping for new hints. Despite occasional clues released by the artist—including partial solutions to specific letter sequences—the final message has remained encrypted since the sculpture’s dedication in 1990.

At 79, and having experienced several health complications in recent years, Sanborn says it is time to entrust the final passage to someone else. Boston-based RR Auction began accepting bids for the full Kryptos archive in October, with the sale running through November 20. Early bids exceeded $200,000.

The archive includes not only the instructions needed to decode K4 but also an alternate paragraph Sanborn refers to as “K5.” It also contains original coding materials for the first three sections and the scrambled texts that Sanborn once showed to the CIA’s Department of Historical Intelligence to ensure the sculpture included no sensitive information.

RR Auction’s executive vice president said Kryptos had “become a worldwide phenomenon,” noting that K4 has challenged both professional codebreakers and amateurs since the early 1990s.

An Accidental Discovery Threatens the Auction

In September, the auction nearly derailed after two researchers unintentionally uncovered the K4 text while examining Sanborn’s papers at the Smithsonian’s Archives of American Art. Writer Jarett Kobek and playwright Richard Byrne, after noticing references in the auction listing, visited the archives and photographed documents containing the original scrambled texts for the sculpture.

Kobek later recalled hoping to find clues about K4’s method, but instead realized they had discovered the text itself. When informed, Sanborn said he was shocked and distressed, describing the moment as “miserable.” He had mistakenly included the scrambled passages in his archived materials years earlier. The documents have now been sealed for 50 years to prevent further access.

RR Auction removed references connecting the listing to the Smithsonian, while acknowledging the researchers’ discovery. The two declined to sign a nondisclosure agreement that would have included sharing auction proceeds. The auction house also sent multiple emails suggesting potential legal action, though no measures were taken.

Despite uncovering the scrambled text, Kobek emphasized that they had not solved the cipher. “They do not have the key,” Sanborn said, underscoring that the decoding method itself remains the true secret within the cryptographic community.

A Debate Over Whether the Secret Should Ever Be Revealed

Among Kryptos followers, there is ongoing debate about whether the solution to K4 should remain hidden. Elonka Dunin, co-moderator of one of the largest Kryptos discussion groups, said many enthusiasts prefer the final cipher to stay undisclosed. For them, the puzzle’s appeal lies in its mystery—not only in the text itself but in the challenge of deciphering it.

Kryptos’s layered design reflects this philosophy. Sanborn developed the passages with help from a retired CIA cryptographer, who demonstrated several potential encoding systems. The structure, Sanborn said, was intended to unravel like a ball of string or a nesting set of Russian dolls, increasing in difficulty as solvers moved through each layer.

Sanborn has expressed hope that the buyer of the archive will honor the sculpture’s spirit, continue interacting with the global community, and avoid releasing the method prematurely.

Kryptos in Culture and Public Memory

Kryptos has been part of American cultural history for decades. It has appeared on the dust jacket of Dan Brown’s “The Da Vinci Code” and inside the author’s later novel “The Lost Symbol.” Codebreaking enthusiasts gather online to exchange theories, while cryptography conferences regularly discuss potential approaches for solving the sculpture’s final section.

Sanborn’s broader career includes more than 50 public artworks, such as a memorial in Odessa, Texas, dedicated to victims of the 2019 mass shooting. But none have matched the reach of Kryptos, a sculpture that exists at the intersection of art, intelligence, secrecy, and public imagination.

As the auction unfolds, interest continues to build around who will become the next keeper of one of America’s most enduring cultural mysteries. Whether the new owner maintains the secrecy or eventually reveals the full solution, the legacy of Kryptos shows no signs of fading.