CIA’s Kryptos sculpture mystery nears end as artist plans auction of final code

One of the CIA’s most enduring puzzles is about to go under the hammer.

Jim Sanborn, creator of the Kryptos sculpture at the agency’s Langley-based headquarters, plans to sell the solution to the artwork’s final unsolved code.

Since its dedication in 1990, Kryptos has intrigued professional and amateur code breakers worldwide. The sculpture features four copper panels with letters cut through them, along with elements such as petrified wood, water and stones.

The first three panels have been solved, revealing clues that range from a deliberate misspelling to geographic coordinates of CIA headquarters. The fourth panel, K4, has resisted all decoding attempts despite Sanborn releasing limited hints over the years.

The auction is set for November and the winning bid expected to fall between $300,000 and $500,000. Alongside the handwritten plain text of K4, the sale will include related papers and a copper proof-of-concept plate Sanborn kept during the sculpture’s creation.

“The power is in the secret,” he told The New York Times. “Without the secret, you have no power.

Decades of failed attempts

Over the years, Sanborn has received thousands of messages from hopeful solvers. About a decade ago, he began charging $50 for a personal response to deter casual guesses and focus on serious contenders. Some have shown remarkable persistence, including one person who has submitted solutions weekly for yearwithout success.

The rise of artificial intelligence has brought a new wave of attempts. Sanborn said that AI-generated solutions often miss the mark entirely, calling them “silly” and noting that they have played a role in his decision to auction the answer. He explained that K4’s brevity makes it impossible to release additional clues without revealing the entire solution.

Kryptos has attracted attention far beyond the cryptography community. References in popular culture, such as Dan Brown’s novels “The Da Vinci Code” and “The Lost Symbol,” have repeatedly revived interest, bringing fresh waves of would-be decoders. Yet none have succeeded in cracking K4.

A legacy beyond kryptos

Sanborn, who turns 80 this year, said he hopes the buyer will keep the secret intact and possibly assume responsibility for verifying future submissions from code breakers. Part of the auction proceeds will fund programs for people with disabilities, while some will be set aside for his personal health needs.

While Kryptos remains his best-known work, Sanborn has created numerous other installations across the globe. Many of his pieces merge art, science and history, including recent works commenting on looted antiquities and forgery.

For Sanborn, the decision to part with Kryptos’s last secret is as much about moving forward as it is about legacy. He described the decades-long mystery as a lingering loose end and said that, artistically, he has long since moved on.

The sale will close a chapter that has fascinated the intelligence community and puzzle enthusiasts alike — though whether the mystery remains sealed may depend entirely on the winning bidder.