The CIA’s Kryptos: America’s Longest-Running Puzzle, Up for Sale

Outside the CIA’s headquarters in Langley, Virginia, stands one of the greatest unsolved puzzles in modern history: Kryptos.

Created in 1990 by American artist James Sanborn, the copper sculpture contains four encrypted messages, known as K1, K2, K3, and K4. While professional and amateur codebreakers — including intelligence experts, computer scientists, and AI systems — have deciphered the first three, the fourth section, K4, has remained unbroken for over three decades.

Now, Sanborn has decided to auction the decryption key and his entire Kryptos archive, which includes code matrices, original CIA contracts, and unseen photographs from the sculpture’s creation.

Kryptos has fascinated millions since its installation, inspiring online communities, university research papers, and even pop culture references in Dan Brown’s “The Da Vinci Code” and “The Lost Symbol.”