Ever since artist James Sanborn unveiled Kryptos , an outdoor sculpture that sits at CIA headquarters, amateur and professional cryptanalysts have been feverishly attempting to crack the code hidden in its nearly 1800-character message. While they have decoded 3 of the 4 panels of ciphertext in the S-shaped copper artwork, the final panel, known as K4, still defies solution. Only one human being on Earth knows the message of K4: Sanborn. But soon someone else will join the club. Sanborn is putting the answer up for sale.

“I'm auctioning off the 97-character plaintext of K4, which is the secret of Kryptos,” Sanborn tells me. He’s even throwing in a curved metal plate that he used as a cutting sample for the panel that now sits at the agency.

Sanborn has hinted that auctioning off the s

See Full Page