Kryptos.

No, sorry, we’re not doing a post about Superman’s dog.

Instead, today we’re discussing how the solution to one of the great unsolved cryptographic mysteries of our time is going up for auction in October.

For the uninitiated, Kryptos is a flowing sculpture made of petrified wood and copper plating, sitting over a small pool of water. It was revealed to the world in 1990, coded by former chairman of the CIA’s Cryptographic Center Edward Scheidt, and designed by artist Jim Sanborn. Designed to both challenge and honor the Central Intelligence Agency, for decades Kryptos has proven to be a top-flight brain teaser for codebreakers both professional and amateur.

There are four distinct sections, utilizing different forms of encryption. And amazingly, the fourth section continues to elude codecrackers to this very day.

It took nearly a decade before anyone announced a solution to the first three encryptions. A computer scientist named Jim Gillogly announced in 1999 that he had cracked passages 1, 2, and 3 with computer assistance.

The CIA, not to be one-upped, then revealed that one of their own employees, an analyst named David Stein, had solved those same three passages the year before, using only pencil, paper, and lunchtime man-hours.

But a 2013 Freedom of Information Act request into records of the National Security Agency revealed that an NSA team actually cracked those same three passages back in 1993 as part of a friendly rivalry between the NSA and CIA, provoked by former NSA director and then-deputy CIA director William O. Studeman.

Passage 1 employs a Vigenère cipher, a letter-shifting cipher that has been used for centuries, also known as a periodic polyalphabetic substitution cipher, if you want to get fancy with it.

The message, penned by Sanborn himself, reads Between subtle shading and the absence of light lies the nuance of iqlusion. [Iqlusion is an intentional misspelling of “illusion.”]

Passage 2 also employs a Vigenère cipher, but utilizes a different keyword than Passage 1. The message, also composed by Sanborn, points toward something hidden nearby:

It was totally invisible. How’s that possible? They used the earth’s magnetic field. x The information was gathered and transmitted undergruund to an unknown location. x Does Langley know about this? They should: it’s buried out there somewhere. x Who knows the exact location? Only WW. This was his last message. x Thirty eight degrees fifty seven minutes six point five seconds north, seventy seven degrees eight minutes forty four seconds west. x Layer two. [Again, there’s an intentional misspelling here with “undergruund.”]

Passage 3 uses a transposition cipher, which relies on the positioning of given letters in order to properly spell out a message. The message is inspired by the words of Howard Carter, the archaeologist who opened King Tut’s tomb:

Slowly, desparatly slowly, the remains of passage debris that encumbered the lower part of the doorway was removed. With trembling hands I made a tiny breach in the upper left-hand corner. And then, widening the hole a little, I inserted the candle and peered in. The hot air escaping from the chamber caused the flame to flicker, but presently details of the room within emerged from the mist. x Can you see anything? q [Again, there’s an intentional misspelling with “desparatly.”]

Although some codebreakers believe the misspellings of “iqlusion,” “undergruund,” and “desparatly” are simply Sanborn’s crafty attempts at misdirection, others believe they are clues hinting at how to crack Passage 4, which is only 97 characters long.

Sanborn has even offered hints to help frustrated solvers in their efforts to unravel the mystery of Passage 4. In 2006, he revealed that letters 64 through 69 in the passage, NYPVTT, decrypt to “Berlin.”

And in 2014, Sanborn revealed that letters 70 through 74, MZFPK, decrypt to “clock.” So the message has something to do with the Berlin Clock, although Sanborn has stated “there are several really interesting clocks in Berlin.”

Finally, in 2020, Sanborn revealed that letters 26 through 34, QQPRNGKSS, decrypt to “northeast.”

And yet, despite all these hints and several decades, K4 remains unsolved. (And to those hoping that AI will prove smarter than humans in this instance, that hasn’t been the case. Sanborn revealed to The New York Times that he has received solutions devised by ChatGPT and described them as “nothing short of fairly silly.”

So, if you win the auction, what do you get?

• the handwritten K4 code, complete with a signed typed letter by Ed Scheidt, the CIA employee and cryptographer behind all four Kryptos codes
• the copper model submitted to the CIA as a sample of the final piece
• photographs relating to the creation of Kryptos
• the original dedication pamphlet signed by late CIA director William Webster
• copies of the coding charts used to encode Kryptos

And apparently, being the secretkeeper for Kryptos can be profitable. Sanborn grew weary of fielding dairy requests and queries for solutions, clues, and other data, and actually started charging a $50 fee for replies. He claims this fee has earned him $40,000 a year!

Sadly, Sanborn feels that he no longer has “the physical, mental or financial resources” to maintain his role as the keeper of K4’s secret, and wishes to hand that responsibility to another, which would allow him time to focus on other artistic endeavors.

And given that he’ll be turning 80 around the same time that the auction should be wrapping up, it’s fair to say he has more than earned this retirement from Kryptos.

The online auction of Kryptos by RR Auction begins on October 17 and closes on November 20 at 7 p.m. ET.

Will you be bidding, fellow puzzler? I fear my budget of — *checks wallet* — $29 is not going to get it done.