Tag Archives: codebreaking

The Kryptos Solution is Auctioned Off… But the Mystery is Far From Over!

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Kryptos is one of the great remaining unsolved puzzles.

A flowing sculpture made of petrified wood and copper plating, sitting over a small pool of water. That’s what you see when you look at Kryptos.

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.

Of the four distinct sections of the Kryptos puzzle, only three have been solved.

After a decade of silence, a computer scientist named Jim Gillogly announced in 1999 that he had cracked passages 1, 2, and 3 with computer assistance. The CIA then announced that one of their analysts, David Stein, had solved them the year before with pencil and paper. Then in 2013, a Freedom of Information Act request revealed an NSA team had cracked them back in 1993!

A curious game of one-upsmanship, to be sure. Something that foreshadowed what would follow years later…

Unfortunately for puzzle fans, K4 remained unsolved.

Eventually, Sanborn began offering hints. In 2006, he revealed that letters 64 through 69 in the passage, NYPVTT, decrypt to “Berlin.” In 2014, he revealed that letters 70 through 74, MZFPK, decrypt to “clock.” In 2020, he revealed that letters 26 through 34, QQPRNGKSS, decrypt to “northeast.”

Still, K4 remained unsolved.

Back in August, I wrote about Sanborn’s impending auction for the solution to the Kryptos puzzle, as Sanborn felt he no longer had “the physical, mental or financial resources” to maintain his role as the keeper of K4’s secret, and wished to hand that responsibility to another.

On November 20th, 2025, the solution to Kryptos sold to an anonymous bidder for $962,500, far above the predicted $300,000 – $500,000 estimate from the auction house.

At the moment, we don’t know if this anonymous bidder will reveal the solution or become the new keeper of the mystery.

You might think that the story of Kryptos would conclude there, for the moment.

But that’s not the case. The auction and its near-million-dollar bid were put into jeopardy by two intrepid investigators and a simple oversight by Sanborn himself.

On September 3rd, not long after I wrote about the upcoming auction, Sanborn received an email with the solved text of K4 from Jarett Kobek and Richard Byrne. They had discovered the solution among Sanborn’s papers at the Smithsonian’s Archives of American Art, after the auction house had mentioned the Smithsonian in their auction announcement.

Kobek and Byrne had discovered Sanborn’s accidental inclusion of the solution in the papers donated to the Smithsonian ten years ago during his treatment for metastatic cancer. “I was not sure how long I would be around and I hastily gathered all of my papers together” for the archives, he said.

Suddenly, the auction was in doubt.

Sanborn confirmed to Kobek and Byrne that they indeed had the correct solution. Later that day, he proposed they both sign non-disclosure agreements in exchange for a portion of the auction’s proceeds. They rejected the offer on the basis that it could make them party to fraud in the auction.

Sanborn reached out to the Smithsonian and got them to block access to his donated materials until the year 2075, to prevent others from following in Kobek and Byrne’s footsteps and further endangering the auction. Meanwhile, lawyers for RR Auction threatened Kobek and Byrne with legal action if they published the text.

Sadly, Kobek and Byrne had been put in an impossible position. They have the solution that diehard Kryptos fans have desired for decades, and the possibility of coercing them into revealing the solution is hardly low. Sanborn’s computer has been hacked repeatedly over the years, and he has been threatened by obsessive fans, even claiming he sleeps with a shotgun just in case.

The auction house did disclose the discovery of K4’s solution to the bidding public, as well as the lockdown of the Sanborn archive at the Smithsonian’s Archives of American Art.

All parties waited to see what would transpire.

Still, with all this uncertainty looming, the auction closed with its $900,000+ bid, and thus far, neither the anonymous bidder nor the team of Kobek and Byrne have released the solution.

Byrne and Kobek say they do not plan to release the solution. But they are also not inclined to sign a legally binding document promising not to do so.

I waited to write about this story in the hopes that something would have been resolved in the weeks following the auction’s conclusion. But sadly, K4’s solution — and Kobek and Byrne’s potential roles in revealing it — remain unknown at the time of publishing this post.

Despite all this, the fact remains: Kryptos fans haven’t cracked K4.

But they know of four possible sources to find the solution: the Smithsonian (which is locked down), the anonymous bidder (similarly inaccessible), Sanborn (who has been fending them off for decades) and sadly, Kobek and Byrne, who remain in the crosshairs of the media, lawyers, and Kryptos enthusiasts. The pressure is mounting.

Jim Sanborn, until recently the steward and keeper of the Kryptos solution…

I suppose the best case scenario would be for someone to legitimately crack K4 and release their solution AND method for solving it.

That would free Kobek and Byrne from their burden and potential legal repercussions. That would be the triumph hoped for when Kryptos was conceived. The auction’s validity would remain intact.

Because even if the plaintext solution is revealed and someone reverse-engineers how it was encrypted, it’s a damp squib of an ending. Kryptos wasn’t solved. It wasn’t figured out. It would be a disappointing way for a rollercoaster of story to wrap up.

Sanborn deserves better. Kobek and Byrne deserve better. Kryptos deserves better.

So get cracking, solvers!

The Founding Fathers of Cryptography?

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It’s Veterans Day, and on an occasion dedicated to giving thanks to all those who served the United States honorably during either war or peacetime, it seemed appropriate to turn our puzzly gaze toward at American history for today’s post.

In fact, let’s look to America’s formative days. We’ve written in the past about George Washington and his creation of America’s first spy ring, and how heavily they relied on encryption and codebreaking techniques to protect America’s earliest secrets.

But as it turns out, Washington was far from the only Founding Father who was a strong proponent of cryptography.

Second president John Adams used a cipher to send letters to his wife Abigail when he was traveling. That cipher was designed by James Lovell, a member of the Continental Congress Committee on Foreign Affairs.

President #3 also relied heavily on ciphers and secret methods of communication. Thomas Jefferson created special ciphers specifically for Meriwether Lewis to use during the Lewis and Clark Expedition to protect the intrepid duo’s findings.

He even developed his own method for encryption. Some call it the wheel cypher, but it’s more commonly referred to as the Jefferson Disk.

These 36 wheels, threaded onto an iron spindle, allow the user to twist them until a message reads out. Each wheel has the letters of the alphabet in a random order.

So how did it work? Well, according to Monticello.org:

As an example, the sender of the message shown in the picture, “COOL JEFFERSON WHEEL CIPHER,” spells the message out and then looks to any other line of text – possibly the one directly above, which on this version of the cipher begins with the letter “N.” The sender then copies the rest of the letters from that line into the correspondence to spell out “NKYG NSUS NXML CQYO TYUH HFTD.”

The man who succeeded Jefferson as president, James Madison, employed encryption for both official documents — like letters between himself and members of the Continental Congress — and communication with other key figures. For instance, he sent a partially encrypted letter to Jefferson that described his plan to introduce a Bill of Rights.

Madison’s fellow contributor to the Federalist Papers, John Jay (later the first Chief Justice of the Supreme Court) always employed ciphers for diplomatic correspondence when traveling outside the US.

[This wooden puzzle is known as Franklin’s Kite.]

And as you might expect, the influential inventor, statesman, and polymath Benjamin Franklin had his hands in codecracking and cryptography as well. He not only created some of the ciphers employed by the Continental Congress, but he also published a book about encryption in the 1740s: George Fisher’s The American Instructor.

The Continental Congress, for their part, passed a resolution ordering ciphers to be used for all messages that couldn’t be safely transmitted otherwise.

In the end, as in the beginning, America doesn’t just love puzzles, it’s founded on puzzly principles.

[For more content involving American history and puzzles, check out our multi-part series on the history of the NSA, as well as the story of how a Tap Code and other puzzly spycraft techniques kept a soldier’s love story alive.]

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The D’Agapeyeff Cipher, Unsolved for 80 Years!

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[Image courtesy of Derek Bruff.org.]

One of my all-time favorite cryptography stories comes from the book The Spy That Couldn’t Spell, a true-life espionage story about a dyslexic man who hid, then encrypted the locations of, thousands of pages of sensitive documents he had stolen from the U.S government.

Why is it one of my favorite stories? Well, because the man in question FORGOT one of the cipher words he used to encrypt the location of his caches.

And it sort of unravels your master plan when you can’t remember a key element of it.

Amazingly enough, this isn’t the only example of a self-trained cryptographer who forgot how to solve his own creation. In fact, one example of this very dilemma remains one of the most famous unsolved codes and ciphers in the world:

The D’Agapeyeff Cipher.

daga

This is the D’Agapeyeff Cipher. This seemingly simple list of numbers contains a secret message. The only problem is… the creator, Alexander D’Agapeyeff, can’t remember how to decrypt it.

When he published a starter book on cryptography — Codes and Ciphers, first edition — D’Agapeyeff included this chain of 5-digit number bundles as a final challenge for the readers to unravel.

One of the first steps many aspiring cryptographers take is to break the numbers down into pairs instead of groups of five:

daga 2

One result of this is the pattern that every pair has 6, 7, 8, 9, or 0 in the tens column and 1, 2, 3, 4, or 5 in the ones column, which doesn’t seem like a coincidence.

And see those sequences where the same number appears three times in a row? Some cryptographers believe that is also not a coincidence.

Then, they cut off the two double-zero pairings at the end — because they believe they were nulls, empty space-filling characters simply designed to fit the 5-letter groupings pattern of the original code as a way to throw off codecrackers. (And, to be fair, D’Agapeyeff himself wrote about null entries in the book Codes and Ciphers.)

If you remove those double-zero pairings, you can arrange the numbers into a 14×14 pairing grid, like so:

daga 3

See those sequences where the same number appears three times in a row? More of them now.

Many cryptographers consider this to be the true starting point of cracking the D’Agapeyeff Cipher.

But then what?

Some believe that the key to solving the grid lies in the Polybius Square, another encryption device mentioned by D’Agapeyeff.

Essentially, you place the alphabet into a 5×5 grid, and use those numbers to encrypt the letters. Here’s a straightforward example:

daga 4

In this case, the word PUZZLE would be 35 45 55 55 31 15.

Another way to use the cipher is to pick a keyword to start it. For instance, if you chose POLYBIUS as the key word, then you go across, then down, writing POLYBIUS and then the rest of the unused letters of the alphabet in order, like so:

daga 5

Instead of 1-5 both across and down, you could do 1-5 across the top and 6-0 across the side, reflecting the pairings in the D’Agapeyeff Cipher.

Or, as someone pointed out, perhaps we’re thinking in the wrong language. Triple-letters are uncommon in English words, but more common in Russian words, and D’Agapeyeff was Russian born.

Overlooking simple things like that can make you miss crucial ways into an encrypted message.

So, do you have any thoughts on how to solve this 80-year-old encrypted challenge, fellow puzzlers? Let us know in the comments section below! We’d love to hear from you.

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Puzzles in Plain Sight: Spinning Yellow Circles edition

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Adobe_Semaphore_Wide_768x512.0

About six months ago, I shared the story of a secret code lurking in plain sight, sitting atop the Capitol Records Building in Los Angeles. It’s not the only time that buildings have made their way into the blog; in previous posts, we’ve discussed the giant crossword adorning the side of an apartment building in Lvov, Ukraine, as well as the optical illusion awaiting art lovers in a Roman palace.

But it was the only time we’ve discussed a secret code being shared on the side of a building.

Until today, that is.

Yes, my friends and fellow puzzlers, there’s another building out there broadcasting secret messages for all to see. It’s also in California. And this one is more devious than the blinking light on the Capitol Records Building.

adobe semaphore 1

Say hello to Almaden Tower, the San Jose headquarters of Adobe, the software company behind Acrobat, Illustrator, and numerous other editing programs.

As you can see, there are four bright yellow circles beside the Adobe logo. These 10-foot-high digital lights all rotate. And if you pay enough attention, you might discover the secret message being broadcast.

The messages began transmitting in 2006. The code was cracked for the first time in 2007, and it wasn’t a brief message either. The lights were secretly transmitting the entire text of the Thomas Pynchon novel The Crying of Lot 49.

You see, the rotating circles allow for a form of semaphore alphabet, a way of secretly forming letters or symbols based on the position of each of the circles. They can be horizontal, vertical, a left-leaning diagonal, or a right-leaning diagonal. The various combinations of these positions create a semaphore alphabet of 256 possible characters.

adobe semaphore 2

But this was only the first part of the encryption. Even if you uncovered and charted this pattern, you still had to decode the secret messages detailing specific key words that would help you break the Vigenere encryption of the actual text.

It took MONTHS for two tech workers to figure out the semaphore language, decipher the code, and uncover the final message.

So naturally, just like the hidden alien language in the animated sci-fi comedy Futurama, it was replaced with a second, more complex code to be unraveled.

That code, which started transmitting in 2012, wasn’t broken until 2017 when a math professor started streaming footage of the Adobe building and charting the various positions of the circles.

But his examination led him to believe that it wasn’t just text being broadcast this time… it was an audio message. After discovering a chain of symbols that he believed was a space or bit of silence in an audio broadcast, he graphed the results, which resembled an audio wave.

It turns out, his suspicions were correct, and further analysis resulted in the true audio being uncovered: Neil Armstrong’s famous message from the moon landing.

Apparently, a new code and message are currently being brainstormed for Adobe’s devious puzzle monument. Who knows what Ben Rubin, the designer, has in store for solvers this time?

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A Puzzly Discovery Under the Sea!

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We’ve talked quite a bit about the importance of Enigma machines in the past.

The quest to crack the unbreakable Nazi code machine spanned the Atlantic Ocean and resulted in never-before-seen collaborations between analysts, codebreakers, and puzzlers from all walks of life, dedicating hours upon hours every day to trying to unravel the secrets of German communications. Cracking the code would be the key to intercepting crucial information and outmaneuvering the Nazi war machine.

We’ve discussed those twin decryption locations — Arlington Hall in the US and Bletchley Park in the UK — as well as the efforts of codebreakers like Elizebeth Smith Friedman to dismantle the work of Nazi spymasters both during and after World War II.

The story of Alan Turing is inextricably linked with that of the Enigma device, even though there were three Polish mathematicians — Rejewski, Rózycki & Zygalski — who had already demonstrated that the Nazi code was breakable and even managed to reverse engineer an Enigma machine.

Strangely, we rarely talk about the Enigma machines themselves. They were dangerously efficient, as explained in this article from Atlas Obscura:

When the Nazis needed to send confidential messages, they entered the dispatches into the machine, which substituted every letter using a system of three or four rotors and a reflector, encrypting the message for a recipient Enigma machine to decode.

Getting Allied hands on one during the war was a top priority, so much so that the standing orders on German ships and U-boats was to throw them overboard and let the sea claim them, rather than risking the chance of the Allies getting ahold of one.

underwater enigma

But the sea doesn’t always keep secrets forever, and a recent dive by a marine biologist team discovered the remains of an Enigma machine in the Bay of Gelting:

He noticed a contraption tangled up in the fishing line the crew had headed down to collect. The device, which at first seemed like an old typewriter sitting under at least 30 feet of water, was a Nazi Enigma machine, likely one of hundreds abandoned and thrown overboard in the dying days of the German war effort.

And those devices still contain valuable information decades later.

Each Enigma machine has a serial number, and if this machine’s number is still legible after decades underwater, it could reveal which ship or Nazi unit the Enigma machine belonged to. This would allow researchers to track the use of the device and what impact its use or its absence had on the war effort overall.

Yes, it’s not just mussels and fish that call this device home, but a readily accessible history of the device itself, if we can only read it.

underwater enigma 2

And now, instead of being protected at all costs by German officers, this machine is now protected by archaeologists and researchers, sitting in a tank of demineralized water in order to flush out the salt and salt water that has so corroded the machine over time. It will spend almost a year in that tank before any restoration efforts can proceed.

Successful recoveries of these machines are understandably rare, and this is a chance to add to the historical record of codebreaking and puzzling during World War II. Here’s hoping we can stumble upon more of these lost treasures in the future.

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Does the History of Cryptography Begin in Ancient Egypt?

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Puzzles in various forms have been with us for thousands of years.

We can look back at examples like riddles from ancient Greece and Sumeria, the Smyrna word square from 79 AD, or inscriptions from New Kingdom-era Egypt between the 16th and 11th centuries BC, which can be read both across the rows and down the columns. (These are informally referred to as “Egyptian crossword puzzles.”)

As it turns out, if we turn our attention to ancient Egypt, we may just find the earliest known example of an encrypted message as well.

If you go hunting on the Internet for the earliest examples of cryptography or encryption, you pretty much get one of three results:

  • The ancient Greek scytale
  • The Caesar cipher
  • The Tomb of Khnumhotep II

Naturally, as someone who fancies himself a puzzle historian, I’ve heard of the first two entries on that list.

The scytale is an encryption method where a piece of leather, hide, or parchment (let’s say leather for this example) is wound around a wooden cylinder of a certain width and length. A message is then written on the wound piece of leather. When removed from the cylinder, the message disappears, leaving only a strip of leather with what looks like a jumble of letters on it. Only someone with an identical cylinder can wrap the piece of leather around it and read the intended message. Our earliest verifiable reference to the scytale is from the Greek poet Archilochus in the 7th century BC.

The Caesar cipher is the most famous example of a letter-shifting substitution code where numbers or other letters represent the letters in your message. For example, if B is K in your cipher, then C is L and D is M, as if the alphabet has shifted. See? Simple. Your average cryptogram puzzle is more complex because you’re not simply shifting your letter choices, you’re randomizing them. The Roman historian Suetonius references Caesar’s use of the cipher in his writings during the rule of Hadrian in the second century AD.

But what about this Egyptian tomb?

The tomb in question was built for Khnumhotep II, a nobleman who lived in the twentieth century BC. He carried many impressive titles, including Great Chief of the Oryx nome, hereditary prince and count, foremost of actions, royal sealer, and overseer of the Eastern Desert. (Seriously, with titles like this around, modern companies can clearly do better than manager, CEO, or senior editor. But I digress.)

The main chamber of his tomb features an inscription carved around 1900 BC. This inscription features some strange hieroglyphics. What makes them strange is that they’re in places where you would expect more common hieroglyphs, and it’s believed by some Egyptologists that these substitutions are no accident.

Some do pass it off as an intentional effort to describe the life of Khnumhotep II in more glowing or dignified terms, utilizing loftier verbiage that would be uncommon to any commonfolk readers, similar to how legalese is used today to impress others or intimidate readers.

But others believe it to be the earliest known example of a substitution cipher, utilizing hieroglyphs rather than letters or numbers. For what reason, you ask? To preserve the sacred nature of their religious rituals from the common people.

Unfortunately, this disagreement among scholars makes it hard to point definitively at the tomb of Khnumhotep II as the first written evidence of cryptography.

I guess this falls into the same black hole as the first bit of wordplay, the first anagram, the first pun, or the first riddle. We’ll never know, because the first examples of all of these would most likely be spoken, not written. It’s not until someone decides to record it — in pictograph form, in a carving, in a bit of ancient graffiti to be discovered centuries later — that it becomes evidence to be discovered centuries later.

And who’s to say that the linguists and cryptography believers aren’t both correct? A substitution cipher is, at heart, simply an agreed-upon way to say one thing represents or means another thing. A euphemism, an idiom, a common slang word… heck, a word you say in front of your kids instead of a swear. These are all very simple substitution ciphers.

The truth is probably somewhere in the middle.

What we do know is that there was some wordplay afoot in the tomb of Khnumhotep II, even if we can’t be sure if the history of ciphers and codes started there.

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