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Comment by Apocryphon | Hacker News Reader

Amazing work, but I can't help but to think that despite all of the effort put into it, it was still cracked by a handful of individuals over the course of a few months using standard statistical/mathematical programming tools.

Why haven't FBI analysts done the same already? Is it conceivable that it was already done, just simply never publicized for whatever unknown government reason? One imagines that solving this publicly unsolvable mystery is actually a standard initiation exercise for new recruits into the elite circles of NSA codebreakers.

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Why haven't FBI analysts done the same already?

This is pretty easy. They are a law enforcement agency. The Zodiac killer was active over 40 years ago and is likely dead of old age. Solving this will not prevent a crime or further any of the FBI's other missions (https://www.fbi.gov/about/mission). It's a great feat, but the capability to do an analysis like this wasn't as generally available when it would have been useful, and now it's just a historical curiosity.

Congratulations to Dr. Blake.

Normally, when you encrypt a message, you have a recipient in mind. When it's one government to another government, or one person to another person, it's safe to assume that the message is authentic and meaningful, and not just designed to waste time, and that a recipient has a way of decoding the message. Normally, the point of encrypting a message is that you want it to be unbreakable by anyone except the intended recipient, and that you're not wasting their time by sending gibberish once decoded.

In this case, it's a deranged serial killer that's sending a message to law enforcement. The sender is someone who kills people for personal gratification, so it's pretty safe to assume that someone who does that might also want to mess with people for the sake of personal gratification. Crucially, there is no intended recipient other than law enforcement, so there would be no reason to include any actual sensitive information because there's no one to send it to other than the FBI. There's no reason to believe that he'd write a message that would give himself up. Real life is not like the fable of Rumpelstiltskin where solving a riddle makes someone honor-bound to give themselves up. Continuing to solve these ciphers probably fed into power trips and sexual gratification for the author.

It is not surprising that an investigative agency did not allocate a ton of resources to decode a message that one could anticipate would say something like "are you having fun with my game yet?" without any other prior information.

Certainly, the FBI in the '60s and '70s would have been unlikely to be expanding much effort towards this situation. Though I think everyone here is assuming that intelligence agencies treat all of these public puzzles with the same degree of utmost seriousness.

Take the Taman Shud mystery- only one death, completely without context. Yet it's mentioned that military analysts took a shot at unravelling the mystery:

> In 1978, following a request from ABC-TV journalist Stuart Littlemore, Department of Defence cryptographers analysed the handwritten text. The cryptographers reported that it would be impossible to provide "a satisfactory answer": if the text were an encrypted message, its brevity meant that it had "insufficient symbols" from which a clear meaning could be extracted, and the text could be the "meaningless" product of a "disturbed mind".

https://en.wikipedia.org/wiki/Tamam_Shud_case

I don't think spies are any less interested in perplexing mysteries than the rest of the public. While I don't expect that an agency would throw all of their manpower at a case such as this, I could imagine individual analysts taking a stab at it on their own time. Maybe the organizations themselves might sponsor side projects as a means to test codebreaking techniques and glean lessons along in the process. I mean, why else does the NSA have a page on the Voynich Manuscript:

https://www.nsa.gov/news-features/declassified-documents/voy...

They even did an entire study on it:

https://archive.org/details/VoynichManuscriptAnElegantEnigma...

Serious agencies dive into less-than-serious studies into exotic or sensationalist topics all of the time. Sometimes for general interest, sometimes for good PR, sometimes simply because of bureaucratic waste. Why else do we hear about military studies of UFOs, from Project Blue Book to recent news stories? Given the enduring mystery of the Zodiac Killer, I can't imagine why some of these professionals- beyond the FBI even- might not have tried to crack it, themselves. And perhaps some have already succeeded.

Edit:

> There's no reason to believe that he'd write a message that would give himself up. Real life is not like the fable of Rumpelstiltskin where solving a riddle makes someone honor-bound to give themselves up.

Despite this, perhaps figuring out the message would've given some sort of psychological insight or contextual clues that could have helped investigators determine the identity of the killer.

Not to mention, your point is refuted retroactively by the case of the BTK Killer, whose taunting anonymous puzzles were his downfall. Though admittedly investigators identified him not by actually solving his puzzles, but by analyzing the medium they were conveyed in.

Well a highschool teacher deciphered one of the letters soon after it was published... so the time wasting excuse doesn't work. As far as resources are concerned:

"July 12, 2016 Update: The FBI has redirected resources allocated to the D.B. Cooper case to focus on other investigative priorities."

-- https://www.fbi.gov/history/famous-cases/db-cooper-hijacking

Here is a much more simple explanation: the FBI is notoriously bad at anything involving encryption or novel dynamics. That is why the Secret Service was so heavily involved in the big hacker crackdown decades ago, because the FBI was totally lost in the sauce. Bank robbery, payrolling informants, and CP they've got down pat.

It was cracked by a handful of individuals PLUS the several hundred/thousand other individuals who tried and failed. It is more reasonably seen as the efforts of every qualified person who gave it serious effort.

The FBI is not going to automatically hire the people who will succeed at this vs. fail valiantly. To get the same results they would have to dedicate the same resources which would be huge.

I don't get the impression that several hundred/thousand individuals had anything to do with this being solved by this person, except perhaps by virtue of not solving it and thereby leaving it to be an open problem with the opportunity to be solved.

After reading the article, this didn't come across as a "standing on the shoulders of giants" situation, but rather that this person by chance had the problem, found it interesting enough to work on, and happened to try the right path to solve it.

Sure but each person seriously attempting it still increased the probability of a solution arising

Sure but still mutually exclusive from this specific attempt.

Right, but if the FBI goes and hires a code breaker, they don’t get one of the three who solved it. They get one of the thousands with the credentials to have a reasonable chance of success. So if the FBI wants to put the three who solved it on the job, they have to deploy the thousand who didn’t because they don’t know the difference between them until it’s solved.

How about the FBI builds a time machine, goes to the future to find out who solved it, then hires those people? I call it self-fulfilling cryptography.

Still survivorship bias. We tend to assume that because they cracked it, anyone like them could've done that in the past. In reality, maybe even the author had a chance of 0.001% to crack it and they just got lucky in choosing the right paths and having the right intuitions.

It's the same in many parts of research. You obviously would've had no chance without their expertise but just because a researcher discovers something new does not mean there's no luck involved.

I think the point of the person to whom you're replying is that it being solved doesn't mean it was as easy as it now looks. When we see it done and we see the methods are not all that novel, we are biased to think that. But the fact that it was not more complete until then and was a subject of fascination for many actually implies the opposite. We're looking at an incredibly rare event and asking why a few specific investigators couldn't have achieved that decades ago.

The "decades ago" caveat is especially key, because they used a computer system with raw performance well within an order of magnitude of today's Top500 supercomputers. I like to point out government incompetence too, but spending that kind of resources banging away at a message from a killer we don't believe has been active for several decades isn't exactly a prudent move.

I wasn't saying that this was actual literally an interview problem for intelligence services. It was sort of a joke riffing off the possibility that this was already solved before, simply because it seems like it's within the technical capabilities of intelligence agencies (and academic research teams, perhaps) to crack this code. And the joke was that it wasn't even for gating purposes, but more like an introductory first homework assignment for the elite of elites.

I'm not diminishing the tremendous work done by these codebreakers, I'm just speculating if it was already achievable by institutions, just not revealed publicly.

You forgot this part, they used Spartan HPC.

"It consists of 72 nodes, each with four NVIDIA P100 graphics cards, which can provide a theoretical maximum of around 900 teraflops."

I don't know how much time and computational power they used, but it explains why the problem was not solved for a long time.

In 1980s, they did not have the computing capacity, even if they had a burning desire.

Now that the capacity is easily available, I bet they have many more recent cases to which to devote a few months of dedicated work.

Maybe even intelligence analysts like cracking puzzles in their spare time. Takes a longer timeframe than a few months, but this mystery has been around for a long time already.

Like I said down thread, there's analysts who pursue the solving of the Kryptos sculpture. Why not this puzzle?

> [T]he CIA revealed that their analyst David Stein had solved the same passages in 1998 using pencil and paper techniques, although at the time of his solution the information was only disseminated within the intelligence community.[9] No public announcement was made until July 1999,[10][11] although in November 1998 it was revealed that "a CIA analyst working on his own time [had] solved the lion's share of it".[12]

my hunch is that they guessed that the ciphers were a diversion created to waste resources

And moreover the previous ciphers didn't reveal anything about the identity of the killer either. It was just propaganda.

Not just propaganda, I think. From what I have read about the Zodiac killer it seems like he took personal delight and thrill in not getting caught and feeling like he was outwitting investigators. Purely for ego.

> Why haven't FBI analysts done the same already?

Because the FBI probably has few or no professional cryptographers. It's possible it could've been solved in a couple of days by the resources in-house at the NSA.

To clarify, I mean they probably have few people who spend time working on the math of crypto. They have lots of people who obviously know how to apply forensic software tools written by others to seized equipment.

While I don't think these other agencies would have been as interested as pursuing a decades-old cold case as a law enforcement effort, I could imagine that other orgs with codebreakers might try it as a side project or even a recreational diversion, much like trying to decrypt the Kryptos sculpture.

Individual analysts from the CIA, DIA, NIST, even foreign ones like the GCHQ, DGSE, Unit 8200, etc. could have tried to decipher the messages, in addition to the FBI. Surely they have the capacity to break this code, if they were inclined to spend some extra time on it. It's not as if these agencies don't recruit from people who already love solving puzzles in their free time.

GCHQ have published two puzzle books in the UK and one of them definitely referred to the Zodiac Ciphers, so it wouldn't surprise me if it was a hobby project of a few of them. I do strongly believe if someone had previously solved it they'd have released it though -- there's nothing damaging in these texts.

The article makes reference to the "FBI Cryptanalysis and Racketeering Records Unit". They appear to have people on staff who do exactly this kind of work.

From the FBI's web page (https://www.fbi.gov/services/laboratory/scientific-analysis/...):

> The Team

> Cryptanalysts and cryptanalyst forensic examiners.

...

> Cryptanalysis

> Decrypt manual codes and ciphers found in letters, notes, diaries, ledgers, and other types of written or electronic communications. Common users of codes include foreign and domestic terrorists, organized crime, gangs, prison inmates, and violent criminals.

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