Interesting story.

One thing I’ve always wondered about: How difficult is it to solve a cipher like the 408? Or, to put it in slightly different terms, how impressive is it that the Hardens solved it in…what was it, five (six?) days?

Honest question to the crypto heads – I have absolutely no idea myself, but my impression has always been that the 408 isn’t all that complicated.

Hi-

As I’ve said on the other MB that you visit, once they had the idea about "i" and the "double L" in "kill," they were halfway home. That was the breakthrough that did it.

Mike

Harden’s obituary, here:

http://www.legacy.com/obituaries/azcent … =156920581

Makes absolutely no mention at all of any military service of any kind. So ex-NSA seems unlikely to me.

As to the 408 cipher itself, it would be considered difficult, but solvable. It mostly depends on how much time and effort one applies, and a little luck helps also. As has been pointed out, once they got the toehold of "I LIKE KILLING" a great deal of the cipher just falls into place.

Incidentally, they did NOT "force a solution to the 408." They found the solution, which is 100% correct. Multiple computer programs can solve it now, and they all reach the same solution. There certainly are such things as forced solutions, and we have all seen many of them in re to the 340 cipher, but that is an entirely different thing.

-glurk

Hi-

Not a crypto guy but I thought a "forced" solution is where you decide to look for certain words or phrases, as opposed to doing whatever else you do to solve a code, like just looking at letter frequency, etc.

Mike

Not a crypto guy but I thought a "forced" solution is where you decide to look for certain words or phrases, as opposed to doing whatever else you do to solve a code, like just looking at letter frequency, etc.

Mike-

While there isn’t really any "formalized parlance" that I know of, a "forced solution" is one that breaks one or more of the generally accepted rules of cryptography, such as switching keys (as needed, randomly), using ‘polyphones’ – i.e., making symbols represent more than one letter, etc. Basically, a "forced" solution is a bad thing.

Looking for words and phrases, etc., is just as valid a part of the solving process as using letter frequencies, bigrams, trigrams, and so on. A good example of a true forced solution is Corey Starliper’s 340 solution from a few years back. Doranchak has a nice writeup on it here:

http://oranchak.com/zodiac/corey/hoax.html

-glurk

I just want to add to glurk’s answer and stress this important difference:

Trying out different words to see if a solution pops out is called a "crib" or "cribbing" (see http://en.wikipedia.org/wiki/Known-plaintext_attack). It is a valid way to attack certain cryptograms, and is part of how the Hardens cracked the 408.

A "forced solution", such as Corey Starliper’s, turns "cribbing" into an application of pure imagination, and typically does not use valid cryptographic methods.

I don’t see what difference Don Harden’s credentials make. *shrug*

smithy-

There is some contingent of people out there who really want to believe that it is ABSOLUTELY AMAZING that a mere schoolteacher could solve Zodiac’s INCREDIBLY DIFFICULT cipher and beat all of the best crypto minds out there, including the CIA, FBI, NSA, Naval Intelligence, etc. And that particular story makes for a good narrative, I suppose.

It isn’t supported by any facts, though. There is no evidence whatsoever that any government agency even made any attempt to solve the 408, much less that they tried and failed. The story keeps getting repeated, though.

Fact is, this type of homophonic cipher is not really that difficult, as I am sure you well know. But I guess some people just refuse to let facts get in the way of a good story…

Nope, Harden’s background doesn’t mean anything. He and his wife solved the 408, released the solution, and it is correct. That’s the end of the story for me.

-glurk

Hi-

Don’t count me among those who refuse to believe that a hobbyist cryptographer could have solved the code. Once you try "open triangle" as "I" and then look in the third part of the code, you see an "open triangle" and two similar "semaphore flags." There is your theoretical "ILL." Once you begin plugging those in, you’re almost home free.

I’ve posted about this on the Proboards MB.

Thank for educating me about cribbing vs. forcing. Now I won’t mix up my terminology being the non-crypto guy I am. Harden cribbed, he didn’t force.

I’m just telling you what someone told me FWIW to see if we can verify or refute this claim. I’m not asserting it is true or that the only way that Harden could have solved the code is to be ex-NSA.

Smithy, maybe you haven’t been around the case long. People ruminate over all sorts of meaningless trivia that is much less relevant to the Zodiac story than Don Harden having worked for a secret code-solving institution before becoming a teacher. F’rinstance, this might explain how he came up with the solution before anyone else did and how he didn’t just stumble onto his methodologies, but rather he was trained to do the type of cribbing he did to solve the code.

Mike

Mike-

Just to be clear on my part, it is just that I have heard that "The Hardens did what NO ONE else could do" story far too many times, and it annoys me more every time I hear it.

What you have said is absolutely correct, and I think you understand the crypto better than most. Once the Hardens got the toehold or the "wedge" of ‘I LIKE KILLING’ the rest of the cipher falls neatly into place.

So far as Don being ex-NSA, as I posted above, his obituary shows nothing about any military service, which is something that would normally be mentioned. So it seems unlikely to me. Also, I found a post by his daughter Leslie on Tom’s board from 2007 that also has no mention of any military/NSA work. It is more about Bettye:

http://www.zodiackiller.com/discus/mess … 1171642363

-glurk

Harden cross-dressed at weekends (I was told a while back from someone who told someone else), was addicted to lemons and swore in Dutch.
That stuff’s for OPORD if you happen to be over there Mike, so they can ruminate.

smithy-

There is some contingent of people out there who really want to believe that it is ABSOLUTELY AMAZING that a mere schoolteacher could solve Zodiac’s INCREDIBLY DIFFICULT cipher and beat all of the best crypto minds out there, including the CIA, FBI, NSA, Naval Intelligence, etc. And that particular story makes for a good narrative, I suppose.

It isn’t supported by any facts, though. There is no evidence whatsoever that any government agency even made any attempt to solve the 408, much less that they tried and failed. The story keeps getting repeated, though.

Fact is, this type of homophonic cipher is not really that difficult, as I am sure you well know. But I guess some people just refuse to let facts get in the way of a good story…

Nope, Harden’s background doesn’t mean anything. He and his wife solved the 408, released the solution, and it is correct. That’s the end of the story for me.

-glurk

I agree with what you say except the part I bolded and italicized. I don’t know about the military but the FBI fid make at least a cursory attempt to solve the 340. I posted some FBI files showing this fact. So I would assume a similar effort was made on the 408.

According to the files, no attempt was made to SOLVE the 408 by any agency. VPD sent it to the navy but it was NOT examined by cryptographers (so say the FBI files). There is no mention of the FBI having a go at it, or even receiving it prior to the Hardens solving it.

After the Hardens solved it, it was sent to the FBI for verification. Going by the known files and documents, this was the first time the FBI received the 408.

Interesting. You may be right Norse. If true I wonder why it was not sent to the FBI? I will look at the FBI files on the 340 and see if they mention the 408.

But yes Mr. Harden was a teacher and he and wife Bettye solved the 408 by virtue of their intelligence, creativity and dogged persistence.