Zodiac 340 cipher solved!

OK, this has absolutely nothing to do with kayak fishing, but I'm a crypto guy. I've also had my students do a fair bit of research on this cipher, and I feel like we were on the right track. But actually getting the solution required good insight, a huge amount of persistence, and some luck, so congratulation to the solver.

Anyways, if you just want to see the solution, go to about 10:35...

Crypto decryption will get the brute force treatment when quantum computing becomes mature.

Amazing.  I wonder how difficult it would be for a person to create such a cipher?  Would an average person with a book on cryptography be able to do it?

Crypto decryption will get the brute force treatment when quantum computing becomes mature.

Assuming quantum computers actually works someday, it won't have any significant effect on the security of symmetric ciphers (things like DES, AES, and so on), but it will be effective against the most popular public key techniques (RSA, Diffie-Hellman). There are "post-quantum" public key systems that will be secure against quantum computing (NTRU, for example), but they are not quite as efficient.

Amazing.  I wonder how difficult it would be for a person to create such a cipher?  Would an average person with a book on cryptography be able to do it?

The prime suspect in the Zodiac murders had been in the Navy. I worked at NSA as a "Cryptologic Mathematician" for 7+ years, and so I have a pretty good idea as to what sort of basic crypto things would be taught to military people during the Zodiac's era. Such a person would certainly have had the knowledge to make the Zodiac ciphers. In fact, when my students and I were trying to break the 340 cipher, we were looking at techniques that would have been known to such a person. Unfortunately, we didn't pick the right combination of things to focus on.

Today, there is a lot more crypto knowledge readily available, and so it would be even easier now--anybody could do it with a little research. But, back then, cryptography was pretty much limited to the military and government.

“ I worked at NSA as a "Cryptologic Mathematician" for 7+ years”

Well that explains a lot.  You used those years of experience and the deep pockets of the federal government to be the only person to decrypt the most worked on cipher of all.... the HALibUt

... to be the only person to decrypt the most worked on cipher of all.... the HALibUt

Ha ha! I only wish I could solve that one...

Creeepy but that’s pretty awesome it’s cracked.