Category Archives: zodiac

Can evolution reveal a killer’s mind?

Computer science professor Dr. Ryan Garlick of University of North Texas has a very interesting setup for his symbolic processing course this semester: Each student’s objective is to contribute towards cracking the unsolved 340-character Zodiac cipher.

From a UNT news article:

Cracking the cipher is a difficult task for more than one reason, which is why Garlick, along with his students, are currently developing several computer software techniques that will hopefully make the process far more feasible.
“There are just too many possible keys to look at them all,” Garlick said. “There are 63 different symbols, and each can represent 26 possible letters (we think), which is just too many possible combinations to evaluate them all.”
This is where the computer techniques they are fashioning will hopefully come in handy. Corey Rosemurgy, an Austin senior and computer science major in Garlick’s class, is currently developing a genetic algorithm to solve the cipher.
“The genetic algorithm that I am developing models itself after the inherent properties of biological evolution and the theory of survival of the fittest where only the strong survive,” Rosemurgy said.

I was very interested to discover this course, since I have been working on a similar approach since around March of this year. In my free time (what little there is), I’ve been running experiments using ECJ, a Java-based evolutionary computing framework. So far, my focus has been on trying to get the algorithm to solve Zodiac’s 408-character cipher, which has a known solution. Using a dictionary-oriented approach, the algorithm was able to find the correct solution using a limited 400-word dictionary. Now I am trying to improve this by adding more words to the dictionary used by the algorithm. The basic idea is to get this test case working well before attempting to have it solve the really difficult 340-character cipher. This has proven to be very difficult, because the search space (number of possible solutions) is extremely large, and there is exactly one correct solution. The needle is tiny, and the haystack is vast. Evolutionary computing methods tend to be better-suited for finding really good solutions, rather than the one best solution, so this approach is quite challenging (if not flawed).

I’m glad that many people are still working on this problem; it would be nice to finally find a solution. Still, there is still a strong possibility that there is no solution, and the cipher is just gibberish designed to keep people unnecessarily busy. If so, then the Zodiac killer succeeded beyond his wildest dreams.

More info:
article | course page (of interest here are the syllabus and powerpoint presentation) | google code page and code repository for zodiac decoder software (this is the repository of software used and developed by students in the course)

The cold case that just won’t die

I was surprised tonight to discover that somebody posted my little Zodiac cipher webtoy on Digg recently, and it has been getting some significant traction there:

I had a lot of fun making it, and I am glad that folks are getting some use out of it. Thanks for the support! I hope we can sustain the Digg Effect!!

I’ve been getting a lot of good feature suggestions from people, such as adding frequency analysis, allowing multiple letters per symbol, and supporting cipher transpositions. I hope to make some of these improvements to the app in the near future.

Zodiac web toy updated

Many thanks to Jeff Hudson for emailing me about some errors that I had in the Zodiac cipher web toy. I’ve made the corrections, and I’ve also posted a few more interesting decodings that I found recently. These decodings are almost certainly gibberish, but they are still kind of fun to find.

Jeff says:

I’ve only just started trying to decode the 340, but the other day i found “crush them into ground up bits” in a single string of characters. I naturally got really excited as this phrase emerged – but unfortunately everything else in the code was complete gibberish 🙁 so i guess it’s back to the drawing board lol.

Click here for the updated Zodiac cipher web toy.

Zodiac web toy

Get our your decoder rings and try out my Zodiac cipher web toy. Crack the code; become instantly famous!

Click the scribblings to try to outsmart the killer.

This cipher is one of the famous unsolved ciphers that the Zodiac serial killer sent to newspapers back in the late 1960s / early 1970s to taunt people about his killings. His first cipher was solved a long time ago. But he sent another cipher, which remains unsolved to this day. Many cryptography experts have tried and failed, which has led to speculation that the cipher is a hoax sent to frustrate and delay detectives working the case. But there are claims that by using statistical analysis, you can tell that the cipher does indeed contain a message (I don’t recall exactly how).

Go break the code!