Zodiackillersite.com

Hey crypto people!

Having read about the Zodiac and his ciphers has made me want to learn more about this subject. Obviously I do not believe I will solve the Zodiac ciphers, but I would like to learn a little about how to crack simple ciphers, however I have no idea where to even start! I am looking for either a book or tutorial that guides you and teaches you to do this. Having read some of the posts on here, it seems like you need a maths degree to do this, but assume I am fairly dumb and cannot do this - would it still be possible to learn? How do you even know which type of cipher is being used as there seem to be an extraordinary number of them around?

So, what advice would you give me? Is there a book(s) you would recommend that teaches this so that even idiots like me can learn it, or do you need to be a math whiz who is also an excellent crossword solver to do it? Are there any online teaching resources? Also, the amount of paperwork needed to solve ciphers seems unreal, are there online tools that can help with this? And what do all the figures on this page mean - http://zodiackillersite.com/viewtopic.php?f=81&t=3196?

Thanks for any advice

Marienbad

David Khan-Codebreakers https://en.wikipedia.org/wiki/The_Codebreakers

Hey marienbad,

You don't need a math degree but some interest and experience with it helps, being able to program also helps but in general there are no requirements other than some common sense. And of course, ask questions. Here are a few basic things among classical cryptography.

Cipher types (possibly mixed):

- Substitution remaps one letter to another one letter/symbol. "ABCABCABC" into "123123123".
- Homophonic substitution/suppression of frequencies remaps one letter to many letters/symbols. The Zodiac 408 and possibly also the 340 fall in this category.
- Polyalphabetism remaps many letters to one letter/symbol.
- Transposition rearranges the letters in a systematic way. "MARIENBAD" into "DABNEIRAM".

Other terminology:

- A plaintext is a text such as this line in any language. The plaintext of the Zodiac 408 starts with "ILIKEKILLINGPEOPLE...".
- A ciphertext is a plaintext that has been encoded with one or more of the cipher types above.

- A unigram or 1-gram is a single letter/symbol such as "E".
- A bigram or 2-gram is a double successive letter/symbol such as "BI".
- A trigram or 3-gram is a tripple successive letter/symbol such as "TRI".
- Etc...

- Frequency analysis looks at repeat counts of unigrams, bigrams and trigrams of ciphertexts, etc... For example, in English the most occurent letter is "E". While the most occurent bigram may be "TH". And the most occurent 7-gram may be "BECAUSE".

My Facebook group has a significant list of resources for learning cryptanalysis and cryptography.
https://facebook.com/groups/763282653806483
Regards
Bart

American Cryptography Association provides multiple cipher method explanations, so does the 'dark chamber' website of Simon Singh (google..). Other sites may relate to side-issues such as Scott Bryce cipher frequencies or any other analysis tool or site (such as Cryptool). You then can start reading, transcripting the cipher, applying your cracking approach. Try not to be overcreative, imo its better to stay on a decryption concept for the cipher you believe it may have been encrypted with (e.g. homophone substitution..don't look for cracking tools or how-to descriptions, even in solid cryptography books you rather won't find anything..the only thing you may find is how to encrypt). You then may start to learn programming, if youre not a programmer yet, for which I'd recommend to not use any object-oriented language (I choose Python which works excellently, however is not as fast as e.g. C could be). After finishing your program you'll find out that your pc has not enough memory, but latter is just a guess. Good luck (the first cipher was cracked during a lazy breakfast..)

QT