How to identify a cipher type from the cipher text?

Hey, I recently done a machine witch contain a forum that was encrypted and I got blocked by that and I had to found the solution online. It seem to me that there was no easy way to find out about the cipher that was use. When I google about technics on how to guess the cipher use, they say it is basically impossible with modern technic and/or maybe with older one, you could use Statistical analysis ( see below for link ) but you’ll need a lot of text. So, my question is, do you have any recommendations on how I could become better at identifying cipher use ?



  1. Statistical Analysis
    Practical Cryptography.
  2. But on modern algorithm, it won’t work (Differential cryptanalysis ??)

From what I know as someone interested in cryptography but who’s not at all an expert, part of what makes a cipher good is it’s actually very hard or impossible to distinguish it from any other one. There are some tools which can use patterns in order to give the likelihood of the ciphertext being encrypted with this algorithm or this one, but nothing 100% reliable (not even close).
I believe I know what box you’re talking about and if I’m not mistaken, there were pretty strong clues in this one, as there were spaces between the words, a word would always be ciphered to the same sequence of characters (as you can see in the signatures of the forum)… those details won’t necessarily make you able to pinpoint the cipher in use, but you could at least rule out a lot of them and proceed one by one with those left.
Anyway, at the end of the day this kind of stuff boils down to guts and experience :slight_smile:

Thank you for your response. I think I will just go and practice some crypto exercises. I heard about that site: ( if that can help someone else )

That website is amazing, I never had the courage to go through all of the challenges, but pretty much 90% of anything I can say I understand in crypto is because of those guys !