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Tetragraphs ???
I thought, English has no tetragraphs ....

cyberwoozle wrote:Tetragraphs ???
I thought, English has no tetragraphs ....

The use of tetragraphs is one of the more conventional methods of determining how "English" a block of text is. A tetragraph is simply the frequency that any four letters will appear in English.

The word "tetragraph" seems to have at least two somewhat differing meanings, one in linguistics (which is what cyberwoozle means) and one in cryptography (which is what laz0r means).

But that is not really the problem here. I have deciphered the text completely, and nevertheless I am totally and utterly stuck and don't know what to do next.

AMindForeverVoyaging wrote:The word "tetragraph" seems to have at least two somewhat differing meanings, one in linguistics (which is what cyberwoozle means) and one in cryptography (which is what laz0r means).

But that is not really the problem here. I have deciphered the text completely, and nevertheless I am totally and utterly stuck and don't know what to do next.

It is very hard to give hints on this without spoiling too much. It took me extremely long to beat this challenge, after the first - pretty straightforward - stage you should take a closer look into what you have done so far. Perhaps you might to write down what you found out so far (this does not necessarily mean the decrypted text itself)

Thanks

This last hint helped? Oh jeeze, what am i doing wrong

What else is vital to make this challenge work, but most people will ignore? You are ignoring one crutial part of any cryptographic message.

Once you have worked out what you might be missing, you then might wish to consider the possible ways of displaying this information. There are multiple ways of displaying this information which in turn causes for different interpretations; some ways will yield results, (not necessarily correct, but indications that you are on the right line), whereas others may be a complete waste of your time.

Hope I haven't alienated you too much! This is, after all, a relatively simple challenge if you are willing to consider all options.

My problem is rather willing (or not willing) than being a blockhead: I've decoded the three sentences (in- and excluding interpunctuation) and since i'm pretty sure, that it is not possible to encrypt two different plaintexts with two different algorithms and get the same ciphertext (the one from the challenge), my conclusion is to continue with analyzing the decrypted sentences in any way and not to concentrate on the original ciphertext again.
And here i'm stuck - even with snibril's hint (standard Unix tools) as well as with the tetragraph hint
And don't worry, you haven't alienated me - the only thing which drives me mad is, that i was at the same point a year ago and i thought, maybe i can refresh my efforts in this one .....

cyberwoozle wrote:My problem is rather willing (or not willing) than being a blockhead: I've decoded the three sentences (in- and excluding interpunctuation) and since i'm pretty sure, that it is not possible to encrypt two different plaintexts with two different algorithms and get the same ciphertext (the one from the challenge), my conclusion is to continue with analyzing the decrypted sentences in any way and not to concentrate on the original ciphertext again.
And here i'm stuck - even with snibril's hint (standard Unix tools) as well as with the tetragraph hint
And don't worry, you haven't alienated me - the only thing which drives me mad is, that i was at the same point a year ago and i thought, maybe i can refresh my efforts in this one .....

It most certainly is possible, however that is beside the point.

Providing you have decrypted the ciphertext into some meaningful plaintext, you don't need to do anything more. It simply becomes a matter of playing around with what you currently have. Tetragraphs are simply a means to decode the ciphertext, however they are completely useless for the next step.

I might be giving this away, but I hope not: Apart from the algorithm to encrypt/decrypt and a chosen plaintext/ciphertext, what else do you need (or produce in the case of cryptanalysis)? Once you work out what I am referring to, simply play around with standard layouts for it.

Wow, got it!
Thanks for all the hints
For me the second part was much harder than the first one, probably because the second one was so easy that i didn't even think about such an idea.

Just solved it, for all those who are struglng with it: look in every direction and seek out meaningfull words

Why there is so often the link to challenges rather to challenges solved ... .
Definitely idea what I hoped to work on another one and failed there.

Of course frequency, digraphs, first letters, last letters, two letter words, three letter words are statistics which navigates easily with the substitution (may be THE is a bit less common in this text as usuall).