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Comment by tgandrews | Hacker News Reader

What's the process for going about decrypting these things? I've seen some that are just base64 and the like - but those have obvious patterns. How are you meant to decrypt something when you don't even know the algorithm? Is it just a series of brute forces against different algos?

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You may be interested in the Matasano crypto challenges: http://www.matasano.com/articles/crypto-challenges/

They walk you through cracking some basic codes, and step up from there.

Have a go at the first one. It's likely to just be a simple cipher:

   AWVLI QIQVT QOSQO ELGCV IIQWD LCUQE EOENN WWOAO
   LTDNU QTGAW TSMDO QTLAO QSDCH PQQIQ DQQTQ OOTUD
   BNIQH BHHTD UTEET FDUEA UMORE SQEQE MLTME TIREC
   LICAI QATUN QRALT ENEIN RKG

You might notice that there are a lot of Q's, perhaps those are E's... You might also look at repeated letters, or common letter pairs.

It doesnt seem like a normal ceasar or ROT algorithm. I am trying it as a "playfair" algorithm at the moment but that seems like a dead end aswell.

Probably not Playfair since there are repeated digraphs.

I've tried caesar shift using Q as E (based on frequency) so M is A but that failed epicly... also tried a viginere using GCHQ as the key word but again failed epicly :L Not even bothering with Playfair. simple letter to Ascii doesn't work either and i really can't be bothered with going stupidly complicated :/

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