XOR ciphers

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XOR ciphers

Post by zaftcoAgeiha on Mon Jul 22, 2013 6:56 pm
([msg=76562]see XOR ciphers[/msg])

Hey guys,
I have two ciphertexts of equal length, each obtained by XORing with the same key of same size.

What is the best way to recover the plaintexts. I got as far as XOR the ciphertext since it is the same as XOR the plaintext, but now im stuck

Any help/tip would be greatly appreciated
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Re: XOR ciphers

Post by Tentra on Tue Jul 23, 2013 1:38 am
([msg=76565]see Re: XOR ciphers[/msg])

I'm fairly sure your only option is brute force. You will just have to try random keys and check the result against a wordlist until you get something readable. This will only be feasible if they key is relatively short and you have an idea of what the message contains (to add it to the wordlist). According to Wikipedia, a XOR cipher with a key as long as, or longer than the message is in theory, uncrackable. Due to it functioning as a one-time pad, which has been proved to be uncrackable.

https://en.wikipedia.org/wiki/XOR_cipher
http://www.pro-technix.com/information/crypto/pages/vernam_base.html
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