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I'm currently studying for a cryptography exam. I've been given ciphertext that has been encrypted by a columnar transposition cipher. I've been given no shift key length or key word, the only thing I know is that only 2 columns have been shifted.

How can I determine the key? Or better yet, is there another way to decipher the ciphertext?

otus
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EMJ
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1 Answers1

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(Although your question is for a long time ago) Transposition ciphers don't change the frequency of letters in their ciphertexts. So, you can implement a frequency attack. For decryption by this you only need the table of frequency of English letters and your ciphertext. (Your encryption scheme here is a Columnar transposition with a key that all its letters are in order except 2 of them.)

ssss1
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