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I have a given string:

OPIESTGAEDNOMRALILDCNEELENLWEATWIEEEAUTHATNCDR

I have basically tried everything, which left me with substitution method with frequency analysis, but still stuck since this is almost impossible to approach, anyone out there who would be willing to help me.

Only hint that is given is that it's a quote from either a movie or book.

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Frequency analysis tells you ...

... that the letter distribution is typical of an English sentence: Many e's, fewer a's, some t's and n's. The cipher probably isn't a substitution cipher.

The cipher is ...

... is a transposition cipher with a columnar transposition of five columns. You can find the number of columns by trying out several possibilities. Rearrange the sentence:

        O P I E S T G A E D
        N O M R A L I L D
        C N E E L E N L W
        E A T W I E E E A
        U T H A T N C D R
(The original columns of the transposition are presented as rows when decoding. Take care to make the first row one character longer, because the message length of 46 leaves a remainder of 1 when dividing by the number of original columns, 5.)

Now read columnwise:

  Once upon a time there was a little engine called Edward.

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  • $\begingroup$ facepalm I'm blind was sure I had been through everything, thx though u just made my life easier spend 24h+ on this $\endgroup$ – Kornelius Pasztor Mar 26 '17 at 18:05
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    $\begingroup$ Kornelius, you should click on the little green checkmark to the left of M Oehm's answer to signify that he correctly answered your question. $\endgroup$ – Gareth McCaughan Mar 26 '17 at 20:04
  • $\begingroup$ i wanted to tell you that this method of encrypting is called Caesar Box. But it is not used as it is very easy to break. $\endgroup$ – nAutAxH AhmAd May 21 '17 at 12:21

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