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Detecting whether incoming textis encrypted or not RRS feed

  • Question

  • I am researching Cryptography. I wanted to know whether any string is just plain text or it has been encrypted by some Cryptography algorithm
    Tuesday, August 13, 2013 12:15 PM

Answers

  • If you can make a few assumptions, then you can work with a few heuristics. For instance, if you can assume that the clear text is in English, you can analyze, in order of complexity:

    - the character set
    - word length distribution
    - frequency distribution of each character
    - placement of punctuation
    - how many words belong to the English dictionary
    - semantics

    This obviously requires that the string is long enough to perform most of the analysis outlined above, but it's highly unlikely that any standard encryption would produce an output that generates a false positive.

    Care to elaborate about what you are trying to achieve?

    --mc

    Tuesday, August 13, 2013 1:29 PM