In another article there by Didier Stephens [0], he posts a link to his GitHub [1] where he provides numerous such tools. Very interesting stuff!

    [0] String Obfuscation: Character Pair Reversal
        https://isc.sans.edu/diary/String%20Obfuscation%3A%20Character%20Pair%20Reversal/29654

    [1] https://github.com/DidierStevens/DidierStevensSuite