A simple cpp program, that receives a file, does a bit-wise "not" for every character, and adds "not" to the extension. Repeated running does the same and removes the "not" from extension. This is a "pseudo-encryption", but very useful to avoid automated filtering software. This way it is possible to send "exe" files (or anything else) without the emails being blocked... First - send the source code, have your (enlightened) recipient compile it, then send the "notted" file. The code is not very efficient though, I only had 30 minutes to invest... :)

notter.cpp

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Nothing．