What is .mse file encryption scheme?
Why would it matter?
It's been compromised for quite a while, anyway.
You're welcome to give a better one. From a company standpoint, what should be important is if it's safe enough, which it's definitely not as there're multiple one-click solutions to decrypt mse files around.
There's a ProTEC (Script Protection System) developed by Daniel Santana and then there's the possibility to write your own C++ plugin that would handle the encryption/decryption. If you don't care about licensing, just making it hard to copy-paste parts of your code, obfuscation might be enough, though - in case of maxscripts, that could be also done with a series of regexes to remove spaces after ]), etc. and by replacing function names and names of locals with meaningless garbage.