how can i transform my code to a dll file?

i have builded a little project, and i want to take it's code and to implement it in another project, but i don't want future programmers to use my code, sssoooo..

1. how do i transform my code to dll files? (so i can reference it to the current project)

2. is there a way to transform the code back to c# code?is the code safe from future changes?
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