I did this in an infosec class in undergrad 15 years ago, inspired by exactly this essay. The first part of the project was to write a program that password protected a file, and the second part was to try and break each other's programs, with full source code access. I think it helped discourage people from trying to deal with mine as opposed to other people's. (Also, several people correctly guessed that it was mine despite the code being nominally anonymous...)