base64 is a very well known function and included in a fair number of languages (e.g. in Python you can use the "base64_codec" or "hex_codec" as an encoding parameter). Given the other things people have gotten tools in this class to do to convert or even eval() things I would not bet against someone coming up with a clever dodge around rules — these systems are non-deterministic and there are a lot of motivated people in the world.