I'm going to update this to 1.13 soon guys don't worry. I just remembered I even made this in the first place lol. The next version will also improve the way encrypted messages are encoded so they can be way longer. What was I thinking with the 2f|5e|d7|etc|etc thing?
It's available for 1.12.2 now. Forge 1.13 isn't available yet sorry, but I can still make a 1.13 compatible version using regular vanilla tweakers if anyone's interested. This shouldn't really matter though because most servers still support the older versions of minecraft anyway.