Please clarify my first point dude? the weird number thing, considering most users wont have "commandline" access to the Bot in order to generate the weird number, it's impossible for another user to add themselves once you've allowed them via the Bot itself.
like if you did: .addauth nick:pass then you'd do the encoding: $encode($2-,m) and then send it onto the script, thus the user would only need to perform 1 step instead of all the ones you've stated: eg.
1) Bot owner authorizes user (via the Menu System you added)
2) User Types: /msg Bot .addauth mytwittername:mypass
3) The bot then converts that string into that weird thing (in this example: bXl0d2l0dGVybmFtZTpteXBhc3M=) and then sends onto the script..
I think this would be much easier from the users point-of-view.