The canonical form of a given key is composed of lowercase letters between A-Z, numbers between 0-9 and the @ symbol. This is pre-generated on both /mob/var/ckey and /client/var/ckey, based on the user's /client/var/key.

var/my_evil_key = "W0w!!IGotLots-ofFunCharacters!!!InHere@@"

world.log << ckey(my_evil_key) // w0wigotlotsoffuncharactersinhere@@