Offline authenticator reimplements whitelist for offline users aswell as making it impossible to spoof other users by changing your username. This gives offline servers a better sense of security and no one can hijack your server by spoofing usernames.
It works like this. Your client sends the server a key (It generates a random key if a key doesnt already exist for that server) and then that key if the user isnt already taken is SAVED under that users name in the server config. But if it IS taken and they send a wrong key for the wrong username they ARENT let into the server and with this i could reimplement whitelist for offline mode.
You dont need to know of the specifications because it is all seamless! If you join a server in offline mode (If ur not spoofing another user) you will join without issue.
BOTH THE CLIENT AND SERVER NEED THIS MOD. Its not like those /register and /login commands but it works similarly it just does all of that stuff automatically BUT if you want to create another instance or keep joining that offline server on another computer you WILL need to copy your offlinepass_client.json file inside of the config.
