For Forge 1.17.1 servers
Download at github.com/Dezzmeister/mcauth/releases

Offline mode authentication mod for servers. If you're running a server in offline mode, it's possible for people to join with an op's name and have access to admin commands, unless you have some kind of authentication to prevent this. This mod adds several authentication commands:


/createaccount <password>  Creates a local account with the given password

/login <password>  Logs in to an existing account with the given password

/changepassword <password>  Changes the password for your account

/clearaccount <username>  Clears the password for a given username. This can only be run by an admin.


Passwords are salted, hashed, and stored in 'authdb.txt' in the server folder. Currently, the mod kicks you if you try to log in with a bad password 5 times, but I'll add an option for an admin to change this limit.

Until creating an account or successfully logging in, you are prevented from doing anything that could modify the world, or from running any commands.


Note: I wrote this in a couple hours because I could not find a similar mod for 1.17.1, so it will have bugs.