Plugin:
TOTOp is a plugin that lets a player be granted operator permissions by entering a 2fa/TOTP code

Usage:

• Download the latest .jar file from the releases page
• Add it to the server's plugins folder
• On start up, a QR code will be printed to the server console
• Scan the QR code with a TOTP app (e.g. google authenticator) to add the code
• On another account connected to the server, run /totop <code> where code is the code found in the app
• The account should have op permissions
• Use /deopme to de-op the account afterwards