SimpleAuth

A simple authentication plugin for Minecraft.
Players who fail to enter the password within a set number of seconds after joining will be kicked.
Players who have authenticated once will be automatically logged in on future joins.

Compatible with: Paper 26.1.2 (Minecraft Java 26.1.2)

Features

• 30-second countdown starts when a player joins (configurable)
• While unauthenticated, the following actions are blocked: movement, chat, other commands, block place/break, interactions, and damage
• Two authentication methods:
  • Type the password directly in chat (recommended — chat from unauthenticated players is not visible to others)
  • /auth <password> command
• Auto-login: Players who have authenticated once are automatically logged in on future joins (identified by UUID)
• The password is never displayed in any server message (prevents leaks)
• Auto-kick on timeout
• /authreload to reload configuration (OP only)
• /authforget to remove your own auto-login registration
• In-game message language is configurable (en / ja)

Installation

1. Copy the built SimpleAuth.jar to your server's plugins folder
2. Start the server (plugins\SimpleAuth\config.yml will be generated automatically)
3. Edit config.yml to set your password, timeout, and language
4. Use /authreload to apply changes (or restart the server)

Configuration (config.yml)

password: "password"      # Authentication password
timeout-seconds: 30       # Time limit for authentication (seconds)
remember-players: true    # true: auto-login after first auth / false: require password every time
language: "en"            # In-game message language: en (English) / ja (Japanese)

Commands

Command	Description	Permission
/auth <password>	Authenticate	Everyone
/authforget	Remove your auto-login registration	Everyone
/authreload	Reload configuration	OP only

Auto-login Details

• The UUID of authenticated players is saved to plugins/SimpleAuth/authed_players.yml
• Players whose UUID matches on the next join are logged in instantly without a password
• Auto-login persists across server restarts
• Use /authforget to remove your registration (e.g., on a shared PC)

---