ServerLogin

ServerLogin is a lightweight authentication mod designed for offline-mode Minecraft servers. It forces players to register or log in after joining the server, effectively preventing unauthorized players from performing any actions before their identity is verified.

This mod is server-side only. Players do not need to install it on their clients; vanilla clients can join the server normally.

Key Features
· Registration / Login System: First-time players must register with /register <password> <confirm password>. Returning players log in with /login <password>.
· Strict Interaction Restrictions: Unauthenticated players cannot move (WASD is disabled), place or break blocks, attack entities, or interact with any blocks (e.g., opening chests, doors, etc.).
· Command Blocking: Apart from /register and /login, unauthenticated players cannot use any commands (including OP commands).
· Auto-Kick on Timeout: Players who fail to log in within 3 minutes will be automatically kicked from the server.
· Smart Reminders: Chat reminders are sent every 15 seconds prompting players to register or log in, with a note: “If you forgot your password, please contact the server administrator.”
· Register-to-Login: Successful registration automatically logs the player in, eliminating the need to enter the password again.
· Fake Player Compatibility: Fully compatible with fake players from Create (Deployer), Curtain, and Carpet mods. Fake players are automatically bypassed and will not trigger any login logic or timeouts.
· Optimized Console Logging: Logged-in players produce no console output; unauthenticated players only show their login status every 10 seconds, significantly reducing log clutter.
· Unauthenticated Player Protection: Unauthenticated players are immune to all damage (mobs, fall, lava, potions, etc.), monsters do not target them, and explosions (e.g., Creepers) will not damage terrain (visual effects remain).

Data Security
Player passwords are never stored in plaintext. The mod uses the BCrypt hashing algorithm with salt to encrypt passwords, ensuring that even if the server files are compromised, player passwords remain highly resistant to cracking.

Password data is saved in the server’s config/loginmod/players.json file.

Commands & Rules
· Registration command: /register <password> <confirm password>
· Login command: /login <password>
· Password rules:
  · Minimum length of 4 characters
  · Case-sensitive (e.g., Abc123 ≠ abc123)
  · Allowed characters: letters (a–z, A–Z), digits (0–9), and underscores (_)