justcaptcha

🛡️ ProstoCaptcha (by JustPlugins)

ProstoCaptcha is a professional-grade anti-bot solution for Velocity proxy servers. Unlike traditional text-based captchas, this plugin leverages the LimboAPI to create a fully interactive verification environment, forcing bots to simulate complex human behavior at the protocol level.

🚀 Key Features

🧩 Multi-Stage Interactive Quests

The plugin features a unique "Quest System" where players must interact with the environment to prove they are human:

• Resource Gathering: High-precision tracking of mining tasks including wood, stone, iron, coal, and diamonds.
• Crafting & Smelting Logic: Sophisticated checks where players must interact with Crafting Tables or Furnaces in a logical sequence (e.g., you cannot use a furnace without first obtaining fuel/ore).
• Action Validation: Deep inspection of player interactions to prevent automated script bypasses.

🗺️ Dynamic Map-Captcha

High-security graphical verification rendered directly on Minecraft maps:

• Advanced Rendering: Uses Graphics2D with anti-aliasing and gradient paints to generate unique codes on the fly.
• OCR Protection: Random font transformations and custom character sets make it extremely difficult for automated OCR bots to read the code.
• Smart Interaction: Dedicated session handling for map updates and input verification.

🪂 Physics-Based Fall Check

A movement-based verification module that monitors gravity and player physics:

• Gravity Analysis: Requires players to perform a controlled fall to prove they are subject to standard game physics.
• Cheat Detection: Detects and blocks "Spider," "Fly," or "SlowFall" hacks by analyzing movement packets in the Limbo world.

🚫 Integrated Anti-VPN & Proxy Detection

Built-in protection against malicious network sources:

• External API Support: Integrated support for providers like ProxyCheck.io.
• Smart Caching: Local TTL-based cache for IP decisions to ensure zero latency for legitimate returning players.

🛠️ Technical Specifications

• Platform: Velocity Proxy (Java 17+)
• Dependencies: LimboAPI (Required).
• Protocol Handling: Custom implementation of BlockDigPacket and UseItemOnBlockPacket for low-level action tracking without overhead.
• Visuals: Full MiniMessage support for modern hex-gradients in BossBars, Titles, and Chat.

📦 Project Structure

• me.prostoac.captcha.protocol: Custom packet decoders for serverbound-only actions, ensuring efficient communication handling.
• CaptchaSessionHandler: The core logic engine managing the entire lifecycle of player verification from join to success.
• CaptchaConfig: Optimized YAML loader with fallback memory defaults for maximum stability.

Developed with ❤️ by JustPlugins Empowering server owners with elite-level protection.