VoidAuth

Mandatory Authentication Mod for Minecraft 26.1–26.1.2 | Fabric | Both-Side Install

VoidAuth is a security authentication mod designed for the Minecraft 26.1 series, requiring both server and client installation. Beyond basic login/registration, it architecturally solves long-standing issues in traditional auth mods — flickering, death-state lockups, and elytra disconnect void traps — while providing full GUI management, fine-grained permissions, and a developer API.

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🚀 Quick Start

1. Install Fabric Loader 0.19.2+ and Fabric API
2. Place VoidAuth in both server and client mods folders
3. Start the server — config auto-generates at config/voidauth.json
4. Players join and type /voidauth register <password> to register, then /voidauth login <password> each visit
5. Type /voidauth help to see all commands (clickable!)

💡 Uses JSON storage by default — zero dependencies, works out of the box. For SQLite/MySQL, just drop the driver jar into the mods folder.

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📋 Requirements

Item	Requirement
Minecraft	26.1 / 26.1.1 / 26.1.2
Java	25
Fabric Loader	0.19.2+
Fabric API	0.145.1+26.1

⚠️ Mandatory both-side install — Clients without VoidAuth will be rejected and prompted to install it.

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✨ Unique Features at a Glance

These features are not found in other Minecraft authentication mods:

#	Feature	One-Liner
🔒	4-Layer Position Lock	Client input freeze + server position sync + move packet intercept + deviation correction — eliminates flickering and X-ray
🌑	Darkness Anti-Bypass	Darkness effect + forced gamma=0 + F3 screen block — even Fullbright can't see through
🪂	Elytra Disconnect Protection	Auto-loads 7×7 chunks on join, prevents void trap after elytra disconnect
💀	Death-State Auto-Recovery	Detects death on logout and auto-respawns on rejoin — no admin intervention needed
⏱️	Flight Check Grace Period	Configurable grace period after login suppresses fly-hack detection during falling/elytra glide
🛡️	BCrypt Truncation Guard	Validates password UTF-8 length ≤ 72 bytes, closes the silent BCrypt truncation vulnerability
🔐	Sequential Character Detection	Blocks abc/123/cba/321 patterns — rejects weak passwords
📝	Admin Audit Log	All admin actions auto-logged, one-click export with timestamp
🔑	Fine-Grained Permission Nodes	7 independent permission nodes, supports Fabric Permissions API
🔌	Developer API	Callback system + data queries + exception isolation for third-party mod integration
🔄	Auto Migration	Config and data auto-migrate on upgrade or storage type switch
🛡️	MySQL Password Protection	Config sync uses placeholder ***, prevents password leak via network
⚙️	bcryptCostFactor Validation	Server enforces range 10–14, prevents DoS via malicious cost factor

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🔍 Unique Features in Detail

🔒 4-Layer Position Lock — Eliminates Login Flickering & X-Ray

Traditional auth mods only intercept move packets server-side, leaving the client free to move — causing flickering and X-ray. VoidAuth implements four coordinated layers:

1. ClientInputMixin — Freezes all keyboard/mouse input
2. tickFreeze() + LockPositionPacket — Locks client to server-specified position, zero velocity + no gravity + render interpolation lock
3. ServerPlayHandlerMixin — Intercepts all move and vehicle move packets
4. ServerPlayerEntityMixin — Actively corrects position deviation, resets fly-check counters

Key innovation: A dedicated LockPositionPayload network packet syncs the server-side coordinates to the client, preventing block-embedding caused by position desync.

🌑 Darkness Anti-Bypass

Traditional mods use Blindness, which Fullbright resource packs easily bypass. VoidAuth uses triple protection:

• Darkness effect — Cannot be penetrated even with max brightness
• Client gamma forced to 0 — Locks render brightness during login, restores after
• F3 debug screen blocked — Prevents coordinate and entity info leaks

⏱️ Flight Check Grace Period

After login, players may still be falling or gliding with elytra. Traditional mods immediately trigger fly-hack detection and kick them. VoidAuth provides a configurable grace period (flightCheckGracePeriodSeconds) that suppresses flight checks, letting players land safely.

🪂 Elytra Disconnect Protection

When a player disconnects mid-elytra-flight and rejoins, traditional mods leave them stuck in the void (chunks not loaded). VoidAuth proactively loads a 7×7 chunk area around the player on join.

💀 Death-State Auto-Recovery

Players who die and disconnect get stuck in a "dead" state on rejoin with traditional mods. VoidAuth records the death state on logout and auto-executes respawn on rejoin.

🛡️ BCrypt 72-Byte Truncation Guard

BCrypt silently truncates passwords beyond 72 bytes. Attackers can exploit this prefix collision to access other accounts. VoidAuth validates UTF-8 byte length and rejects passwords exceeding 72 bytes.

🔐 Sequential Character Detection

Beyond requiring letters + digits, VoidAuth detects ascending/descending sequences (e.g. abc, 123, cba, 321) to reject weak passwords.

📝 Admin Audit Log

All admin actions are automatically logged to logs/voidauth-admin.log. Export a timestamped copy with /voidauth exportlog.

🔑 Fine-Grained Permission Nodes

Permission Node	Action
voidauth.admin.reset	Reset player password
voidauth.admin.setpassword	Force-set password
voidauth.admin.delete	Delete player account
voidauth.admin.list	View player list
voidauth.admin.reload	Reload config
voidauth.admin.config	Modify config
voidauth.admin.exportlog	Export admin log

Falls back to OP check when Fabric Permissions API is not installed.

🔌 Developer API & Callback System

VoidAuthAPI.registerCallback(new AuthCallbackAdapter() {
    @Override
    public void onAuthenticated(UUID uuid) { /* Login success */ }
});

Set<UUID> authenticated = VoidAuthAPI.getAuthenticatedPlayers();
Optional<PlayerData> data = VoidAuthAPI.getPlayerData(uuid);

• AuthCallbackAdapter provides empty implementations for selective override
• Callback exceptions are auto-isolated — one failing callback won't affect others

🔄 Auto Migration

• Config: Automatic version migration on mod upgrade — no lost settings
• Data: Automatic migration when switching storage type (JSON → SQLite → MySQL)

🛡️ MySQL Password Protection

Config sync packets replace the MySQL password with ***. The server only updates the password when the client sends a non-empty, non-placeholder value.

⚙️ bcryptCostFactor Validation

Server enforces BCrypt cost factor range 10–14, preventing DoS via maliciously high values.

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🎮 Full Feature List

Player Commands

Command	Description	Click Behavior
/voidauth login <password>	Login	Fills command, type password
/voidauth register <password>	Register	Fills command, type password
/voidauth info	View personal info	Click to execute
/voidauth changepassword	Open change password GUI	Click to execute
/voidauth email	Open email management GUI	Click to execute
/voidauth unregister	Delete account (requires confirmation)	Fills command, confirm after prompt
/voidauth help	Show help menu	Click to execute

Admin Commands

Command	Description	Permission	Click Behavior
/voidauth reset <player>	Reset player password	voidauth.admin.reset	Fills command, type player name
/voidauth setpassword <player> <password>	Force-set password	voidauth.admin.setpassword	Fills command, type name & password
/voidauth list [page]	View registered players	voidauth.admin.list	Click to execute
/voidauth delete <player>	Delete player account	voidauth.admin.delete	Fills command, type player name
/voidauth reload	Reload config	voidauth.admin.reload	Click to execute
/voidauth config	Open config GUI	voidauth.admin.config	Click to execute
/voidauth exportlog	Export admin log	voidauth.admin.exportlog	Click to execute

💡 All commands in the help menu are clickable. Commands requiring parameters auto-fill into the chat bar.

GUI Screens

• Login Screen — With countdown timer, auto-kick on timeout
• Register Screen — Optional email binding during registration
• Change Password Screen — Old + new + confirm password fields
• Email Management Screen — Bind / change / unbind modes
• Config Management Screen — Visual editor for all settings
• Account Management Screen — Unified entry point

Security

• BCrypt password hashing (configurable cost factor 10–14)
• Password strength validation (min 6 chars + letters & digits + sequential char detection + 72-byte cap)
• Login failure lockout (configurable attempts & duration)
• Same-IP auto-login (configurable validity period)
• Account deletion with confirmation + effect cleanup + data purge

Data Storage

Storage	Description	Dependency
JSON	Default, zero-dependency	None
SQLite	For small-medium servers	Install sqlite-jdbc in mods folder
MySQL	For large servers / multi-server	Install mysql-connector-j in mods folder

Data auto-migrates when switching storage type. Falls back to JSON with a warning if driver is missing.

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🔧 Optional Dependencies

Dependency	Purpose	Installation
sqlite-jdbc	SQLite storage	Place jar in mods folder
mysql-connector-j	MySQL storage	Place jar in mods folder
Fabric Permissions API	Fine-grained permissions	Place in mods folder

Auto-fallback to defaults (JSON storage + OP permission check) when not installed. Core features unaffected.

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⚙️ Configuration

Setting	Default	Description
loginTimeoutSeconds	120	Login timeout (seconds)
maxPasswordAttempts	5	Max password attempts
lockDurationMinutes	30	Account lock duration (minutes)
bcryptCostFactor	10	BCrypt cost factor (10–14)
ipAutoLoginEnabled	true	Enable same-IP auto-login
ipAutoLoginDurationHours	24	Auto-login validity (hours)
storageType	json	Storage type (json/sqlite/mysql)
flightCheckGracePeriodSeconds	30	Flight check grace period (seconds)
mysqlHost	localhost	MySQL host
mysqlPort	3306	MySQL port
mysqlDatabase	voidauth	MySQL database name
mysqlUsername	root	MySQL username
mysqlPassword		MySQL password
mysqlPoolSize	5	MySQL connection pool size

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📜 Developer API

// Add dependency
dependencies {
    modImplementation "com.voidauth:voidauth:1.0.0"
}

// Register callback
VoidAuthAPI.registerCallback(new AuthCallbackAdapter() {
    @Override
    public void onAuthenticated(UUID uuid) { /* Login success */ }
});

// Data queries
Optional<PlayerData> data = VoidAuthAPI.getPlayerData(uuid);
Set<UUID> authenticated = VoidAuthAPI.getAuthenticatedPlayers();
boolean isAuth = VoidAuthAPI.isAuthenticated(uuid);

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❓ FAQ

Q: Can players join without VoidAuth installed?
A: No. Clients without VoidAuth are rejected and prompted to install it.

Q: Do I need to login in singleplayer?
A: No. The host player auto-authenticates in singleplayer (including LAN).

Q: How do I switch storage type?
A: Change storageType in config/voidauth.json and restart. Existing data auto-migrates.

Q: What if I forget my password?
A: Admins can use /voidauth reset <player> to reset it.

Q: Which Minecraft versions are supported?
A: 26.1, 26.1.1, and 26.1.2. Not compatible with older versions.

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📄 License

© 2025 VoidAuth. All Rights Reserved.

This mod is closed-source software. All rights are reserved. Without prior written authorization from the author, the following are prohibited:

• Decompiling, reverse engineering, or disassembling this software
• Modifying, adapting, or creating derivative works
• Distributing, re-licensing, or selling the source code of this software
• Removing or altering any copyright notices in this software

Users are granted a non-exclusive, non-transferable license to install and use this software solely for personal, non-commercial purposes.