AntiSeedCracker

Version: 3.1.0  |  Target: Minecraft 26.1.2  |  Author: SunsetRQ7_

AntiSeedCracker is a professional, multi-layer world seed protection plugin for Paper, Purpur, Folia, and Spigot. It blocks every known technique a player can use to recover your world seed, protecting your server from ESP clients and seed-cracking tools.

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Features

Protection Layer	Description
Login & Respawn Packet Spoofing	Replaces the hashed seed in JOIN_GAME and RESPAWN network packets with a per-player cryptographically random fake seed. Operates at the Netty I/O level via PacketEvents before any client ever receives the real value.
Dynamic Seed Rotation	Periodically assigns each online player a new random fake seed (configurable interval, minimum 30 s). Defeats crackers that accumulate packets across multiple sessions.
Plugin API Protection	Patches the NMS seed field via reflection every second so any plugin calling World.getSeed() receives a rotating fake value. Re-applies unconditionally to prevent other plugins from undoing the patch.
Eye of Ender Redirection	Intercepts thrown Eyes of Ender and redirects their velocity toward a per-player fake stronghold location. Applies a ±8° angular jitter to prevent exact triangulation across repeated throws.
/locate Spoofing	Cancels /locate and replies with convincingly fake coordinates. Stronghold queries use the player's stable fake location for consistency.
/seed Command Block	Blocks /seed, /minecraft:seed, /getseed, /worldseed, and any extra commands configured in config.yml for players, console, and RCON. Also strips seed commands from tab-complete results.
End Spike Randomization	Shuffles the bedrock cap heights of all 10 End obsidian pillars at world load and after each dragon respawn cycle. Breaks the vanilla height fingerprint {76, 79, 82 … 103} that uniquely identifies the seed.
End City Glass Replacement	Replaces magenta stained glass in End City chunks with purpur blocks on first load. Prevents End City coordinate fingerprinting via the distinctive glass pattern.
Treasure & Explorer Map Scrambling	Intercepts MAP_DATA packets and randomises the on-map position of every structure icon (buried treasure, woodland mansion, ocean monument, and others).
Audit Log	Appends every blocked command, spoofed packet, and redirected Eye to a flat-file TSV log in plugins/AntiSeedCracker/logs/. Zero external dependencies — no SQLite.

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Compatibility

Platform	Supported
Paper 26.1.2	✔
Purpur 26.1.2	✔
Folia 26.1.2	✔ (region-threaded scheduling)
Spigot 26.1.2	✔ (BukkitScheduler fallback)

Runtime: Java 25 or higher is required.

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Installation

1. Download AntiSeedCracker-3.1.0.jar from Releases.
2. Place it in your server's plugins/ folder.
3. Start or restart the server.
4. Edit plugins/AntiSeedCracker/config.yml to your preference.
5. Run /asc reload to apply changes without restarting.

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Commands

Command	Description	Permission
/asc reload	Reloads config and restarts all protection tasks	antiseedcracker.admin
/asc status	Shows which protection layers are active	antiseedcracker.admin
/asc stats	Displays aggregate event counts from the audit log	antiseedcracker.admin
/asc info	Shows version, author, platform, and update status	antiseedcracker.admin

The antiseedcracker.admin permission defaults to server operators.

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Configuration

seed_obfuscation:
  intercept_login: true
  intercept_respawn: true

seed_rotation:
  enabled: true
  interval_seconds: 60

structure_protection:
  end_spikes:
    enabled: true
    worlds:
      - world_the_end
    modify_world: true
  end_cities:
    enabled: true
    worlds:
      - world_the_end
    modify_world: true
  spoof_locate_command:
    enabled: true
    max_offset: 2000

plugin_api_protection:
  enabled: true

eye_of_ender_protection:
  enabled: true
  worlds:
    - world
  fake_stronghold_min_distance: 800
  fake_stronghold_max_distance: 4000

update_checker:
  enabled: true
  modrinth_id: "YOUR_MODRINTH_PROJECT_ID"

database:
  enabled: true
  log_events: true
  max_event_age_days: 30

treasure_map_protection:
  enabled: true

extra_blocked_commands:
  - "seedcracker"
  - "seedfind"
  - "worldseedinfo"

modify_world Warning

Setting modify_world: true for End spikes or End cities permanently changes world data. Spike bedrock caps are moved to shuffled positions and End City magenta glass is replaced with purpur blocks. These changes persist across restarts. Set to false to disable physical world modifications while keeping all other protection layers active.

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World Safety

AntiSeedCracker never reads, stores, or logs the real world seed. The only world modifications performed are:

• Moving bedrock cap blocks on End obsidian pillars (when end_spikes.modify_world: true).
• Replacing magenta stained glass in End City chunks with purpur blocks (when end_cities.modify_world: true).

Both modifications use physicsUpdate: false to prevent block-update cascades. Each chunk is tagged with a Persistent Data Container key so the modification runs at most once per chunk across all server restarts. No terrain, biome, or structure data outside these specific block types is ever altered.

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Folia Threading Model

All block mutations are dispatched to the region thread owning the relevant chunk via RegionScheduler (Folia) or the main thread (Paper/Spigot). Packet interceptors run on the Netty I/O thread and only perform ConcurrentHashMap lookups. The seed rotation and world-seed broadcast tasks run on the AsyncScheduler (Paper/Folia) or an asynchronous BukkitTask (Spigot).

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Known Bypass Mitigations

Attack Vector	Mitigation
Login/Respawn packet interception	PacketEvents HIGHEST-priority intercept
/seed, /getseed, /worldseed	PlayerCommandPreprocessEvent + ServerCommandEvent + RemoteServerCommandEvent blocking
Eye of Ender triangulation	Per-player fake stronghold + ±8° jitter
/locate structure triangulation	Spoofed coordinate output, consistent per-player stronghold fake
Treasure / explorer maps	MAP_DATA packet decoration scrambling
End spike height fingerprinting	Full Fisher-Yates shuffle of pillar cap heights
End City coordinate fingerprinting	Magenta glass block replacement
Other plugin API (world.getSeed())	NMS field reflection patch, re-applied unconditionally every second
Tab-complete exposure	TabCompleteEvent filtering
RCON seed commands	RemoteServerCommandEvent blocking

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Building from Source

Requires Maven 3.6+ and JDK 25. The project compiles against folia-api 26.1.2 (Java 25 class files) and produces a Java 25 output jar.

# Windows
set JAVA_HOME=C:\Program Files\Java\jdk-25.0.3
mvn clean package

# Linux / macOS
export JAVA_HOME=/path/to/jdk-25
mvn clean package

The shaded jar is produced at target/AntiSeedCracker-3.1.0.jar. PacketEvents is bundled and relocated to me.legendcraft.antiseedcracker.lib.packetevents.

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License

All rights reserved. Redistribution without permission is prohibited.