AntiESP

A Paper plugin that makes ESP / wallhack / xray cheats far less useful by never sending the client information it should not be able to see in the first place.

Three independent protections in one plugin:

Everything is configurable in config.yml, and every feature can be turned off individually.

Requirements

• Paper 1.21.8 (or a compatible build) — the plugin uses the Paper API
• Java 21
• Optional: PacketEvents — required for packet mode (cave filling / freecam protection) and for keeping hidden players in the tab list. Without it the plugin still runs, just with the block-mode feature set.

Installation

1. Drop AntiESP-1.0.0.jar into your server's plugins/ folder.
2. (Recommended) Drop PacketEvents into plugins/ as well.
3. Start the server — plugins/AntiESP/config.yml is generated on first run.
4. Before going live with packet mode, run the identity-test once (see Ore obfuscator).

Building from source

mvn clean package

The jar ends up in target/AntiESP-1.0.0.jar. Both dependencies are provided, so nothing is shaded in — the jar stays tiny.

1) Player hiding

For every viewer/target pair the plugin ray-traces the line of sight (Amanatides & Woo voxel traversal, RayTracer) and picks one of three states:

• VISIBLE — close by or in clear sight: nothing changes.
• NAMETAG — occluded at medium range: the player model and hitbox are hidden, but a floating name (a proxy TextDisplay) stays visible.
• GONE — occluded and far away: completely invisible.

Hiding starts at min-distance (default 12 blocks) and only when more than walls-to-hide opaque blocks are in the way. Several target points on the body are checked — a player is only hidden when all of them are occluded, so nobody pops out of existence while half-visible around a corner.

Key options:

Sneaking hides the nametag immediately instead of waiting for the next tick.

Note: a visible nametag still roughly gives away a position. Set keep-nametags: false for the strongest protection.

2) Block disguise

Valuable block-entities are replaced with stone (disguise-as) via sendBlockChange for viewers that are far away or looking through walls. Walk closer than reveal-distance and the real block comes back, so containers open normally. Uses only the Bukkit API — no ProtocolLib, no PacketEvents.

By default chests, trapped chests, ender chests, barrels, hoppers, droppers, dispensers, all shulker boxes, spawners, trial spawners, vaults, brewing stands, beacons, furnaces, blast furnaces, smokers and decorated pots are disguised. Edit the block-disguise.blocks list, or set all-block-entities: true to cover every block-entity (signs and banners included — this is noticeable).

3) Ore obfuscator (anti-xray)

A fully self-contained anti-xray implementation — no Paper anti-xray, no Orebfuscator. Real ores are sent as stone/deepslate and fake ore veins are grown in natural Y ranges and vein sizes.

Two modes:

Ores that border air are left real — you would see them anyway — so the world "normalizes" itself exactly where a player could legitimately look. In packet mode a proximity reveal flood-fills through the connected cave air you are standing in and uncovers the whole cave system, direction-independently, spread across a few ticks. Revealed blocks stay revealed until relog. Nether and End are not obfuscated at all.

The fake pattern is seeded from a secretSalt generated with SecureRandom at every server start (RAM only) XOR'd with the chunk coordinates: stable per chunk (no flickering), but not reproducible without the salt.

Test packet mode first. Rewriting the chunk binary format is version sensitive. Set ore-obfuscation.identity-test: true, restart, and check that the world looks normal — that decodes and re-encodes every chunk packet without changing anything. If it looks fine, set it back to false.

Full details, tuning advice and the honest limitations (notably: anyone who knows the world seed can regenerate ore positions server-side, no client-side obfuscation can prevent that) are in docs/ANTI-XRAY.md.

Commands & permissions

packet-mode and identity-test are only applied on a server restart, not via /antiesp reload.

Project layout

src/main/java/dev/antiesp/
  AntiESPPlugin.java          entry point, events, commands
  PlayerVisibilityService.java player hiding + proxy nametags
  TabListKeeper.java          keeps hidden players in the tab list (PacketEvents)
  BlockDisguiseService.java   container/block-entity disguise
  OreObfuscationService.java  anti-xray, block mode
  ChunkPacketObfuscator.java  anti-xray, packet mode (CHUNK_DATA rewriting)
  ProximityRevealer.java      persistent flood-fill cave reveal
  RayTracer.java              voxel ray tracing for occlusion counting
src/main/resources/
  config.yml, plugin.yml
docs/ANTI-XRAY.md             in-depth anti-xray documentation (German)

Performance notes

• Packet mode computes per chunk on the Netty threads; results are cached (max-cache-chunks, default 6000) and invalidated when blocks are mined.
• Only player block-breaking invalidates the cache — TNT, pistons and water do not, currently.
• The proximity reveal only re-floods when you move to a new block, mine, or join; standing still and turning around costs nothing.