Modrinth
Plugin
Grim Anticheat
Fully async, multithreaded, predictive, open source, 3.01 reach, 1.005 timer, 0.01% speed, 99.99% antikb, "bypassable" 1.8-1.21 anticheat
Minecraft product info
Important product information
Compatibility, Minecraft versions, loaders, and external source data.
Type
Plugin
Access
Free
Latest version
2.3.74-85dd3d9
Downloads
542 718
Loaders / Platforms
bukkit
fabric
folia
paper
purpur
spigot
Minecraft versions
1.7.2 – 1.21.11
1.7.3
26.1
26.1.1
26.1.2
26.2
Categories
game-mechanics
management
utility
Description
Detailed information
# GrimAC
GrimAC is an free open source Minecraft anticheat designed to support the latest versions of Minecraft. It currently supports minecraft versions 1.8-1.21. Geyser players are fully exempt.
This project is considered feature-complete for the 2.0 (open-source) branch. If you would like a bug fix or enhancement and cannot sponsor the work, pull requests are welcome. A premium version is planned, which will offer additional subscription-based paid checks, such as heuristics.
## Installation notes
- **Java 17 is now required.** More information [here](https://github.com/GrimAnticheat/Grim/wiki/Updating-to-Java-17).
- Paper, Spigot, and Folia are currently supported.
- If you use Geyser, place Floodgate on the backend server so grim can exempt bedrock players. Grim cannot access the Floodgate API if it is on the proxy.
- If you use ViaVersion, it should be on the backend server as movement is highly dependent on client version.
## Support & wiki information
- Support & discussion: [Discord](https://discord.grim.ac)
- Report issues: [Issues](https://github.com/GrimAnticheat/Grim/issues/new/choose)
- Wiki & examples: [Wiki](https://github.com/GrimAnticheat/Grim/wiki)
## Developer API
Grim's API allows you to integrate Grim into your own plugins.
- API repository: [GrimAPI](https://github.com/GrimAnticheat/GrimAPI)
- Wiki info: [Wiki](https://github.com/GrimAnticheat/GrimAPI)
## How to compile
1. `git clone https://github.com/GrimAnticheat/Grim.git`
2. `cd Grim`
3. `./gradlew build`
4. The final jar will compile into the build/libs folder
## Grim supremacy
What makes Grim stand out against other anticheats?
### Movement Simulation Engine
* We have a 1:1 replication of the player's possible movements
* This covers everything from basic walking, swimming, knockback, cobwebs, to bubble columns
* It even covers riding entities from boats to pigs to striders
* Built upon covering edge cases to confirm accuracy
* 1.13+ clients on 1.13+ servers, 1.12- clients on 1.13+ servers, 1.13+ clients on 1.12- servers, and 1.12- clients on 1.12- servers are all supported regardless of the large technical changes between these versions.
* The order of collisions depends on the client version and is correct
* Accounts for minor bounding box differences between versions, for example:
* Single glass panes will be a + shape for 1.7-1.8 players and * for 1.9+ players
* 1.13+ clients on 1.8 servers see the + glass pane hitbox due to ViaVersion
* Many other blocks have this extreme attention to detail.
* Waterlogged blocks do not exist for 1.12 or below players
* Blocks that do not exist in the client's version use ViaVersion's replacement block
* Block data that cannot be translated to previous versions is replaced correctly
* All vanilla collision boxes have been implemented
### Fully asynchronous and multithreaded design
* All movement checks and the overwhelming majority of listeners run on the netty thread
* The anticheat can scale to many hundreds of players, if not more
* Thread safety is carefully thought out
* The next core allows for this design
### Full world replication
* The anticheat keeps a replica of the world for each player
* The replica is created by listening to chunk data packets, block places, and block changes
* On all versions, chunks are compressed to 16-64 kb per chunk using palettes
* Using this cache, the anticheat can safely access the world state
* Per player, the cache allows for multithreaded design
* Sending players fake blocks with packets is safe and does not lead to falses
* The world is recreated for each player to allow lag compensation
* Client sided blocks cause no issues with packet based blocks. Block glitching does not false the anticheat.
### Latency compensation
* World changes are queued until they reach the player
* This means breaking blocks under a player does not false the anticheat
* Everything from flying status to movement speed will be latency compensated
### Inventory compensation
* The player's inventory is tracked to prevent ghost blocks at high latency, and other errors
### Secure by design, not obscurity
* All systems are designed to be highly secure and mathematically impossible to bypass
* For example, the prediction engine knows all possible movements and cannot be bypassed