# QuantumAC
\n**A lightweight, server-side anti-cheat plugin for PaperMC 1.21.1 \u2013 1.21.11**<\/p>\n
—<\/p>\n
QuantumAC is a server-side anti-cheat plugin built specifically for PaperMC. It catches the most common cheats through a combination of movement analysis, packet inspection, and world-state occlusion \u2014 without relying on client-side modifications.<\/p>\n
All detections happen on the server. There is nothing a cheat client can do about packets that were never sent, or a lagback it never saw coming.<\/p>\n
## Checks<\/p>\n
– **Flight** \u2014 detects sustained upward or level movement in air. Lagbacks the player to their last safe ground position.
\n– **Speed** \u2014 flags horizontal movement beyond vanilla limits, accounting for sprinting, speed potions, ice, soul sand, and post-knockback momentum.
\n– **KillAura** \u2014 detects unnatural attack patterns: inhuman attack rate, multi-target switching within a single swing window, and robotic aim angle consistency via packet analysis.
\n– **NoFall** \u2014 catches suppressed fall damage. Reapplies blocked damage and lagbacks on confirmed damage-free landings, with mace smash and wind-charge exemptions.
\n– **BoatFly** \u2014 detects upward boat movement beyond vanilla physics.
\n– **Criticals** \u2014 flags critical hits landed while the player is grounded, blocking hit-consistent criticals cheats.
\n– **FastBreak** \u2014 enforces minimum block break times relative to tool efficiency and block hardness.
\n– **AntiESP** \u2014 server-side entity and block entity occlusion. Hidden entities and block entities are never sent to the client, so no ESP mod can reveal them.
\n– **AntiJesus** \u2014 detects players when they walk on water\/lava and gives them warnings.
\n– **AntiVelocity** \u2014 server side physics calculations for hacks such as AntiKnockback.
\n– **BadPacket** \u2014 enforces physical packet integrity by blocking malformed rotation data (NaN), spoofed Y-coordinates used for MaceDMG and Freecam exploits, and impossible movement deltas beyond vanilla limits.
\n– **AntiScaffold** \u2014 prevents air place and placing blocks without looking at the general direction.<\/p>\n
## Features<\/p>\n
– Violation level system with configurable thresholds for alerts, kicks, and bans
\n– Lagback on movement violations \u2014 no teleport spam, just a clean snap to last safe position
\n– In-game GUI to toggle individual checks at runtime without reloading
\n– Staff alerts with configurable violation threshold
\n– Per-check configuration: enable\/disable, thresholds, multipliers, and VL costs
\n– `quantumac.bypass` permission for staff or trusted players<\/p>\n
## Requirements<\/p>\n
– PaperMC 1.21.x
\n– ProtocolLib 5.4.0
\n– packetevents 2.12.1<\/p>\n
## Commands<\/p>\n
| Command | Description | This is an anti cheat plugin that supports PaperMC 1.21.x. It has unique features such as AntiFreeCam together with all regular checks other AntiCheats would have.<\/p>\n","protected":false},"featured_media":127550,"template":"","meta":{"_minecraft_slug":"quantumac","_minecraft_project_id":"ouJ68uCh","_minecraft_author":"alpgbayrak","_minecraft_license":"LicenseRef-All-Rights-Reserved","_minecraft_downloads":14,"_minecraft_follows":1,"_minecraft_client_side":"unsupported","_minecraft_server_side":"required","_minecraft_storage_type":"zip","_minecraft_archive_name":"quantumac.zip","_minecraft_size_bytes":825508,"_minecraft_version_count":7,"_minecraft_updated_at":"2026-05-15T22:50:59.172968Z","_minecraft_date_created":"2026-05-07T22:40:39.584160Z","_minecraft_date_modified":"2026-05-14T19:01:49.439871Z","_minecraft_project_url":"https:\/\/modrinth.com\/mod\/quantumac","_minecraft_icon_attachment_id":127550,"_minecraft_imported_at":"2026-06-07T12:04:10+00:00","_minecraft_import_hash":"d60049202c9a9d84e8648f9a35e4214d","_minecraft_versions":"","_minecraft_links":"","_minecraft_gallery":"","_minecraft_api_metadata":""},"mod_category":[89,126,127,92],"mod_loader":[132],"minecraft_version":[37,40,41,73,74,38,78,79,80,81,82],"class_list":["post-127549","mod","type-mod","status-publish","has-post-thumbnail","hentry","mod_category-game-mechanics","mod_category-management","mod_category-paper","mod_category-utility","mod_loader-paper","minecraft_version-1-21-1","minecraft_version-1-21-10","minecraft_version-1-21-11","minecraft_version-1-21-2","minecraft_version-1-21-3","minecraft_version-1-21-4","minecraft_version-1-21-5","minecraft_version-1-21-6","minecraft_version-1-21-7","minecraft_version-1-21-8","minecraft_version-1-21-9"],"yoast_head":"\n
\n|—|—|
\n| `\/quantumac checks` | Open the check toggle GUI |
\n| `\/quantumac reload` | Reload config |
\n| `\/quantumac alerts` | Toggle staff alerts for yourself |
\n| `\/quantumac violations