YoriAC — AI-Powered Anti-Cheat

Protect your server with server-side physics prediction.
Built from scratch by SparkyNox. Special Thanks to GrimAC for inspiration.

What is YoriAC?

YoriAC is a Paper anti-cheat plugin that goes beyond simple event-based checks.
Instead of just measuring raw distances or speeds after the fact, YoriAC runs a server-side physics simulation engine — it predicts exactly where a player should be, how fast they should move, and what their Y velocity should be at every tick.

If the client's position deviates beyond the predicted tolerance → cheat detected.

This makes YoriAC significantly harder to bypass than traditional anti-cheats that rely on flat thresholds.

✦ How It Works

Most anti-cheats check: "Is this player moving too fast?"
YoriAC checks: "Is this player moving faster than our physics simulation says is physically possible — accounting for their speed potions, surface type, sprint state, ping, and momentum?"

Every check feeds into a 3-Strike system:

Strike	Action
⚠ Strike 1	In-game warning message
⚠⚠ Strike 2	Final warning — loud staff alert
☠ Strike 3	Temporary IP ban (default: 15 min)

AI Combo Detection: If a player triggers 3+ different checks simultaneously, YoriAC auto-escalates directly to Strike 3 — no waiting.

✦ Check Modules (11 Total)

⚔ KillAura

Hit rate analysis (hits per second)
Swing timing — inhuman intervals between attacks
Multi-target detection — hitting many entities in a short window
Snap rotation — both axes snapping simultaneously only during active combat
VL decay — violations reset after 5 seconds of clean play

🖱 AutoClicker

CPS exceeding human capability
Click consistency analysis — perfectly uniform intervals = bot

💨 Speed

Prediction-based — server calculates exact max speed per tick
Accounts for: sprint, sneak, Speed/Slowness potions, ice, soul sand, slime, honey, blue ice
Momentum bonus for legitimate sprinting
Grace ticks after taking damage/knockback

🦅 Flight

Prediction-based — compares actual Y velocity against gravity simulation
Detects: sustained airborne ticks, ascending when gravity says falling
Exempt: elytra, levitation, slow falling, creative, vehicles

🪂 NoFall

Server-side fall distance accumulation (not relying on client)
Mid-air fall distance reset detection (classic bypass caught)
Delayed damage check — verifies fall damage was actually taken on landing

📏 Reach

Bounding box distance — uses closest point on entity hitbox, not center
Accounts for player velocity at time of hit (momentum compensation)
Separate attack and interact reach limits

⏱ Timer

Lag-aware — high ping players get proportional leniency
10-second rolling window (smooths out lag bursts)
Requires 3 consecutive bad windows before flagging
Ping tiers: >300ms, >150ms, >80ms each get extra buffer

📦 BadPackets

Sprint + Sneak simultaneously (impossible in vanilla)
Flight packet without permission
Sneak speed bypass detection

🏗 Scaffold

Blocks placed per second
Rotation mismatch — placing below while looking up
Sprint-bridge detection — full sprint speed while placing blocks below

🌊 Jesus

Walking on water surface detection
Speed analysis — legitimate swimming is much slower than walking speed
Sustained check (8+ ticks) to avoid false flags from transitions

🎒 Inventory

ChestStealer / InventoryManager detection
Click interval analysis — inhuman speeds flagged

✦ Staff Features

Real-time alerts — every violation broadcasts to players with yoriac.alerts
Strike alerts — sound notifications on each strike (louder on Strike 3)
Verbose mode — per-player detailed violation logging (/y verbose)
Auto-expiring IP bans — no manual cleanup needed

✦ Commands

Command	Description
`/y info`	Plugin info + active checks
`/y reload`	Reload config live
`/y verbose`	Toggle verbose logging (your player)
`/y strikes <player>`	View a player's current strikes
`/y resetstrikes <player>`	Clear a player's strikes
`/yban <player> [reason]`	Manually IP ban a player

✦ Permissions

Permission	Default	Description
`yoriac.admin`	OP	All commands
`yoriac.alerts`	OP	Receive violation alerts
`yoriac.bypass`	false	Bypass all checks

✦ Compatibility

Version	Status
Paper 1.21	✅ Supported
Paper 1.21.1	✅ Supported
Paper 1.21.4	✅ Supported
Paper 1.21.11	✅ Supported
Java	21+ required

Spigot is not supported — Paper only.

✦ Configuration

Everything is tunable in config.yml — every check can be individually disabled, thresholds adjusted, violation counts changed, and ban duration set. No restart needed — /y reload applies changes live.

settings:
  ban-duration-minutes: 15
  verbose-mode: false
  alert-sound: true

checks:
  killaura:
    enabled: true
    max-hits-per-second: 8
    violations-to-flag: 6
  timer:
    enabled: true
    expected-pps: 20
    max-deviation-percent: 25

✦ Why YoriAC?

Feature	Basic AC	YoriAC
Speed check	Flat multiplier	Physics simulation
Flight check	Airborne ticks	Gravity prediction
Reach check	Center distance	Bounding box
Timer check	1s burst window	10s rolling + ping-aware
NoFall	Damage event only	Server-side simulation
False positives	High	Low (VL decay, grace ticks)
Lag handling	Poor	Ping-tiered leniency

Made with ❤️ by SparkyNox — Part of the Yori ecosystem.
Special Thanks to GrimAC for inspiration on predictive detection approaches.

YoriAC/Anti-Cheat