Anti-Dupe

Overview

Anti-Dupe 3.2 is an enterprise-grade anti-duplication system for Paper Minecraft servers. Rather than relying solely on inventory scanning, Anti-Dupe combines a transaction ledger, event verification, cross-inventory auditing, and trusted transaction authorization to accurately distinguish legitimate gameplay from duplication exploits.

Designed to protect both vanilla and heavily-modded servers, Anti-Dupe preserves normal gameplay while maintaining strict protection against unauthorized item creation.

Core Features

• Immediate event-based verification
• Hybrid inventory scanning
• Transaction Ledger
• Trusted Transaction Framework
• Trusted Plugin Whitelisting
• Shop Plugin Compatibility
• Stack-safe accounting
• UUID tracking for unique items
• Cross-inventory duplicate detection
• Automatic chunk scanning
• Deep inventory auditing
• Safe removal & recovery
• SQLite transaction database
• Daily rotating log files
• Discord webhook alerts
• Multi-language support
• Console verbosity controls
• Administrator whitelist
• Original item preservation

Trusted Transaction Framework

One of the biggest additions in Anti-Dupe 3.2 is the Trusted Transaction Framework.

Instead of assuming every increase in inventory is suspicious, Anti-Dupe now determines why an item was created before enforcement occurs.

Legitimate item generation can now be authorized by trusted systems including:

• Shop plugins
• Economy plugins
• Future plugin integrations
• Other approved transaction sources

This dramatically reduces false positives while maintaining strict duplicate detection.

Trusted Plugin Compatibility

Anti-Dupe no longer trusts every custom inventory.

Transactions are only considered legitimate when BOTH conditions are met:

1. The inventory title matches an approved pattern.
2. The inventory originates from a trusted plugin.

Example:

compatibility:
  external-plugin-inventories:
    enabled: true
    grace-delay-ticks: 4

    trusted-plugins:
      - UltimateShop

    title-patterns:
      - shop
      - store
      - market

Additional plugins may be added:

trusted-plugins:
  - UltimateShop
  - EconomyShopGUI
  - ShopGUIPlus

Matching is case-insensitive.

This greatly reduces the attack surface compared to trusting inventory titles alone.

Shop Plugin Support

Anti-Dupe now works correctly with modern shop plugins.

Examples:

• UltimateShop
• EconomyShopGUI
• ShopGUIPlus
• Other inventory-based shop plugins

Trusted purchases:

• Update the ledger automatically
• Register newly created items
• Skip duplicate warnings
• Skip recovery creation
• Skip Discord alerts
• Continue protecting player inventories

⚠️⚠️⚠️ Trusted Plugin Security Risk ⚠️⚠️⚠️

Adding a plugin to trusted-plugins tells Anti-Dupe to accept qualifying item transactions from that plugin as legitimate.

This means Anti-Dupe may be unable to detect duplication glitches, item-generation bugs, or exploitable transaction errors originating inside that trusted plugin.

If a trusted shop, crate, auction, reward, or economy plugin contains a bug that allows players to receive extra items, Anti-Dupe can treat those items as authorized and update the ledger accordingly.

Only whitelist plugins that you:

• Fully trust
• Keep updated
• Have tested carefully
• Obtained from a reputable source
• Actively monitor for exploit reports

Keep the trusted plugin list as small as possible. Do not whitelist general-purpose plugins or plugins that do not need to create items.

Removing a plugin from trusted-plugins restores normal Anti-Dupe enforcement for its inventory transactions.

Scanner Configuration

scanner:
  enabled: true

  online-inventory-minutes: 5
  ender-chest-minutes: 10
  loaded-containers-minutes: 15
  uuid-crosscheck-minutes: 15
  ledger-audit-minutes: 30

  players-per-batch: 10

  automatic-chunk-scans: true
  chunk-scan-delay-ticks: 20

Scanner tasks are staggered to minimize server impact.

Scan Frequency

Immediate Event Verification

Anti-Dupe verifies every inventory transaction immediately after Minecraft finishes processing it.

Protected events include:

• Inventory Click
• Shift Click
• Number Key Swap
• Drag Distribution
• Stack Split
• Stack Merge
• Double Click Collect
• Offhand Swap
• Hopper Transfer
• Item Pickup
• Item Drop
• Crafting
• Smithing
• Anvil
• Grindstone
• Villager Trading
• Player Login
• Player Logout
• Container Open
• Container Close

Cursor items are included in every transaction snapshot, preventing false positives during normal stack splitting.

Deep Scan Commands

Everything

/antidupe scan all

Players

/antidupe scan players

Ender Chests

/antidupe scan ender

Containers

/antidupe scan containers

Current Chunk

/antidupe scan chunk

The full scan checks:

• Online players
• Ender Chests
• Loaded containers
• Inventory entities
• Chest Minecarts
• Hopper Minecarts
• UUID registry
• Ledger totals
• Stack fingerprints

Automatic Chunk Scanning

Whenever a chunk loads:

• Wait 20 ticks
• Scan every supported inventory

Supported inventories:

• Chest
• Trapped Chest
• Barrel
• Shulker Box
• Hopper
• Furnace
• Blast Furnace
• Smoker
• Brewing Stand
• Crafter
• Dropper
• Dispenser

Supported entities:

• Chest Minecart
• Hopper Minecart
• Inventory-holding entities

Transaction Ledger

Unlike traditional anti-dupe plugins, Anti-Dupe maintains an authoritative transaction ledger.

Every legitimate item creation updates the ledger.

Examples include:

• Mining
• Crafting
• Smelting
• Trading
• Trusted shop purchases

Unauthorized increases continue through duplicate detection.

The ledger never automatically "learns" duplicated quantities.

Stack-safe Accounting

Stackable items retain normal vanilla behavior.

Instead of assigning UUIDs to every stack, Anti-Dupe uses:

• Item fingerprints
• Ledger totals
• Transaction accounting
• Cross-inventory quantity verification

This preserves vanilla stacking while still detecting unauthorized quantity increases.

Unique Item Protection

Items with a maximum stack size of one receive hidden UUIDs.

Tracked data includes:

• UUID
• Player
• Inventory
• Slot
• Timestamp
• Fingerprint

Duplicate UUIDs result in:

1. Original preserved
2. Duplicate backed up
3. Duplicate removed
4. Recovery entry created
5. Administrators notified

Safe Removal & Recovery

Before any duplicate is removed, the complete ItemStack is written to:

plugins/Anti-Dupe/recovery.yml

Stored information:

• Material
• Amount
• Name
• Lore
• Enchantments
• Durability
• Components
• Persistent Data
• Player
• UUID
• World
• Coordinates
• Detection Reason
• Timestamp
• Recovery ID
• Restore Status

If backup fails:

• Item is NOT removed
• Severe error is logged

Recovery Commands

/antidupe recovery list

/antidupe recovery player <player>

/antidupe recovery restore <id>

/antidupe recovery restore <id> <player>

Permission:

antidupe.recovery

Administrator Whitelist

/antidupe whitelist add <player>

/antidupe whitelist remove <player>

/antidupe whitelist check <player>

/antidupe whitelist list

Stored:

plugins/Anti-Dupe/admin-whitelist.yml

Permission:

antidupe.whitelist

Testing Command

/dupe

Duplicates the held item for testing.

Ignores:

• Whitelist
• OP status
• antidupe.bypass

Permission:

antidupe.dupe

Console Verbosity

Anti-Dupe now includes configurable console logging levels.

warnings:
  console: true
  console-verbosity: low

Levels:

Critical recovery failures are always logged.

Discord alerts, recovery records and administrator notifications are unaffected.

Private Detection Notifications

Players never receive duplicate alerts.

Notifications are sent only to:

• Server Console
• Authorized Administrators
• Daily Log Files
• Discord

Permission:

antidupe.notify

Daily Logs

Location:

plugins/Anti-Dupe/logs/

Format:

anti-dupe-YYYY-MM-DD.log

Automatically rotated daily.

Discord Webhook Alerts

Rich embeds containing:

• Player
• UUID
• World
• Coordinates
• Detection Time
• Detection Reason
• Removed Item
• Removed Quantity
• Recovery ID

Configuration:

discord:
  enabled: true
  webhook-url: ""
  username: "Anti-Dupe"
  avatar-url: ""
  locale: en_US
  embed-color: "#FFB000"
  include-coordinates: true
  role-mention: ""

Webhook delivery is asynchronous.

Multi-language Support

Supported languages:

• de_DE
• en_US
• es_ES
• fr_CA
• fr_FR
• it_IT
• ja_JP
• pl_PL
• pt_BR
• ru_RU
• tr_TR
• uk_UA
• zh_CN

Configuration:

language:
  default: en_US
  use-client-locale: true

Language files:

plugins/Anti-Dupe/lang/

Discord alerts may use a separate language.

Permissions

antidupe.admin
antidupe.notify
antidupe.whitelist
antidupe.recovery
antidupe.dupe
antidupe.bypass

Recommended Deployment

Begin with:

mode: AUDIT

Test:

• Crafting
• Smelting
• Trading
• Shops
• Hoppers
• Ender Chests
• Stack Splitting
• Stack Merging
• Modded Containers

Once verified:

mode: QUARANTINE

Quarantine mode:

1. Preserve the original item.
2. Backup the duplicate.
3. Remove the duplicate.
4. Record the incident.
5. Notify administrators.
6. Send Discord alerts.
7. Allow administrator restoration.

Anti-Dupe 3.2 combines transaction accounting, trusted plugin authorization, UUID tracking, ledger verification, hybrid scanning, and automated recovery into a comprehensive anti-duplication platform designed to protect modern Paper servers without disrupting legitimate gameplay.