Container Protect

Container Protect is a lightweight container protection plugin for Spigot/Paper servers that lets players secure their chests, barrels, and shulker boxes with a personal passcode — keeping griefers and thieves out for good.
Players set a master passcode the first time they lock a container. From then on, a single command is all it takes to lock any container they place. To access their locked containers, players authenticate once per session using

/open <password>

— no need to re-enter the passcode every time they open a chest. When they log out, the session resets automatically.
Owners can also build a personal trust list using

/trust <player-name>

granting specific players permanent access to all their containers without a passcode. Removing someone is just as easy with

/untrust <player-name>

.
Protection goes beyond just clicks — Container Protect blocks hoppers, droppers, and hopper minecarts from automatically extracting or inserting items into locked containers, closing every common automation exploit. Locked blocks also cannot be physically broken until the owner explicitly unlocks them first, preventing destruction-based bypasses entirely.
All lock data, passcodes (stored as SHA-256 hashes), and trust lists are persisted in a local SQLite database, so protection survives server restarts with zero configuration required.
Commands:

/lock · /open · /unlock · /trust · /untrust · /cp help

Supports: Chests · Trapped Chests · Barrels · All Shulker Box variants · Double Chests

A plugin by Luminex.