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Icon GIF (minor showcase)
Crafting Keys
Crafting a key gives the key and a duplicate (2 keys) Unique key id everytime a key is crafted
Key id displayed
Keys and locked containers show their lock/key id in the inventory
Key duplication
Duplicate a key with a copper ingot in a smithing table
Locking
Lock a container using a smithing table
Locking examples
locking a hopper, furnace and chest
Unable to open locked container
Trying to open a locked container without its key will not let you open it but give you a message (above the hot bar)
Pushing items into a locked container
A locked container will disable any hopper, dropper or dispenser facing it that does not share the same lock/key id however a hopper will allow any input, so it will not disable such blocks from pushing items into it
Pulling items from a locked container
A locked container will disable any hopper trying to pull items from the container unless that hopper shares the same lock/key id
Key Customizations
There are currently 7 total key skins