About
Keyhole Block is a custom item made especially for Blackblock.
The Keyhole Block emits a redstone signal when the correct key is used on it.
Explanation
This is the Keyhole's GUI.
The top slot is where you can put your Passport.
When a Keyhole has a Passport, only the owner of that passport will be able to open the GUI again.
On the first row you can put any key that is allowed to trigger this Keyhole.
(To make sure nobody can just craft the same key and pick your lock, you should engrave the key.)
Insert Output Operation Cards on the bottom row to make the keyhole block emit a redstone signal.
The number of cards determines the signal strength: 1 card will output a redstone signal of 1, 15 cards will emit a redstone signal of 15.