After looking for hour online for my adventure map with no success I decided to take some ideas and expand upon them. This door uses hopper, checks for a feather named "Door Key" and opens the door. Destroying the key and resetting with no effort of any kind required. 






Perfect for dungeons, or homes if you like, a little bit of red-stone know how and you can even change what item is required to open the door (as long as it can be put into a stack)


As far as I know this is the first self resetting locking door with a key.


More builds like this at balatr0.wix.com/crudilexmc