This is my Newest creation and my first it is a redstone doorway. Except for fact that you can break the doorway there is no way to enter. Unless you activate the "keyhole" with a hoe. The person who wants to enter must "ask permission" by turning on the lever. Then, inside the doorway a torch will be on indicating a person wants to get in. But that's not all! You can also

-Open the door from inside.
-Enter from outside

Another feature is that there is a piston blocking the holes in the iron door for extra privacy!