Redstone key

A key, either very rare or exclusive to creative, that is redstone based and allows the opening of iron doors and trap doors when held in hand. I'd like to see two variants, a damaged key that's only good for one use, and one with a tool meter. Two single use keys could be combined with 1-7 gold nuggets on a crafting table to make a key with a meter, 7 for a full meter. Maybe 8-10 uses on a full key before it breaks all the way.