Apparently this is not a doctored photo.  The Defendius door chain can be purchased from the artist, Art Lebedev.  As I gave it some thought, it seems more than a clever gimmick.  It's really quite thought-provoking.  

http://www.artlebedev.com/everything/defendius/defendius1.jpg

See:
http://www.artlebedev.com/everything/defendius/

On one level, it seems the work makes a statement about the psychology of the owner.  Would one put it on the inside or outside of the door?  Would one access it from inside or out?  An important aspect of a chain lock is that the chain must be a very specific length.  Too long?  Insecure.  Too short?  Too secure!  For this chain lock, different uses have different implications.  

Let's take the conventional usage, where chain and authorized user are both inside.  Authorized, in this case, means "got in previously by some means and smart/patient enough to complete the maze."  It implies the chain length is long enough to complete the maze, but not so long that it can be completed with an arm through the door!   Everyone will agree this is a hassle, unless the purpose is to prevent visitors of subpar intelligence or determination from letting in others!
 
But what about the more interesting case of lock inside and authorized user outside?  What does "authorized" mean here?  What does it imply about the chain length?  What’s most interesting is that any lock is just a way of visually concealing a combination of pin lengths that yields access!  Isn't a key, then, just a way of encoding that combination into a convenient, reusable, physical form?  If so, the key, in this use case, might be our brain's knowledge of the maze and our arms ability to put that key to physical form without looking, and with our arm through the door!

To me, art that gets more interesting as you approach it from new angles is great art!

-- LukeSamaha