Saftey Prints

How about a lock key combo that uses the thing that can't be duplicated or stolen, you fingerprint? I know what your thinking, chessy sci-fi here we come. But this is the new part, you fingerprint is read when you place your finger thumb on the 'key' (part you carry) and is transmitted out the front via a sort of information beam. This information is then aimed twords a general area around the entrance and is read. Only pre approved fingerprints are accepted (family, landlord etc.).

Visitors, house sitters etc. can get a kind of guest key that has the capapbility to beam a strangers fingerprint. The best part about this is that your home system records the fingerprint used with the visitor key, so voila' your problem of just anyone using it is solved with the fact that a criminal can't say they weren't there, there fingerprints prove it. It would make unlocking your door with stuff loading you down easier.