Logic: Locking boxes

I will pay 20 tokens to the person who posts the first correct reply to this

You want to send a valuable object to a friend. You have a box which is more than large enough to contain the object. You have several locks with keys. The box has a locking ring which is more than large enough to have a lock attached. But your friend does not have the key to any lock that you have. How do you do it? Note that you cannot send a key in an unlocked box, since it might be copied


The answer uses a similiar technique to many of today public/private encryption techniques.

Hi,

I think I have found a solution.

You should send your friend the box unlocked, and inside the box there should be one of your locks. Your friends introduces one of his locks inside the box, and uses the lock he has received (your lock) to lock the box. Then he sends the locked box to you. When you receive the box, as you have the correct key, you can unlock the box. Then you should introduce the valuable object inside the box, and then lock it with your friends lock. When your friend receives the box he will be able to unlock it as you have used his lock

I hope it is clear enough :?:

JC

Correct

That pretty much explains how PGP works as well

The official answer is
Attach a lock to the ring. Send it to her. She attaches her own lock and sends it back. You remove your lock and send it back to her. She removes her lock.


Siliconhell