You want to send a valuable object to a friend securely. You have a box which can be fitted with multiple locks, and you have several locks and their corresponding keys. However, your friend does not have any keys to your locks, and if you send a key in an unlocked box, the key could be copied en route. How can you send the object securely?
My solution, (4am in the morning), take the box and send your locks unlocked over inside the box with a question, that he should only know the answer to.
Have your friend put his own locks unlocked in this box, answer the question and then lock the box with your locks.
Put all your keys in the box, with his locks securing the outside. Then have him send back the box with nothing on or in it.
Put your item in the box and lock it with all your locks.
I think that covers it.