I am trying to find all the solutions and put them together at a single place, So feel free to add comments and if you have a solution please do post . Cheers … 🙂
Here is the puzzles link : http://www.wuriddles.com/
Question : 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?
Alternative, more precise phrasing: Andy and Grant are staying in different rooms in the same hotel. Andy needs to give a gold pendant to Grant, but spies are trying to assassinate Andy and Grant so neither of them can leave their room. The only way they can transfer objects is by using the bellhops. Both Andy and Grant have a safe with a large clasp that can be secured with a padlock. Both Andy and Grant have a padlock and a corresponding key. (So 1 gold pendant, 2 safes, 2 padlocks, and 2 keys.) But the bellhops are thieves. Anything that is not padlocked in the safe will be stolen by the bellhops – including any unlocked padlocks, the keys or the pendant. How can Andy transfer the gold pendant to Grant without it being stolen? (where both sides have encryption capability, and where unsecured items are taken away rather than just copied?)
My Solution : Andy will put the gold pendent in the box and then locks with Andy’s lock and passes the box to Grant. Now Grant will put on his lock and then passes back to Andy. Now Andy removes his lock and passes back to Grant and its done ….. 😛 So simple, right …. 😛