Sorry, but I don't think that this solution is correct. This is a classic "Alice and Bob" security/encryption problem. G should place the amulet in his own safe

Sorry, but I don't think that this solution is correct. This is a classic "Alice and Bob" security/encryption problem. G should place the amulet in his own safe, lock it with the padlock and send it to K. K then adds her own padlock onto the safe and locks it (now there are 2 padlocks locking the safe). K sends the safe back to G and G unlocks his padlock. He sends the safe back to K whereupon she may unlock the only remaining padlock with her own key. See http://en.wikipedia.org/wiki/Public-key_cryptography#A_postal_analogy http://en.wikipedia.org/wiki/Public-key_cryptography#A_posta... for more.