Sending locked chests
The reward for this one is 20 ED.
The year is 1980, there are two special agents, one in west germany and one in east germany. They need a way to safely transport messages and small things between themselves. These two agents have never seen eachother before in their life, and nobody gave them a key to anything. They cannot send any sorts of keys or other items in the mail, nor can they visit eachother to exchange anything. All that can be sent back and forth is the chest.
They use a medium sized strong chest. It's got rings around it so it can be locked very securely using padlocks. Each of them has a padlock, it's very very strong and it's got a very good key, so there's no chance of anyone else unlocking it or smashing the lock with some tool.
The chest is also *very* strong. No hammer or other tool can open it by force.
How will they send messages and things amongst themselves safely? To make this a bit easyer, let's assume that if the people at the border can't open the box, they ignore it and allow it to be delivered to the address. (it cant be opened by force, so as long as it's locked it can't be open).
You cannot stick messages to the bottom of the chest - it's not so heavy that they couldnt lift it and check the bottom
Hint: speed of the shipment isnt important. Even if it takes a few months for one agent to get something the other agent has sent him, that's ok.
