Trunks and padlocks without shared key

1. Don't try to open the other person's lock.
2. Shipping does not have to be done in a single trip.
3. The protection can change from one lock to another without disappearing at any time.

Answer: It can be done in three shipments of the trunk. 1. You put the contents in the trunk, close it with your padlock and send it.

1. The other person can't open it, but adds their own lock and gives the trunk back to you.
2. You remove your lock and send it again.
3. The other person receives the trunk closed with its padlock, opens it with his key and accesses the contents. The trunk never travels open. First your lock protects it; then they both protect him; Finally, only the other person's padlock protects him. The idea is not to share a key, but to pass the protection from one lock to the other.