[charlesdenault]

Assuming cryptography exists in Kleptopia, couldn't he use a padlock with a combination and transmit this electronically?

[agf]

Two points -- one, that's outside of the problem statement, so no, you can't use cryptography. Two, public-key cryptography uses an exact analogy of the physical-world method, so if you have access to a cryptographic solution you've already solved the problem.