What you will need:
3-people (sender, network person, receiver), 1 sheet of paper, & some coins

Procedure:
The sending person counts the value of the coins, writes the value on the paper, & wraps the coins in the paper.  Then the sending person hands the "packet" to the network person.

The network person passes the packet to the receiver.

The receiver opens the packet & checks to see if the value = coins.  If yes, the receiver asks for another packet, if no, the receiver asks for that packet again.

That's it.  (When finished return coins).