Formulated in Layer Zero Whitepaper
- Every message m sent over the network is coupled with a transaction t on the sender-side chain.
- A message m is delivered to the receiver if and only if the associated transaction t is valid and has been committed on the sender-side chain.
- Person A sends token to B - transaction 1
- Only when Person B confirms that transaction 1 is valid, Person B sends another coin/message/balance to Person A