Node tries to decrypt all the message it receives to see if it was for them. It's there in the whitepaper: >Just like Bitcoin transactions and blocks, all user

Node tries to decrypt all the message it receives to see if it was for them. It's there in the whitepaper: >Just like Bitcoin transactions and blocks, all users would receive all messages. They would be responsible for attempting to decode each message with each of their private keys to see whether the message is bound forthem.