A messaging system for exchanging messages between nodes in a network via a broker that uses a publish-subscribe message protocol, which nodes have object identifications (IDs). Messages between the nodes are routed using the object IDs of the nodes. Secure communication is provided using authentication according to digital certificates being used as first and second tiers by a commissioning broker and a data broker, respectively, in which the second tier certificate used by the data broker has a shorter lived expiration time.