A node system implements a method for node relay communication. A description of a flow entry including an address in a flow and a private key is received. The flow entry and the private key are stored in a database indexed to a flow ID. A packet comprising an authentication code and packet data including packet sequence information and a Flow ID is received. A look up in the database of a flow entry corresponding to the Flow ID of the packet is performed. The packet is either ignored or forwarded to the address in the flow, depending on the result of the look-up.