Abstract: A network interface for secure multiprotocol data communication includes a doorbell circuit, a processor, memory, and a bridge circuit. The doorbell circuit responds to physical I/O addresses of the host that are mapped by a memory management unit by a registration process. An application program seeking to use a multiprotocol channel must register the virtual address of host memory where data for communication is or will be stored and register the virtual address of a page of I/O addresses. Access to the doorbell functions and to the host memory via the memory management unit are therefore denied when the requesting process identifier does not successfully compare with the process identifier for the process that performed the registrations. A password may be stored in the network interface in association with a multiprotocol channel identifier and stored in association with the virtual to physical map used for communication.