The routing protocols used to disseminate routing information throughout the Internet are not protected from intruders or faulty router participants. This paper reports on work in progress to protect the OSPF routing protocol through the use of cryptography, specifically, digital signatures. The routing information is signed with an asymmetric cryptographic algorithm, allowing each router recipient to check the source and integrity of the information. This paper discusses the fundamental issues in security of routing protocols, reviews the basics of OSPF operation, describes the proposed design and discusses remaining vulnerabilities.

A symmetric connection management service between two service access points is specified, using a state transition system and safety and progress requirements. At each access point. the user can request connection establishment, request connection termination, and signal whether or not they are willing to accept connection requests from the remote user. The protocol can indicate connection establishment, connection termination, and rejection of a connection establishment request. The authors then specify a protocol and verify that it offers the service, given communication channels between the access points that can lose, reorder, and duplicate messages, but which guarantee delivery of a message that is repeatedly sent. The protocol achieves the service using 2-way and 3-way handshakes, and can be directly combined with any existing single-connection data transfer protocols to provide a transport layer protocol that offers both connection management and data transfer services. The protocol and service are compared to TCP and its intended service, and to ISO TP Class 4 and its intended service.>

In a computer network, the transport layer uses the service offered by the network layer and in turn offers its users the transport service of reliable connection management and data transfer. We provide a formal specification of the transport service in terms of an event-driven system and safety and progress properties. We construct three verified transport protocols that offer the transport service. The first transport protocol assumes a perfect network service, the second assumes loss-only network service, and the third assumes loss, reordering and duplication network service.