In current network routing domains, routing information exchange usually lacks protection based on confidentiality. This makes network routing vulnerable to a variety of security attacks. In this paper, we present a framework to provide confidentiality for a link state routing protocol. This framework involves creation of a trust structure among routers as well as key management. Routing information is encrypted so that it can be accessed only by authorized routers. We present an implementation framework for our approach by extending Open Shortest Path First (OSPF), a commonly deployed link-state routing protocol. Based on our performance assessment, we have found that the additional cost in implementing our scheme has fairly moderate impact on the overall performance.