Efficient Security Mechanisms for Routing Protocolsa

As our economy and critical infrastructure increasingly rely on the Internet, securing routing protocols becomes of critical importance. In this paper, we present four new mechanisms as tools for securing distance vector and path vector routing protocols. For securing distance vector protocols, our hash tree chain mechanism forces a router to increase the distance (metric) when forwarding a routing table entry. To provide authentication of a received routing update in bounded time, we present a new mechanism, similar to hash chains, that we call tree-authenticated oneway chains. For cases in which the maximum metric is large, we present skiplists, which provides more efficient initial computation cost and more efficient element verification; this mechanism is based on a new cryptographic mechanism, called MW-chains, which we also present. For securing path vector protocols, our cumulative authentication mechanism authenticates the list of routers on the path in a routing update, preventing removal or reordering of the router addresses in the list; the mechanism uses only a single authenticator in the routing update rather than one per router address. We also present a simple mechanism to securely switch one-way chains, by authenticating the next one-way chain using the previous one. These mechanisms are all based on efficient symmetric cryptographic techniques and can be used as building blocks for securing routing protocols.