Hop Chains: Secure Routing and the Establishment of Distinct Identities

Abstract

We present a secure routing protocol that is immune to Sybil attacks, and that can tolerate initial collusion of Byzantine routers, or runtime collusion of non-adjacent Byzantine routers in the absence of collusion between adjacent routers. For these settings, the calculated distance from a destination to a node is not smaller than the actual shortest distance from the destination to the node. The protocol can also tolerate initial collusion of Byzantine routers and runtime collusion of adjacent Byzantine routers but in the absence of runtime collusion between non-adjacent routers. For this setting, there is a bound on how short the calculated distance is compared to the actual shortest distance. The protocol makes very weak timing assumptions and requires synchronization only between neighbors or second neighbors. We propose to use this protocol for secure localization of routers using hop-count distances, which can be then used as a proof of identity of nodes.