VALNET: Privacy-preserving multi-path validation

Abstract

Network path validation (or simply, path validation) provides network end-hosts with the ability to enforce the network paths they want their packets to traverse. Path validation also enables each on-path node to validate whether a packet has followed the same path specified by the respective source node. Traditional networking uses single-path routing. Multi-path routing provides on-path nodes (including the source node) with the flexibility to choose a path, among a set of options available to them, in order to forward a packet to the same destination node. Multi-path validation combines these two notions: a source node, instead of choosing a single path, can choose a set of paths to send its packets to a destination node; and each of the other on-path nodes can verify whether a packet has indeed traversed one of the legitimate paths (the paths designated by the source) and can further select any of these legitimate paths downstream to forward packets to the destination node. The source node typically embeds the set of paths in a packet-header to enable path validation at each on-path node. However, this results in several privacy issues and makes the underlying network prone to certain attacks. In this work, we introduce privacy-preserving multi-path validation with two privacy notions: path privacy and index privacy. We design VALNET, a network that achieves privacy-preserving multi-path validation. We analyze the security as well as the performance of VALNET. VALNET finds numerous use cases (e.g., in secure and private military communications between base stations and on-field devices such as sensor nodes and drones), where data communications need to take place over multiple paths (enforced by the end-hosts) for enhanced reliability, and privacy of any of these paths must not be compromised even if some of the on-path nodes are compromised. To the best of our knowledge, VALNET is the first work that addresses privacy concerns in the context of multi-path validation.