Mitigating Routing Attacks with Local Trust in DHTs

Distributed Hash Tables (DHTs) have been used as a common building block in many distributed applications, including Peer-to-Peer (P2P), Cloud and Grid Computing. However, there are still important security vulnerabilities that hinder their adoption in today’s large-scale computing platforms. For instance, routing vulnerabilities have been a subject of intensive research but existing solutions are mainly based on redundancy. Regarding redundancy, there exist well-studied techniques that strengthen DHTs against routing attacks. The trouble is that the introduction of redundancy increases communication costs and might significantly reduce scalability. Therefore, it seems reasonable to focus on improving the quality of routing paths in terms of forwarder reliability. In this thesis, we present Sophia, a novel and generic security technique which combines iterative routing with local trust to fortify routing in DHTs. Sophia strictly benefits from first-hand observations about the success/failure of a node’s own lookups to improve forwarding paths. Moreover, unlike redundant routing, Sophia dynamically protects routing without introducing additional network overhead. To the best of our knowledge, this is the first work which exploits a local trust system to fortify routing in DHTs. We compared the performance of Sophia with redundant routing techniques in the Kademlia DHT. Our simulation framework considers both stable and dynamic scenarios as well as several threat models. In our simulations, Sophia obtained significant improvements regarding routing resilience, self-adjustment and network traffic reduction compared with traditional routing redundancy techniques.