Preventing Sybil attacks in chord and Kademlia protocols

Abstract

Structured p2p overlay networks, such as chord, Kademlia, CAN, pastry and tapastry allow participant to generate multiple identities on shared physical node. This practice of Sybil attacks introduces the risks of damaging the routing protocol and blocking access to information by impeding queries. Most existing security monitoring mechanisms are inefficient when applied to structured p2p overlay networks. In this work we propose a monitoring strategy allowing the decrease of Sybil nodes rate. We investigate this problem and find ways to detect suspicious behaviours. The key idea of our solution is to use the attack against the attack. We use Sybil attacks to infiltrate and launch monitor peers under different strategies to maximise the likelihood of detection. We were able to infiltrate and monitor in-depth the overlay using a small number of Sybils introduced in strategic zones, which allows us to estimate the number of malicious nodes. The proposed strategy is evaluated against the use of multiple identities both in chord and Kademlia protocols as most cited and popular p2p overlay networks. We find that adoption of limited number of monitors makes Sybil attacks ineffective.