Accountable File Indexing against DDoS Attacks in Peer-to-Peer Networks

Peer-to-peer (P2P) networks are vulnerable from malicious attacks by anonymous users. By populating unprotected peers with poisoned file indices, the attacker can launch a poisoning DDoS (distributed denial-of-service) attacks on any host in the network. We solve this security problem with identity-based signatures contained in file indexes to establish peer accountability. We prove that index accountability can effectively block index-poisoning DDoS attacks in any open P2P environment. A new Accountable Indexing Protocol (AIP) is proposed to enforce peer accountability. This protocol is applicable to all P2P file-sharing networks, either structured or unstructured. The system allows gradual transition of peers to become AIP-enabled. We develop an analytical model to characterize the poison propagation patterns. The poisoning model is validated by simulated AIP experiments on large-scale P2P networks over one million of peer nodes.