Ensuring Content Integrity for Untrusted Peer-to-Peer Content Distribution Networks

Many existing peer-to-peer Content Distribution Networks (CDNs) such as Na Kika, CoralCDN, and CoDeeN are deployed on PlanetLab, a relatively trusted environment. But scaling them beyond this trusted boundary requires protecting against content corruption by untrusted replicas. This paper presents Repeat and Compare, a system for ensuring content integrity in untrusted peer-to-peer CDNs even when replicas dynamically generate content. Repeat and Compare detects misbehaving replicas through attestation records and sampled repeated execution.