Reputation management for collaborative content distribution

We propose a reputation-based trust management system, ROCQ, to reduce unauthentic and corrupted file transfers in end-user collaborative content-distribution systems. Such systems are characterized by the splitting of large files into (optionally encoded) blocks and the simultaneous downloading of several blocks from different nodes to speed up content distribution. All nodes must cooperate and provide correct content for such systems to function smoothly. If malicious nodes are present, they can quickly bring the system to a halt by introducing fake blocks in the network making it impossible to reconstruct the original file. ROCQ (reputation, opinion, credibility and quality) uses feedback from past interactions among nodes to create node reputations. This allows detection of malicious nodes in a transaction-based network. We study the performance of ROCQ as used in a content distribution network. We find that ROCQ decreases the likelihood of a user receiving fake blocks by up to 16%, and, hence, significantly reduces bandwidth waste.