Multi Path Considerations for Anonymized Routing: Challenges and Opportunities

Recently, there has been a surging interest on anonymizer technologies as a result of increasing privacy concerns and censorship barriers on the Internet. Tor network has emerged as the most popular option in avail. However, popularity of Tor network is under threat of growing user frustration over low throughput and long latencies. Coincidentally, multi-path routing proposals have become popular in tackling similar performance issues in various contexts from the data center networks to the inter-domain routing. In this work, we apply multi-path techniques to overcome limitations in Tor´s path construction and rigid congestion avoidance mechanisms which are major factors behind the unsatisfactory user experience. Multi-path mechanisms nicely complement underlying onion-routing mechanisms of Tor via exploiting diversity in the Tor network. Our preliminary evaluation on live Tor network revealed significant potential of performance improvements especially increasing throughput i.e., up to 4 times speed up in data transmission durations. Also, multi-path mechanisms may increase reliability of the overall system against congestion or service-interruption based attacks in return of an acceptable anonymity tradeoff.