Performance Measurements and Statistics of Tor Hidden Services

Tor (The Onion Routing) provides a secure mechanism for offering TCP-based services while concealing the hidden server’s IP address. In general the acceptance of services strongly relies on its QoS properties. For potential Tor users, provided the anonymity is secured, probably the most important QoS parameter is the time until they finally get response by such a hidden service. Internally, overall response times are constituted by several steps invisible for the user. We provide comprehensive measurements of all relevant latencies and a detailed statistical analysis with special focus on the overall response times. Thereby, we gain valuable insights that enable us to give certain statistical assertions and to suggest improvements in the hidden service protocol and its implementation. 1

Performance measurements of Tor hidden services in low-bandwidth access networks

Abstract. Being able to access and provide Internet services anonymously is an important mechanism to ensure freedom of speech in vast parts of the world. Offering location-hidden services on the Internet requires complex redirection protocols to obscure the locations and identities of communication partners. The anonymity system Tor supports such a protocol for providing and accessing TCP-based services anonymously. The complexity of the hidden service protocol results in significantly higher response times which is, however, a crucial barrier to user acceptance. This communication overhead becomes even more evident when using limited access networks like cellular phone networks. We provide comprehensive measurements and statistical analysis of the bootstrapping of client processes and different sub-steps of the Tor hidden service protocol under the influence of limited access networks. Thereby, we are able to identify bottlenecks for low-bandwidth access networks and to suggest improvements regarding these networks.