A Composite-Metric Based Path Selection Technique for the Tor Anonymity Network

TL;DR

This paper introduces a new composite-metric based path selection algorithm for the Tor network that improves performance and security by combining bandwidth, uptime, and delay metrics, requiring only client-side software updates.

Contribution

The paper presents a novel path selection algorithm for Tor that enhances performance and security using multiple metrics without modifying network nodes.

Findings

Performance doubled with the new algorithm compared to current Tor.

Only client-side software upgrade needed, no network node modifications.

Improved security and user experience in the Tor network.

Abstract

The Tor anonymous network has become quite popular with regular users on the Internet. In the Tor network, an anonymous path is created by selecting three relays through which the connection is redirected. Nevertheless, as the number of Tor users has increased substantially in recent years, the algorithm with which the relays are selected affects the performance provided by the Tor network. More importantly as the performance suffers, users will leave the network, resulting in a lower anonymity set and in turn lower security provided by Tor network. In this paper, we proposed an algorithm for improving performance and security of the Tor network, by employing a combination of different metrics in the process of the path selection between the source and destination node. These metrics are bandwidth and uptime of relays as node conditions and delays between the relays as a path condition. Through a number of experiments we show that we could double the performance observed by end users when using the proposed technique as opposed to the current Tor path selection algorithm. More importantly, the proposed technique only requires a software upgrade on the client side, and other Tor nodes do not need to be modified.