Departmental Papers (CIS)

Document Type

Conference Paper

Date of this Version



Reprinted from:
Micah Sherr, Matt Blaze, and Boon Thau Loo. Scalable Link-Based Relay Selection for Anonymous Routing. In 9th Privacy Enhancing Technologies Symposium (PETS 2009), August 2009, Lecture Notes on Computer Science 5672, pp. 73–93
DOI: 10.1007/978-3-642-03168-7_5

The original publication is available at


The performance of an anonymous path can be described using many network metrics – e.g., bandwidth, latency, jitter, loss, etc. However, existing relay selection algorithms have focused exclusively on producing paths with high bandwidth. In contrast to traditional node-based path techniques in which relay selection is biased by relays’ node-characteristics (i.e., bandwidth), this paper presents the case for link-based path generation in which relay selection is weighted in favor of the highest performing links. Link-based relay selection supports more flexible routing, enabling anonymous paths with low latency, jitter, and loss, in addition to high bandwidth. Link-based approaches are also more secure than node-based techniques, eliminating “hotspots” in the network that attract a disproportionate amount of traffic. For example, misbehaving relays cannot advertise themselves as “low-latency” nodes to attract traffic, since latency has meaning only when measured between two endpoints. We argue that link-based path selection is practical for certain anonymity networks, and describe mechanisms for efficiently storing and disseminating link information.



Date Posted: 14 September 2009