SaTor: Satellite Routing in Tor to Reduce Latency

2024-06-21

arXiv.org

AI Summary

Tor suffers from high latency due to geographical distance, degrading user experience; conventional acceleration techniques often compromise path randomness, undermining anonymity. This paper proposes the first satellite-communication-based acceleration framework for Tor that preserves its existing routing infrastructure while jointly optimizing low latency and strong anonymity. Our key contributions are: (1) seamless integration of satellite links into the Tor architecture without protocol modification; (2) a circuit-aware dynamic offloading strategy that selectively migrates high-latency path segments to low-latency satellite channels on demand; and (3) a dedicated simulation platform incorporating realistic satellite channel measurements. Evaluation under a deployment scenario with the top 1,000 relays shows that over 35% of circuits achieve an average latency reduction of 27.6 ms, with peak improvements reaching 450 ms during worst-case periods.

Technology Category

• Search and Optimization: Distributed Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Constraint Satisfaction and Optimization: Satisfiability

Application Category

• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

High latency is a critical limitation within the Tor network that has a negative impact on privacy conscious web users' experience and web application responsiveness. A key factor exacerbating Tor latency is the creation of lengthy circuits that span across geographically distant regions, causing significant transmission delays. To address this issue, a common strategy involves modifying Tor's circuit building process to reduce the likelihood of selecting lengthy circuits. However, this strategy compromises Tor's routing randomness, increasing the risk of deanonymization. Reducing Tor's latency while minimizing security degradation presents a challenge. This paper proposes SaTor, a latency-reducing scheme for Tor using satellite routing technology. SaTor proposes equipping Tor relays with satellite network access, utilizing satellite transmission to accelerate slow circuits, without biasing the existing path selection process. Our SaTor performance evaluation, using a simulator we developed along with real-world measurements, shows that over the long term, SaTor provides an expected speed-up of 27.6ms for over 35% of circuits in general cases, and 450ms during the slowest times, with the top 1k relays equipped with satellite service. Our research uncovers a viable way to overcome Tor's latency bottleneck, serving as a practical reference for its future enhancement.

Problem

• Tor Network
• High Latency
• Privacy Sacrifice

Innovation

• Satellite Technology
• Tor Network Optimization
• Latency Reduction