FlashFlow：Tor的安全速度测试
FlashFlow: A Secure Speed Test for Tor
摘要：
Tor网络使用测量系统来估计其中继的转发能力并平衡它们之间的流量。该系统已被证明容易受到对抗性操纵。此外，其在良性环境中的准确性和有效性从未得到充分量化。我们首先通过分析Tor度量数据并在实时网络上进行实验来获得这样的量化。我们的研究结果表明，Tor目前低估了其真实容量约50%，并不正确地平衡了15- 25%的流量。然后，为了解决安全性和准确性的问题，我们提出了FlashFlow，一个系统来测量Tor继电器的容量。我们的分析表明，FlashFlow限制恶意中继获得最多1.33倍的真实容量的容量估计。通过现实的互联网实验，我们发现，FlashFlow测量中继容量至少89%的准确率95%的时间。通过仿真，我们发现FlashFlow可以在不到5小时的时间内使用3个带宽为1 Gbit/s的测量器测量整个Tor网络。最后，使用FlashFlow进行负载均衡的模拟表明，与TorFlow相比，网络权重误差减少了86%，而50 KiB、1 MiB和5 MiB传输时间的中位数分别减少了15%、29%和37%。此外，FlashFlow还能产生更一致的客户端性能：传输超时的中位率降低了100%，而50 KiB、1 MiB和5 MiB传输时间的标准差分别降低了55%、61%和41%。我们还发现，随着总客户端流量负载的增加，性能改进相对于TorFlow增加，这表明FlashFlow更适合支持网络增长。
英文摘要：
The Tor network uses a measurement system to estimate its relays' forwarding capacity and to balance traffic among them. This system has been shown to be vulnerable to adversarial manipulation. Moreover, its accuracy and effectiveness in benign circumstances has never been fully quantified. We first obtain such a quantification by analyzing Tor metrics data and performing experiments on the live network. Our results show that Tor currently underestimates its true capacity by about 50% and improperly balances its traffic by 15-25%. Then, to solve the problems with security and accuracy, we present FlashFlow, a system to measure the capacity of Tor relays. Our analysis shows that FlashFlow limits a malicious relay to obtaining a capacity estimate at most 1.33 times its true capacity. Through realistic Internet experiments, we find that FlashFlow measures relay capacity with at least 89% accuracy 95% of the time. Through simulation, we find that FlashFlow can measure the entire Tor network in less than 5 hours using 3 measurers with 1 Gbit/s of bandwidth each. Finally, simulations using FlashFlow for load balancing shows that, compared to TorFlow, network weight error decreases by 86%, while the median of 50 KiB, 1 MiB, and 5 MiB transfer times decreases by 15%, 29%, and 37%, respectively. Moreover, FlashFlow yields more consistent client performance: the median rate of transfer timeouts decreases by 100%, while the standard deviation of 50 KiB, 1 MiB, and 5 MiB transfer times decreases by 55%, 61%, and 41%, respectively. We also find that the performance improvements increase relative to TorFlow as the total client-traffic load increases, demonstrating that FlashFlow is better suited to supporting network growth.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
