Distributed Detection of Tor Directory Authorities Censorship in Mexico

The Tor network relies on individuals to set up relays for it to operate. Campaigns have in the past been successfully made to invite more people to join, and the network currently consists of close to 6,500 relays, spread globally. Although the Latin American region has many characteristics that make it natural to expect a wide participation in Tor, it has lagged behind most of the world in its Tor activity — Both considering client usage and participation as relays. This study focuses on the difficulties the Mexican user community has faced in setting up Tor relays, and presents how –and why– we deployed a relatively very simple and unsophisticated network censorship reporting system, as well as the results we have received so far. While this is still considered a work in progress, it has yielded important results as an aide allowing to specify the needed characteristics for potential relays, with a clear, measurable result

Proof-of-Work as Anonymous Micropayment: Rewarding a Tor Relay

In this paper we propose a new micropayments scheme which can be used to reward Tor relay operators. Tor clients do not pay Tor relays with electronic cash directly but submit proof of work shares which the relays can resubmit to a crypto-currency mining pool. Relays credit users who submit shares with tickets that can later be used to purchase improved service. Both shares and tickets when sent over Tor circuits are anonymous. The analysis of the crypto-currencies market prices shows that the proposed scheme can compensate significant part of Tor relay operator\u27s expenses

Spartan Daily, May 12, 1958

Volume 45, Issue 125https://scholarworks.sjsu.edu/spartandaily/12615/thumbnail.jp

Scalable and Anonymous Group Communication

Today\u27s Internet is not designed to protect the privacy of its users against network surveillance, and source and destination of any communication is easily exposed to third party observer. Tor, a volunteer-operated anonymity network, offers low-latency practical performance for unicast anonymous communication without central point of trust. However, Tor is known to be slow and it can not support group communication with scalable performance. Despite the extensive public interest in anonymous group communication, there is no system that provides anonymous group communication without central point of trust. This dissertation presents MTor, a low-latency anonymous group communication system. We construct MTor as an extension to Tor, allowing the construction of multi-source multicast trees on top of the existing Tor infrastructure. MTor does not depend on an external service (e.g., an IRC server or Google Hangouts) to broker the group communication, and avoids central points of failure and trust. MTor\u27s substantial bandwidth savings and graceful scalability enable new classes of anonymous applications that are currently too bandwidth-intensive to be viable through traditional unicast Tor communication---e.g., group file transfer, collaborative editing, streaming video, and real-time audio conferencing. We detail the design of MTor and then analyze its performance and anonymity. By simulating MTor in Shadow and TorPS using realistic models of the live Tor network\u27s topology and recent consensus records from the live Tor network, we show that MTor achieves 29% savings in network bandwidth and 73% reduction in transmission time as compared to the baseline approach for anonymous group communication among 20 group members. We also demonstrate that MTor scales gracefully with the number of group participants, and allows dynamic group composition over time. Importantly, as more Tor users switch to group communication, we show that the overall performance and bandwidth utilization for group communication improves. Finally, we discuss the anonymity implications of MTor and measure its resistance to traffic correlation attacks