Abstract: Although past censorship research has largely fo-cused on blocking in highly centralized networks such as China’s, censorship in decentralized networks is on the rise. It was long thought that large-scale censorship on decentralized networks with thousands of ISPs was prohibitively difficult. Our in-depth investigation of the mechanisms underlying decentralized infor-mation control in Russia shows that such large-scale censorship can be achieved in decentralized networks through inexpensive commodity equipment. This new form of information control presents a host of problems for censorship measurement, in-cluding difficulty identifying censored content, requiring measurements from diverse perspectives, and variegated censorshipmechanisms that require significant effort to identify in a robust manner.
By working with activists on the ground in Russia, we ob-tained five leaked blocklists signed by Roskomnadzor, the Russian government’s federal service for mass communications, along with seven years of historical blocklist data. This authoritative listcontains domains, IPs, and subnets that ISPs have been requiredto block since November 1st, 2012. We used the blocklist from April 24 2019, that contains 132,798 domains, 324,695 IPs, and 39 subnets, to collect active measurement data from residential, datacenter and infrastructural vantage points. Our vantage points span 361 unique ASes that control approx. 65% of Russian IP addres sspace.
Our findings suggest that data centers block differently fromthe residential ISPs both in quantity and in method of blocking, resulting in different experiences of the Internet for residential network perspectives and data center perspectives. As expected,residential vantage points experience high levels of censorship. While we observe a range of blocking techniques, such as TCP/IP blocking, DNS manipulation, or keyword based filtering, wefind that residential ISPs are more likely inject blockpages with explicit notices to users when censorship is enforced. Russia’s censorship architecture is a blueprint, and perhaps a forewarning of what and how national censorship policies could be implemented in many other countries that have similarly diverse ISPecosystems to Russia’s. Understanding decentralized control willbe key to continuing to
Recommended citation: ‘Reethika Ramesh, Ram Sundara Raman, Matthew Bernhard, Victor Ongkowijaya, Leonid Evdokimov, Anne Edmundson, Steven Sprecher, Muhammad Ikram, and Roya Ensafi, "Decentralized Control: A Case Study of Russia", In Network and Distributed Systems Security (NDSS), 2020.’