Analyzing inconsistencies in the Tor consensus


Every distributed system needs some way to list its current participants. The Tor networks consensus is one way of tackling this challenge. But creating a shared list of participants and their properties without a central authority is a challenging task, especially if the system is constantly targeted by nation state attackers. This work carefully examines the Tor consensuses created in the last two years, identifies weaknesses that did already impact users, and proposes improvements to strengthen the Tor consensus in the future. Our results show undocumented voting behavior by directory authorities and suspicious groups of relays that try to conceal the fact that they are all operated by the same entity.

Proc. iiWAS2021: The 23rd International Conference on Information Integration and Web Intelligence