Security and Performance Implications of BGP Rerouting-resistant Guard Selection Algorithms for Tor

Tor is the most popular anonymization system with millions of daily users and, thus, an attractive target for attacks, e.g., by malicious autonomous systems (ASs) performing active routing attacks to become man in the middle and deanonymize users. It was shown that the number of such malicious ASs is significantly larger than previously expected due to the lack of security guarantees in the Border Gateway Protocol (BGP). In response, recent works suggest alternative Tor path selection methods prefering Tor nodes with higher resilience to active BGP attacks.