FINDING · EVALUATION

Across four analyzed exclusion rounds, a minority of rejected relays consistently accounted for over 50% of the security contribution (measured by individual path-compromise protection against AS, IXP, and relay adversaries) provided by all excluded relays combined, enabling selective prioritization of relay update outreach.

From 2026-dejaeghere-sociotechnical-aspects-tor — Sociotechnical Aspects of Tor Relay Rejection · §6, Abstract · 2026 · arXiv preprint

Implications

When relay exclusions are unavoidable, focus operator outreach on the highest-security-contributing relay subset first — contacting this minority captures the majority of the security benefit at lower communication cost.
Circumvention networks should implement per-relay security-contribution metrics to rank which relays to prioritize retaining during infrastructure transitions or forced version upgrades.