FINDING · EVALUATION

Combining six onion search engines/repositories plus clearnet search engines, Tor2web-style DNS leakage, and 20 days of self-run crawling (2.9 million pages), the authors assembled 482,614 unique v3 onion addresses — the largest known collection. Verifying against HSDir blinded public keys showed the collected addresses accounted for 25% of observed blinded keys but were responsible for 66% of all successful service descriptor downloads, confirming a heavy-tailed usage distribution.

From 2025-h-ller-evaluating — Evaluating Onion Address Collection Methods · §4, §5 · 2025 · Free and Open Communications on the Internet

Implications

A small fraction of onion addresses accounts for most descriptor downloads; privacy-sensitive circumvention onion services (Cwtch, Briar) that avoid public indexing will be systematically underrepresented in any collection-based study — measurement results about 'Tor onion usage' are skewed toward popular/ commercial services, not dissident use cases.