FINDING · DETECTION
IP-based website fingerprinting achieves 93–94% top-1 accuracy on dual-stack incomplete websites (those with any IPv4-only third-party dependencies) using both IPv4 and IPv6 fingerprints across 228K sites. For dual-stack complete sites (all resources reachable over IPv6), accuracy drops to 56% over IPv4 and 45% over IPv6. The discriminating signal comes almost entirely from secondary resource IPs: using only the primary domain's IP yields 5–8% accuracy regardless of protocol.
From 2026-ahmad-more-space-less — More Space, Less Privacy? Measuring the Effectiveness of IP-based Website Fingerprinting in IPv6 · §6.1, Table 1 · 2026 · PoPETs 2026
Implications
- Circumvention proxies that terminate at a shared IP (CDN-fronted or Cloudflare-proxied) dramatically reduce fingerprintability of individual destinations—this is a concrete structural argument for CDN-fronted transports over direct proxy IPs.
- Ensure that every third-party resource loaded by users (ads, analytics, fonts) also routes through the proxy; a single IPv4-only dependency leaks the site identity and raises accuracy from ~45% to ~94%.
Tags
Extracted by claude-sonnet-4-6 — review before relying.