Website fingerprinting over encrypted proxy/VPN tunnels on DataCon-Website reaches only 46.30% Tail-F1 for infrequent destination classes even with the best evaluated method—substantially below the 85.70% Tail-F1 achieved on mobile applications (NUDT-Mobile)—reflecting that rare encrypted website traffic classes remain significantly harder for ML classifiers regardless of model architecture improvements.
From 2026-wang-curv-tail-lightweight-long-tailed — Curv-Tail: Lightweight Long-Tailed Encrypted Traffic Classification with Discrete Packet-Length Encoding and Lorentz Prototypes
· §3.2, Table 1
· 2026
· arXiv preprint
Implications
Novel circumvention protocols deployed in small user populations naturally occupy tail-class positions where classifier accuracy is lowest; maintaining novelty through regular protocol or routing updates provides a measurable structural evasion advantage rather than requiring active obfuscation.
Routing circumvention traffic through VPN/proxy tunnels to a diverse set of destinations exploits the long-tail accuracy gap—the classifier's per-class F1 degrades sharply for infrequent destinations, making high-diversity exit traffic harder to classify even with specialized architectures.