FINDING · DEFENSE
UPGen's generator samples 18 independent parameters to produce 4.2×10^22 distinct structured encrypted protocols (entropy 38.4 bits). Each proxy is assigned a unique generated protocol, so identifying one protocol exposes only a single proxy. The generator was designed by studying 27 real-world encrypted protocols and sampling from observed structural patterns (greeting strings, handshake patterns, field orderings, key encodings).
From 2025-wails-censorship — Censorship Evasion with Unidentified Protocol Generation · §2.4, Table 1 · 2025 · USENIX Security Symposium
Implications
- Deploy a per-proxy unique protocol rather than a single shared transport; a censor must develop a new classifier for each proxy rather than blocking the entire network with one rule.
- Protocol parameters should be sampled from features observed in real-world encrypted protocols so that generated protocols blend into the tail of benign encrypted traffic without mimicking any single known protocol exactly.
Tags
Extracted by claude-sonnet-4-6 — review before relying.