FINDING · DEPLOYMENT

Flash proxies successfully relayed Tor traffic from within China in December 2011, but the test relied on a simple HTTP-based rendezvous blockable by IP address; the authors identify rendezvous — getting just a few bytes (the client's IP address) out of the censored region — as the bottleneck that determines whether the entire proxy system remains operational.

From 2012-fifield-evading — Evading Censorship with Browser-Based Proxies · §4.4, §6 · 2012 · Privacy Enhancing Technologies Symposium

Implications

Invest in multiple parallel rendezvous channels (cloud storage APIs, steganographic HTTP cookie embedding, social platforms) before scaling proxy capacity — a fast proxy pool is useless if the rendezvous step is blocked.
Prefer rendezvous targets whose blocking would cause large collateral damage to legitimate commerce (e.g., major cloud storage providers like S3) to raise the political cost of blocking for the censor.