Abstract:
As censorship infrastructure evolves, it increasingly threatens the internet’s role as a provider of freely accessible information. In countries like China or Russia, access to websites is already restricted for millions through devices that monitor user connections and analyze protocol information to block undesirable content. Recently, censorship in Russia further advanced to target QUIC, one of the core protocols of HTTP/3. QUIC internally relies on the TLS protocol, which the censorship architecture uses to identify undesirable websites.
In this study, we analyze the advancement of QUIC censorship in Russia, China, and Iran. We evaluate circumvention strategies against the censorship architecture in Russia and assess which of these strategies are compatible with common web servers. As a result, we validated the existing censorship in Russia and identified novel QUIC censorship in China. Further, we identified strategies on the QUIC and TLS level that effectively circumvent censorship while remaining compatible with common server implementations.