Web censorship measurements of HTTP/3 over QUIC

Abstract

Web traffic censorship limits the free access to information, making it a global human rights issue. The introduction of HTTP/3 (HTTP over QUIC) yields promising expectations to counteract such interference, due to its novelty, build-in encryption, and faster connection establishment. To evaluate this hypothesis and analyze the current state of HTTP/3 blocking, we extended the open-source censorship measurement-tool OONI with an HTTP/3 module. Using an input list of possibly-blocked websites, real-world measurements with HTTPS and HTTP/3 were conducted in selected Autonomous Systems in China, Iran, India, and Kazakhstan. The presented evaluation assesses the different blocking methodologies employed for TCP/TLS versus the ones employed for QUIC. The results reveal dedicated UDP blocking in Iran and major IP blocklisting affecting QUIC in China and India.