Every censor has a fingerprint: how China, Saudi Arabia, Turkey, Russia & Iran block differently

Censorship is usually reported as yes/no, but HOW a country blocks is as telling as what — and the method leaves a fingerprint. Aggregating every blocking measurement by technique, the major censors look strikingly different, and the differences match the research literature. China stands out for TCP-reset injection (15% of its blocking measurements on a base of 8,213 — 3-7x any other country), the Great Firewall's textbook behavior: on-path middleboxes forge a TCP RST to tear down the connection rather than dropping packets. Saudi Arabia is the mirror image — 41% DNS manipulation, by far the highest, a centralized DNS-filtering regime rather than packet surgery. Turkey has the most diverse toolkit measured — DNS 24%, header manipulation 12%, TCP-reset 11%, DPI 11% all materially present — matching its documented escalation from DNS tampering (famously circumvented by writing 8.8.8.8 on walls) to SNI/DPI as users routed around each method. Russia (34%) and Iran (22%) lean on connection interference with little RST or DNS poisoning in the classified signal — consistent with Russia's TSPU equipment degrading rather than cleanly resetting connections. Honest caveats: 39-52% of blocks (CN/RU/IR) carry no pinned method (method-unresolved, not no-block), so percentages describe the classified slice; sampling volume varies (South Korea excluded at ~45 measurements); technique mix shifts over time as censors and circumventers co-evolve. Read it as a qualitative fingerprint, not a precise budget. Live: /v1/measurement/techniques?country=XX.