DNSSEC fails to withstand legal attacks because governments can legally compel DNS authority operators to manipulate entries and certify the changes; the trust chains DNSSEC establishes mirror DNS zone delegations and therefore inherit the same jurisdictional vulnerabilities. A Danish police incident demonstrated the collateral damage: 8,000 legitimate domains were accidentally removed when censorship procedures were executed against a single target. Chinese DNS injection has been shown to have worldwide effects on name resolution through out-of-bailiwick NS record chains.

GNS uses a proof-of-work-gated network flood for key revocation, requiring an adversary to block flood traffic on every path between the revocation origin and all peers to suppress it. This is substantially more robust than X.509 certificate revocation lists, which an adversary can render ineffective by simply blocking access to CRL servers — a weakness severe enough that browser vendors must bundle revocation lists inside software updates.

§A.5 defense

GNS encrypts all DHT queries and responses using a zone-private-key-derived symmetric key (h = x·l mod n; query = H(hG)) such that a passive DHT observer can only mount a confirmation attack — requiring simultaneous knowledge of both the zone's public key and the specific label. Without both values, an adversary observing DHT traffic cannot determine the label, zone, or record data; even fully participating malicious DHT nodes see only opaque signed blobs unlinkable to their originating query.

§4 defense

GNS bounds the trusted computing base (TCB) for any individual name resolution to fewer than approximately 125 entities (constrained by name label length) and makes the full trust chain transparent to the user. By contrast, even simple DNS lookups can silently depend on correct answers from over 100 DNS zones; China's DNS injection caused global collateral damage precisely because out-of-bailiwick NS record chains made the full trust graph invisible to resolvers and users alike.

§5 evaluation

Blockchain-based naming systems such as Namecoin are insufficient under a strong adversary model where a nation-state can muster more computational resources than all other participants combined, allowing it to produce alternative valid chain histories. This vulnerability is most acute during system bootstrapping and in censored regions where the user base is small, precisely the conditions under which a censorship-resistant naming layer is most needed.

§6 evaluation

The June 2025 Iran shutdown—carried out during the Iran-Israel war beginning ~June 19—did not use BGP route withdrawals as in 2019. Instead, authorities applied service-level restrictions at the national border: DNS poisoning of foreign destinations, protocol whitelisting permitting only pre-approved domestic services, and DPI to block circumvention-tool traffic. Iran's international traffic fell roughly 90% while the country's BGP routes remained advertised, making the shutdown invisible to BGP-based monitoring systems. OONI measurement volume, which totalled 121,333 in June 2025, collapsed to under 200 submissions on June 19-20.

2025-iran-shutdown-measurement Executive Summary / §2 dpidns-poisoningport-blockingip-blocking

Article 19 documents that Iran's National Information Network (NIN / SHOMA) was designed with explicit reference to China's Great Firewall as a model, with institutional mirroring: Iran's Supreme Council of Cyberspace parallels China's Cyberspace Administration of China, and both governments share a "cyber sovereignty" doctrine used to justify domestic content controls and cross-border technology transfer. The report frames Iran's filtering infrastructure as deliberately architected to replicate GFW capabilities, not as an independently developed system.

2026-article19-tightening-the-net §2, §3 dpisni-blockingdns-poisoningip-blockingbgp-hijackthrottling

Article 19 documents that Iran combines technical filtering with formal coercion of major foreign platforms (including Telegram, Instagram, and WhatsApp) to comply with content removal orders under threat of full blocking. The report notes that Iran's 2022 Women Life Freedom protests accelerated platform blocking when foreign operators refused compliance, demonstrating that the censorship system operates in two modes: coerce-and-allow for compliant platforms, block for non-compliant ones. Domain fronting via these platforms is therefore subject to sudden revocation if political conditions change.

2026-article19-tightening-the-net §6 ip-blockingdns-poisoningthrottling

Both Firefox and Chromium leak cleartext DNS before establishing encrypted DNS connections: they first send an unencrypted UDP DNS query to resolve the DoH server's domain (e.g., doh.opendns.com). An in-path censor can intercept and poison this initial query, making encrypted DNS in browsers completely ineffective without additional circumvention of the resolver-lookup step. Additionally, Chromium always includes the SNI extension in the encrypted DNS TLS handshake (e.g., "doh.opendns.com"), leaking the resolver identity even after the initial lookup. No resolver requires SNI to be present for certificate validation when the resolver's IP certificate is configured.

2026-lange-towards §2.4, §7, §10 dns-poisoningsni-blocking

DNS censorship of encrypted protocols is inconsistent in both China and Iran. In China, Yandex resolvers are censored only when the SNI extension is present; omitting SNI bypasses censorship for these resolvers. In Iran, DoH requires SNI omission for Quad9, Google, Adguard, CleanBrowsing, and NextDNS resolvers, but works with SNI for Yandex and Cisco resolvers. These inconsistencies suggest resolvers have been accidentally missed by censors, highlighting the value of automated tools that trial all resolver-mode combinations rather than hard-coding a single strategy. The support evaluation found 47 resolvers supporting DoH, 16 supporting DoH3, and only 8 supporting DoQ out of ~65 tested.

2026-lange-towards §6.2, Table 2 dns-poisoningsni-blockingip-blocking

DPYProxy-DNS tested 8 circumvention modes against DNS censorship from vantage points in Iran (AS201295, Mashhad) and China (AS4837, China Unicom). In Iran, DoQ was entirely uncensored even with the SNI extension present; DoH3 worked for all Cloudflare and NextDNS resolvers. Iran's censor operates in-path (not on-path like the GFW), making the "Last Response" mode (wait 3s for the last UDP reply) ineffective in Iran but highly effective in China. Auto-mode averaged 12.32s (median 8.28s) in Iran and 13.78s (median 12.90s) in China to discover a working combination.

2026-lange-towards §6.2, §6.3 dns-poisoningsni-blockingip-blocking