Publius encrypts content under a symmetric key K, then splits K into n shares using Shamir secret sharing such that any k shares reconstruct K. Each server stores the encrypted document plus one share, so an adversary must corrupt or destroy n−k+1 servers to censor the document, and increasing n or decreasing k raises the bar proportionally.

Publius cryptographically binds the URL to both the document content and the key shares via name_i = wrap(H(M · share_i)). Any unauthorized modification to the stored encrypted file, a share, or the URL itself causes the tamper check to fail, preventing silent content substitution by a malicious server.

§3.2, §3.3 defense

A malicious server operator with write access can mount a redirection attack by inserting a fake update file pointing to adversary-controlled content. If the client retrieves only k shares and Mallory controls k collaborating servers, all k update URLs match and the client proxy follows the redirect. A 1-bit non-updatable flag in the Publius URL blocks this vector by instructing clients to ignore all update files.

§5.2 evaluation

Publius's delete mechanism requires the publisher to supply H(server_domain · PW) per server rather than a bare password, preventing any single malicious server from learning the global password and deleting the document from all hosting servers. However, the paper acknowledges that an adversary who identifies the publisher can apply coercive ('rubber-hose') methods to obtain the URL and password directly from the author, bypassing all cryptographic protections.

§3.4, §5.5 defense

Publius provides source anonymity once content is published but offers no connection-based anonymity at upload time. A network-layer eavesdropper between the publisher and the servers, or a server's connection log, can reveal the publisher's IP address. The paper explicitly states that Publius must be combined with a mix-network or crowd-anonymity tool (e.g., Crowds, Onion Routing) to protect publisher identity during the upload phase.

§5.4 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

Chinese users treat full proxy/VPN (Shadowsocks, V2Ray/Clash, commercial VPNs) as the '终极大杀器' (ultimate solution) for bypassing GitHub DNS poisoning, implying that lighter-weight DNS-only fixes fail in some network environments where the censor adds firewall-layer blocking beyond DNS.

2026-anon-6-github-dns §3 使用代理或 VPN dns-poisoningip-blocking

Rule-based proxy tools (Clash, Shadowsocks, V2Ray) are documented as the most reliable solution for accessing GitHub from China, with split-tunneling rules routing only GitHub traffic through the proxy while keeping domestic traffic on the direct path. Git command-line tools require explicit proxy configuration (git config --global http.proxy http://127.0.0.1:7890) to route clone/push operations, as they do not inherit system proxy settings automatically.

2026-anon-github-2026-6-dns §方法二 dns-poisoningip-blocking

The GFW blocks GitHub via DNS poisoning across at least four domains — github.com, assets-cdn.github.com, github.global.ssl.fastly.net, and raw.githubusercontent.com — causing connection timeouts and page-load failures for mainland China users. The block is persistent as of February 2026, affecting both browser access and command-line git operations.

2026-anon-github-2026-6-dns Introduction / §方法一 dns-poisoningip-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