Alibi Routing proves packets avoided a forbidden geographic region using physical impossibility: a relay MACs forwarded packets, and the observed RTT must satisfy (1+δ)·R(s,r) < min_{f∈F}{R(s,f)+R(f,r)}, where the minimum RTT to any point in F is estimated as (3/c)·ShortestDistance(q,F) — fiber-optic links at 2/3 the speed of light. This proof requires only GPS coordinates and local RTT measurements, no BGP modifications or PKI.

On a 370-node PlanetLab deployment, Alibi Routing achieved near 100% success avoiding both the USA and China (Tables 1–2) with an average search cost of 1.0–1.66 nodes contacted (Table 4). In simulation over 20,000 globally distributed nodes, success rates were 93–100% at δ=0.5–1.0 with average search cost under 40 nodes (Table 3), capping TTL at 7.

§6.3, Tables 1–4 evaluation

For the vast majority of source-destination pairs avoiding the USA or China on PlanetLab, Alibi Routing introduces less than 50% latency inflation; some pairs even see latency improvement due to overlay shortcutting (Figure 9). Latency inflation is relatively insensitive to the inequality factor δ when relays are successfully found.

§6.3, Figure 9 evaluation

Property 1 proves that a peer inside a forbidden region F cannot satisfy the safety condition: appearing safe would require reporting an RTT lower than (3/c)·distance(peer,F), a physical impossibility. Property 2 follows: all trustworthy peers ignore packets routing through F regardless of attacker-controlled neighbor sets, making Alibi Routing safe without assuming honest neighbor selection.

§5 defense

Alibi Routing fails for source-destination pairs close to or inside the forbidden region: approximately 10% of pairs cannot provably avoid China and 22% cannot avoid the USA at δ=1.0 (Figure 5), with a strong monotonic correlation between proximity to the forbidden region and the number of available relays (Figure 6). Additionally, about 50% of nodes in target regions fail the alibi condition when avoiding the USA due to its BGP routing centrality causing actual paths to transit it despite geographic distance (Figure 7a).

§6.1–6.2, Figures 4–7 evaluation

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

On March 28, 2022, Russian ISP RTComm (AS8342) hijacked Twitter's IPv4 prefix 104.244.42.0/24 for approximately 45 minutes (12:05–12:50 UTC) and announced it to the global Internet as a blocking measure. The hijack was blunted because Twitter had preemptively registered RPKI route origin authorizations (ROAs) for its prefixes, causing RPKI-validating ASes worldwide to reject the hijacked route.

2023-ramesh-network §4.3 bgp-hijackasn-blackholing

For China (a highly connected, routing-capable adversary), the gossip protocol combined with any symmetric decoy routing design requires only 5 heavyweight downstream stations plus 880 lightweight upstream gossip stations — versus 880 heavyweight stations for purely symmetric designs. Five downstream stations alone impact 78% of routes from Chinese users, while a single downstream station already covers nearly 25% of traffic.

2018-bocovich-secure Table 2 / §3.2 bgp-hijack

Any one of five Indian ASes — each needing control of only its BGP-speaking routers — can individually censor traffic for all ~896 Indian ASes via IP prefix hijacking. For example, AS4755 (Tata Comm.) fake advertisements can impact 955 ASes total (896 Indian + 41 foreign); AS9730 (Bharti Telesonic) requires as few as 7 edge routers to execute such an attack.

2017-gosain-mending §4.3, Table 4 bgp-hijack

If India deployed centralized filtering at its key ASes, approximately 121,931 foreign-origin paths (1.15% of all Internet paths to censored sites worldwide) that transit Indian ASes would experience collateral blocking, affecting non-Indian users in Finland, Hong Kong, Singapore, Malaysia, the US, and elsewhere who have no connection to Indian censorship law.

2017-gosain-mending §4.1, §4.4 ip-blockingbgp-hijack

Through Internet-scale BGP simulation against China, downstream-only decoy routing (Waterfall) with a single decoy AS provides equivalent resistance to routing attacks as a traditional upstream decoy system (e.g., Telex) with 53 decoy ASes. This efficiency gain arises because censoring ISPs can selectively re-route upstream traffic per destination but must re-route all or none of downstream traffic through each provider AS, making downstream-only routing far more expensive to evade.

2017-nasr-waterfall §4.1.1 bgp-hijack