I2P

P2P Infrastructure

The Invisible Internet Project — an anonymous, censorship-resistant overlay network layer implementing garlic routing (a variant of onion routing). Every I2P router participates in routing for others, using unidirectional tunnel pairs and a distributed Kademlia DHT network database. Designed for internal darknet communication (.i2p sites, email, torrents) rather than clearnet outproxying.

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Details

License Public Domain + BSD-style licenses (majority public domain; some cryptographic routines BSD-licensed; GPL for some bundled apps)
Dev Status 🟢 Active
Dev Status Detail Released (production; current stable version 0.9.67 as of 2025)
Owner I2P Project (volunteer collective, largely pseudonymous developers) / StormyCloud Inc. (supporting infrastructure since 2025)
Governing Body None (I2P volunteer collective, largely pseudonymous; StormyCloud Inc. provides supporting infrastructure since 2025 but does not govern the protocol)
Country International (distributed, pseudonymous developer team; no single country)
Start Year 2003
Stack Java (primary I2P router implementation); C++ (i2pd lightweight implementation); multiple language bindings
Funding Donations only; OTF (onboarding support); StormyCloud Inc. (infrastructure support 2025)
Last Investigated Mar 9, 2026

Topology view

This tool in the centre and the things it is directly related to. Each line names the kind of relationship.

Topology view: I2PThis tool in the centre and the things it is directly related to. Each line names the kind of relationship.I2PFreenet (Based on)FreenetHyphanet (Based on)HyphanetNoise Protocol Framework (Based on)NoiseProtocol Fra…Reticulum (Basis for)Reticulum

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Use Case Domains

Platform Evolution & Sovereignty Communication

Affordances

Self-hostable End-to-end encrypted

P2P Infrastructure Attributes

Origins Freenet/Hyphanet (fork); IIP (Invisible IRC Project); mix network research; Kademlia DHT
Database Kademlia-based distributed network database (netDb) for routing metadata; no application-layer data store
Data Formats I2NP (I2P Network Protocol) messages; arbitrary application data encapsulated in garlic messages
Mobile Support No (desktop daemon; web console at localhost:7657)
Web Support Yes (web console interface accessible locally)
Native Apps Yes (Java router for Linux/macOS/Windows; i2pd C++ variant; Android via i2pd-android)
Terms Free (donation-funded; core project does not solicit donations directly)
Funds Unknown (donation amounts not publicly disclosed; OTF support amount undisclosed)
Based On Freenet (censorship-resistant storage concept); Kademlia DHT; mix network research; garlic routing extends onion routing
P2P Architecture Garlic routing (unidirectional tunnel pairs; packet-switched; multiple messages bundled per garlic); Kademlia DHT for peer discovery
Overlay Network Global (self-organizing network database; no central directory servers; rotating floodfill routers maintain netDb)
Content Addressing No (router-identity-addressed, not content-addressed; application-layer content addressing possible)
Local-First N/A (routing infrastructure; data transits encrypted tunnels, not stored at network layer)
E2EE Yes — three layers: garlic encryption (message delivery verification), tunnel encryption, inter-router transport encryption
Byzantine Fault Tolerance No (reputation-based peer selection; no Byzantine fault tolerant consensus)
Signature ElGamal/ECIES (encryption); Ed25519/DSA (signatures); X25519 (key exchange in ECIES-X25519 mode)
Permissions N/A (open routing; all I2P routers contribute to network)
Protocol Maturity / Standardization Community Standard (open specification, published protocol docs; no formal standards body)
Infrastructure Function Anonymous routing; Censorship circumvention (internal darknet focus)
Threat Model Mass surveillance; Traffic analysis; Targeted surveillance; Metadata exposure
Volunteer / Node Model Volunteer-operated (every I2P router automatically routes for others; no dedicated relay class)
Traffic Visibility No content (three-layer encryption); No metadata (unidirectional tunnels mean each router sees only previous/next hop)
Active Deployment Scale ~55,000 router nodes worldwide (Wikipedia/research, as of 2024-2025)

Relationships

How this tool connects to other tools and organizations, from relationships reviewed by the OpenHaven data steward. They describe how projects connect, not how good they are.

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