Overview
I2P (Invisible Internet Project) is a fully decentralized, peer-to-peer anonymous network layer that enables applications to send messages to each other pseudonymously and securely. Unlike Tor, which is optimized for anonymous access to the public web via exit nodes, I2P is architected as a 'network within a network,' primarily focused on internal communication and hosting hidden services known as 'eepsites.' The technical architecture utilizes 'Garlic Routing,' an evolution of onion routing that bundles multiple messages together to thwart traffic analysis and timing attacks. In 2026, I2P maintains its position as the premier infrastructure for resilient, distributed applications that require high-degree anonymity without centralized points of failure. The network employs unidirectional tunnels, separating inbound and outbound traffic to maximize security. Its NetDB (Network Database) uses a Distributed Hash Table (DHT) to manage routing without a central directory. As global surveillance and censorship intensify, I2P’s integration with modern protocols like SSU2 (Secure Semi-reliable UDP) and its ongoing transition from Java-based routers to high-performance C++ implementations (i2pd) ensure its relevance for secure IoT, encrypted messaging, and private metadata-free file sharing systems.