Notifies the client that a new message has been received from the network.
Instructs the router to deliver a payload to a specific I2P Destination.
The is the standard interface through which client applications interact with an I2P router to send and receive data across the anonymous network. By decoupling the application logic from the complex routing and encryption tasks of the network, I2CP allows developers to build privacy-focused tools—such as secure messaging or file-sharing systems—without needing to implement the underlying peer-to-peer (P2P) protocol themselves. Core Functionality and Architecture i2p-cp
: The router builds inbound tunnels and requests a "LeaseSet" from the client. This LeaseSet serves as a signed set of "entry points" that other peers can use to reach the application anonymously. Key I2CP Message Types Message Type SendMessage
: Since I2P is a packet-switched network where messages can be lost or delayed, I2CP is inherently asynchronous, allowing applications to manage their own reliability or use the built-in streaming library for TCP-like behavior. The Initialization Process Notifies the client that a new message has
: I2CP handles the high-level requests from applications (e.g., "send this data to this destination") and translates them into the lower-level tunnel and Garlic routing mechanisms used by the I2P network.
: The client sends a protocol version byte (typically 0x2A ) to ensure compatibility. By decoupling the application logic from the complex
I2CP operates as a message-based protocol, facilitating communication between two primary components: the (the application) and the Router (the I2P node).