The Invisible Internet Project (I2P) is a garlic routing using overlay network and darknet that allows applications to send messages to each other pseudonymously and securely. Uses include anonymous Web surfing, chatting, blogging and file transfers. The software that implements this layer is called an I2P router and a computer running I2P is called an I2P node.
License: Open Source
Calypso is designed for user-friendliness and multi-platform support, making it accessible for everyday users. In contrast, I2P offers a more complex but highly anonymous network, ideal for users prioritizing privacy and security.