https://en.wikipedia.org/wiki/I2P

I2P and Tor both aim to provide anonymous internet browsing but differ in their architectures and methods. Tor (short for The Onion Router) uses a system of layered encryption to route internet traffic through a network of volunteer-operated servers. This creates a series of encrypted layers (hence the onion analogy) that mask the user's IP address and data content from any would-be observers.

In contrast, I2P uses a garlic routing technique, where multiple messages are bundled together into a single encrypted packet. This method enhances privacy by making it more difficult for anyone to analyze the traffic and link the data back to specific users.

Also, Tor supports access to the open internet (clearnet), while I2P only allows access to websites and services (known as eepsites) within its own networks. Outproxies, which are similar to Tor exit nodes, can be used to access the clearnet with I2P. However, this reduces privacy as your data leaves the network and is a less common use case.