Tor vs I2P

Two jobs, side by side

I2P's own introduction draws the line, and it is worth taking from them rather than from a chart that pretends to score "privacy" out of ten. Tor, they say, works toward fast anonymous access out to the ordinary internet. I2P works toward a resilient network in itself. The table is that sentence, plus the mechanics that follow from it.

On the whole, Tor and I2P complement each other in their focus — Tor works towards offering high speed anonymous Internet outproxying, while I2P works towards offering a decentralized resilient network in itself.

They add that either network could in theory do the other's job, and that neither project has the people to do both well. That is a better frame than "I2P is Tor but stronger." It is a different tool, maintained by a different project, for a visit that mostly never leaves.

What Tor is already for

Tor sends you out, and it also lets a site hide. The three-relay path, what your provider can see, and why an onion site has no exit relay are already written in how Tor works. The short version, so this page can stand alone: your traffic passes three volunteer computers, the last of them steps onto the ordinary internet when the destination is a normal website, and an onion address never takes that step. The browser that does this is Tor Browser. Installing it, and checking the file is genuine, is the setup guide.

That design is why Tor is the default in every other guide here. The sites people mean by "the dark web" are onion sites. The ordinary web, reached anonymously, is an exit relay. I2P does not replace either of those. It sits beside them.

What I2P keeps inside

I2P is a neighborhood that mostly talks to itself. You run a router, the program finds peers, and the sites you visit are other participants whose names end in .i2p. Your location stays off the site, and the site's location stays off you, for the same kind of reason an onion site hides: the meeting happens inside the network. The difference is where the network is willing to go afterward.

The paths are one-way. I2P's documentation says each side builds two tunnels, one out and one in, so a single round trip uses four tunnels. Tor's circuit is a two-way street of three relays. I2P's trip is four one-way lanes. The project presents that as a way to route around a congested or failed peer without tearing down a whole circuit. It is also more machinery for one page to load, which is the honest answer when someone asks why I2P feels heavier.

In I2P, tunnels are unidirectional. Each party builds two tunnels, one for outbound and one for inbound traffic. Therefore, four tunnels are required for a single round-trip message and reply.

Leaving the neighborhood is optional, and it is someone else's choice. If the name you asked for does not end in .i2p, I2P's web proxy can hand the request to an outproxy, a destination run by a volunteer who decided to carry traffic out. I2P says the network itself is not an outproxy network, and that no one becomes an outproxy automatically. Those exits have the same awkward position a Tor exit relay has: they see the site you asked for. There are fewer of them, you pick them from a list you supply, and the project treats them as a proof of concept under a weaker threat model. For the ordinary web, Tor is the network that was built for the trip.

Why "garlic" is still onion

You will see I2P described as garlic routing, as if the vegetable were a new invention. I2P's own page says garlic routing "as a general concept is identical to onion routing": a message wrapped in layers, each hop peeling one. The piece they treat as the actual difference is bundling. Several messages can ride in one envelope, which they call cloves, so a reply instruction and the message itself travel together. They then say this bundling is only one of many differences from Tor, and that it may not be enough on its own to justify a different name.

So the label is theirs, and the caution is theirs too. Use "garlic" when you are reading their docs. Do not hear it as a second, stronger kind of anonymity. The anonymity comes from the layered path and from staying inside the network, the same two ideas Tor uses for onion sites, built as one-way tunnels and aimed at a different destination.

When a second address helps

A second address helps when the problem is blocking. One network is censored, or flooded, or simply down, and the other still answers. Mars publishes a Tor onion and also runs on I2P for that reason: a flood against the onion does not, by itself, take the other entrance down. The account is the same. That is a real convenience, and it is the whole of the convenience.

It does not help when the problem is the server. Kingdom Market was reachable on Tor and on I2P, and it was seized in December 2023 because a misconfigured web server leaked the machine's real address. Once police had the building, both doors opened onto the same raid. Two networks made the market harder to knock offline. They did not make it harder to find. The case page has the dates and the header leak. The lesson that belongs here is only the split: reachability is not survival.

The same split applies to a signature. An I2P address can be cloned as easily as an onion address, by a name that looks almost right. Whichever entrance you use, the address still has to be one the operator's key signed. That check does not change because you arrived by a different road. It is the PGP verification guide.

Where the program comes from

The official I2P router is at geti2p.net. The site has the installers and the documentation for checking them. A build from a search ad is the same mistake as a Tor Browser from a search ad. This page stops there on purpose. A second setup manual would only repeat the project's own, and it would blur the decision this page is for: whether you need the neighborhood at all.

For almost every reader of this site, the answer is no. Tor Browser already reaches onion sites and the ordinary web. Add I2P when a place you already have a reason to trust offers an address that ends in .i2p, and the Tor entrance is blocked. Do not add it because a market listed both and the listing looked like protection. Kingdom's listing looked like protection. The server header did not care.

Common questions about Tor vs I2P