Suggestion: WebAssembly

[gkgoat1]

(Based on #1) Running I405 in a browser would help with layer 7 tunneling, as well as making the setup slightly less hard

[markasoftware]

There are a few issues, one is that I405 (at least as part of an Interstate Circuit) is designed to be run 24/7 as a daemon, which isn't how browsers are typically used.

If I405 is not run 24/7, then an adversary can gain information. For example, in an Interstate Circuit, the adversary knows that only web traffic happening at about the same time as your I405 tunnel is running can possibly be part of your circuit, which over a long period of time could seriously narrow down their search.

Running in the browser also opens up to tons of side-channel attacks based on variations in packet timing (in the vein of the issues described in the real-time tuning docs). Now there's not just the uncertainty of the kernel, but also the whole browser runtime, which can presumably choose to pause and resume webassembly threads, and adds a lot of networking abstractions which may delay packets in a way that reveals information to an attacker. I also don't think you can send arbitrary UDP packets very well from a browser (though maybe you can with WebRTC?), and if you relied on TCP/websockets then the side-channels attacks get much worse because of how complex the TCP stack is and how its timing and behavior could reveal information about other activity on the same machine.

Now with all the pessimism out of the way, there could still be some value to having I405 in a browser. As you mentioned, it's easier to set up. In a true Interstate Circuit, the real difficulty is anonymously buying the servers, not installing the I405 client, so this ease of set up doesn't help much for Interstate Circuits. However, I can imagine a cool feature (that websites would have to opt-in to) where you use I405 to connect to the website (probably over WebRTC), instead of just HTTPS. Then, the attacker has no idea about the metadata you're sending to and from that website! It wouldn't be truly anonymous like an interstate circuit (adversary still knows roughly when you're communicating, and who you are communicating with) but would hide lots of metadata about what you're communicating.

This has just turned into a massive brain dump without any solid conclusions. Browser integration is not something I'm going to be working on any time soon but happy to continue discussing any ideas you have about how I405 could be useful in a browser.