Onion Browser

tldr: A minimal, open-source web browser for iOS that tunnels web traffic through Tor.


I’ve been interested in Tor for quite some time, mostly out of curiosity and a nerdy (though sometimes fleeting) interest in cyber security/encryption/code breaking. (I think a lot of geek-types can relate to the same sort of “hacker nostalgia”, probably rooted in literature and film.) I’ve found the mere idea of an underground “darknet/deep web” interesting, as well.

I’ve screwed around with iPhone and iPad development in the past and although I’ve brought a few projects to feature-completion (the most recent being over 18 months ago), I haven’t actually “completed” one myself, in the sense that said project ends up on the App Store by my own hand. (They’ve all been handed off to a client or mothballed for one reason or another.)

And there’s at least one existing Tor-enabled browser on the iOS App Store that I’ve looked at but have been unimpressed with — to the tune of crashes, lack of cookie support, issues with POST requests, etc.

So I thought I’d try my hand at building a Tor-integrating iOS app and — since the idea seemed novel enough (or at least, lacked documentation of how one would even begin such a task) — I figured I could document and open-source the project to give back to the community a little bit.

What I ended up with is not the shiniest app and it is not the most fully-featured, third-party web browser for iOS. But it’s quite stable, works for almost all manner of Tor-powered web browsing that I and others have tested, and provides a few basic niceties that other “anonymizing” iOS browsers do not. (Namely, user-agent spoofing and ability to choose a cookie policy.)


The more technical notes and references can be found in the repository README (with some more references in the LICENSE). As time allows I’ll perhaps write a blog post or so about techniques I used, quirks and things I discovered, etc. A list of security caveats is on the product page.

(An interesting technical thought for now: the dependency build scripts and the “TorWrapper/AppDelegate” bits which integrate and control the Tor client could be applied to other iOS apps to provide Tor-enabled access, for example an e-mail client for the Tor Mail POP3/IMAP/SMTP services (since they reside in a hidden service), iOS clients for hidden services of other protocols such as IRC, etc.)


I plan on selling Onion Browser for $0.99. (Update 5/3: Removed block of text regarding donating a percentage of the proceeds to the Tor Project and the Electronic Frontier Foundation. As per App Store guidelines, donations as part of the app price are verboten; I cannot advertise that any portion of app sales are directly going to donation, but plan on continuing to donate to these organizations privately. I implore others to also consider donating on their own.)

It’s primarily on sale (rather than free) because I’d like to somewhat recoup my iOS Developer Program subscription cost (and perhaps make a small amount) while still making the app accessible to people who are unable to afford their own Developer Program subscription to build/install their own device copies of this app (since the source code is free). (I renewed my own iOS Developer Program subscription after over a year hiatus of iOS development just for this app.) I think selecting the lowest price point is a fair trade between public accessibility and my own overhead cost.


That’s the summary and status for the time being. Check out the product page and the GitHub project and feel free to comment here or on Hacker News.

Comments