Onion service interaction

Overview  •  Writing  •  Code and data  •  Contact


The Tor anonymity network is primarily known as a tool that enables client anonymity. Users can download Tor Browser to browse the web anonymously, making it harder for governments, corporations, and individuals to monitor their browsing activity. In addition to client anonymity, the Tor network provides server anonymity in the form of onion services (a.k.a. hidden services) which allow operators to expose a TCP service while hiding its IP address. Several popular web sites have now set up corresponding onion services, including DuckDuckGo, ProPublica, The New York Times, and Facebook.

Onion services differ from normal web services in several aspects; for example in their unusual domain format (an example is expyuzz4wqqyqhjn.onion, The Tor Project's onion site) and in the way users discover new onion services. In this research project, we are trying to understand how users deal with these differences by administering a survey to Tor users and by conducting a series of semi-structured interviews. A sound understanding of how users interact with onion services will allow privacy engineers to both improve onion service usability and better protect Tor users from surveillance, censorship, and other attacks.


Code and data

You can find more information about our project and some code in our GitHub repository:

git clone https://github.com/citp/onion-service-usability.git

Data complementary to our work is available below.


We are a team of computer scientists from Princeton University. If you have any questions please send an email to Philipp: phw@nymity.ch


This research was supported by the Center for Information Technology Policy at Princeton University and by the National Science Foundation Awards CNS-1540066, CNS-1602399, CNS-1664786, and

Last update: 2018-07-10