Protection of Privacy on the Internet

JAP (called JonDo in the scope of the commercial JonDonym anonymous proxy servers - AN.ON remains free of charge) makes it possible to surf the internet anonymously and unobservably.


JAP is a software development within the Project Anonymity in the Internet sponsored by the German Research Foundation and the Federal Ministry of Economics and Technology. The Project works closely with the Independent Center for Data Privacy Schleswig-Holstein. You can learn more about data privacy at the Virtual Data Privacy Office

What is JonDo?

The JonDonym/AN.ON technology is based on the principle of multiple (layered) encryption, distribution and processing. This procedure does not only protect your Internet activities from being observed by third parties (against your access provider, WLAN hackers, advertising services and websites), but also against observation by the individual JonDonym providers themselves (against JonDonym service operators and their billing providers).


JonDo is an application that spoofs your own IP address for Internet access using certain applications (e.g. by the web browser).
JonDo multiply encrypts the data sent over JonDonym. Neither your access provider nor JonDonym operators (except for the last mix one in each cascade) can see your plaintext data.
JonDo is an Anti-Censorship-Application that allows access to otherwise blocked Internet sites. Users may configure their JonDo as aforwarding server in order to allow others access to the JonDonym service.
JonDo is open source and free. The program offers access to both free and paid (premium) services.
JonDo filters and anonymizes HTTP headers – but only for unencrypted connections (not HTTPS). You should additionally use JonDoFox in order to also filter encrypted connections.
JonDo is available on all major systems (Windows, Mac OS X, Linux).
JonDo was and is developed by the JonDos GmbH in cooperation with German universities (TU Dresden, Universität Regensburg) and privacy organizations (Unabhängiges Landeszentrum für Datenschutz Schleswig-Holstein).

How it works



Instead of connecting directly to a webserver, users take a detour, connecting with encryption through several intermediaries, so-called Mixes. JAP uses a predetermined sequence for the mixes. Such a sequence of linked mixes is called a Mix Cascade. Users can choose between different mix cascades.

Since many users use these intermediaries at the same time, the internet connection of any one single user is hidden among the connections of all the other users. No one, not anyone from outside, not any of the other users, not even the provider of the intermediary service can determine which connection belongs to which user. A relationship between a connection and its user could only be determined if all intermediaries worked together to sabotage the anonymization. Click here for more

The intermediaries (mix providers) are generally provided by independent institutions which officially declare, that they do not keep connection log files or exchange such data with other mix providers. JAP shows the identity and number of organisations in each Mix cascade in detail, and verifies this information by cryptographic means. The users are thus able to selectively choose trustable mix cascades.

Developers :

Project Leadership

Mix server operation contact
University of Regensburg, Department of Business Informatics
Chair Management of Information Security
Prof. Dr. Hannes Federrath
D-93040 RegensburgTechnical University Dresden, Institute for System Architecture
Chair of Privacy and Data Security
Stefan Köpsell
D-01062 Dresden

Download JonDo latest client

JAP Anonymity Official Home Page