Java Anon Proxy
| Company type | Private |
|---|---|
| Industry | Internet privacy, Anonymity network |
| Predecessor | JAP (Java Anon Proxy) |
| Founder | Contributors from Technische Universität Dresden, Universität Regensburg, and Privacy Commissioner of Schleswig-Holstein |
| Defunct | August 2021 |
| Fate | Discontinued |
| Headquarters | Germany |
Area served | Worldwide |
| Products | JonDonym anonymity service, JonDo client software, ANONdroid proxy client for Android |
| Owner | Jondos GmbH (after June 2007) |
| Website | www |
Java Anon Proxy (JAP), also referred to as JonDonym, functioned as a proxy solution designed to facilitate Web browsing with revocable pseudonymity. The software was developed through a collaboration between Technische Universität Dresden, Universität Regensburg, and the Privacy Commissioner of Schleswig-Holstein, with the client application implemented in Java. The service was discontinued in August 2021.
Offering cross-platform compatibility and free access, JAP directed user requests through a Mix Cascade—a method that interleaves data streams from multiple users to improve anonymity. JonDonym was compatible with all platforms supporting Java, while ANONdroid served as its dedicated proxy client for Android devices.
Design
Users of the JonDonym client could choose from various Mix Cascades, which are collections of anonymizing proxies operated by independent entities. Contrary to peer-to-peer anonymity systems like Tor and I2P, where proxy nodes remain anonymous, JonDonym’s relays were publicly identified, enabling users to decide which operators they trusted. This openness, however, exposed the relays to potential targeting by hackers, government agencies, or lobbying groups. Such exposure has resulted in legal challenges, including court rulings that transferred control of some relays to the German government. To reduce these risks, relays were distributed internationally and integrated with Tor networks.
Performance and uptime varied depending on the operators managing the Mixes within each cascade. While increasing the number of users improved overall anonymity, it could also diminish individual connection speeds and available bandwidth.
Cost, name change and commercial service
Although JonDonym remained free for users, after university funding ended on 22 June 2007, development responsibilities shifted to Jondos GmbH—a startup created by original project contributors. This company concentrated on enhancing resistance against blocking mechanisms to maintain accessibility from countries with restrictive Internet policies.
As part of this transition, the JAP client was rebranded as JonDo, and the service formerly known as AN.ON adopted the name JonDonym. Most Mix Cascades were operated by small and medium-sized enterprises across several nations, each comprising three mix servers to bolster security. Service providers guaranteed sufficient capacity to support anonymous browsing speeds ranging between 30 and 50 kbit/s. While free cascades continued operating, they typically lacked the low latency, multiple mixes per cascade, or assured bandwidth found in commercial offerings.
Privacy
User activity could only be exposed if every Mix within a cascade collaborated by logging and correlating information. Operators committed voluntarily not to retain logs, making it difficult for adversaries to infiltrate all nodes in an extended cascade.
In July 2003, the German BKA secured a warrant compelling Dresden Mix operators to log visits to a website hosting illegal material. In response, AN.ON implemented a crime detection feature and released the altered source code transparently. Despite criticism, this functionality remains active on the Dresden Mix; while retroactive tracing is technically unfeasible, user anonymity now persists only until a surveillance court order is issued. This measure aligns with AN.ON’s threat model rather than constituting a security vulnerability.
To mitigate pressure from local authorities, the system expanded its relay infrastructure internationally; cascades spanning multiple countries require coordinated law enforcement action for user identification. AN.ON publishes annual reports detailing surveillance court orders and continues research aimed at developing crime detection methods that better preserve privacy.
Since May 2006, JonDonym’s client has supported access to the Tor and Mixminion networks. These integrations remain in early beta development stages.
See also