University of Hamburg
Department of InformaticsWorking group Security in Distributed Systems


gMix aims to simplify the design and evaluation of mix-based systems. gMix is an open research project targeted at researchers who want to design novel mix concepts and developers interested in building practical mix systems. The gMix project provides

  • reference implementations (plug-ins) of several existing mix concepts [Plug-in List]
  • a framework that allows to compose mix networks out of those plug-ins [Paper]
  • several components to evaluate and compare those mix networks [Paper 1, 2]:
    • a Discrete-Event-Simulator for fast experiments
    • a Testbed for more complex emulation-based experiments
    • a Traffic Suite that allows to extract workloads from trace files recorded in real networks to simulate the users of the mix networks [Paper 1, 2]
    • an Experiment Repository that allows to repeat experiments and reuse experiment setups of previous research [Experiment Repository]
All gMix components are included in the gMix virtual machine image along with tutorials and a development environment [DOWNLOAD]. The source code is available on GitHub under GPLv3.


Mixes are a technique for anonymous communication. Numerous mixing strategies have been proposed since David Chaum suggested the basic mix concept three decades ago.

While some practical systems like Tor, JonDonym, I2P and Mixminion are available, the majority of the proposed mix techniques has never been deployed publically or compared under realistic conditions.


New gMix VM and Tutorials are online [URL]

New version of gMix framework available on GitHub [URL]

New website is online

Paper accepted for Elsevier Computers & Security journal :-)

Experiment descriptions, executables and source code for the paper Workload Modelling for Mix-based Anonymity Services are online now [URL]

Paper about EncDNS accepted at ESORICS 2014 :-)

See more...