The Disadvantages of Free MIX Routes and How to Overcome Them

  • Oliver Berthold
  • Andreas Pfitzmann
  • Ronny Standtke
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2009)


There are different methods to build an anonymity service using MIXes. A substantial decision for doing so is the method of choosing the MIX route. In this paper we compare two special configurations: a fixed MIX route used by all participants and a network of freely usable MIXes where each participant chooses his own route. The advantages and disadvantages in respect to the freedom of choice are presented and examined. We’ll show that some additional attacks are possible in networks with freely chosen MIX routes. After describing these attacks, we estimate their impact on the achievable degree of anonymity. Finally, we evaluate the relevance of the described attacks with respect to existing systems like e.g. Mixmaster, Crowds, and Freedom.


Active Attack Attack Model Incoming Message Route Length Message Blocking 
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  1. 1.
    Oliver Berthold, Hannes Federrath, Marit Köhntopp: Project “Anonymity and Unobservability in the Internet”; Workshop on Freedom and Privacy by Design; in: Proceedings of the Tenth Conference on Computers, Freedom & Privacy; CFP 2000: Challenging the Assumptions; Toronto/Canada, April 4–7, 2000; ACM, New York 2000; 57–65; Scholar
  2. 2.
    Oliver Berthold, Hannes Federrath, Stefan Köpsell: Web MIXes: A system for anonymous and unobservable Internet access. Proceedings ofWorkshop on Design Issues in Anonymity and Unobservability, July 25–26, 2000 in Berkeley.Google Scholar
  3. 3.
    David Chaum: Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms. Communications of the ACM 24/2 (1981) 84–88.CrossRefGoogle Scholar
  4. 4.
    The Freedom Network Architecture. Zero-Knowledge-Systems, Inc., 1998.
  5. 5.
    Andreas Pfitzmann: Diensteintegrierende Kommunikationsnetze mit teilnehmerüberprüfbarem Datenschutz; University Karlsruhe, Department of computer science, Dissertation, Feb. 1989, IFB 234, Springer-Verlag, Heidelberg 1990.Google Scholar
  6. 6.
    Andreas Pfitzmann, Birgit Pfitzmann, Michael Waidner: ISDN-MIXes-Untraceable Communication with Very Small Bandwidth Overhead. Proc. Kommunikation in verteilten Systemen, IFB 267, Springer-Verlag, Berlin 1991, 451–463.Google Scholar
  7. 7.
    M. G. Reed, P. F. Syverson, D. Goldschlag: Anonymous Connections and Onion Routing. IEEE Journal on Selected Areas in Communication. Spezial Issue on Copyright and Privacy Protection, 1998.

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Oliver Berthold
    • 1
  • Andreas Pfitzmann
    • 1
  • Ronny Standtke
    • 2
  1. 1.Dresden University of TechnologyGermany
  2. 2.SecunetDresden

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