Paper 2016/729

Attacks on cMix - Some Small Overlooked Details

Herman Galteland, Stig F. Mjølsnes, and Ruxandra F. Olimid


Chaum et al. have very recently introduced cMix as the first practical system that offers senders-recipients unlinkability at scale. cMix is claimed by its authors to be secure unless all nodes collude. We argue their assertion does not hold for the basic description of the protocol and sustain our statement by two different types of attacks: tagging attack and insider attack. For each one, we discuss the settings that make it feasible and possible countermeasures. By this, we highlight the necessity of implementing additional mechanisms that at first have been overlooked or have only been mentioned as additional features.

Available format(s)
Publication info
Preprint. MINOR revision.
cryptographic protocolssender-recipient unlinkabilityanonymitymixnetsattacks
Contact author(s)
ruxandra olimid @ ntnu no
2016-08-24: revised
2016-07-27: received
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Creative Commons Attribution


      author = {Herman Galteland and Stig F.  Mjølsnes and Ruxandra F.  Olimid},
      title = {Attacks on cMix - Some Small Overlooked Details},
      howpublished = {Cryptology ePrint Archive, Paper 2016/729},
      year = {2016},
      note = {\url{}},
      url = {}
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