Solving the Discrete Logarithm Problem for Packing Candidate Preferences

  • James Heather
  • Chris Culnane
  • Steve Schneider
  • Sriramkrishnan Srinivasan
  • Zhe Xia
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8128)


Ranked elections are used in many places across the world, and a number of end-to-end verifiable voting systems have been proposed to handle these elections recently. One example is the vVote system designed for the Victorian State Election, Australia. In this system, many voters will give a full ranking of up to 38 candidates. The easiest way to do this is to ask each voter to reorder ciphertexts representing the different candidates, so that the ciphertext ordering represents the candidate ranking. But this requires sending 38 ciphertexts per voter through the mixnets, which will take a long time. In this paper, we explore how to “pack” multiple candidate preferences into a single ciphertext, so that these preferences can be represented in the least number of ciphertexts possible, while maintaining efficient decryption. Both the packing and the unpacking procedure are performed publicly: we still provide 38 ciphertexts, but they are combined appropriately before they enter the mixnets, and after decryption, a meet-in-the-middle algorithm can be used to recover the full candidate preferences despite the discrete logarithm problem.


Lookup Table Vote System Discrete Logarithm Problem Homomorphic Encryption Candidate Preference 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© IFIP International Federation for Information Processing 2013

Authors and Affiliations

  • James Heather
    • 1
  • Chris Culnane
    • 1
  • Steve Schneider
    • 1
  • Sriramkrishnan Srinivasan
    • 1
  • Zhe Xia
    • 2
  1. 1.Department of ComputingUniversity of SurreyGuildfordU.K.
  2. 2.Department of ComputingWuhan University of TechnologyChina

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