Practical Strategy-Resistant Privacy-Preserving Elections
Recent advances in cryptography promise to let us run complex algorithms in the encrypted domain. However, these results are still mostly theoretical since the running times are still much larger than their equivalents in the plaintext domain. In this context, Majority Judgment is a recent proposal for a new voting system with several interesting practical advantages, but which implies a more involved tallying process than first-past-the-post voting. To protect voters’ privacy, such a process needs to be done by only manipulating encrypted data.
In this paper, we then explore the possibility of computing the (ordered) winners in the Majority Judgment election without leaking any other information, using homomorphic encryption and multiparty computation. We particularly focus on the practicality of such a solution and, for this purpose, we optimize both the algorithms and the implementations of several cryptographic building blocks. Our result is very positive, showing that this is as of now possible to attain practical running times for such a complex privacy-protecting tallying process, even for large-scale elections.
This work was supported in part by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013 Grant Agreement no. 339563 – CryptoCloud).
- [APB+04]Aditya, R., Peng, K., Boyd, C., Dawson, E., Lee, B.: Batch verification for equality of discrete logarithms and threshold decryptions. In: Jakobsson, M., Yung, M., Zhou, J. (eds.) ACNS 2004. LNCS, vol. 3089, pp. 494–508. Springer, Heidelberg (2004). https://doi.org/10.1007/978-3-540-24852-1_36CrossRefMATHGoogle Scholar
- [DFK+06]Damgård, I., Fitzi, M., Kiltz, E., Nielsen, J.B., Toft, T.: Unconditionally secure constant-rounds multi-party computation for equality, comparison, bits and exponentiation. In: Halevi, S., Rabin, T. (eds.) TCC 2006. LNCS, vol. 3876, pp. 285–304. Springer, Heidelberg (2006). https://doi.org/10.1007/11681878_15CrossRefGoogle Scholar
- [PS99]Poupard, G., Stern, J.: On the fly signatures based on factoring. In: ACM CCS 1999, pp. 37–45. ACM Press, November 1999Google Scholar
- [TRN08]Teague, V., Ramchen, K., Naish, L.: Coercion-resistant tallying for STV voting. In: 2008 USENIX/ACCURATE Electronic Voting Workshop, EVT 2008, 28–29 July 2008, San Jose, CA, USA, Proceedings (2008)Google Scholar