Time, Privacy, Robustness, Accuracy: Trade Offs for the Open Vote Network Protocol
Résumé
Open vote network is a secure multi-party protocol allowing to compute a sum of integer votes without revealing their values. As such, it has several applications in social choice and financial applications.
An inherent limitation of OV-Net is its lack of robustness against denial-of-service attacks, which occur when at least one of the voters initiates the protocol but (maliciously or accidentally) does not complete it. Unfortunately such a situation is very likely to occur in any real-world implementation of the protocol. This will cost serious time delays from either waiting for the failing parties and perhaps having to perform extra protocol rounds with the remaining participants.
This paper provides a solution to this problem by extending OV-Net with mechanisms tolerating a number of unresponsive participants. The price to pay is a carefully controlled privacy loss, an increase in computation, and a statistical loss in the accuracy.