A Blind Coupon Mechanism Enabling Veto Voting over Unreliable Networks

A Blind Coupon Mechanism (BCM) allows spreading of alerts quietly and quickly over unreliable networks. The BCM primitive ensures that alerts are efficiently broadcast while the nature of these signals are securely hidden. However, current BCM proposals are limited to indicating a single bit of information and also lack natural privacy properties. In this paper, we develop a new BCM solution that allows the transmission of several alerts privately and in one shot. This extension perfectly suits a new kind of applications, that is (absolute) veto voting over unreliable networks, in which multiple decisions are reached using only simple peer-to-peer communications. Our enhanced BCM efficiently supports the spread of votes over unreliable networks while hiding whether these votes contain any or several vetoes. We prove our BCM solution secure and illustrate its use for veto voting protocols in limited communication infrastructures.