Voting is a means to agree on a collective decision based on available choices (e.g., candidates), where participants (voters) agree to abide by their outcome. To improve some features of e-voting, decentralized solutions based on a blockchain can be employed, where the blockchain represents a public bulletin board that in contrast to a centralized bulletin board provides $100\%$ availability and censorship resistance. A blockchain ensures that all entities in the voting system have the same view of the actions made by others due to its immutable and append-only log. The existing blockchain-based boardroom voting solution called Open Voting Network (OVN) provides the privacy of votes and perfect ballot secrecy, but it supports only two candidates. We present BBB-Voting, an equivalent blockchain-based approach for decentralized voting than OVN, but in contrast to it, BBB-Voting supports 1-out-of-$k$ choices and provides a fault tolerance mechanism that enables recovery from stalling participants. We provide a cost-optimized implementation using Ethereum, which we compare with OVN and show that our work decreases the costs for voters by $13.5\%$ in terms of gas consumption. Next, we outline the extension of our implementation scaling to magnitudes higher number of participants than in a boardroom voting, while preserving the costs paid by the authority and participants -- we made proof-of-concept experiments with up to 1000 participants.

翻译：投票是一种基于现有选择(例如候选人)商定集体决定的手段,参与者(选民)同意遵守他们的投票结果。为了改进电子投票的某些特点,可以采用基于一个块链的分散化解决方案,因为块链代表一个公共公告栏,而与中央公告栏相比,该公告栏提供100美元,抵制审查。一个块链确保投票系统中的所有实体对其他人由于无法变动和只附件的日志而采取的其他行动持有相同的看法。现有的以块链为基础的董事会投票解决方案(公开投票网)提供了投票的隐私和完美的投票保密,但只支持两个候选人。我们提出了BBB-Voting,这是对分散投票的相等的以块链为基础的办法,而不是中央公告栏,提供了100美元的供应量和1美元的限制。BB-Voting则支持1美元以外的选择,并提供了一种能让参与者从拖延的日志中恢复的错误容忍机制。我们利用Eieum(我们与公开投票网比较)提供成本优化的执行,并显示我们的工作将成本降低下一轮选民费用,同时以13.5美元的比例提高选民的参加率。