一種區塊鏈上無收據的投票協議

Abstract

投票是現代民主的重要過程，然而自然會面臨強迫和腐敗的問題。隨著區塊鏈技術的興起，在區塊鏈上進行此類活動因其能提供安全、透明且去中心化的投票系統而引起關注。然而，由於區塊鏈本質上是一個公開帳本，這樣的設計將導致關於投票人隱私的問題隨之而來。 本文中，我們提出了一個使用區塊鏈作為公開計票的無收據投票協議。通過將操作權限分離為負責驗證選民身份的身份機構和負責生成加密選票和計票的投票機構，我們確保在保護選民隱私的同時，允許任何第三方驗證投票和計票的完整性。該協議利用同態加密進行計票狀態，並使用RSA簽名進行選票驗證。在假設兩個主辦機構都是誠實的情況下，該協議實現了無收據的特性。

Voting, an important process of modern democracy, is naturally subject to coercion and corruption. With the rise of blockchain technology, conducting such campaign on blockchain has drawn attention with its potential to provide a secure, transparent and decentralized voting system. However, with the nature of blockchain being a public ledger, concerns about the privacy arise. In this work, we present a receipt free voting protocol utilizing blockchain as public tally. By separating operating authority into identity authority which is responsible for verifying the voter’s identity and voting authority which is responsible for generating encrypted ballots and tallying, we ensure that the privacy of voters is protected while allowing any third party to verify the integrity of the vote and the tally. The protocol make use of homomorphic encryption for the tally state and blind signature for ballot verification. The protocol achieve receiptfreeness assuming that both authority is honest.