Democracies are built upon secure and reliable voting systems. Electronic voting systems seek to replace ballot papers and boxes with computer hardware and software. Proposed electronic election schemes have been subjected to scrutiny, with researchers spotting inherent faults and weaknesses. Inspired by physical voting systems, we argue that any electronic voting system needs two essential properties: ballot secrecy and verifiability. These properties seemingly work against each other. An election scheme that is a complete black box offers ballot secrecy, but verification of the outcome is impossible. This challenge can be tackled using standard tools from modern cryptography, reaching a balance that delivers both properties. This tutorial makes these ideas accessible to readers outside electronic voting. We introduce fundamental concepts such as asymmetric and homomorphic encryption, which we use to describe a general electronic election scheme while keeping mathematical formalism minimal. We outline game-based cryptography, a standard approach in modern cryptography, and introduce notation for formulating elections as games. We then give precise definitions of ballot secrecy and verifiability in the framework of game-based cryptography. A principal aim is introducing modern research approaches to electronic voting.

翻译：民主制度建立在安全可靠的投票系统之上。电子投票系统旨在以计算机硬件与软件替代纸质选票与票箱。现有电子选举方案已受到严格审查，研究人员发现了其固有的缺陷与弱点。受物理投票系统启发，我们认为任何电子投票系统必须具备两项核心属性：选票保密性与结果可验证性。这两种属性在表面上相互制约：完全黑箱化的选举方案虽能保证选票保密性，却使结果验证无法实现。借助现代密码学的标准工具，这一矛盾可得到解决，从而达成两种属性的平衡。本教程旨在向电子投票领域外的读者阐释这些核心理念。我们将介绍非对称加密与同态加密等基础概念，并以此描述通用电子选举方案，同时最大限度减少数学形式化表述。我们概述现代密码学的标准方法——基于博弈的密码学，并引入将选举建模为博弈的形式化表达。随后，我们在基于博弈的密码学框架下给出选票保密性与可验证性的精确定义。本教程的主要目标在于向读者系统介绍电子投票的现代研究方法。