Electronic voting is a promising alternative to increase turnout and participation of citizens in democracy. However, designing and implementing secure e-voting systems is incredibly challenging, because such a system must satisfy two conflicting properties simultaneously: secrecy of the individual vote, and integrity of the final outcome. Other aspects relevant to practical e-voting systems are usability, resistance to voter coercion, transparency and auditability. Hence, deployed e-voting systems must conform not only with technical and security requirements, but also with the local voting culture and the electoral rules.

There are two types of e-voting systems deployed in practice: voting machines, introduced earlier in multiple countries as an automation mechanism; and cryptographic voting systems, which count encrypted votes in some verifiable manner. The most advanced among the latter systems, referred to as end-to-end-verifiable (E2E), offer greater transparency and auditability, by allowing voters to check if their votes were cast as intended and counted as cast. This property comes at some cost in usability and complexity due to the more sophisticated cryptographic algorithms.

Researchers from our group have contributed to improving e-voting systems in multiple ways, spanning both types of deployed e-voting systems:

• Cryptographic voting: better ways to encrypt [1] and anonymize votes [2], or to verify E2E elections [3]. More recently, we are interested in designing cryptographic voting protocols for alternative electoral systems.
• Security analysis of voting machines: concrete attacks and countermeasures against voting machines deployed in Brazilian elections [4], collecting almost 10 years of contributions to their security [5].

Electronic voting has the potential to boost citizen participation and strengthen democracy by making voting more accessible. However, ensuring both voter privacy and election integrity is a complex challenge. Advances in cryptographic voting and secure voting machines enhance transparency and trust, helping prevent fraud and coercion. By improving the security and usability of e-voting systems, especially in diverse electoral contexts, this research supports fairer, more inclusive elections, ultimately empowering citizens and safeguarding democratic processes.