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The 2024 US presidential election showcased the public’s growing enthusiasm for prediction markets and citizen journalism. However, while blockchain-backed offerings promise to empower citizens like never before, the most pressing issue impacting the future of our government remains voter privacy and security. Paper systems are costly and slow, and current electronic voting systems lack privacy, transparency, and accessibility—undermining trust in democracy.
Enter zero-knowledge proofs: a cryptographic method that ensures privacy-preserving, succinct, and unfalsifiable proofs that offer a transformative solution for national elections. By enabling verifiable, tamper-proof votes, ZKPs can revolutionize democratic processes, ensuring voter privacy, election integrity, and transparency without reliance on trusted authorities. ZKPs have the potential to unlock mathematically secure democracies.
### Understanding Where and How Paper Ballots Went Wrong
Despite technological advancements in every function of our everyday lives, the United States voting system still largely relies on paper ballots. In fact, in August of this year, it was projected that 98% of all votes for presidential candidates in November would be cast on paper. While paper systems are often seen as secure, they inherently require trust and leave voter data vulnerable to breaches, misuse, and identity theft.
Additionally, traditional systems offer little transparency or mechanisms for voters to verify their vote’s integrity, fueling public skepticism and disinformation. For example, the 2020 US elections saw widespread allegations partly because voters lacked a reliable way to verify results independently. As we’ve seen, insecure systems erode trust and perpetuate myths about electoral integrity.
### How Traditional Methods of Electronic Voting Offer Flawed Systems
While electronic systems were introduced to modernize elections and reduce costs, they still pose a significant risk to fair elections and come with trade-offs in security and trust. That’s because these systems rely on centralized intermediaries, making them vulnerable to tampering, coercion, and privacy violations.
Early attempts to address these issues, such as blockchain-based systems, introduce decentralization and self-tallying. However, these blockchain-based systems often fell short of addressing scalability and securing voters’ personal information. The lack of any true privacy inherent in current decentralized blockchain technology runs the risk of compromising voter privacy, exposing both a voter’s identity and ballot choices, not unlike paper or traditional electronic systems.
What’s needed is a technological system that can ensure voter integrity and privacy and prevent manipulation while reducing the data that’s stored on-chain—something that allows for faster and more efficient vote processing without compromising security. This is where ZKP technology stands out. By resolving the trade-offs between transparency and privacy while maintaining scalability, ZKPs provide a foundation for secure, verifiable, and efficient voting.
### Introducing ZK Proofs: The Next-Gen Solution to Voter Integrity
ZKPs offer the very solution needed to protect voter privacy and enable scalable voting processes. That’s because ZKPs allow a voter to prove eligibility or vote validity without revealing their identity or vote choice, ensuring both privacy and integrity in the process. To do so, ZKPs rely on mathematical principles that enable the verification of claims, such as vote validity in elections, without disclosing any personal data or sensitive details. Additionally, ZK off-chain computations can address scalability issues in blockchain-based e-voting systems. By reducing on-chain storage requirements, this system makes handling large-scale elections feasible while maintaining transparency, privacy, and universal verifiability.
Here’s a more in-depth look at how ZKPs can build mathematically secure democracies and resolve issues with existing electronic voting systems:
1. **Protecting Voter Anonymity**: ZKPs allow voters to authenticate the validity of their vote or other documentation without revealing underlying personal data or documents, thus protecting their privacy. This is made possible through the three components of the ZKP’s algorithm: completeness, soundness, and zero-knowledge. Completeness works like this: if a statement (X) is true, and both the prover and the verifier correctly follow the protocol, the verifier must accept the proof as true. The proof cannot be falsified, ensuring reliability. Similarly, the soundness component means that if the statement (X) is false, the verifier will not be convinced by the proof, even if everyone follows the protocol correctly.
2. **Enabling Decentralized Record-Keeping**: In a ZKP system, a decentralized and transparent ledger (the blockchain) records votes, establishing accountability and security.
3. **Ensuring Voting Transparency and Integrity**: ZKPs enable a collusion-resistant system that empowers voters to verify that their vote was accurately recorded in the tally without revealing their vote preferences, ensuring trust and integrity in the voting process.
4. **Establishing Mathematical Security**: ZKPs provide robust guarantees, confirming that the voting protocol is secure.
### Real-World Applications of ZKPs in Voting
ZKP-based voting is no longer theoretical. In October 2024, Georgia’s leading opposition party, the United National Movement, launched “United Space,” an identity app built by Rarimo, a protocol specializing in decentralized digital identities. This app utilizes blockchain and ZKPs to ensure secure and anonymous voting, aiming to combat low voter turnout by rewarding participation and protecting voter identities.
Other projects like zkPassport, Anon Aandhaar, and OpenPassport demonstrate the potential for integrating ZKPs into identity verification systems, proving attributed information like nationality or age without exposing privacy information.
### Existing Limitations of ZKP-based Identification
While ZKPs offer groundbreaking potential for secure voting systems, they still face challenges, particularly their reliance on passports for verification. Passport ownership is not universal—only around 50% of the US population holds a valid passport, and rates are much lower in many developing countries. Moreover, passports lack biometric validation, making them susceptible to fraud through stolen or counterfeit documents. Corrupt issuing authorities could theoretically manipulate voting outcomes by creating invalid documents that nonetheless pass verification.
Another fundamental challenge lies in the persistence of cryptographic signatures associated with revoked or replaced passports. Even when a document is no longer valid, its digital signature often remains usable, introducing a risk of misuse. Finally, many ZKP-based systems rely on a single point of verification—typically a passport—rather than aggregating attestations from multiple sources, such as national ID systems, banking institutions, or mobile carriers. This reliance increases the likelihood of system failures or manipulation.
A solution to these challenges exists in expanding the sources of identity verification to include attestations from diverse and trusted attestors. Incorporating biometric validation into the passport verification process could significantly reduce risks associated with stolen or borrowed documents. Additionally, the development of cryptographic standards that allow for the invalidation of outdated signatures would address vulnerabilities posed by revoked or replaced documents.
ZKPs represent a paradigm shift in secure voting, addressing vulnerabilities in traditional and blockchain-based systems. By enabling mathematically secure, privacy-preserving elections, ZKPs have the potential to foster trust, transparency, and participation in democratic processes. As ZKP technology evolves, it holds the potential to unlock democracies that are not only secure but also more inclusive, equitable, and participatory.
This article was co-authored by
**Andre Omietanski** and **Amal Ibraymi**.
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**Andre Omietanski** is general counsel at Aztec Labs, which is developing the privacy-first Layer-2 on Ethereum that enables developers to build privacy-preserving applications while ensuring compliance. Andre spent over a decade at White & Case in London, where he left as counsel, gaining extensive, global, and diverse experience in complex traditional finance transactions. Prior to joining Aztec Labs, he was a crypto advisor to early-stage startups in the Ethereum, Cosmos, and Polkadot ecosystems.
**Amal Ibraymi** is the legal counsel at Aztec Labs, where she supports the company’s legal efforts to advocate for privacy-enhancing technologies and decentralized finance. Before joining Aztec, Amal was a privacy associate at the New York and Paris offices of Willkie Farr & Gallagher, where she advised on data protection, cryptography, and global privacy compliance. Amal also previously worked at the Office of Legal Affairs at the United Nations Secretariat in New York City, the International Court of Arbitration of the International Chamber of Commerce in Hong Kong, and as a Privacy Fellow at the OECD in the Paris headquarters. Amal is dually trained in the U.S. and France, holding an LLM from NYU School of Law and a JD/MA from Sciences Po Paris.