We propose implementing a Cardano-native version of the Minimal Anti-Collusion Infrastructure MACI: a protocol originally developed for Ethereum to enable private, verifiable, and collusion-resistant on-chain voting in Aiken. This includes the development of all the involved smart contracts, such as the Poll contract and the ProcessorAndTallier contract, and a friendly user interface. This proposal covers every cryptographic primitive necessary for the protocol.

Cardano's governance framework emphasizes decentralized decision-making by empowering ADA holders to propose and vote on projects that shape the ecosystem's future. However, the inherent transparency of blockchain transactions poses significant challenges to voter privacy and the integrity of the voting processes. Since all on-chain activities are publicly visible, it becomes feasible for external parties to verify how individuals voted, thereby facilitating coercion, vote-buying, and collusion. This transparency, while beneficial for auditability, inadvertently compromises the confidentiality of voters' choices, potentially deterring participation and undermining trust in the governance system.

Moreover, the absence of robust and efficient mechanisms to ensure vote anonymity and resistance to collusion limits the effectiveness of Cardano's democratic processes. This not only affects the fairness and inclusivity of decision-making but also hinders the network's ability to evolve securely and equitably. Addressing these issues is crucial to uphold the principles of decentralization and to foster a resilient governance model that truly reflects the collective will of the Cardano community.

Implementing Minimal Anti-Collusion Infrastructure (MACI) on Cardano would significantly enhance the network's governance by introducing a voting system that ensures privacy and resists collusion. By leveraging zero-knowledge proofs (zk-SNARKs), MACI enables voters to cast their ballots anonymously, making it cryptographically infeasible for them to prove how they voted. This mechanism effectively deters bribery and coercion, as malicious actors cannot verify if a voter complied with their demands. Additionally, zk-SNARKs allow for the verification of vote tallies without revealing individual votes, ensuring both the integrity and confidentiality of the election process.

Integrating MACI into Cardano's governance framework would position the network at the forefront of secure and private decentralized decision-making. It would empower stakeholders to participate in governance without fear of surveillance or undue influence, fostering a more inclusive and trustworthy environment.

Milestones with estimated duration:

• PollDeployer and Poll smart contracts development - 2 months.
• PollProcessorAndTallier smart contract development - 1 month.
• zk-SNARK Integration - 1 month.
• User Interface development - 1 month.

The project time is estimated in 5 months.

Team structure:

1 Full-Time Smart Contract Developer: $50,000 / ₳100,000

1 Full-Time ZK Engineer: $56,250 / ₳112,500

1 Project Management / Community Manager: $12,500 / ₳25,000

The project time is estimated in 5 months. Team structure:

1 Full-Time Smart Contract Developer

1 Full-Time ZK Engineer

1 Project Management / Community Manager

Eryx is a worker-owned labor cooperative with almost 15 years of experience solving complex problems involving mathematics and software. We are a group of nerdy PhDs with a solid background in math and computer science. Our team has extensive experience in blockchain development, cryptography, and privacy-focused protocols, which gives us the expertise required to successfully deliver the project. Among other things, we’ve been core contributors to the Lambdaworks library and implemented the CircleSTARKS protocol in GPU alongside with Nethermind. This involved implementing several ZK cryptographic primitives (field operations, polynomial commitment schemes, FRI protocols, FFTs), in different platforms and languages. Furthermore, we implemented a proving system based on the Plonk protocol. During this project we wrote a simple interface to design circuits. It included basic operations and conditionals that made the building blocks for more complex cryptographic primitives. We also developed a Plonky2 backend for Aztec's Noir, funded by the Ethereum Foundation.

In relation to this proposal, we have extensive experience in Aiken smart contract development, including previously funded proposals under Project Catalyst such as the development of an API for zk proofs verification in Aiken. We also wrote zk circuits for cryptographic primitives such as hash functions and elliptic curve operations. We are active contributors to the ENCOINS protocol, currently deployed on the Cardano mainnet with privacy-preserving features. Currently, we are researching the integration of ZK systems with the EUTxO model.

All code and documentation will be available on a Github repository.

Many members of the community have expressed interest in improving the privacy and integrity of governance mechanisms, as concerns around voter privacy and vote-buying have been recurrent themes.

Also, there’s increasing engagement from the Cardano technical community around Zero-Knowledge Proofs (ZKPs), especially since the introduction of support for SNARKs and Plutus V3 in the Conway (Voltaire) era. Projects like Midnight (a privacy-oriented sidechain) show institutional alignment with the need for on-chain privacy. This proposal extends that logic into governance tooling.

With the launch of Voltaire, Cardano is transitioning toward a fully on-chain governance system, which naturally demands stronger mechanisms for vote privacy.

This protocol makes use of zkSNARK verification in smart contracts. Therefore, we need certain ZK tooling in Aiken. Luckily, this is being currently developed by us in the context of this grant: https://projectcatalyst.io/funds/13/cardano-open-developers/designing-an-api-for-zk-snark-proof-verification-in-aiken-eryx