Modulo-P

Overview

Modulo-P is a small software team that builds privacy tools based on zero-knowledge proofs, a kind of cryptography that lets someone prove a fact is true without showing the data behind it¹. Its main audience is developers, who can add its code libraries to their own apps for private checks such as anonymous voting. Modulo-P publishes that code publicly on GitHub².

Modulo-P works on Cardano. Its three listed members are a mathematician, a full-stack Web3 developer, and a Plutus smart contract developer, and the team's stated mission is to use that expertise to serve emerging Cardano projects¹. They met during the Cardano EMURGO BUILD 2023 hackathon, where the team was one of the winners in its category³. Its research has received grants from Project Catalyst, Cardano's community-voted funding program⁴.

Key Features

• Proof checks that run on Cardano. The ak-381 library, written in the Aiken smart contract language, lets a Cardano app verify Groth16 proofs, a compact type of zero-knowledge proof, and works with the Circom and SnarkJS proof tools².
• Anonymous membership and voting. Cardano-Semaphore adapts Semaphore, a protocol first built for Ethereum, so a person can prove they belong to a group and send a vote or message without revealing who they are. The contracts also reject anyone who tries to signal twice⁵.
• A shared starting point for secure proofs. Together with Encoins, Modulo-P ran a Catalyst-funded Powers of Tau ceremony, where many participants add secret randomness to build the setup that Groth16 proofs need on Cardano⁶. Other projects can reuse this shared setup and only complete a second step tailored to their own application⁷.
• Private checks against transaction blacklists. With Encoins and Eryx, the team built a Proof of Innocence tool, which lets users of privacy services show their funds did not come from a blacklisted set of transactions without revealing which transaction is theirs^8,9.
• A playable demo of the idea. Modulo-P's zk-Mastermind turns the classic code-breaking game into a zero-knowledge demo. The code maker proves each clue is honest while the secret colors stay hidden, and the game runs on Hydra, a Cardano add-on for fast transactions away from the main chain¹⁰.

What to Expect

Developers get the most from Modulo-P. The ak-381 README explains how to add the library to an Aiken project and includes a script that walks through the full Groth16 process: setup, proof creation, and verification². Cardano-Semaphore builds and runs its tests with the standard Aiken commands, and its README explains identities, groups, and signals in plain terms before the code⁵.

Curious visitors will find a website at modulo-p.io with team profiles, a video of the Mastermind proof of concept, and a litepaper. The litepaper explains why the game uses Hydra: when the team built it, checking these proofs took more computing than a normal Cardano transaction allowed¹¹. A separate transparency page lists what the team delivered for its Fund 10 grant, including research, proof-checking contracts, and the ak-381 library⁴.

Projects weighing a collaboration can read the joint Proof of Innocence proposal, which describes each partner team's background and experience⁸. Agustín Salinas of Modulo-P has also presented the team's zero-knowledge tooling at a Cardano Developers Office Hours session¹².