zkPark

Urban cities face growing congestion, much of it caused by drivers circling in search of parking. Studies show that up to 30% of traffic in dense areas is due to this problem. On-street parking is often limited, expensive, and strictly enforced which is leading to fines even for brief overstays. Public garages, while available, are often costly, inconveniently located, or full during peak times, leaving drivers with few flexible, affordable options.

At the same time, thousands of homeowners and businesses have unused parking spaces that sit idle for most of the day. These could offer a valuable alternative but go untapped. Many owners are hesitant to share due to trust issues, security concerns, and the lack of a simple system to handle bookings and payments. While these spaces have strong potential to generate passive income, existing platforms don’t provide the infrastructure to make it easy or safe.

To solve these problems, we are building a peer-to-peer (P2P) parking platform powered by zero-knowledge (zk) proofs. Our solution allows everyday drivers to find, book, and use nearby parking spots, while enabling property owners to list and earn from their unused spaces, all with complete transparency, privacy, and trust. The system is made up of two mobile applications and a Raspberry Pi-based smart parking meter.

1. The user app allows drivers to sign up or log in, search for available parking spots near their location or destination, and book them for custom timeframes—perfect for short-term parking. Once the driver arrives, the Raspberry Pi-based meter at the spot detects the car, automatically starts the session, and ends it when the car leaves. The system calculates the duration, determines the price, and records the session on-chain. Zero-knowledge proofs ensure that all sensitive information, like user identity and location, remains private while still being verifiable.

2. The owner app is designed for property owners who want to monetize their vacant parking spots. Owners can onboard by submitting a lease document and a government-issued ID for ownership verification. Using zk proofs, the system verifies their credentials without ever exposing personal information. Upon successful verification, owners receive a unique decentralized identifier (DID) on-chain and can list their space with availability and pricing settings. Every time their spot is used, the system calculates the reward and sends it directly to their wallet, turning the space into a passive income asset.

3. The Raspberry Pi-based smart meter is the backbone of automation in this platform. It detects vehicle presence, logs the start and end of each session, calculates usage, and interacts with the blockchain to initiate fair and trustless reward payouts. All actions are recorded on-chain using cryptographic zk proofs, ensuring that sessions are auditable, tamper-proof, and secure—without revealing sensitive data about the user or location.

By combining decentralized identity (DID), zk proofs, blockchain technology, and IoT sensors, we’re creating a parking ecosystem that’s private, fair, and community-driven. Drivers benefit from affordable, flexible parking without risk of fines, and property owners can easily convert their unused space into a reliable income stream. Our platform aims to transform parking into a trustless, shared utility that reduces urban congestion and unlocks the value of unused assets for everyone.

This project brings together zero-knowledge cryptography, decentralized storage, IoT hardware, and mobile development to create a fully trustless and privacy-preserving P2P parking platform. At the heart of it is Noir, a domain-specific language for zero-knowledge proofs, which I used to build circuits that handle core functions like document verification, user login, parking session validation, and payment calculation—all without revealing sensitive data.

For user authentication, I integrated noir-jwt into the React Native apps, enabling zk-based login where credentials can be verified without being exposed. Similarly, space owners can prove their ownership of a parking spot by submitting a lease document and ID, which are verified using Noir-generated zk proofs. These proofs are submitted and verified on-chain, ensuring trustless onboarding.

I used 0G decentralized storage to store all off-chain data in a secure, tamper-resistant manner. This includes user profiles, session records, zk proof metadata, and real-time heartbeat logs from the parking meters. The heartbeat system helps track whether a parking spot is currently available, adding live visibility for users.

The hardware component of the system is built with a Raspberry Pi paired with an infrared (IR) sensor, which detects when a vehicle enters or leaves a spot. Once a car parks, the meter automatically starts the session, and when the car leaves, it ends the session and calculates the total duration. This data is bundled into a zk proof and synced to 0G and the blockchain.

To verify the zk proofs, I deployed a solidity verifier smart contract on the Sepolia testnet. This contract checks that all actions, like session times, ownership claims, and user logins, are valid, without needing to expose any raw data. This on-chain validation ensures the entire system is verifiable and secure while preserving user privacy.

The mobile experience is delivered via two apps built in React Native—one for drivers to find and book spots, and one for owners to onboard and manage their listings. The apps connect to the Raspberry Pi meter, the 0G storage layer, and the Sepolia smart contract for full end-to-end interaction.

One particularly clever implementation was creating a minimal zk circuit in Noir to validate the time-based pricing logic itself. This ensures users are charged fairly based on how long they parked, without needing to reveal exact timestamps—bringing transparency and privacy together in a novel way.

Altogether, this system showcases the power of combining zk proofs with real-world hardware and decentralized systems to solve everyday problems in a secure, automated, and privacy-first way.