CypherShare3

This project enables secure and decentralized file exchange between two blockchain wallets, ensuring privacy and authenticity through integrated identity verification. By leveraging blockchain technology, users can transfer files directly, without intermediaries, while providing cryptographic proof of both sender and recipient identities. This approach guarantees data integrity, confidentiality, and trustless interactions within a fully decentralized ecosystem.

We built our project using a Next.js front-end and an Express.js back-end, all connected to a Solidity smart contract deployed on the blockchain. For identity verification, we integrated World ID, leveraging its SDK context to seamlessly authenticate users within our Miniapp environment.

File uploads are handled via the IPFS protocol, with Filecoin as our decentralized storage solution. Filecoin was essential because it guarantees long-term, tamper-proof, and censorship-resistant storage-exactly what we needed to ensure users’ files remain safe, accessible, and truly decentralized.

World ID was a game changer for us when it came to authentication and privacy. By using World ID, we could verify users’ identities in a privacy-preserving way, making sure that only real, unique users could access or exchange files, all without exposing their sensitive information.

Our smart contract then manages file permissions, allowing users to grant access for other wallet addresses to securely download files within the Miniapp. The hackiest part was tightly integrating World’s identity proof and Miniapp’s context with our file access logic, ensuring that only verified users can interact with files, all without compromising on decentralization or user experience.

Both Filecoin and World ID were crucial: Filecoin provided us with truly decentralized storage, while World ID enabled secure, privacy-first identity verification—allowing us to deliver a safe and trustless file exchange platform.