International Association
for Cryptologic Research

Non-fungible tokens (NFTs) are a blockchain application that has recently witnessed significant success. However, NFT marketplaces are majorly built on popular blockchain platforms that do not provide privacy tools. As a result, NFTs are easily visible to everyone. This has naturally given rise to various issues, including stolen/duplicate NFTs and attacks like shill trading. Furthermore, this architecture fails to reflect the real-life privacy notion as it digitizes unique physical goods. In this project, we build Paras - a blockchain-agnostic protocol that offers privacy to NFTs. Specifically, one may hide the real NFTs and only display a reference to them on marketplaces, hide seller and bidder identities, hide bid values and user wallet balances.

Paras is based on cryptographic primitives, such as, threshold encryption and robust secret sharing. It does not rely on any trusted execution environments for security, unlike some existing protocols in this direction.