Resolver Contract: Toward an NFT Verification Method with Enhanced Linkability

NFT is a prominent blockchain technology product that seeps into society after cryptocurrency. Most NFT structures use URL(s) to access external off-chain storage, where the associated asset’s metadata information or the asset itself is stored. This practice is commonly done due to its simplicity, gas cost consideration, or even the possibility of doing on-chain storage. However, questions could be raised for this mainstream NFT structure: What happens if the URL cannot be accessed? Is there any way to verify that an asset is an NFT, suppose the URL is broken? Issues regarding the linkability between an NFT and its asset and the impracticality of NFT verification are rarely highlighted, exposing users to risks such as purchasing an "empty NFT," potentially resulting in growing distrust toward NFT. This paper aims to answer these concerns by proposing a method that preserves and enhances NFTs to their respective asset’s linkability while acting as an NFT verification tool. The method involves registering, mapping, and storing the asset’s hash value with its related NFT information in a resolver smart contract while enabling verification for NFT minted in different blockchain networks.