Application and Limitations of Digital Signature Schemes for Implementing Non-Fungible Token (NFT): Exploring Designated Confirmer Signatures and Blockchain Technology for Non-Fungible Token (NFT) Implementation

The ERC721 standard defines a Non-Fungible Token (NFT) as an identifier that uniquely identifies digital data recorded on a blockchain. The NFT currently in use claim to ensure the uniqueness of the contents associated with the NFT by taking advantage of the tamper-resistant characteristics of the blockchain data. Besides, digital signatures based on public-key encryption is a representative technique to prevent digital data from being falsified, and its application to NFT is also discussed. In this study, we first consider an NFT implementation by applying a designated confirmer signature using an interactive verification method without using blockchain technology. We design an NFT issuance protocol that guarantees the uniqueness of data with a designated confirmer signature, and evaluate the security of the protocol. Moreover, we compare it with existing blockchain implementations. By analyzing the both methods, we aim to provide insights into the potential applications and performance in using designated confirmer signatures for NFT. Our findings contribute to the ongoing research on secure and efficient mechanisms for ensuring the integrity and uniqueness of digital assets in decentralized systems.