# A Non-Fungible Token and Blockchain-Based Cotton Lint Traceability Solution
## 1 Introduction
As a token based on blockchain technology, an NFT can explicitly reflect the ownership of digital assets and allow holders to trade ownership interests in their underlying assets. The NFT is unique and irreplaceable; each token is a unique entity and is not interchangeable with any other token. Each NFT has a transparent ownership attribution that is corroborated and recorded through the underlying blockchain technology, thus enhancing the stability of the value of the corresponding digital assets and traceability throughout [14]. In the textile industry, NFTs can encode the quality parameters and characterisation information of cotton and are applied to track the complete data chain of lint from cultivation up to the end consumer [15]. Therefore, we innovatively propose a complete traceability solution for cotton lint quality that integrates blockchain technology and NFTs, aiming to solve the problems associated with order transactions and lint quality certificate authentication in the lint supply chain, to enhance the transparency and trust of the whole industry chain. In this solution, we transform seed cotton and cotton lint entities into unique assets in a digital form that are uniquely identified through NFTs. The main contributions of our solution are as follows:  
* We propose an integrated solution based on blockchain technology to efficiently manage the ownership of seed cotton and lint in the lint supply chain and digitise lint inspection and certification through NFTs. * In our solution, we innovatively integrate the distributed storage technology of IPFS to ensure the secure and permanent storage of NFT metadata. With this integrated design, we effectively avoid the inefficiency and high cost of storing large amounts of data directly on the blockchain. * In our work, we use a system architecture design methodology and a sequence diagram model to plan, describe and interpret our solution in detail. These graphical toolsprovide a comprehensive view of the participants' and consumers' behavioural patterns and process logic in critical interaction scenarios, especially for the core processes such as the seed cotton auction. * We use the Solidity programming language to design and implement critical functional modules of smart contracts to support our proposed blockchain-based supply chain management solution for cotton lint. These smart contracts have been carefully written and rigorously tested, covering functions such as ownership transfer, seed cotton auction mechanisms, lint inspection and certification NFT issuance, and they have been successfully deployed in the Ethernet test network environment. The rest of the paper is structured as follows: in Section 2, we review related work using blockchain and NFTs; in Section 3, we propose a solution based on blockchain and NFTs; in Section 4, we describe the details of the smart contract implementation of our solution; in Section 5, we test and validate the smart contract; in Section 6, we evaluate and analyse the deployment of our smart contract; and, finally, Section 7 summarises our contributions.