###### Abstract
However, the practical application of NFT seems to have not fully achieved the originally envisioned effect. In every NFT transaction activity, there is a tokenization process of the original work, which will transfer the copyright from the owner to the buyer to be included in a smart contract, which means that in every NFT transaction, there will be a simultaneous transfer of rights from the same creation or ownership license [9]. Although the blockchain can provide a unique token identity for digital content and record transaction details, it cannot prove the identity of the author nor the authenticity and originality of the digital content [10]. At the same time, the easy availability of digital content, NFT casting tools, and casting tutorials on the Internet has intensified digital copyright infringement [11]. In addition, after the infringement is discovered, the blockchain platform is unable to technically and logically decompose the infringing NFT into black hole addresses [12; 13], and the remedies available to the platform are extremely limited. On the other hand, collusion between NFT service platforms and digital content creators is motivated and achievable. NFT has gradually entered the public eye since 2021, and not many users currently know and use NFT. Consumers without mature cognition rely more on similarity detection tools developed by service platforms to determine the originality of NFTs. However, in the field of similarity detection, the detection agency's judgment on whether a sample is plagiarized depends on artificially set thresholds [14]. The adjustability of this threshold determines the likelihood of collusion. In addition, in the field of detection, it is common to detect collusion between the executing party and the executed party [15]. Especially in the NFT market, where the value assessment mechanism is not yet complete, facing huge profit temptations, counterfeit entities, and NFT service platforms may collude in plagiarism in order to make huge profits. Evolutionary Game Theory (EGT) originates from the idea of biological evolution, which describes the process of bounded rational entities continuously responding to external shocks through imitation, learning, trial, and error under information asymmetry conditions [16]. Evolutionary Stability Strategy (ESS) and replicator dynamics are two core concepts in evolutionary game theory. ESS is a strategy that dominates a population for a long time and remains stable even in the face of small changes or mutations in other strategies. Replicator dynamics is a mathematical model that describes how the proportions of different strategies in a population change over time, where the rate of growth of a strategy is proportional to its advantage relative to the mean fitness. The replicator dynamic equation refers to a simple imitation of the dominant strategy by bounded rational group players, expressed by a dynamic differential equation or a system of differential equations. Therefore, the use of evolutionary games can accurately describe the development and changes in strategy selection, which is suitable for studying the behavior of copyright protection subjects in the NFT market. The situation of NFT infringement is theoretically feasible and has been confirmed in practice. Studying the regulatory strategies for digital copyright protection in response to the collusion phenomenon in the NFT casting process has important practical significance in stimulating the production of original high-quality content, strengthening cultural digitization construction, and promoting the healthy development of the digital publishing industry chain. Therefore, this study constructed a three-party game evolution model including digital content creators, NFT service platforms, and government regulatory authorities. The focus is on discussing the following three issues: 1 How to establish an evolutionary game model for digital copyright protection considering collusion behavior in NFT infringement scenarios?