# A Blockchain Copyright Protection Model Based on Vector Map Unique Identification
###### Abstract  
Combining blockchain technology with digital watermarking presents an efficient solution for safeguarding vector map files. However, the large data volume and stringent confidentiality requirements of vector maps pose significant challenges for direct registration on blockchain platforms. To overcome these limitations, this paper proposes a blockchain-based copyright protection model utilizing unique identifiers (BCPM-UI). The model employs a distance ratio-based quantization watermarking algorithm to embed watermark information into vector maps and then generates unique identifiers based on their topological and geometric parameters. These identifiers, rather than the vector maps themselves, are securely registered on the blockchain. To ensure reliable copyright verification, a bit error rate (BER)-based matching algorithm is introduced, enabling accurate comparison between the unique identifiers of suspected infringing data and those stored on the blockchain. Experimental results validate the model's effectiveness, demonstrating the high uniqueness and robustness of the identifiers generated. Additionally, the proposed approach reduces blockchain storage requirements for map data by a factor of 200, thereby meeting confidentiality standards while maintaining practical applicability in terms of copyright protection for vector maps. vector map copyright protection; blockchain; unique identification; geometric feature; topological feature +
Footnote †: journal: Accepted: 20 November 2021  
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Footnote 1: Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210023, China; [EMAIL_ADDRESS]  
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Footnote 1: Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210023, China; [EMAIL_ADDRESS]  
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Footnote 2: State Key Laboratory Cultivation Base of Geographical Environment Evolution, Nanjing 210023, China
verification systems often rely on centralized servers or third-party institutions, which introduce vulnerabilities. Centralized systems are susceptible to failures and cyberattacks that can compromise the entire verification process [6; 7]. Furthermore, the inclusion of personal or sensitive information in watermarks [8] raises concerns about potential misuse or unauthorized access by third-party institutions. The emergence of blockchain technology offers a transformative solution for the secure and reliable verification of digital watermarks [9]. Blockchain's distributed and decentralized architecture ensures data integrity and trustworthiness by storing watermark information on multiple nodes across the network [10]. As an immutable distributed ledger, blockchain encrypts and hashes data records, making them resistant to tampering or deletion once registered [11]. Additionally, blockchain facilitates the tracing of watermark propagation paths, recording every instance of data copying or dissemination. This traceability enables copyright holders to quickly identify infringements and take legal action to protect their rights [12]. Despite these advantages, the unique characteristics of vector map data introduce challenges for blockchain-based copyright protection. Vector maps comprise extensive geographic information [13], including coordinates, line segments, and polygons. These data demand substantial storage capacity when registered on blockchain nodes. Moreover, the high confidentiality requirements of vector maps render direct registration impractical. Therefore, a mathematical approach is urgently needed to construct unique identifiers from vector maps, allowing these identifiers--rather than the full maps--to be registered on the blockchain. This approach not only reduces storage demands but also facilitates the efficient verification and traceability of map data origins and integrity. Currently, unique identifiers for vector maps are often generated using hash algorithms, which ensure strong differentiation between datasets [14; 15].