Multi-Level Encryption Method For Geospatial Data By Considering Spatial Distribution Features

In the context of the era of big data,information security is receiving more and more attention,especially the security of geographical information.With the vigorous development of internet technology and geographic information technology,the collection,storage,access,transmission and application of geospatial data have become faster,and the ensuing security risks brought about by the leakage and theft of geospatial data have also received increasing attention.In particular,with the rapid development of smart city construction,new technologies and industries such as autonomous driving and high-precision maps have put forward higher demands on the sharing,transmission and personalized application of high-precision geospatial data.Therefore,how to encrypt and protect highly sensitive geospatial data from the perspective of data itself is particularly important,and is also an important bridge to promote geospatial data sharing,give full play to the value of geospatial data,and realize the transformation from high-precision geospatial data to intelligent geographic information services.Based on the traditional cryptography theory,national and international scholars have proposed many classical methods for geospatial data encryption by combining the theories of signal processing,DNA computing and chaotic systems.but most of the existing geospatial data encryption methods adopt the overall encryption strategy,ignoring the heterogeneous characteristics of the spatial distribution of geographic elements,making the encryption methods lack flexibility and difficult to achieve local encryption and hierarchical encryption,and leaving much room for improvement for security and encryption efficiency.To this end,based on the existing research,this paper considers the characteristics of vectorial geographic data and remote sensing image data itself,and proposes a multi-level encryption method for geospatial data by drawing on the idea of sub-regional multi-classification authorization in data access,so as to provide a new idea for the research of geospatial data encryption in network transmission environment.The main research work of this paper includes:(1)Aiming at the problem of geospatial data encryption and transmission,this paper concludes the existing geospatial data encryption methods at home and abroad systemically,summarizes the relevant research work on existing vector and remote sensing image data encryption methods,points out the imperfections of the existing research,puts forward the main research contents of this paper,and determines the research framework and ideas of this paper.(2)To address the problem that the existing vector geographic data encryption methods ignore the spatial distribution characteristics of each entity element,lack flexibility and are difficult to achieve local information encryption and decryption,this paper proposes a vector geographic data encryption method based on multi-level spatial indexing.Fully considering the spatial position relationship of vector elements,drawing on the idea of spatial database indexing,on the basis of partition and index construction of vector geographic data,vector geographic data encryption is realized based on chaotic system and discrete cosine transform method.Finally,the method is applied to real data to verify the effectiveness of the method.Compared with the existing methods,the encryption efficiency is significantly improved,and the local encryption and decryption function is realized.(3)To address the problem that the existing remote sensing image encryption methods ignore spatial variability of texture features of remote sensing images,resulting in low encryption efficiency and poor adaptiveness and scalability to image content,this paper proposes a remote sensing image data encryption method that considers the spatial differences of textures.The method draws on the idea of content-based multi-level authorization,divides and grades remote sensing images in blocks,and realizes hierarchical encryption of image blocks based on chaotic systems of different dimensions.Finally,the method is applied to real data to verify the effectiveness of the method and shows that it can not only effectively achieve information hiding of remote sensing image data,but also has high encryption efficiency and security.(4)Aiming at the application requirements of the current spatiotemporal big data management system and crowdsourced data collection and cloud update system,a prototype geospatial data encryption and decryption system is designed and developed based on the vector and remote sensing image data encryption method proposed in this paper,which can provide an effective data security protection tool for the secure transmission and sharing of geospatial data in the network.Finally,the paper reviews and summarizes the whole work,and looks forward to some problems to be further studied.