| With the popularization of computer and Internet,the GIS vector map has been extended to the public and the government.In the military field,GIS vector map has been widely attention and application,become the basis of modern war.In the current era of network and information,it is more convenient to obtain and copy the geographic information products.At the same time,geographic information security has been challenged.Therefore,the security of map data needs to be protected by encryption technology to prevent illegal theft and distribution.However,the current vector map data encryption technology mainly depends on the traditional encryption technology,there is encryption efficiency is not high,damage the original data structure,data volume expansion and other issues.In this paper,we analyze the main encryption techniques of vector map data,which are the encryption and technology based on traditional encryption algorithm,the encryption technology based on chaotic system and the scrambling encryption technique of vector map data.The advantages and disadvantages of the three encryption technologies are obtained.Although it can meet certain encryption needs,not practical.This paper designs a hierarchical encryption scheme,batch encryption scheme and secure distribution scheme,and proposes a vector map data encryption algorithm based on chaotic sequence.Hierarchical encryption,the encryption scheme is encrypted according to the level of the map,which is beneficial to the fine management of the vector map data.In addition,only the core part of the vector map data is encrypted and the encryption efficiency is improved.Then,the batch encryption scheme is introduced,That is,multiple users request multiple files encryption scheme,the scheme on the premise of guarantee safety to improve the efficiency of encryption.Finally,the introduction of a secure distribution scheme,this scheme can solve the security problems of symmetric encryption key distribution on the network.The core of this paper is based on the chaotic sequence encryption algorithm,which expounds the encryption principle of the encryption algorithm and encryption process.The algorithm is mainly based on the pseudo-random sequence generated by the chaotic system.By using the chaos sequence to the initial value and the randomness of the chaotic sequence,the horizontal and vertical coordinates of the elements are randomly differentiated,and then the one-dimensional discrete cosine Transform,and select the encryption DC value,and thenone-dimensional discrete cosine transform,and finally again randomized scrambling to achieve the purpose of encrypting the entire element.Compared with the traditional encryption algorithm,the encryption method has the advantage of preserving the original data structure and resisting the aggressive attack. |
