Research Of Combination Decryption Model For Vector Geographic Data Considering Overall Transformation And Random Disturbance

Vector geographic data is a kind of geographical data with the most basic,universal applicability and the highest frequency of use.It is the carrier and framework for various types of information and data and plays an important role in economic construction,social development and national defense construction,and is related to national security and benefits.The laws and regulations of our country put forward explicit requirements on the confidentiality of the sharing and application of basic geographic data.The confidential geographic data need to be transformed into the geographic data that meet the requirements of the public precision through technological means such as decryption.According to the characteristic and requirements of decryption of vector geographic data,based on the analysis of the existing decryption model,a decryption model which takes the overall transformation and random perturbations into account is established based on the generalized ellipsoid transformation differential formula and Chebyshev Polynomial.Meanwhile,the corresponding algorithm of decryption and recovery is also designed.The combination decryption model and its error control algorithm are focused in this paper.Finally,the decryption system is developed to verify the decryption model established in this paper.The main contents and conclusions of this paper are as follows:(1)Research of decryption model based on the generalized ellipsoid transformation differential formula.The projected coordinates are mapped to the ellipsoid surface for decryption with the generalized ellipsoid transformation differential formula.Iterating the movement parameters of ellipsoid to make the decryption close to the decryption target.Solving the parameters of decryption model to establish the decryption model.The algorithm of decryption and recovery based on the generalized ellipsoid transformation differential formula is designed.The algorithm has the characteristics of overall controllable,topological preserving and exact reversible.(2)Research of decryption model based on the Chebyshev Polynomial.The decryption model for vector data based on Chebyshev Polynomial is established in this paper.The decryption error control algorithm based on the Control point's offset is designed by iterating Control point's offset to make the decryption close to the decryption target.The decryption and recovery algorithm based on Chebyshev Polynomial is designed.This decryption algorithm is safe,smooth continuous and its error is random.(3)Research of combination decryption model considering overall transformation and random disturbance.Combination decryption model can combine the advantages of single model,and has higher complexity that hard to attack.The generalized ellipsoid transformation differential formula and Chebyshev Polynomial are combined in this paper.The error control algorithm of combination decryption model is researched,the overall deformation is controllable,the error distribution is random,the topology is maintained well using this decryption algorithm.This decryption model meets the requirement of safe and available of the decryption of vector geographic data.(4)Development of the decryption system of vector data and the evaluation of the decryption model.The decryption system is developed based on the decryption models established in this paper,and the system mainly includes the functions of decryption and recovery.The experimental data is used to verify the decryption model,and the comprehensive evaluation of the model is made from the aspects of safety,availability and controllability to verify the effectiveness of the model proposed in this paper.