Research On Application Of Document Image Parallel Encryption Method Based On Cascaded Hyperchaos

With the increasing development of Internet technology,especially the international pandemic caused by the novel coronavirus,the world economy has suffered huge losses.Nowadays,people are more dependent on the Internet.Online shopping,online office,online government and other software have been deeply embedded in daily work and life.The use of the Internet to facilitate the office and life at the same time,information security problems also come one after another,become an important factor restricting the development of the network environment.Information encryption is one of the effective techniques to solve the constraints.This paper proposes a parallel encryption method of official document image based on cascaded hyperchaos,in which the normalized two-dimensional Logistic chaotic map and super Lorenz chaotic map are cascaded,and the periodic trigonometric function perturbation and random sampling consistency algorithm are added to achieve the effect of expanding the key space,producing anti-chaos degradation characteristics and improving the pseudo-random of chaotic sequence;The cascaded hyperchaos sequence generator and the cascaded hyperchaos parallel image encryption algorithm are proposed.The received sequence data is distributed evenly to each slave node through MPI.Each slave node calculates the chaotic map iterative calculation,chaotic key conversion,and document image block encryption processing,which effectively improves the quality of ciphertext image and image encryption efficiency;The Web end software of the official document image encryption system is designed,and the approval method based on the authorization code is adopted,which effectively proves the universality of the official document image encryption scheme designed in this paper in the application field.The experiment uses chaotic phase diagrams and NIST testing to analyze the statistical characteristics of the generated chaotic pseudorandom sequences,and performs difference analysis,statistical analysis,information entropy,key analysis,noise attack resistance,image quality analysis,and bit accuracy analysis on official documents and their ciphertext images to analyze the quality of ciphertext images.The experimental results show that the improved cascaded hyperchaotic map meets the requirements of NIST testing and has stronger sequence randomicity.The generated key has a large enough key space and strong sensitivity,and can effectively resist exhaustive attacks,differential attacks,noise attacks,and statistical attacks.Finally,the parallel optimization improvement analysis is performed by analyzing the parallel acceleration ratio of the encryption system,the average system running time under different processor cores and image file sizes,and the average time percentage of each encryption step.The experimental results prove that the encryption scheme described in this article can effectively improve the efficiency of document images with different image sizes through parallel computing optimization.