Research And Soft Implementation Of Color Image Encryption Algorithm Based On Chaotic Map

As the speed of the popularity of the network and the development of the Internet technological are faster and faster,which resulting in an increasing number of digital color images transmitting over the network.These color images may be related to personal privacy,corporate interests,military secrets or national security.The best way to protect some certain important information of the color images not been illegally steal by the non-authorized users is to encrypt them,while the color images are storge and transmission.The image encryption based on chaotic map is a recently developing image encryption.Chaos is a natural encryption system,because the chaotic systems have many properties which have corresponding counterparts in traditional cryptosystems, such as ergodicity,sensitivity to initial condition/system control parameters and random like behavior,which can be connected with some conventional cryptographic properties of good ciphers,such as confusion,diffusion,balance,avalanche properties, etc.The irregular two-dimensional plane of the chaos is the best condition for image encryption.However,most of the previous image encryption algorithms study on the gray images which are not suitable for the color images,because the color image has characteristics of large amounts of data and highly correlation of pixels.Therefore,this paper selects the Color Image Encryption Algorithm Based on the Chaotic Map as a research topic,respectively propose a new color image encryption algorithm based on coupled chaotic map and a novel color image encerption algorithm based on the Logistic map.And also make comparison and analysis of two kinds of encryption algorithm performance.At last designed software for two kinds of the color image encryptions and encryption algorithm performance evaluation based on MFC and Matlab 7.0.The contributions of this dissertation can be summarized as follows:(1) A new color image encryption algorithm based on coupled chaotic map.Based on the nature of coupled chaotic systems and combined with the characteristics of the digital color image that large amount of data,strong correlation between pixels and high real-time transmission requirements,this paper designs a new chaotic map image encryption algorithm which is suitable for digital color images. The algorithm uses two kinds of one-dimensional chaotic maps combine with a coupled chaotic map to realize the encryption of digital color image;The algorithm uses the ciphertext of the single-channel digital color image conbine with the key to realize to greatly increase the diffusion of single-channel digital color image;The algorithm fuses the ciphertext and the key of the red,green,blue channel to realize to greatly increase the diffusion of the red,green,blue channel of color image.The simulation results show that the algorithm has the characteristics that a large enough key space,high key sensitivity,extremely fast encryption and decryption speed, without prejudice of the image quality.This algorithm is very suitable for the video or image real-time encryption transmission.(2) A novel color image encerption algorithm based on the Logistic map.We present a novel secure cryptosystem for direct encrypting color images based on typical Logistic map.The Logistic map cryptography technique is a symmetric key cryptography.In this algorithm,the one pixel in channel R/G/B of cipher text are mixed with the typical Logistic map to encrypt the next channel G/B/R color image pixel one by one to greatly increase the diffusion of the red,green,blue channel of color image.The simulation results show that the proposed color image encryption technique can balance the tradeoffs between the speed and security and is suitable for the real-time secure image and video communication applications.And also compare and analyze the performance of two kinds of color image encryption algorithm based on chaotic map that presented in this paper. (3) Designed software for the color image encryption and encryption algorithm performance evaluation.Based on two kinds of the encryption algorithms and evaluation criteria proposed in this paper,this paper has developed a application software by the MFC and Matlab7.0 tools.The software is directly compiled by the VS2002.net platform and generate.exe executable file,which can run independent of the VS2002.net platform and Matlab platform.The software realizes all the performance of the two kinds of encryption algorithms designed in this paper,and has some advantages as a beautiful interface,easy operation,and intuitive algorithm evaluation function and so on.This software is ideal for private,corporate,military,national actual security application of the image.