Research On Digital Image Encryption Technology

The digital image information security, follows the new question which this computer network and the multimedia technical rapid development produces. In recent years, image information is more and more popular on the net, but because some image information involves individual privacy and national security, must take the way to transmit secretly, so the image encryption is being paid attention to, studying the image encryption has important realistic meanings.The groundwork herein can be divided into several following parts:1. The article introduces the current situation of the development of background, research of the digital image encryption and extensive practice application briefly at first, then has explained ABC of the digital image systematically, including digitization and mathematics of image express, the characteristic, basic statistic of the digital image, digital image of the digital image encrypt the theory block diagram transmitted and encrypting the characteristic of the image etc., on this basis, have summed up existing image encryption method and characteristic in the world in detail, and belong to the whole classification to it, offer the theoretical foundation for follow-up study.2. It has studied the digital image encryption based on modern password system. On the basis of recommending classics such as DES, AES and RSA to encrypt the algorithm principle emphatically, have carried on comparative analysis to their performance, emulation realizes the encryption method of digital image based on DES and AES algorithm, resist and attack the analysis of performance to the encryption method of digital image based on AES algorithm especially, can't resist the deficiency that noise, cutting out and JPEG,etc. attack effectively to it, propose a kind of improvement algorithm, combine existing classical Aronld and put the haphazard algorithm and improve this kind of encryption algorithm, on the basis of guaranteeing algorithm security like this, the ones that have strengthened the algorithm are stupid and excellent, the experimental result reveals this kind of improvement has increased the advantage of this algorithm.3. Encrypt algorithms after putting forward two kinds of digital images based on that DCT vary the land, digital image encryption method and encryption method of digital image based on that DCT vary and put combining together with Arnold arbitrarily combined with the matrix of Chaos arbitrarily are put to vary on the basis of DCT, the contrast of the artificial experimental result analysis indicates, these two kinds of encryption methods have better security and stupid and excellent. Image after not encrypting shear, attack, add gauss low to strain wave, carry on JPEG compress while being coherent, histogram take, strengthen luminance,etc. attack or interfere with, especially, the primitive image after deciphering one " The original appearance " The all right full restoration will come out, therefore, this kind is varied on the basis of DCT and should be obviously superior to the encryption method of digital image based on AES with other ones that put digital image encryption method that the haphazard algorithm combines together stupidly and excellently, and this kind of algorithm relatively has higher security.