Image Encryption Algorithm Based On Wavelet Transform Research

Image encryption is belongs to the category of the digital image processing，and also belongs to the field of information security，image encryption is theguarantee of the network transport security.Nowadays，with the rapid development ofscience and technology，image encryption technology also gradually got a lot of theattention，a variety of encryption methods verified and used.Image encryption isactually a clear image transform into a human eye couldn’t observe the content of theimage， namely by mathematical transformation and some other ways to hide clearto express the content of the image itself.In the image encryption process is dividedinto the airspace and frequency domain encryption，encryption is usually carried outduring the airspace，but a method of frequency domain encryption is more secure，more robust against JPEG compression method.So this article combined with themethod of combining frequency domain and the airspace is proposed based on asmall ripple of chaotic sequence encryption algorithm， and in view of the currentimage encryption scheme based on traditional wavelet transform convolutionoperation，calculation problems such as complicated，time-consuming，introducingthe wavelet lifting algorithm， in order to improve the execution efficiency of thealgorithm.At the same time because of the chaotic systems with pseudo randomnessand sensitive to initial value，parameters，such as characteristics， puts forward achaotic sequence scrambling transformation scheme of affine transformation， and inthe design of pixel gray value to replace two-dimensional logistic chaotic map wasintroduced， and the idea of two kinds of replacement， namely first carried out onthe low frequency coefficient after wavelet decomposition matrix scrambling， andwavelet reconstruction after the replacement of image pixels instead.The keygenerated by multiple chaotic sequence control，so the key space is greater than thesingle chaotic sequence generated by key space，at the same time avoid the singlechaotic sequence in the process of the image is encrypted again not security.Finallythrough the test and resistance to interference of encrypted image attack testing，encryption performance is good，the algorithm is verified，higher resistance againstperformance is more security encryption algorithm.