Image Cryptography using Parameterized Multiband Eigen Wavelet Filterbank

Abstract

In this paper, we present an eigen filterbank based approach for image cryptography. The proposed method consists of designing a wavelet filterbank using eigenfilter based approach and use the designed filterbank for image encryption with new methodology. We have extended an eigenfilter based approach for the design of multiband two-channel filter bank. This method is based on designing multiband analysis filter, followed by the design of complementary multiband synthesis filter. The designed filterbank has various user defined parameters (key) like, number of bands in the filter spectrum, cutoff frequency of individual frequency band and the level of decomposition. Based on the selection of these parameters we can design a unique filterbank, which can be used for the image encryption. At the decryption end, the original image can be reconstructed only if user selected parameters are known. We present few design examples for the illustration purpose. We also give detail of complexity analysis of the entire cryptography system and also present the time analysis. The proposed approach provides more number of user parameters as compared to state-of-art methods, which can be used as more secure key. It is also observed that the computation time of the proposed approach is comparable.