Visually Meaningful Image Encryption Scheme Based on DWT and Schur Decomposition

A visually meaningful image encryption scheme with an asymmetric structure based on the discrete wavelet transform (DWT) and Schur decomposition is proposed in this study. First, RSA algorithm used to generate initial values for chaotic system produce random sequence. Then, both scrambling diffusion operations are performed plain obtain preencrypted image. Moreover, applied upper triangular orthogonal matrices. Second, cover scrambled followed by a DWT operation. Four subbands then formed, namely, LL, HL, LH, HH. Finally, former matrix embedded into LH HH produced After application of inverse operation, final secret can be obtained. No one identify any useful information about from image, nor anybody know that there hidden Experimental simulations show normalized correlation between original approximately 0.9997. Therefore, imperceptible communications.