Compressing Encrypted Images Using the Integer Lifting Wavelet

Compressing the encrypted data remains a challenging task. In this paper, we propose a new compression scheme using the integer lifting wavelet transform (ILWT). In particular, the original image is decomposed with the ILWT, and the coarsest and detail subbands are encrypted via the stream and permutation ciphers, respectively. These encrypted subbands are then transmitted to the third party like network or storage service providers, and imposed with the lossless and lossy compression, respectively. Upon receiving the compressed and encrypted bit stream, the receiver conducts the successive decompression and decryption to reconstruct the original image. Experimental simulations show that the proposed algorithm achieves favorable rate-distortion performance with low computational time and reasonable high-level security. Also, it obtains significant improvement over the prior art and considerably outperforms the conventional JPEG with original, unencrypted images as inputs.