Image compression-encryption algorithm based on chaos and compressive sensing

An image encryption scheme based on compressive sensing (CS) and chaos is proposed. Firstly, the plain image is transformed into the sparse coefficient matrix by discrete wavelet transform (DWT). Secondly, to achieve compression and encryption, the sparse coefficient matrix is measured by the measurement matrix, which is constructed by the Logistic-Tent system (LTS). This process can effectively reduce storage space or transmission bandwidth of the image. Finally, the resulting measurement value matrix is re-encrypted by executing dual random index permutation and bit-level diffusion to improve security of the cryptosystem, and then the cipher image is obtained. In addition, the SHA 256 hash value of the original image is utilized to calculate the initial value and parameter of LTS, making the proposed algorithm robust to known-plaintext and chosen-plaintext attacks. The simulation results show that our algorithm has good image compression-encryption capability and security performance.