Exploiting optical chaos for double images encryption with compressive sensing and double random phase encoding.

Images as a common information carrier are widely disseminated and used at present, meanwhile, image security and privacy protection are also facing severe tests. To enhance the security of images, an asymmetric double color images cryptosystem introduced optical chaos technology is proposed based on compression sensing (CS) and double random phase encoding (DRPE). It is the first time that the combination of CS, DRPE and optical chaos technology is demonstrated to the best of our knowledge. By means of the optical chaos keys generated by a constructed optical chaos model, the two color images are first decomposed into their respective Red–Green–Blue (RGB) channels, CS based on discrete wavelet transform is then performed for the first encryption. Afterwards, the second encrypion of DRPE in fractional Fourier transform domain (FrFT) with optical chaos technology is also used, and the asymmetric encryption by carrying out equal modulus decomposition (EMD) with optical chaos keys further enhance the security finally. Simulation results and security analysis confirm that the cryptosystem owns multi-layer protection and adequate resistance to brute-force attack, statistical attack, differential attack, noise attack and chosen-plaintext attack, which is efficient and capable of guaranteeing the security of images and can provide an alternative solution for image security and privacy protection. • Proposing an image cryptosystem based on CS and DRPE using optical chaos. • Applying optical chaos to DRPE, CS, and EMD, multi-layer protection is established. • A real laser chaos system is to realize the all-optical phase mask process for DRPE. • Greatly saving the storage space and transmission cost of the ciphertext image. [ABSTRACT FROM AUTHOR]