Optical image encryption algorithm based on phase-truncated short-time fractional Fourier transform and hyper-chaotic system

To increase the robustness against common attacks, a novel image encryption algorithm is proposed based on the phase-truncated short-time fractional Fourier transform (PTSTFrFT) and the hyper-chaotic system. In the algorithm, the original image is divided into four sub-images to be encoded indepe…