Asymmetric multiple-images cryptosystems based on discrete multipleparameters fractional Fourier transforms

摘要

There are many free parameters in discrete multiple-parameters fractional Fourier transforms. These parameters can beapplied as encryption keys that make a cryptosystem safer. In this paper, the extended versions of discrete Fouriertransforms are employed into an existing asymmetric multiple-images cryptosystem. The resulting encryption system isbased on phase and amplitude truncations, which is the reason that the system is asymmetric. The phase combinationoperation during encoding makes the random phase key required for decoding, which enhances security of decoding. Thediscrete Fourier transform is replaced by discrete multiple-parameters fractional Fourier transforms to increase thenumber of free parameters and sensitivity of errors without decreasing the sensitivity of phase and amplitude keys.Related computer experiments are performed to validate our proposed methods.