Key Validity Using the Multiple-Parameter Fractional Fourier Transform for Image Encryption

As a symmetric encryption algorithm, multiple-parameter fractional Fourier transform (MPFRFT) is proposed and applied to image encryption. The MPFRFT with two vector parameters has better security, which becomes the main technical means protect information security. However, our study found that many keys of are invalid, greatly reduces its In this paper, we propose new reformulation analyze it using eigen-decomposition-type (FRFT) weighted-type FRFT as basis functions, respectively. results show effective extremely limited. Furthermore, extended methods based on MPFRFT, also have security risk key invalidation. Theoretical analysis numerical simulation verify point view. Our discovery important reference value for class generalized methods.