Abstract
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 to protect information security. However, our study found that many keys of the MPFRFT are invalid, which greatly reduces its security. In this paper, we propose a new reformulation of MPFRFT and analyze it using eigen-decomposition-type fractional Fourier transform (FRFT) and weighted-type FRFT as basis functions, respectively. The results show that the effective keys are extremely limited. Furthermore, we analyze the extended encryption methods based on MPFRFT, which also have the security risk of key invalidation. Theoretical analysis and numerical simulation verify our point of view. Our discovery has important reference value for a class of generalized FRFT image encryption methods.
Highlights
Transform for Image Encryption.With the rapid development of information technology, image transmission has become an important means of communication
Our study found that many parameter keys are invalid
multiple-parameter fractional Fourier transform (MPFRFT) is widely used in information security, and its security mainly depends on parameter keys
Summary
The development of new image encryption algorithms has become the focus of research. In 2008, Tao et al proposed an image encryption method based on multiple-parameter fractional Fourier transform (MPFRFT) [3]. Our research shows that many parameter keys of either the MPFRFT or its modified schemes are invalid, and it cannot obtain a larger key space with the increase of the weighting term. This is determined by the periodicity of the basis function itself, and we will present a detailed analysis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
