Multiple-image Encryption Based On The Fractional Fourier Transform

In recent years, the fractional Fourier transform and its application is a hot spot in information processing research. The fractional Fourier transform is derived from the traditional Fourier transform. The fractional Fourier transform not only can be used in the applications of the Fourier transform, but also show some new features. These characteristics make fractional Fourier transform can be used as an important mathematical tool in optics and digital signal processing. Today, information security is so important that attracted so much attention. The fractional Fourier transform has many features that can make the image encryption system simple, practical and secure. As the increasing demand for information, multiple image encryption technology becomes important. In this paper, the conventional optical image encryption technology was reviewed first. The double random phase encoding technology is introduced second. Then we introduced the weakness of the double random phase encoding technology when the encryption system was attacked by the chosen-plain attack. After this, the next chapters of this paper focus on how to resolve this problem and we give out two methods by ourselves. The first method is called minimum cipher-text multiple-image encryption technology based on the fractional Fourier transform, and the second method is called asymmetric multiple images encryption based on the fractional Fourier transform. Computer simulations are performed to verify the feasibility of the proposed algorithm. Lastly, the conclusion was presented.