Securing information using fractional Fourier transform in digital holography

In this paper, we demonstrate a fully digital technique using double random Fourier, and fractional plane encryption. The input image to be encrypted is multiplied by a phase mask, and either its Fourier or fractional Fourier transform is obtained. Using interference with a wave from another random phase mask, the encrypted data (Fourier or fractional hologram) is recorded digitally. The decryption key is also recorded as a digital hologram, called the key hologram. An electronic key generated in the PC is multiplied with the encrypted hologram, and a Fourier or fractional Fourier transform (encrypted image) is obtained. This decryption key hologram, the electronically generated key (random phase code), and the encrypted image can be transmitted through communication channels. The retrieval is carried out by all-digital means. (C) 2004 Elsevier B.V. All rights reserved.