Phase-only optical encryption based on the zeroth-order phase-contrast technique

A phase-only encryption/decryption scheme with the readout based on the zeroth-order phase-contrast technique ZOPCT, without the use of a phase-changing plate on the Fourier plane of an optical system based on the 4f optical correlator, is proposed. The encryption of a gray-level image is achieved by multiplying the phase distribution ob- tained directly from the gray-level image by a random phase distribution. The robustness of the encoding is assured by the nonlinearity intrinsic to the proposed phase-contrast method and the random phase distribution used in the encryption process. The experimental system has been implemented with liquid-crystal spatial modulators to generate phase- encrypted masks and a decrypting key. The advantage of this method is the easy scheme to recover the gray-level information from the de- crypted phase-only mask applying the ZOPCT. An analysis of this de- cryption method was performed against brute force attacks. © 2009 Society

[1]  H Toyoda,et al.  Lossless light projection. , 1997, Optics letters.

[2]  Bahram Javidi,et al.  Resistance of the double random phase encryption against various attacks. , 2007, Optics express.

[3]  Jesper Glückstad,et al.  Dynamic array generation and pattern formation for optical tweezers , 2000 .

[4]  Y Sheng,et al.  Programmable optical phase-mostly holograms with coupled-mode modulation liquid-crystal television. , 1995, Applied optics.

[5]  Bahram Javidi,et al.  Optical image encryption using input plane and Fourier plane random encoding , 1995, Optics & Photonics.

[6]  Yunlong Sheng,et al.  Optical implementation of image encryption using random phase mask and speckle-free phase Fresnel hologram , 1997, Defense, Security, and Sensing.

[7]  Yunlong Sheng,et al.  Optical implementation of image encryption using random phase encoding , 1996 .

[8]  Stanley E. Monroe,et al.  Complex characterization of the Epson liquid crystal television , 1993, Defense, Security, and Sensing.

[9]  G. Cirino,et al.  Zeroth-order phase-contrast technique. , 2007, Applied optics.

[10]  P C Mogensen,et al.  Phase-only optical decryption of a fixed mask. , 2001, Applied optics.

[11]  J. Goodman.  Introduction to Fourier optics , 1969 .

[12]  Luiz Goncalves Neto.  Implementation of image encryption using the phase-contrast technique , 1998, Defense + Commercial Sensing.

[13]  Colin Soutar,et al.  Determination of the physical properties of an arbitrary twisted-nematic liquid crystal cell , 1994 .

[14]  Brian K. Jones,et al.  Modulation characteristics of the Epson liquid crystal television , 1992 .

[15]  P C Mogensen,et al.  Phase-only optical encryption. , 2000, Optics letters.

[16]  Y Sheng,et al.  Full-range, continuous, complex modulation by the use of two coupled-mode liquid-crystal televisions. , 1996, Applied optics.

[17]  B Javidi,et al.  Optical image encryption based on input plane and Fourier plane random encoding. , 1995, Optics letters.

[18]  Bahram Javidi,et al.  Optical and Digital Techniques for Information Security , 2004 .

[19]  Bahram Javidi,et al.  Fully phase encrypted image processor , 1999 .