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Optical Engineering

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

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 obtained 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 decrypted phase-only mask applying the ZOPCT. An analysis of this decryption method was performed against brute force attacks.

Paper Details

Date Published: 1 September 2009
PDF: 5 pages
Opt. Eng. 48(9) 098201 doi: 10.1117/1.3223629
Published in: Optical Engineering Volume 48, Issue 9
Show Author Affiliations
José Carlos Pizolato, Univ. de São Paulo (Brazil)
Luiz G. Neto, Univ. de São Paulo (Brazil)


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