Fault tolerances using toroidal zone plate encryption

We present an analysis of the sensitivity to misalignment, illuminating wavelength change or construction parameters alterations for a zone plate used in an encryption method. The security system is based on a computer generated toroidal phase mask. We use a processor where this phase mask is placed in the Fourier plane of the object to be encrypted. As the original-data recovering is performed by using the conjugate of the encryption mask, a perfect match with the original conditions or the mask characteristics influences not only on the quality of the decrypted image, but also in the success of the method. Our results show that the scheme is an optimized design concerning both data storage and encryption as exhibit less degenerate noise while keeping the security standards of other methods. (c) 2005 Elsevier B.V. All rights reserved.