Role of phase key in the double random phase encoding technique: An error analysis

School of Electrical, Electronic and Mechanical Engineering, College of Engineering, Mathematics and Physical Sciences, Optoelectronic Research Centre, University College Dublin, Belfield, Dublin 4, Ireland.
Applied Optics (Impact Factor: 1.78). 07/2008; 47(21):3808-16. DOI: 10.1364/AO.47.003808
Source: PubMed


We perform a numerical analysis of the double random phase encryption-decryption technique to determine how, in the case of both amplitude and phase encoding, the two decryption keys (the image- and Fourier-plane keys) affect the output gray-scale image when they are in error. We perform perfect encryption and imperfect decryption. We introduce errors into the decrypting keys that correspond to the use of random distributions of incorrect pixel values. We quantify the effects that increasing amounts of error in the image-plane key, the Fourier-plane key, and both keys simultaneously have on the decrypted image. Quantization effects are also examined.

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    • "The robustness of the encrypted ghost image under eavesdropping evaluate with the normalized root mean square (0 NRMS 1) ⩽ ⩽ which NRMS 0 = and NRMS 1 = denote the lowest and the highest security of the encryption system, respectively and is calculated as [14] [21] "
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    ABSTRACT: Selective computational ghost imaging (SCGI) is a technique which enables the reconstruction of an N-pixel image from N measurements or less. In this paper we propose an optical encryption method based on SCGI and experimentally demonstrate that this method has much higher security under eavesdropping and unauthorized accesses compared with previous reported methods.
    Full-text · Article · Sep 2014 · Journal of optics
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    • "Furthermore, two dimensional optical encryption processing has been extended into a three dimensional spacebased encryption processing, where each pixel of the image is axially considered as one particle and phase-shifting digital holography technique is applied to the diffraction of all pixels in space (particles) [71] [72] [73] [74]. In the context of cryptography and cryptoanalysis, both chosen-plaintext [60] and known-plaintext attack [75] [76] [77] on DRPE have been examined, as have several other attacking methods [78] [79] [80] [81] [82] and the key space of DRPE technique itself [83] [84] [85] [86] has also been analysed. In this paper we review a number of optical image encryption methods proposed in the literature based on the architecture of the classic optical Double Random Phase Encoding (DRPE) system. "
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    ABSTRACT: Abstract In this paper we review a number of optical image encryption techniques proposed in the literature inspired by the architecture of the classic optical Double Random Phase Encoding (DRPE) system. The optical DRPE method and its numerical simulation algorithm are first investigated in relation to the sampling considerations at various stages of the system according to the spreading of the input signal in both the space and spatial frequency domains. Then the several well-known optically inspired encryption techniques are examined and categorized into all optical techniques and image scrambling techniques. Each method is numerically implemented and compared with the optical DRPE scheme, in which random phase diffusers (masks) are applied after different transformations. The optical system used for each method is first illustrated and the corresponding unitary numerical algorithm implementation is then investigated in order to retain the properties of the optical counterpart. The simulation results for the sensitivities of the various encryption keys are presented and the robustness of each method is examined. This overview allows the numerical simulations of the corresponding optical encryption systems, and the extra degree of freedom (keys) provided by different techniques that enhance the optical encryption security, to be generally appreciated and briefly compared and contrasted.
    Full-text · Article · Jan 2013 · Optics & Laser Technology
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    ABSTRACT: We analyze optical encryption systems using the techniques of conventional cryptography. All conventional block encryption algorithms are vulnerable to attack, and often they employ secure modes of operation as one way to increase security. We introduce the concept of conventional secure modes to optical encryption and analyze the results in the context of known conventional and optical attacks. We consider only the optical system "double random phase encoding," which forms the basis for a large number of optical encryption, watermarking, and multiplexing systems. We consider all attacks proposed to date in one particular scenario. We analyze only the mathematical algorithms themselves and do not consider the additional security that arises from employing these algorithms in physical optical systems.
    Full-text · Article · Nov 2008 · Journal of the Optical Society of America A
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