Pure optical dynamical color encryption

Centro de Investigaciones Ópticas, CONICET La Plata-CIC, and UID OPTIMO, Facultad de Ingenieria, Universidad Nacional de La Plata, PO Box 3 CP 1897, La Plata, Argentina.
Optics Express (Impact Factor: 3.49). 07/2011; 19(15):13779-86. DOI: 10.1364/OE.19.013779
Source: PubMed


We introduce a way to encrypt-decrypt a color dynamical phenomenon using a pure optical alternative. We split the three basic chromatic channels composing the input, and then each channel is processed through a 4f encoding method and a theta modulation applied to the each encrypted frame in every channel. All frames for a single channel are multiplexed. The same phase mask is used to encode all the information. Unlike the usual procedure we do not multiplex the three chromatic channels into a single encoding media, because we want to decrypt the information in real time. Then, we send to the decoding station the phase mask and the three packages each one containing the multiplexing of a single channel. The end user synchronizes and decodes the information contained in the separate channels. Finally, the decoding information is conveyed together to bring the decoded dynamical color phenomenon in real-time. We present material that supports our concepts.

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Available from: Roberto Torroba, Dec 16, 2013
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    • "Combining the Arnold transform and color-blend operations, a color image method has been proposed [14]. A dynamical color encryption algorithm has been represented by hiding the information from the three components [15]. The multi-color visual cryptography has been introduced for information security [16]. "
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    ABSTRACT: We present a color image encryption algorithm by using chaotic mapping and Hartley transform. The three components of color image are scrambled by Baker mapping. The coordinates composed of the scrambled monochrome components are converted from Cartesian coordinates to spherical coordinates. The data of azimuth angle is normalized and regarded as the key. The data of radii and zenith angle are encoded under the help of optical Hartley transform with scrambled key. An electro-optical encryption structure is designed. The final encrypted image is constituted by two selected color components of output in real number domain.
    Full-text · Article · Aug 2013 · Optics and Lasers in Engineering
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    • "The Hartley transform (HT), which is effectively a real Fourier transform without any phase information, has also been proposed for the use in optical DRPE systems [41] [42] [43] [44] [45]. In addition, the DRPE has been investigated for use in multiple-image encryption [46] [47] [48] and color image encryption [49] [50] [51] [52] [53] [54] [55] [56]. The image scrambling techniques, which can be viewed as computer based numerical preprocessing procedure, have also been applied in conjunction with theDRPE system using the Jigsaw transform (JT) [57] [58] [59] and the Arnold transform (ART) [60] [61] [62] [63] [64]. "
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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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    • "We get different approaches that solve these problems based on optical and opto-digital strategies implemented in different setups [6] [7]. There is another tactic, known as theta modulation [8], based on modulating the encrypted information before the multiplexing procedure [9] [10]. A closer look to the mechanism involved in the procedure leads us to implement a new strategy that will introduce a better energy distribution and a consequent improvement in the decrypted images. "
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    ABSTRACT: We present an improvement to the theta modulating techniques for multiplexing encrypted images. We introduce sinusoidal phase gratings finding an increase in the contrasts of the decrypted images thanks to energy redistribution.
    Full-text · Conference Paper · Oct 2012
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