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Bhopal, India

Maulana Azad National Institute of Technology Bhopal , also known as National Institute of Technology, Bhopal , formerly Maulana Azad College of Technology , is an Institute of National Importance under the NIT Act situated in Bhopal, Madhya Pradesh, India. It is part of the group of publicly funded institutions in India known as National Institute of Technology. Wikipedia.


Abuturab M.R.,Maulana Azad National Institute of Technology
Applied Optics | Year: 2013

A color information cryptosystem based on optical interference principle and spiral phase encoding is proposed. A spiral phase mask (SPM) is used instead of a conventional random phase mask because it contains multiple storing keys in a single phase mask. The color image is decomposed into RGB channels. The decomposed three RGB channels can avoid the interference of crosstalks efficiently. Each channel is encoded into an SPM and analytically generates two spiral phase-only masks (SPOMs). The two SPOMs are then phase-truncated to get two encrypted images and amplitude-truncated to produce two asymmetric phase keys. The two SPOMs and the two asymmetric phase keys can be allocated to four different authorized users. The order, the wavelength, the focal length, and the radius are construction parameters of the SPM (or third SPOM) that can also be assigned to the four other different authorized users. The proposed technique can be used for a highly secure verification system, so an unauthorized user cannot retrieve the original image if only one key out of eight keys is missing. The proposed method does not require iterative encoding or postprocessing of SPOMs to overcome inherent silhouette problems, and its optical setup alleviates stringent alignment of SOPMs. The validity and feasibility of the proposed method are supported by numerical simulation results. © 2013 Optical Society of America. Source


Abuturab M.R.,Maulana Azad National Institute of Technology
Applied Optics | Year: 2013

A novel information authentication system, i.e., an asymmetric optical interference of two beams in the gyrator transform (GT) domain, is proposed. In this algorithm, the input color image is divided into R, G, and B channels. The complex field of each channel is constructed by the inverse Fourier transform of the channel attached with a random phase function. The phase-only mask (POM) and amplitude-only mask (AOM) are analytically derived from the complex field. The POM and AOM are separately gyrator transformed. The two asymmetric phase keys and two encrypted images are obtained by the amplitude truncations and phase truncations of the transform images, respectively. Finally, the encoded image is produced by the interference of two encrypted images. The two asymmetric keys and two angle parameters of the GT are regarded as additional keys for each channel to enhance the security level of the cryptosystem. The noniterative authentication procedure is devoid of any silhouette problem. The proposed system can be implemented digitally or optically, and its architecture is free from optical misalignment problems. The theoretical analysis and numerical simulation results both validate the proposed technique. © 2013 Optical Society of America. Source


Abuturab M.R.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2012

A novel color-information encryption technique based on discrete cosine transform and radial Hilbert phase mask in gyrator transform domain is proposed. In this work, the radial Hilbert phase function is employed as selected phase mask. Before the encryption, the original color image is converted into independent channels, i.e. red, green, and blue. Each channel is encrypted using first random phase mask and discrete cosine transform at input plane, and then the first gyrator transform is executed. The obtained image is again encrypted using second random phase mask and discrete cosine transform at frequency plane, and then transmitted through radial Hibert phase mask. The gyrator transform is performed on the transmitted image. The integral orders of radial Hibert phase mask and transformation angles of gyrator transform in each channel provide supplementary keys to enhance the security. The proposed system evades the misalignment problems. Numerical simulations are demonstrated to test the security, validity, and efficiency of the proposed algorithm. © 2012 Elsevier Ltd. All rights reserved. Source


Rafiq Abuturab M.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2012

A new method for securing color image using discrete cosine transform in gyrator transform domain structured-phase encoding is proposed. In this proposal, the structured phase mask is a zone plate phase function. The input color image to be encrypted is decomposed into three channels: red, green, and blue. Each of these channels is encrypted independently by changing its spatial distribution of pixel value by discrete cosine transform, and encoded with structured phase mask. The gyrator transform is performed on resultant spectrum. Structured phase mask, discrete cosine transform, and gyrator transform are employed twice in this proposed method. The construction parameters of structured phase mask and angle parameters of gyrator transform in each channel are principal encryption keys. The schematic electro-optical implementation has been presented. The proposed architecture does not require axial movements. The effectiveness of the proposed algorithm is demonstrated against the chosen and known plaintext attacks. Numerical simulations are made to verify the security, validity, and capability of the proposed method. © 2012 Elsevier Ltd. All rights reserved. Source


Abuturab M.R.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2012

In this paper, we propose a new method for securing color information based on Arnold transform in gyrator transform domain. A color image is first separated into red, green and blue component images, and each of these component images is then independently encrypted into first random phase mask placed at input image plane, and employed first Arnold transform and gyrator transform. The second random phase mask is placed at gyrator transform plane, and employed second Arnold transform and gyrator transform. The system parameters of Arnold transform and gyrator transform in each channel serve as additional keys in color image encryption and decryption, and hence enhances the security of the system. Numerical simulations are presented to confirm the security, validity and possibility of the proposed idea. © 2011 Elsevier Ltd. All rights reserved. Source

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