Maulana Azad National Institute of Technology

www.manit.ac.in
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.


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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.


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.


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.


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.


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.


Abuturab M.R.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2014

A new asymmetric cryptosystem using Schur decomposition in gyrator transform (GT) domain is introduced. In this approach, the color image to be encoded is first dissociated into red, green and blue channels and then modulated by multiplying three different random phase masks. The three modulated color channels are combined into one gray image by using convolution. The convoluted image is gyrator transformed. The gyrator spectrum is then amplitude- and phase-truncated. The asymmetric decryption phase keys for red, green and blue channels are generated digitally during the encryption process. The phase-truncated image is divided into U and T parts by Schur decomposition. Finally, U and T parts are independently gyrator transformed to obtain two encoded images, which can be assigned to a joint authorized user (or two authorized users). GT evades optical alignment problems. The Schur decomposition represents an intermediate step in SVD decomposition, and thus requires less number of computations. The multiplication order of Schur decomposition, three transformation angles of GT, and three asymmetric keys are regarded as decryption keys, which boost the degree of security against existing attacks. The proposed encryption process can be carried out digitally, while the decryption process can be realized optically. Numerical simulations prove the validity and security of the proposed approach. © 2014 Elsevier Ltd.


Abuturab M.R.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2013

A novel method for color-information security system based on joint-extended gyrator transform correlator is introduced. In this method, the color image is split into three-color channels: red, green, blue. Each color channel bonded to a random phase mask and a random phase key code are gyrator transformed separately. The two obtained information multiplexed to form a joint gyrator power spectrum, which is again gyrator transformed to get a joint-extended gyrator power spectrum. The same phase key code is used in both the data encryption and decryption. The three-color channels are independently encrypted and decrypted to avoid the interference of crosstalks. The decrypted image is obtained without any noise and distortion. The angle parameters of gyrator transform in each channel are additional encryption keys for enhancing the security. The proposed system has resistant against chosen- and known plaintext attacks. The calculated values of mean square error and peak signal-to-noise ratio support the noise-free recovery of original color image. The implementation of opto-electronic setup has been proposed. The validity and feasibility of the proposed method are demonstrated by numerical simulations. © 2012 Elsevier Ltd.


Abuturab M.R.,Maulana Azad National Institute of Technology
Optics and Lasers in Engineering | Year: 2013

A novel color image encryption algorithm based on Arnold- and discrete Hartley transform in gyrator transform domain is proposed. In this method, a color image is segregated into red, green, and blue channels. Each channel is permutated by first Arnold transform operation and the spatial distribution of pixel value is changed by first discrete cosine transform at image plane. The resulting image is encoded by discrete Hartley transform. The encoded information is again permutated by second Arnold transform and the spatial distribution of pixel value is changed by second discrete cosine transform at frequency plane, and finally gyrator transform is executed. The period and iterative number of Arnold transform, and transformation angles of gyrator transform in each channel are main keys, which increase the security of the proposed system. The proposed method can be well protected under chosen- and known plaintext attacks. Numerical simulations are conducted to illustrate the security, validity, and feasibility of the proposed method. © 2012 Elsevier Ltd.


Abuturab M.R.,Maulana Azad National Institute of Technology
Applied Optics | Year: 2012

A novel method for encoding color information based on a double random phase mask and a double structured phase mask in a gyrator transform domain is proposed. The amplitude transmittance of the Fresnel zone plate is used as structured phase-mask encoding. A color image is first segregated into red, green, and blue component images. Each of these component images are then independently encrypted using first a random phase mask placed at the image plane and transmitted through the first structured phase mask. They are then encoded by the first gyrator transform. The resulting information is again encrypted by a second random phase mask placed at the gyrator transform plane and transmitted through the second structured phase mask, and then encoded by the second gyrator transform. The system parameters of the structured phase mask and gyrator transform in each channel serve as additional encryption keys and enlarge the key space. The encryption process can be realized with an electro-optical hybrid system. The proposed system avoids problems arising from misalignment and benefits of a higher space-bandwidth product. Numerical simulations are presented to confirm the security, validity, and possibility of the proposed idea. © 2012 Optical Society of America.


Abuturab M.R.,Maulana Azad National Institute of Technology
Applied Optics | Year: 2012

A novel asymmetric color information cryptosystem based on an optical coherent superposition method and phase-truncated gyrator transform (GT) is proposed. In this proposal, an original color image is converted into three independent channels, i.e., red, green, and blue. Each channel is separated into a random phase masks (RPM) and a key phase mask (KPM) using a coherent superposition method. The KPM is a modulation of the RPM by the color channel and used as decryption key. The same RPM, which is independent of plaintext, can be chosen for different images of the same size; however, KPMs, which are related to the original color images, are different. The RPM and the KPM are independently gyrator transformed. Then two gyrator spectra are, respectively, phase truncated to obtain two encoded images and amplitude truncated to generate two asymmetric phase keys. The KPM and two phase keys provide asymmetric keys. The transformation angles of the GT give additional keys for each channel and thus offer a high-level robustness against existing attacks. The proposed optical design is free from axial movement. Numerical simulations are demonstrated to verify the flexibility and effectiveness of the proposed method. © 2012 Optical Society of America.

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