scholarly journals Optical Image Encryption Using Devil’s Vortex Toroidal Lens in the Fresnel Transform Domain

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Hukum Singh ◽  
A. K. Yadav ◽  
Sunanda Vashisth ◽  
Kehar Singh
Keyword(s):  
Image Encryption ◽  
Mean Squared Error ◽  
Random Phase ◽  
Optical Image ◽  
Phase Mask ◽  
Digital Implementation ◽  
Key Space ◽  
Fresnel Transform ◽  
Encrypted Images ◽  
Optical Image Encryption

We have carried out a study of optical image encryption in the Fresnel transform (FrT) domain, using a random phase mask (RPM) in the input plane and a phase mask based on devil’s vortex toroidal lens (DVTL) in the frequency plane. The original images are recovered from their corresponding encrypted images by using the correct parameters of theFrTand the parameters of DVTL. The use of a DVTL-based structured mask enhances security by increasing the key space for encryption and also aids in overcoming the problem of axis alignment associated with an optical setup. The proposed encryption scheme is a lensless optical system and its digital implementation has been performed using MATLAB 7.6.0 (R2008a). The scheme has been validated for a grayscale and a binary image. The efficacy of the proposed scheme is verified by computing mean-squared-error (MSE) between the recovered and the original images. We have also investigated the scheme’s sensitivity to the encryption parameters and examined its robustness against occlusion and noise attacks.

A No Interference Optical Image Encryption by a Fresnel Diffraction and a Fourier Transformation

2012 ◽  
Vol 459 ◽  
pp. 461-464
Author(s):  
Huai Sheng Wang
Keyword(s):  
Image Encryption ◽  
Digital Image ◽  
Fourier Transformation ◽  
Random Phase ◽  
Fresnel Diffraction ◽  
Optical Image ◽  
Phase Mask ◽  
Phase Plate ◽  
Encrypted Image ◽  
Optical Image Encryption

A no interference optical image encryption is put forward in this paper. The encrypting process is composed of a Fresnel diffraction and a Fourier transformation. A digital image coded with a random phase plate first takes a Fresnel diffraction. The diffraction function is enlarged and coded with another random phase mask. At last the enlarged function undergoes a Fourier transformation. The real part of the transformed function is defined as an encrypted image. In decrypting process, first the encrypted image takes an inverse Fourier transformation. Then the upper left corner of the transformed function is intercepted. According to the space inversion of the transformed function, if the intercepted function takes an inverse Fresnel diffraction, the original digital image can be restored from the final diffraction function. Because there is no interference process in encryption and decryption, the optical system is relatively simple and the quality of restored image is very good

scholarly journals Optical Image Encryption Based on Chaotic Baker Map and Double Random Phase Encoding

2013 ◽  
Vol 31 (15) ◽  
pp. 2533-2539 ◽  
Author(s):  
Ahmed M. Elshamy ◽  
Ahmed N. Z. Rashed ◽  
Abd El-Naser A. Mohamed ◽  
Osama S. Faragalla ◽  
Yi Mu ◽  
...  
Keyword(s):  
Image Encryption ◽  
Random Phase ◽  
Optical Image ◽  
Phase Encoding ◽  
Chaotic Baker Map ◽  
Double Random Phase Encoding ◽  
Random Phase Encoding ◽  
Optical Image Encryption ◽  
Baker Map

An Asymmetric Optical Cryptosystem of Double Image Encryption Based on Optical Vortex Phase Mask Using Gyrator Transform Domain

2020 ◽  
Vol 13 (4) ◽  
pp. 672-685
Author(s):  
Hukum Singh ◽  
Mehak Khurana
Keyword(s):  
Image Encryption ◽  
Random Phase ◽  
Optical Vortex ◽  
Phase Mask ◽  
Double Random Phase Encoding ◽  
Random Phase Encoding ◽  
Key Space ◽  
Gyrator Transform ◽  
Root Operation ◽  
Phase Truncation

Background: Optical Vortex (OV) has attracted attention amongst many researchers. Paper proposes a nonlinear scheme of image encryption based on Optical Vortex (OV) and Double Random Phase Encoding (DRPE) in the Gyrator Transform (GT) domain under phase truncation operations. Objective: The amplitude and phase truncation operation in the image encryption generates two decryption keys and convert the method to nonlinear. It has also been proposed opto-electronically. Original image can only be decrypted with correct values of OV, GT rotation angles and Decryption Keys (DKs). Methods: A novel asymmetric image encryption scheme, using optical vortex mask has been proposed in view of amplitude and phase truncation operation. The scheme becomes more strengthened by the parameters used in the Optical Vortex (OV) and by taking the (n)th power operation in the encryption path and (n)th root operation in the decryption path. Results: It shows that for each of the encryption parameters, binary image has greater sensitivity as compared to the grayscale image. This scheme inflates the security by making use of OV-based Structured Phase Mask (SPM) as it expands the key space. The scheme has also been investigated for its robustness and its sensitivity against various attacks such as noise and occlusion attacks under number of iterations. Conclusion: This scheme provides solution to the problem of key space with the use of GT rotational angles and OV phase mask thus enhances the security. The scheme has been verified based on various security parameters such as occlusion, noise attacks, CC, entropy etc.

scholarly journals Optical Image Encryption System Using Several Tilted Planes

Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 116 ◽  
Author(s):  
Juan M. Vilardy O. ◽  
Carlos J. Jimenez ◽  
Cesar O. Torres M.
Keyword(s):  
Image Encryption ◽  
Plane Waves ◽  
Random Phase ◽  
Angular Spectrum ◽  
Optical Image ◽  
Optical Diffraction ◽  
Fourier Plane ◽  
Encrypted Image ◽  
Tilted Plane ◽  
Optical Image Encryption

A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical system, in order to obtain the encrypted image. In this work, we propose to use tilted planes for the Fourier and the output planes of the optical DRPE encryption system with the purpose of adding two new security keys, which are the angles of the tilted planes. The optical diffraction on a tilted plane is computed using the angular spectrum of plane waves and the coordinate rotation in the Fourier domain. The tilted distributions at the intermediate and output planes of the optical DRPE encryption system are the second RPM and the encrypted image, respectively. The angles of the tilted planes allow improvement to the security of the encrypted image. We perform several numerical simulations with the purpose of demonstrating the validity and feasibility of the proposed image encryption system.

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