Enhancement of security using structured phase masked in optical image encryption on Fresnel transform domain

We propose an angle multiplexing method for optics-based image encryption using a phase-only computer-generated hologram (POCGH) in the tilted Fresnel transform (TFrT) domain. Modified Gerchberg-Saxton algorithms, based on the three types of rotation manipulation in both the hologram and reconstruction planes, are used with their corresponding TFrT parameters to extract the phase-only functions (POFs) of the target images. All the extracted POFs are then phase-modulated and summed to obtain the final POCGH, which is capable of multiplexing and avoiding overlap in the reconstructed images. The computer simulation results show that the images corresponding to the various rotation manipulations at the hologram and image reconstruction planes can be successfully restored with high correlation coefficients. Due to the encrypted nature of the multiplexed images, a higher system security level can be achieved, as the images can only be correctly displayed when all the required parameters in the TFrT are available. The angle sensitivity on the image quality for each manipulation is also investigated.

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Optical image encryption using random-vortex structured phase masks in fractional Hartley transform domain

13th International Conference on Fiber Optics and Photonics ◽

10.1364/photonics.2016.tu4a.68 ◽

2016 ◽

Cited By ~ 1

Author(s):

Hukum Singh

Keyword(s):

Image Encryption ◽

Optical Image ◽

Transform Domain ◽

Hartley Transform ◽

Optical Image Encryption ◽

Fractional Hartley Transform

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

International Journal of Optics ◽

10.1155/2015/926135 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 33

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.

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