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Mrinal Kanti Mandal

Publications and source records attributed to Mrinal Kanti Mandal.

2 recordsLinked to original sources

An Ideal Random Number Generator Based on Quantum Fluctuations and Rotating Wheel for Secure Image Encryption

In the era of digitization secure transmission of digital images has become essential in real world applications. Image encryption is an effective technique for protecting image data from unauthorized access. The security of encrypted data strongly depends on the quality of the random numbers used as the encryption key. In this paper, we proposed a hybrid random number generator based on quantum fluctuations and an algorithmically inspired rotating wheel. The wheel contains integer values from 0 to 255 that are shuffled using quantum fluctuations generated by time-evolving the quantum kicked rotor model. There are four pre-defined tapping positions in the rotating wheel to collect the number sequences. The wheel rotation speed is dynamically varied after each set of tapping to enhance unpredictability. The entropy of the number sequence obtained from the rotating wheel attains the ideal value of 8 (in an 8 bit representation). Further, the generated number sequences exhibit a flat histogram and nearly zero correlation, indicating strong randomness. The generated sequences are applied to the image encryption and analyzed cryptographically. Experimental results demonstrate a near ideal entropy of 7.997, an NPCR of 99.60%, low correlation in all directions, and low PSNR for encrypted images. These results confirm that the proposed random number generator achieves efficient and high-security performance, making it suitable for the security of consumer applications such as mobile healthcare imaging, biometric authentication, QR-based and multimedia communication on smart devices.

cs.CR↗

The relaxation time of OH bond for hydrogen impurity in LiNbO3

The one dimensional model for the dynamic of hydrogen in lithium niobate is explained by adopting Morse potential. The diffused hydrogen substitutes Lithium and it makes bonding with one oxygen atom of a facet of oxygen-triangle. The bonds will be stretched to set up anharmonic vibration. The damped anharmonic oscillation is derived to explain the dynamics of hydrogen as an impurity. The thermal fluctuation is studied by Fokker Planck equation has an important role to determine the diffusion constant for substitutional hydrogen. The hydrogen diffusion constant and relaxation time are calculated to support the proposed theory and existing experimental results. The concentration of substitutional hydrogens is studied with the help of Boltzmann distribution.

cond-mat.mtrl-sci↗