Shabieh Farwa

Degradation effect of Auger recombination and built-in polarization field on GaN-based light-emitting diodes

In this work, theoretical investigation of the influence of Auger recombination coefficient and built-in polarization field on the internal quantum efficiency (IQE) in terms of lateral-vertical single quantum well (SQW) as well as multiquantum well (MQW) GaN-based blue light-emitting diodes are presented. The degradation effect of the built-in polarization field on the IQE of vertical light-emitting diodes is used to strengthening the Auger recombination coefficient in comparison to lateral light-emitting diodes. This result has been found consistent in both single-as well as multi-quantum well structures. In addition, when Auger recombination coefficient has been included in the analysis, vertical multiquantum well structure shows more degradation in the IQE in comparison to the lateral structures. The effect has been dominant in vertical MQW case.

An Image Encryption Technique based on Chaotic S-Box and Arnold Transform

In recent years, chaos has been extensively used in cryptographic systems. In this regard, one dimensional chaotic maps gained increased attention because of their intrinsic simplicity and ease in application. Many image encryption algorithms that are based on chaotic substitution boxes (S-boxes) have been studied in the last few years but some of them appear to be vulnerable to robustness. We, in this paper, propose an efficient scheme for image encryption that utilizes a composition of chaotic substitution based on tent map with the scrambling effect of the Arnold transform. The proposed construction algorithm for substitution box is, on one hand, straightforward and saves omputational labour, while on the other, it provides highly efficient performance outcomes. The understudy scheme uses an S-box, that is based on 1-D chaotic tent map. We partially encrypt the image using this S-box and then apply certain number of iterations of the Arnold transform to attain the fully encrypted image. For decryption we apply the reverse process. The strength of the proposed method is determined through the most significant techniques used for the statistical analysis and it is proved that the anticipated algorithm shows coherent results.

A novel encryption scheme for high-contrast image data in the Fresnelet domain

In this paper, a unique and more distinctive encryption algorithm is proposed. This is based on the complexity of highly nonlinear S box in Flesnelet domain. The nonlinear pattern is transformed further to enhance the confusion in the dummy data using Fresnelet technique. The security level of the encrypted image boosts using the algebra of Galois field in Fresnelet domain. At first level, the Fresnelet transform is used to propagate the given information with desired wavelength at specified distance. It decomposes given secret data into four complex subbands. These complex sub-bands are separated into two components of real subband data and imaginary subband data. At second level, the net subband data, produced at the first level, is deteriorated to non-linear diffused pattern using the unique S-box defined on the Galois field F28. In the diffusion process, the permuted image is substituted via dynamic algebraic S-box substitution. We prove through various analysis techniques that the proposed scheme enhances the cipher security level, extensively.

Uniformly Alpha-Quasi-Convex Functions Defined by Janowski Functions

In this work, we aim to introduce and study a new subclass of analytic functions related to the oval and petal type domain. This includes various interesting properties such as integral representation, sufficiency criteria, inclusion results, and the convolution properties for newly introduced class.

To Study the Effect of the Generating Polynomial on the Quality of Nonlinear Components in Block Ciphers

Substitution box ( -box), being the only nonlinear component, contributes to the confusion creating capability of a cryptosystem. Keeping in view the predominant role of -box, many design algorithms to synthesize cryptographically stronger -boxes have gained pivotal attention. A quick review of these algorithms shows that all these ideas mainly concentrate on the choice of bijective Boolean functions, with nonobservance to the irreducible polynomial that generates the Galois field. In this paper, we propose that the selection of irreducible polynomial has a deep influence on the highly desirable features of an -box such as nonlinearity, strict avalanche, bit independence, linear approximation probability, and differential approximation probability. We underpin our claim by investigating a detailed model, which deploys the same algorithm but different polynomials and produces unusual changes in the results regarding the performance parameters of -box.

RETRACTED: Fresnelet approach for image encryption in the algebraic frame

In this manuscript, a novel, more efficient method to encrypt an image in the Fresnelet domain is proposed. The uniqueness of the presented algorithm depends on the Fresnelet transform based image decomposition in conjunction with an algebraically synthesized substitution box. The high- nonlinearity induced by the eccentrically designed S-box boosts the security of proposed scheme. In this two-steps encryption algorithm, firstly, we apply the Fresnelet transform to propagate information with desired wavelength at a specified distance. This results in the decomposition of the secret image data into four complex subbands. These complex sub-bands are further partitioned into real subband data and imaginary subband data. At second step, the net subband data, produced at the first level, is diffused by a unique iterative substitution approach based on the algebraic structure of Galois field F28. In the diffusion process, the permuted image is substituted via algebraic substitution algorithm. We prove through significant analysis techniques that the proposed scheme offers a highly elevated security level in encryption.