Digital images are a popular source of information and play an important role in several applications. However, the large amount of available data in the form of images causes serious security ...concerns. Although digital images are widely available, the storage of these images requires a large amount of data. Compression is an efficient way to reduce image size and efficiently utilize network resources. In this study, a joint encryption and compression technique, namely, ECiS, is developed to solve the two major issues with digital images outlined above. To achieve high security, we encrypt an image by using DNA, SHA-256, and a chaotic-based encryption technique. To reduce the bandwidth or storage space demand, we compress the encrypted image by using a compression technique based on zero memory set partitioned embedded block (ZM-SPECK). The strength of our ECiS technique is performing the analysis by applying several standard tests, including key analysis, statistical analysis, differential analysis, and time cost evaluation on a USC-SIPI dataset. Furthermore, the extensive evaluations on the dataset demonstrate that the proposed technique is secure and has a lower memory and encryption overhead than similar techniques.
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Measurement of effective thermal conductivity (λe) and effective thermal diffusivity (χe) of twin pellets of Se90In10 bulk chalcogenide glass has been carried out in the temperature range from 303 to ...323K and cooling from 323 to 303K using transient plane source (TPS) technique. In the heating process variation of effective thermal conductivity (λe) and effective thermal diffusivity (χe) is observed. Both quantities are found to be maximum at 313K, which lies in the vicinity of glass transition temperature (Tg). During the cooling process λe and χe remain same at all temperatures. Such type of behavior shows thermal hysteresis in this sample, which can be explained on the basis of structural change of the Se90In10 bulk chalcogenide glass.
The calorimetric parameters of glassy Se
98−x
Cd
2
In
x
(
x
= 0, 2, 6 and 10) alloys were investigated using differential scanning calorimetry (DSC) under non-isothermal conditions at different ...heating rates of 5, 10, 15 and 20 K min
−1
. The composition dependencies of activation energy of glass transitions (
E
g
), crystallization activation energy (
E
c
), fragility index (
F
), Hruby number (
K
gl
) and rate constant (
K
p
) were evaluated from DSC curves. Results indicate that kinetic parameter varies with In content in Cd–Se glassy matrix. It is observed that crystallization activation energy (
E
c
) and
K
p
are minimum and
K
gl
is maximum for Se
92
Cd
2
In
6
glass. Therefore, Se
92
Cd
2
In
6
glass is the most thermally stable glass and has highest glass-forming ability in this series. It can be explained by chemical bond theory of solids.
Effective charge separation and use of hot charge carriers are considered to be the most essential factors affecting the activity of an excellent energy harvester. Herein, we have successfully ...decorated 3 nm of CdSe quantum dots (QDs) on the surface of reduced graphene oxide (rGO) using solvothermal method. Formation of CdSe–rGO nanocomposite (NC) has been confirmed by X-ray diffraction pattern, transmission electron microscopy and Raman analysis. Further, the emission spectrum of CdSe–rGO NC shows quenching of emission of CdSe QDs on the surface of rGO nanosheet. To elucidate this phenomenon, we have carried out time-correlated single-photon counting (TCSPC) measurements, which reveal efficient electron transfer, as the exciton lifetime of CdSe QDs in the NC is significantly reduced compared to bare CdSe QDs. Owing to the efficient electron transfer, this NC showed big boost in total shielding effectiveness (
SE
T
= 29 dB) when compared to graphene (
SE
T
= 23 dB) in electromagnetic interference shielding application.
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•TiO2 ETL in PSCs for potential ability of electron transfer and long-time stability.•Development of multilayer ETLs, surface passivation, and doping of metal cations in TiO2.•New ...opportunities and future challenges need more directed research actions are also focussed.
Titanium dioxide (TiO2) is widely applied as an electron transport layer (ETL) in perovskite solar cells (PSCs) due to its remarkable potential ability of electron transfer and long-time stability in PSCs. However, the requirement of high annealing temperature and the existence of hysteresis effect in TiO2-based PSC devices hindered its future applicability in commercial photovoltaic. Recently, various new strategies such as the incorporation of interfacial layer between ETL and absorber, the development of multilayer ETLs, surface passivation, and doping of metal cations in TiO2 have significantly improved the device performance and long-term stability of PSC. Amongst, doping engineering in TiO2 ETL has received more attention due to improved charge transportation ability and elimination of hysteresis. Doping of new ions in ETL materials is the most efficient way to tailor the band structure and modulate the electron mobility. However, in most cases, the basic mechanisms of doping engineering in electron extracting materials are still lacking. The present featured article investigated the scientific requirement and challenges combined with doping engineering in TiO2 ETL.
The continuous development of Industry 5.0 technology has brought great convenience to people's work and life. However, during digital data transmission and storage, the data may be accessed by ...unauthorized persons, resulting in privacy disclosure. Therefore, efficient data protection is always a high demand to solve this realistic problem. This work proposes a secure encryption algorithm, SIELNet, for colour images. First, we introduce a new three-dimensional chaotic map to encrypt colour images, obtaining the cipher images with a relationship to the plain images. We provide its excellent chaotic behaviour through standard randomness test. Secondly, we use a customized residual dense spatial network to perform the task of lossy image reconstruction from an encrypted, compressed image, which solves the constrained super-resolution task. Extensive experimental results on four public datasets demonstrate the superior performance of SIELNet against state-of-the-art techniques with excellent reconstruction quality. We believe the secure design of SIELNet can contribute to the favourable data integrity application of Industry 5.0.
Nowadays, it is very common for healthcare professionals or staff to transmit digital data in the form of images over public channels or store it on hard drives or third-party clouds. However, ...unauthorised users and cloud-service providers may view or abuse these sensitive images. This research proposes a generative adversarial network (GAN)-based watermarking for encrypted images to prevent data leakage in healthcare scenarios. The technique uses a combination of a chaotic map and randomised singular value decomposition (RSVD) to encrypt the image first. Subsequently, a GAN model is developed for watermark generation by hiding multiple marks within an image. Later, the encrypted image is marked by embedding the generated watermark for copyright protection and authentication. This fundamentally solves the problem of copyright violation and privacy leakage of medical data. Experimental results have demonstrated that the proposed method is imperceptible and successfully resists various attacks. The obtained results confirmed the superiority of this method over other techniques, which makes it more suitable for healthcare applications.
•A GAN-based watermarking to protect medical images in healthcare scenarios.•3D Chaotic map & RSVD-based encryption to provide confidentiality to medical images.•Encrypted medical image is marked using transform technique to verify authenticity.•Experiments shows that method is imperceptible, secure and robust against attacks.
Over recent years, the volume of big data has drastically increased for medical applications. Such data are shared by cloud providers for storage and further processing. Medical images contain ...sensitive information, and these images are shared with healthcare workers, patients, and, in some scenarios, researchers for diagnostic and study purposes. However, the security of these images in the transfer process is extremely important, especially after the COVID-19 pandemic. This paper proposes a secure watermarking algorithm, termed WatMIF, based on multimodal medical image fusion. The proposed algorithm consists of three major parts: the encryption of the host media, the fusion of multimodal medical images, and the embedding and extraction of the fused mark. We encrypt the host media with a key-based encryption scheme. Then, a nonsubsampled contourlet transform (NSCT)-based fusion scheme is employed to fuse the magnetic resonance imaging (MRI) and computed tomography (CT) scan images to generate the fused mark image. Furthermore, the encrypted host media conceals the fused watermark using redundant discrete wavelet transform (RDWT) and randomised singular value decomposition (RSVD). Finally, denoising convolutional neural network (DnCNN) is used to improve the robustness of the WatMIF algorithm. The simulation experiments on two standard datasets were used to evaluate the algorithm in terms of invisibility, robustness, and security. When compared with the existing algorithms, the robustness is improved by 20.14%. Overall, the implementation of proposed watermarking for hiding fused marks and efficient encryption improved the identity verification, invisibility, robustness and security criteria in our WatMIF algorithm.
Electromagnetic interference (EMI) pollution has now become a subject of great concern with the rapid development of delicate electronic equipment in commercial, civil, and military operations. There ...has been a surge in pursuit of light-weight, adaptable, effective, and efficient EMI screening materials in recent years. The present article addresses a simple and sensitive approach to synthesize a core/shell carbon nanotube/MoS2 heterostructure supported on reduced graphene oxide (CNT/MoS2-rGO nanohybrid) as an efficient electromagnetic shielding material. The structural and morphological characteristics were accessed through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy, augmenting successful formation of the CNT/MoS2-rGO nanohybrid. The shielding performance of the as-synthesized samples has been accessed in a wide frequency range of 8–12 GHz. A CNT/MoS2-rGO nanohybrid demonstrates a better EMI shielding performance in comparison to MoS2 nanosheets and MoS2-rGO nanohybrid individually. The CNT/MoS2-rGO nanohybrid having a thickness ∼1 mm shows excellent total shielding effectiveness (SET) as high as 40 dB, whereas MoS2 and MoS2-rGO hybrid lags far, with the average value of SET as 7 and 28 dB, respectively. It also demonstrates that the nanohybrid CNT/MoS2-rGO shields the EM radiation by means of absorption through several functional defects and multiple interfaces present in the heterostructure. Herein, we envision that our results provide a simple and innovative approach to synthesize the light-weight CNT/MoS2-rGO nanohybrid having flexibility and high shielding efficiency and widen its practical applications in stealth technology.
Nowadays, there is an increasing tendency to upload images to online platforms acting as information carriers for various applications. Unfortunately, the unauthorized utilization of such images is a ...serious concern that has significantly impacted security and privacy. Although digital images are widely available, the storage of these images requires a large amount of data. This study aims to address these issues by developing an improved encryption–compression-based algorithm for securing digital images that reduces unnecessary hardware storage space, transmission time and bandwidth demand. First, the image is encrypted using chaotic encryption. Then the encrypted image is compressed using wavelet-based compression in order to make efficient use of resources without any information about the encryption key. On the other side, the image is decompressed and decrypted by the receiver. The security assessment of the proposed algorithm is performed in different ways, such as differential and statistical, key sensitivity, and execution time analysis. The experimental analysis proves the security of the method against various possible attacks. Furthermore, the extensive evaluations on a real dataset demonstrate that the proposed solution is secure and has a low encryption overhead compared to similar methods.
