Abstract

In a distributed network, we consider two special nodes called the sender S and the receiver R that are connected by n node-disjoint (except for S and R) bi-directional wires. Out of these n wires, the adversary can control at most t wires (of its choice) in Byzantine fashion. In this setting, our goal is to design a message transmission protocol Π that assures the following two conditions hold: (1) by the end of the protocol Π, R gets the correct message m transmitted by S without any error (perfect reliability), and (2) the adversary learns no information aboutm, whatsoever, in information theoretic sense (perfect secrecy). Protocols that satisfy these two conditions are known as the Perfectly Secure Message Transmission (PSMT) protocols.

Abstract

The combination of two overlapping technologies (bigdata and cloud computing) helps easy access to the evolving applications. In this context, there is a serious requirement of ensuring the transmission of data securely in order to improve the productivity over the public channel. Since the data collected by various sources are strictly private and confidential, there is also a great requirement to deal with the privacy preservation of the bigdata. To handle this issue, a new privacy-preserving bigdata collection technique in cloud computing environment, called 2PBDC, has been designed, which allows secure communication between the bigdata gateway nodes and the cloud servers. 2PBDC is shown to be secure against various known attacks against an active/passive adversary through the formal security verification as well as informal security analysis. A detailed comparative study among 2PBDC and other existing schemes has been conducted. This study shows that 2PBDC offers a better trade-off among the security and functionality features and communication and computation overheads while these are compared with other schemes.

Abstract

Optical sensing for chemical analysis is emerging as it provides advantages such as good sensitivity, selectivity, electromagnetic immunity, etc. This work presents a low-cost, robust and easy to use technique for measurement of bulk water property changes, specifically pH, total dissolved solids (TDS), and turbidity. The designed multi-wavelength sensing mechanism is capable of measuring the absorption of light emitted by three different LEDs after passing through water. The optical responses obtained using this mechanism are then related to parameter changes of water for quality measurement. The results show that measurements for pH, TDS, and turbidity have a linear regression coefficient of 0.9691, 0.9729 and 0.76 respectively. By utilizing narrowband light sources of characteristic wavelengths for the target parameters, a compact and portable device can be designed for rapid measurements. This can work …

Abstract

In this work, we exhaustively investigate 1 → 2 local and nonlocal broadcasting of entanglement as well as correlations beyond entanglement (geometric discord) using asymmetric Pauli cloners with most general two qubit state as the resource. We exemplify asymmetric broadcasting of entanglement using 'Maximally Entangled Mixed States'. We demonstrate the variation of broadcasting range with the amount of entanglement present in the resource state as well as with the asymmetry in the cloner. We show that it is impossible to optimally broadcast geometric discord with the help of these asymmetric Pauli cloning machines. We also study the problem of 1 → 3 broadcasting of entanglement using non-maximally entangled state (NME) as the resource. For this task, we introduce a method we call successive broadcasting which involves application of 1 → 2 optimal cloning machines multiple times. We compare and contrast the performance of this method with the application of direct 1 → 3 optimal cloning machines. We show that 1 → 3 optimal cloner does a better job at broadcasting than the successive application of 1 → 2 cloners and the successive method can be beneficial in the absence of 1 → 3 cloners. We also bring out the fundamental difference between the tasks of cloning and broadcasting in the final part of the manuscript. We create examples to show that there exist local unitaries which can be employed to give a better range for broadcasting. Such unitary operations are not only economical, but also surpass the best possible range obtained using existing cloning machines enabling broadcasting of lesser entangled states. This result opens up a new direction in exploration of methods to facilitate broadcasting which may outperform the standard strategies implemented through cloning transformations

Abstract

Bell non-locality and steering are essential features of quantum mechanics which mark significant departures from classical notion. They basically refer to the presence of quantum correlations between separated systems which violate a non-local inequality, the violation being not possible if we restrict ourselves only to classical correlations. In view of the importance of such unique correlations one may be interested to generate more non-local states starting from a few, a protocol which is termed as broadcasting. However in the present submission we show that if one restricts to broadcasting through quantum cloning, then such non-local states cannot be broadcasted. Our study is done in the purview of the Bell-CHSH inequality and a steering inequality pertaining to three measurement settings. We also find suitable restrictions on the Werner and Bell diagonal states which will make them unsteerable under any number of measurement settings, after broadcasting.

Abstract

We propose a new measure of relative incompatibility for a quantum system with respect to two noncommuting observables, and call it quantumness of relative incompatibility. In case of a classical state, order of observation is inconsequential, hence probability distribution of outcomes of any observable remains undisturbed. We define relative entropy of the two marginal probability distributions as a measure of quantumness in the state, which is revealed only in presence of two non-commuting observables. Like all other measures, we show that the proposed measure satisfies some basic axioms. Also, we find that this measure depicts complementarity with quantum coherence. The relation is more vivid when we choose one of the observables in such a way that its eigen basis matches with the basis in which the coherence is measured. Our result indicates that the quantumness in a single system is still an interesting question to explore and there can be an inherent feature of the state which manifests beyond the idea of quantum coherence.

Abstract

Quantum mechanical properties like entanglement, discord and coherence act as fundamental resources in various quantum information processing tasks. Consequently, generating more resources from a few, typically termed as broadcasting is a task of utmost significance. One such strategy of broadcasting is through the application of cloning machines. In this article, broadcasting of quantum resources beyond 2 ⊗ 2 systems is investigated. In particular, in 2 ⊗ 3 dimension, a class of states not useful for broadcasting of entanglement is characterized for a choice of optimal universal Heisenberg cloning machine. The broadcasting ranges for maximally entangled mixed states (MEMS) and two parameter class of states (TPCS) are obtained to exemplify our protocol. A significant derivative of the protocol is the generation of entangled states with positive partial transpose in 3 ⊗ 3 dimension and states which are absolutely separable in 2 ⊗ 2 dimension. Moving beyond entanglement, in 2 ⊗ d dimension, the impossibility to optimally broadcast quantum correlations beyond entanglement (QCsbE) (discord) and quantum coherence(l1-norm) is established. However, some significant illustrations are provided to highlight that non-optimalbroadcasting of QCsbE and coherence are still possible

Abstract

In this brief report, we prove that the robustness of coherence (ROC), in contrast with many popular quantitative measures of quantum coherence derived from the resource-theoretic framework of coherence, may be a subadditive for a specific class of multipartite quantum states. We investigate how the subadditivity is affected by admixture with other classes of states for which ROC is superadditive. We show that pairs of quantum states may have different orderings with respect to relative entropy of coherence, l1-norm of coherence and ROC and numerically study the difference in ordering for the chosen pairwise coherence measures.

Abstract

This work presents the design of a low phase noise LC oscillator (LCO) for a phase locked loop (PLL)-free receiver (RX), which is used for wireless sensor nodes based healthcare applications. A detailed analysis of phase noise of free running LCO has been presented under the influence of offchip components, which are very often inevitable in biomedical radios. Based on the analysis, a low power cross coupled LCO has been optimally designed for Medical Device Radiocommunication (MedRadio) band, which is a recommended communication band for biomedical applications. The proposed LCO has been fabricated in 180 nm CMOS technology. Measurement results show that the LCO consumes 140 μW power from 1.8 V supply and exhibits a phase noise of -103 dBc/Hz at an offset of 300 kHz, which closely matches with the post layout simulation results. Measurement results also show that the proposed …

Abstract

Fog computing (fog networking) is known as a decentralized computing infrastructure in which data, applications, compute as well as data storage are scattered in the most logical and efficient place among the data source (i.e., smart devices) and the cloud. It gives better services than cloud computing because it has better performance with reasonably low cost. Since the cloud computing has security and privacy issues, and fog computing is an extension of cloud computing, it is therefore obvious that fog computing will inherit those security and privacy issues from cloud computing. In this paper, we design a new secure key management and user authentication scheme for fog computing environment, called SAKA-FC. SAKAFC is efficient as it only uses the lightweight operations, such as one-way cryptographic hash function and bitwise exclusive-OR (XOR), for the smart devices as they are resource-constrained in nature. SAKAFC is shown to be secure with the help of the formal security analysis using the broadly accepted RealOr-Random (ROR) model, the formal security verification using the widely-used Automated Validation of Internet Security Protocols and Applications (AVISPA) tool and also the informal security analysis. In addition, SAKA-FC is implemented for practical demonstration using the widely-used NS2 simulator.