Key Pool Research Articles

Dynamic secret-key provisioning in quantum-secured passive optical networks (PONs).

Quantum cryptography (QC) is currently under investigation to build highly secure optical communication networks. QC requires distribution of quantum keys (also called "secret" keys) on separate wavelength channels than those used to transmit the encrypted data. Hence, we propose a quantum-secured passive optical network (QS-PON) that supports both i) the traditional wavelength channels for secured data transmission, and ii) a quantum key distribution network (QKDN) running on separate dedicated wavelengths. The QKDN generates and stores secret keys that are then assigned to users' demands served on traditional PON channels. To generate secret keys, quantum transmitters at the optical network units (ONUs) exchange qubits with a quantum receiver at the optical line terminal (OLT). Then, the generated secret keys are stored in quantum key pools (QKPs) installed at both OLT and the ONUs and assigned to users' demands. Point-to-multipoint QKD systems have been experimentally demonstrated over various forms of quantum access networks (QANs), showing that an efficient mechanism to generate and assign quantum keys based on traffic requests is a critical component of QANs. In this study, we present a new QS-PON architecture, and we propose a dynamic secret-key provisioning (DSKP) algorithm that effectively generates and assigns secret keys from users' demands. Our proposed DSKP algorithm features two phases, the lowest-first secret-key generation (LF-SKG) phase and the hierarchical-clustering secret-key consumption (HC-SKC) phase. In this study, we also provide an analytical model that describes how secret keys are generated and consumed in QKPs. In our illustrative numerical evaluation, we compare our algorithm for secret-key provisioning with a baseline IPACT-based solution in terms of service-rejection ratio, time-slot utilization, and guard- and relay-time saving. Results show that DSKP reduces service-rejection ratio and guard- and relay-time of about 16% and 39.54%, respectively.

A Gray Image Encryption Technique Using the Concept of Water Waves, Chaos and Hash Function

In this article, an innovative encryption technique is developed by getting the inspiration from the natural up-down water wave’s phenomena that changes a reflection on pond’s surface. The plain image is considered as water pond and stones are throwing on the pond to diffuse the pixels. The direction of diffusion follows the pattern of natural water waves in 360 degrees. The distance traveled by the waves depend upon the weight of the stone i.e. heavier is the stone, longer will be the distance. Each layer of pixels in image represents Crest (Up) and Troughs (Down) around the hitting point of stone. The number of Crest and Troughs generated by a stone in radius are measured and are categorized into 1 to 6 or six levels (Layers). The concept of Crest and Trough in encryption are achieved by addition and subtraction of pseudo-random numbers in the pixel’s intensity. The pseudo random numbers are generated from Logistic map and transformed into stones of different weights ranges from 0-255. Before substitution, the pixels are shuffled in 1-dimensional vector using the index values of random numbers. The hash value is used for modification of initial seeds of the Logistic map. The initial seeds of the Logistic map are modified by the output of 256-bit hash function. Finally, the simulated results are compiled which ascertains that the projected algorithm achieves the required security standard with large pool of secret keys.

Factors influencing water immersion during labour: qualitative case studies of six maternity units in the United Kingdom

BackgroundWater immersion during labour can provide benefits including reduced need for regional analgesia and a shorter labour. However, in the United Kingdom a minority of women use a pool for labour or birth, with pool use particularly uncommon in obstetric-led settings. Maternity unit culture has been identified as an important influence on pool use, but this and other possible factors have not been explored in-depth. Therefore, the aim of this study was to identify factors influencing pool use through qualitative case studies of three obstetric units and three midwifery units in the UK.MethodsCase study units with a range of waterbirth rates and representing geographically diverse locations were selected. Data collection methods comprised semi-structured interviews, collation of service documentation and public-facing information, and observations of the unit environment. There were 111 interview participants, purposively sampled to include midwives, postnatal women, obstetricians, neonatologists, midwifery support workers and doulas. A framework approach was used to analyse all case study data.ResultsObstetric unit culture was a key factor restricting pool use. We found substantial differences between obstetric and midwifery units in terms of equipment and resources, staff attitudes and confidence, senior staff support and women’s awareness of water immersion. Generic factors influencing use of pools across all units included limited access to waterbirth training, sociodemographic differences in desire for pool use and issues using waterproof fetal monitoring equipment.ConclusionsCase study findings provide new insights into the influence of maternity unit culture on waterbirth rates. Access to pool use could be improved through midwives based in obstetric units having more experience of waterbirth, providing obstetricians and neonatologists with information on the practicalities of pool use and improving accessibility of antenatal information. In terms of resources, recommendations include increasing pool provision, ensuring birth room allocation maximises the use of unit resources, and providing pool room environments that are acceptable to midwives.

A Secure Scheme Based on One-Way Associated Key Management Model in Wireless Sensor Networks

To achieve security in wireless sensor networks (WSNs), it is important to be able to encrypt messages sent among sensor nodes by using shared keys between them. Due to resource constraints, achieving such key agreement in WSNs is nontrivial. Previous research indicates that key management schemes using deployment knowledge can significantly improve the performance of WSNs. Nevertheless, in these schemes, resilient local connectivity and resilient global connectivity become unstable when deployment error changes. To resolve the above problem, in this article, a one-way associated key management model is proposed. In this model, the key pool consists of two layers: 1) the global layer and 2) the local layer. According to different deployment errors, the number of keys allocated from the global key pool and local key pools can be dynamically adjusted, thereby improving the stability of networks' performance. In multiphase sensor networks, analysis and simulation indicate that our scheme has better adaptability in applications where deployment error changes as compared with related schemes.

A Membrane-Bound Diacylglycerol Species Induces PKCϵ-Mediated Hepatic Insulin Resistance

Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance (HIR); however, the key lipid species and molecular mechanisms linking these conditions are widely debated. We developed a subcellular fractionation method to quantify diacylglycerol (DAG) stereoisomers and ceramides in the endoplasmic reticulum (ER), mitochondria, plasma membrane (PM), lipid droplets, and cytosol. Acute knockdown (KD) of diacylglycerol acyltransferase-2 in liver induced HIR in rats. This was due to PM sn-1,2-DAG accumulation, which promoted PKCϵ activation and insulin receptor kinase (IRK)-T1160 phosphorylation, resulting in decreased IRK-Y1162 phosphorylation. Liver PM sn-1,2-DAG content and IRK-T1160 phosphorylation were also higher in humans with HIR. In rats, liver-specific PKCϵ KD ameliorated high-fat diet-induced HIR by lowering IRK-T1160 phosphorylation, while liver-specific overexpression of constitutively active PKCϵ-induced HIR by promoting IRK-T1160 phosphorylation. These data identify PM sn-1,2-DAGs as the key pool of lipids that activate PKCϵ and that hepatic PKCϵ is both necessary and sufficient in mediating HIR.

Microplastics in the agroecosystem: Are they an emerging threat to the plant-soil system?

Despite plastics providing great benefits to our daily life, plastics accumulating in the environment, especially microplastics (MPs; defined as particles <5 mm), can lead to a range of problems and potential loss of ecosystem services. Current research has demonstrated the significant impact of MPs on aquatic systems, but little is known about their effects on the terrestrial environment, especially within agroecosystems. Hereby, we investigated the effect of MPs type and amount on plant growth, soil microorganisms, and photoassimilate carbon (C) allocation. MPs had a negative, dose-dependent impact on plant growth affecting both above- and below-ground productivity (−22.9% and −8.4%). MPs also influenced assimilated 14C allocation in soil (+70.6%) and CO2 emission (+43.9%). Although the activity of β-glucosidase was suppressed by MPs, other C- and N-cycling related enzyme activities were not affected. The type and amount of MPs in soil greatly altered C flow through the plant-soil system, highlighting that MPs negatively affect a range of C-dependent soil functions. Moreover, MPs increased the soil microbial biomass (+43.6%; indicated by PLFAs), and changed the structure and metabolic status of the microbial community. The evidence presented here suggests that MPs can have a significant impact on key pools and fluxes within the terrestrial C cycle with the response being both dose-dependent and MPs specific. We conclude that MPs in soil are not benign and therefore every step should be made to minimise their entry into the soil ecosystem and potential to transfer into the food chain.

Quantum-Secure Microgrid

Existing microgrid communication relies on classical public key systems, which are vulnerable to attacks from quantum computers. This paper uses quantum key distribution (QKD) to solve these quantum-era microgrid challenges. Specifically, this paper makes the following novel contributions: 1) it devises a novel QKD simulator capable of simulating QKD protocols; 2) it offers a QKD-based microgrid communication architecture for microgrids; 3) it shows how to build a quantum-secure microgrid testbed in an RTDS environment; 4) it develops a key pool sharing (KPS) strategy to improve the cyberattack resilience of the QKD-based microgrid; and 5) it analyzes the impacts of critical QKD parameters with the testbed. Test results provide insightful resources for building a quantum-secure microgrid.

Multi-Tenant Provisioning for Quantum Key Distribution Networks With Heuristics and Reinforcement Learning: A Comparative Study

Quantum key distribution (QKD) networks are potential to be widely deployed in the immediate future to provide long-term security for data communications. Given the high price and complexity, multi-tenancy has become a cost-effective pattern for QKD network operations. In this work, we concentrate on addressing the online multi-tenant provisioning (On-MTP) problem for QKD networks, where multiple tenant requests (TRs) arrive dynamically. On-MTP involves scheduling multiple TRs and assigning non-reusable secret keys derived from a QKD network to multiple TRs, where each TR can be regarded as a high-security-demand organization with the dedicated secret-key demand. The quantum key pools (QKPs) are constructed over QKD network infrastructure to improve management efficiency for secret keys. We model the secret-key resources for QKPs and the secret-key demands of TRs using distinct images. To realize efficient On-MTP, we perform a comparative study of heuristics and reinforcement learning (RL) based On-MTP solutions, where three heuristics (i.e., random, fit, and best-fit based On-MTP algorithms) are presented and a RL framework is introduced to realize automatic training of an On-MTP algorithm. The comparative results indicate that with sufficient training iterations the RL-based On-MTP algorithm significantly outperforms the presented heuristics in terms of tenant-request blocking probability and secret-key resource utilization.

Programmable Quantum Networked Microgrids

Quantum key distribution (QKD) provides a potent solution to securely distribute keys for two parties. However, QKD itself is vulnerable to denial of service (DoS) attacks. A flexible and resilient QKD-enabled networked microgrids (NMs) architecture is needed but does not yet exist. In this article, we present a programmable quantum NMs (PQNMs) architecture. It is a novel framework that integrates both QKD and software-defined networking (SDN) techniques capable of enabling scalable, programmable, quantum-engineered, and ultra-resilient NMs. Equipped with a software-defined adaptive post-processing approach, a two-level key pool sharing strategy and an SDN-enabled event-triggered communication scheme, these PQNMs mitigate the impact of DoS attacks through programmable post-processing and secure key sharing among QKD links, a capability unattainable using existing technologies. Through comprehensive evaluations, we validate the benefits of PQNMs and demonstrate the efficacy of the presented strategies under various circumstances. Extensive results provide insightful resources for building QKD-enabled NMs in practice.

Quantum Key Distribution Over Double-Layer Quantum Satellite Networks

Quantum key distribution (QKD) has attracted much attention on secure communications across global networks. QKD over satellite networks can overcome the limitations of terrestrial optical networks, such as large attenuation over long distance fiber channel and difficulty of intercontinental domain communications. Different QKD networks (around the world) can intercommunicate through quantum satellites, leading to a global quantum network in near future. This raises a new resource allocation and management problem of QKD involving multiple satellite layers and distributed ground stations. Using existing schemes, a single satellite cannot perform QKD for ground stations for the whole day. Moreover, the research problem is more challenging due to limitations of satellite coverage: limited cover time of low earth orbit (LEO) satellite, high channel losses of geostationary earth orbit (GEO) satellite, etc. To overcome these limitations, our study proposes a double-layer quantum satellite network (QSN) implemented quantum key pool (QKP) to relay keys for ground stations. We propose a new architecture of trusted-repeater-based double-layer quantum satellite networks, comprising GEO and LEO satellites. We also address the routing and key allocation (RKA) problem for key-relay services over QSNs. We propose a novel joint GEO-LEO routing and key allocation (JGL-RKA) algorithm to solve the RKA problem. Simulative results show that the proposed scheme can increase success probability of key-relay services significantly. We also present the impact of different route selections mechanisms, number of satellite links, satellite node capability, and service granularity on network performance.

KaaS: Key as a Service over Quantum Key Distribution Integrated Optical Networks

In the Internet Age, optical networks are vulnerable to numerous cyberattacks, and conventional key distribution methods suffer from the increased computational power. QKD can distribute information-theoretically secure secret keys between two parties based on the principles of quantum mechanics. Integrating QKD into optical networks can leverage existing fiber infrastructures with wavelength division multiplexing for the practical deployment of secret keys, and accordingly employ the secret keys for optical-layer security enhancement. Then, how to efficiently deploy and employ secret keys over QKD-integrated optical networks are emerging as two challenges. This article proposes a framework of key as a service (KaaS, i.e., providing secret keys as a service in a timely and accurate manner to satisfy the security requirements) to jointly overcome these two challenges. To enable the typical functions (i.e., secret-key deployment and employment) in KaaS, two secret-key virtualization steps, that is, key pool (KP) assembly and virtual key pool (VKP) assembly, are introduced. Also, we illustrate a new QKD-integrated optical network architecture from a holistic view, where the control layer is implemented by software defined networking for efficient network management. A time-shared KP assembly strategy and an on-demand VKP assembly strategy are presented for KaaS implementation. The success probabilities of KP assembly and VKP assembly are defined to evaluate the benefits of KaaS for efficiently deploying and employing secret keys as well as for security enhancement over QKD-integrated optical networks.

A Hybrid Key Pre-distribution Scheme for Wireless Sensor Networks

Key management in wireless sensor networks (WSNs) is the basic service for deploying security policies. In this paper, we combine q-composite scheme with polynomial scheme to propose a hybrid key pre-distribution scheme for WSNs. The characteristic of the scheme is that a partial polynomial is preloaded for each sensor node, and then a polynomial share stored by each node is used to generate a corresponding key pool. Perform the corresponding hash operation on the generated keys to hide part of the key information of the nodes. Then select the corresponding number of processed generation keys to distribute to each node. The scheme introduces a random key method, which avoids the "t-secure" problem faced by the conventional polynomial scheme and achieves the significant improvement of network security. The corresponding key is generated using the polynomial share preloaded on the sensor node, which has a higher connectivity than the polynomial scheme. Theoretical and simulation results show that the propose scheme not only enhances the network secure connectivity, but also improves the node’s anti-capture attack capability when compared to other schemes.

Multi-tenant secret-key assignment over quantum key distribution networks.

Quantum key distribution (QKD) networks are promising to progress towards widespread practical deployment over existing fiber infrastructures in the near future. Given the high cost and difficulty of deploying QKD networks, multi-tenancy becomes promising to improve cost efficiency for future QKD networks. In a multi-tenant QKD network, multiple QKD tenants can share the same QKD network infrastructure to obtain secret keys for securing their data transfer. Since the secret-key resources are finite and precious in QKD networks, how to achieve efficient multi-tenant secret-key assignment (MTKA) to satisfy the secret-key demands of multiple QKD tenants over QKD networks becomes a significant problem. In this regard, this study addresses the MTKA problem over QKD networks. A new multi-tenant QKD network architecture is proposed based on software defined networking (SDN) and quantum key pool (QKP) techniques. A secret-key rate sharing scheme is presented and a heuristic algorithm is designed to implement efficient MTKA over QKD networks. A new performance metric, namely matching degree (MD) that reflects the balance between QKD network secret-key resources and QKD tenant requests, is defined and evaluated. Simulation studies indicate that high QKD tenant requests accommodation and efficient secret-key resource usage can be achieved via maximizing the value of MD.

An Image Segmentation Encryption Algorithm Based on Hybrid Chaotic System

Image encryption is an effective technology to protect digital image confidentiality. This paper presents an image segmentation encryption algorithm based on a hybrid chaotic system. First, a chaotic sequence is obtained by iterating a Quantum Cellular Neural Network (QCNN), and then it is scrambled by a 4-D hyperchaotic system to generate a key pool. Second, the chaotic pointers generated by 3-D chaotic systems and QCNN with different initial values are used to get the keys for image segmentation, scrambling, and diffusion from the key pool. Then, the plain-image is divided into two blocks by the chaotic segmentation method and scrambled by intra-block and inter-block pixel exchange. In addition, two blocks are statically diffused, and the cipher-image is obtained by dynamic diffusing after combining the image blocks. Especially, the key pool increases the efficiency of the proposed algorithm, and chaotic segmentation reduces the cipher-image pixel correlation. Finally, the simulation results and performance analysis indicate that the proposed algorithm has a well-security, high sensitivity, and faster speed.

Time-Scheduled Quantum Key Distribution (QKD) Over WDM Networks

Quantum key distribution (QKD) networking over wavelength-division multiplexing (WDM) network infrastructure provides a new paradigm for secure communications across the networks. With limited wavelength resources in existing WDM networks, how to efficiently schedule QKD to provision sufficient secret keys over WDM networks becomes a new challenge. This study proposes a new time-scheduled scheme in combination with quantum key pool (QKP) technique to overcome this challenge. A new architecture of QKD-over-WDM networks is presented, in which QKPs are constructed to decouple secret-key resources from the underlying infrastructure for timely secret-key provisioning. In the time-scheduled scheme, routing, wavelength, and time-slot allocation (RWTA) problem is proposed for efficient QKP construction (QKPC) over WDM networks, in which three sub-problems (i.e., secret-key consumption, time-slot allocation, and time-slot continuity) are discussed, respectively. An integer linear programming (ILP) model and a novel joint path-and-link-based RWTA (JPL-RWTA) heuristic algorithm are designed to solve the RWTA problem, in which the three sub-problems are addressed together. Simulation results indicate that the ILP model and JPL-RWTA algorithm are effective approaches to obtain the positive balance between resource utilization of QKPC and successful probability of QKPC (SPQKPC). Moreover, the SPQKPC can be increased at the cost of reducing the flexibility of secret-key consumption, the uniformity of time-slot allocation, and the proportion of time-slot continuous QKPC to time-slot discrete QKPC requests.

An attack resistant key predistribution scheme for wireless sensor networks

Most of the key management schemes do not consider the attacking behavior of the adversary making such schemes less practical in real world. By knowing the adversarial behavior, several countermeasures against them can be effectively and efficiently designed by the defender/network designer. In this paper, we investigate the problem of node capture attack and propose a secure hybrid key predistribution scheme (HKP-HD) for wireless sensor networks (WSN). This scheme combines the robustness of the q-composite scheme with threshold resistant polynomial scheme. The proposed scheme aims to make the network more resistant against the node capture attacks. Adversary is assumed to be intelligent that tends to exploit different vulnerabilities present in network to build an attack matrix. It aims to destroy complete network with least number of nodes based on the attack matrix. As a countermeasure, the network designer constructs similar attack matrix based on the vulnerabilities in the network by considering sink as a major influencing factor. This matrix is used to calculate the attack coefficient of every node of the network that determines its probability of attack by the adversary. A hash chain based on maximum value of attack coefficient along with the multiple key pools is used to reduce the probability of the key compromise and communication overhead of the proposed scheme. The simulation results demonstrate that the proposed scheme has reduced probability of key compromise, communication overhead and storage overhead as compared to other schemes.

Effects of sorption on biodegradation of low-molecular-weight organic acids in highly-weathered tropical soils

Low molecular weight organic acids (LMWOAs) are key pools regulating carbon (C) stabilization and destabilization in tropical forest soils. The variation in clay contents and mineralogy between sites or within a profile might regulate magnitude of LMWOA sorption and biodegradation in tropical soils poor in short-range-order (SRO) Al/Fe oxides. We analyzed soil solution concentration, sorption isotherms, and mineralization kinetics of 14C-radiolabeled acetate, oxalate, citrate, and glucose. The sorption capacities of LMWOAs increased with clay contents, but not with the abundance of SRO clay minerals. Sorption can reduce mineralization rates of multivalent LMWOAs (oxalate and citrate) and its effects could increase with increasing clay contents, especially in the clay-rich Bt horizon or in the clayey soil profile. The microbial respiration rates from LMWOAs and monosaccharides are primarily regulated by substrate availability and microbial biomass in the tropical soils, while mineralization of multivalent LMWOAs can be limited by sorption especially in the clayey soil horizon or profile. The smaller sorption capacities in the organic and sandier soil horizons could contribute to fast turnover of organic matters through LMWOA pools in tropical forest soils.

Analyzing Connectivity of Heterogeneous Secure Sensor Networks

We analyze connectivity of a heterogeneous secure sensor network that uses key predistribution to protect communications between sensors. For this network on a set $\mathcal{V}_n$ of $n$ sensors, suppose there is a pool $\mathcal{P}_n$ consisting of $P_n$ distinct keys. The $n$ sensors in $\mathcal{V}_n$ are divided into $m$ groups $\mathcal{A}_1, \mathcal{A}_2, \ldots, \mathcal{A}_m$. Each sensor $v$ is independently assigned to exactly a group according to the probability distribution with $\mathbb{P}[v \in \mathcal{A}_i]= a_i$ for $i=1,2,\ldots,m$, where $\sum_{i=1}^{m}a_i = 1$. Afterwards, each sensor in group $\mathcal{A}_i$ independently chooses $K_{i,n}$ keys uniformly at random from the key pool $\mathcal{P}_n$, where $K_{1,n} \leq K_{2,n}\leq \ldots \leq K_{m,n}$. Finally, any two sensors in $\mathcal{V}_n$ establish a secure link in between if and only if they have at least one key in common. We present critical conditions for connectivity of this heterogeneous secure sensor network. The result provides useful guidelines for the design of secure sensor networks. This paper improves the seminal work [1] (IEEE Transactions on Information Theory 2016) of Ya{\u{g}}an on connectivity in several aspects (omitted due to arxiv abstract's character limitation; see the paper for details).

Deployment Based Attack Resistant Key Distribution with Non Overlapping Key Pools in WSN

Many current key management schemes do not effectively consider the attack probability and assume it to be same for every sensor node. However, for some applications like disaster management and mi...

A Pre-Shared Key Pool Scheme for Wireless Sensor Networks Based on Time.

A Pre-Shared Key Pool Scheme for Wireless Sensor Networks Based on Time.