Untrusted Nodes Research Articles

Practical AgentChain: A compatible cross-chain exchange system

Blockchain is a decentralized ledger system that enables transactional consensus among untrusted nodes. Due to the independence between blockchains, it is tough to complete asset exchange tasks between diverse chains. Facing this problem, multiple cross-chain exchange schemes were proposed, but they have not been widely used due to various defects in terms of compatibility, flexibility, security, and practicability.In this paper, we construct a comprehensive cross-chain exchange system called Practical AgentChain. Various coins can be mapped to the corresponding tokens on Practical AgentChain for trading. One or multiple trading operators can spontaneously form a service deposit pool on existing blockchains and register a trading group for profit using the well-designed smart contract called Agent Contract. All the trading groups competitively provide cross-chain exchange services. Clients with exchange currency requirements can freely select an appropriate trading group to request services, such as mapping assets to tokens or withdraw tokens. The choice of the trading group is made according to the group’s deposit and the group members’ reputation recorded on the Agent Contract. This system also incorporates Town crier as the reliable Data Oracle system for obtaining the status of cross-chain transactions and combines a matching exchange protocol to ensure the fairness of on-chain token exchange.In addition, we design an impartial service arbitration mechanism and a deposit allocation scheme to ensure the reliability of the system. Through security analysis, our system can resist re-use attacks, denial-of-service attacks and resolve service availability issues. We modify the Town crier adaptively and combine it with Ethereum to implement the simulation. The experimental results show that Practical AgentChain is efficient and low-cost. Besides, our system can be deployed on any existing blockchain that supports smart contracts since the system’s architecture is highly portable.

Low-Complexity Transmit Power Control for Secure Communications in Wireless-Powered Cognitive Radio Networks.

In this study, wireless-powered cognitive radio networks (WPCRNs) are considered, in which N sets of transmitters, receivers and energy-harvesting (EH) nodes in secondary networks share the same spectrum with primary users (PUs) and none of the EH nodes is allowed to decode information but can harvest energy from the signals. Given that the EH nodes are untrusted nodes from the point of view of information transfer, the eavesdropping of secret information can occur if they decide to eavesdrop on information instead of harvesting energy from the signals transmitted by secondary users (SUs). For secure communications in WPCRNs, we aim to find the optimal transmit powers of SUs that maximize the average secrecy rate of SUs while maintaining the interference to PUs below an allowable level, while guaranteeing the minimum EH requirement for each EH node. First, we derive an analytical expression for the transmit power via dual decomposition and propose a suboptimal transmit power control algorithm, which is implemented in an iterative manner with low complexity. The simulation results confirm that the proposed scheme outperforms the conventional distributed schemes by more than 10% in terms of the average secrecy rate and outage probability and can also considerably reduce the computation time compared with the optimal scheme.

A Distributed Security SDN Cluster Architecture for Smart Grid Based on Blockchain Technology

This paper proposes a smart grid distributed security architecture based on blockchain technology and SDN cluster structure, referred to as ClusterBlock model, which combines the advantages of two emerging technologies, blockchain and SDN. The blockchain technology allows for distributed peer-to-peer networks, where the network can ensure the trusted interaction of untrusted nodes in the network. At the same time, this article adopts the design of an SDN controller distributed cluster to avoid single point of failure and balance the load between equipment and the controller. A cluster head was selected in each SDN cluster, and it was used as a blockchain node to construct an SDN cluster head blockchain. By combining blockchain technology, the security and privacy of the SDN communication network can be enhanced. At the same time, this paper designs a distributed control strategy and network attack detection algorithm based on blockchain consensus and introduces the Jaccard similarity coefficient to detect the network attacks. Finally, this paper evaluates the ClusterBlock model and the existing model based on the OpenFlow protocol through simulation experiments and compares the security performance. The evaluation results show that the ClusterBlock model has more stable bandwidth and stronger security performance in the face of DDoS attacks of the same scale.

Measurement-device-independent quantum key distribution for nonstandalone networks

Untrusted node networks initially implemented by measurement-device-independent quantum key distribution (MDI-QKD) protocol are a crucial step on the roadmap of the quantum Internet. Considering extensive QKD implementations of trusted node networks, a workable upgrading tactic of existing networks toward MDI networks needs to be explicit. Here, referring to the nonstandalone (NSA) network of 5G, we propose an NSA-MDI scheme as an evolutionary selection for existing phase-encoding BB84 networks. Our solution can upgrade the BB84 networks and terminals that employ various phase-encoding schemes to immediately support MDI without hardware changes. This cost-effective upgrade effectively promotes the deployment of MDI networks as a step of untrusted node networks while taking full advantage of existing networks. In addition, the diversified demands on security and bandwidth are satisfied, and network survivability is improved.

Sensing as a service in Internet of Things: Efficient authentication and key agreement scheme

Internet of Things (IoT) sensing capabilities are now available as a public service. This new model, called sensing as a service (S2aaS), allows data owners to sell and/or exchange data with consumers interested in large open markets. However, the openness of the service industry makes the IoT-based S2aaS model more susceptible to malicious attacks. In this article, we propose a simple, efficient, and secure key agreement scheme for IoT-based S2aaS model. Users in the proposed system can securely and quickly access public services through a simple website rather than a traditional smart card. To simulate a real S2aaS environment, the cloud is treated as an untrusted node in the proposed method, and not all channels are secure. The fuzzy extractor and elliptic-curve Diffie–Hellman algorithms are used in conjunction with symmetric encryption and hash functions to establish a secure key agreement and data exchange session. In critical and frequent intervals, heavy processes are avoided. The proposed scheme's security has been informally analyzed and formally proven using the Automated Validation of Internet Security Protocols and Applications tool. The results show that our scheme satisfies the security requirements.

An enhanced OFDM light weight physical layer encryption scheme

The broadcast nature of wireless networks makes them susceptible to attacks by eavesdroppers than wired networks. Any untrusted node can eavesdrop on the medium, listen to transmissions and obtain sensitive information within the wireless network. In this paper, we propose a new mechanism which combines the advantages of two techniques namely iJam and OFDM phase encryption. Our modified mechanism makes iJam more bandwidth efficient by using Alamouti scheme to take advantage of the repetition inherent in its implementation. The adversary model is extended to the active adversary case, which has not been done in the original work of iJam and OFDM phase encryption. We propose, through a max min optimization model, a framework that maximizes the secrecy rate by means of a friendly jammer. We formulate a Zero-Sum game that captures the strategic decision making between the transmitter receiver pair and the adversary. We apply the fictitious play (FP) algorithm to reach the Nash equilibria (NE) of the game. Our simulation results show a significant improvement in terms of the ability of the eavesdropper to benefit from the received information over the traditional schemes, i.e. iJam or OFDM phase encryption.

Quantum repeaters in space

Long-distance entanglement is a very precious resource, but its distribution is very difficult due to the exponential losses of light in optical fibres. A possible solution consists in the use of quantum repeaters, based on entanglement swapping (ES) or quantum error correction. Alternatively, satellite-based free-space optical links can be exploited, achieving better loss-distance scaling. We propose to combine these two ingredients, quantum repeaters and satellite-based links, into a scheme that allows to achieve entanglement distribution over global distances with a small number of intermediate untrusted nodes. The entanglement sources, placed on satellites, send quantum states encoded in photons towards orbiting quantum repeater stations, where ES is performed. The performance of this repeater chain is assessed in terms of the secret key rate achievable by the BBM92 cryptographic protocol. We perform a comparison with other repeater chain architectures and show that our scheme, even though more technically demanding, is superior in many situations of interest. Finally, we analyse strengths and weaknesses of the proposed scheme and discuss exemplary orbital configurations. The integration of satellite-based links with ground repeater networks can be envisaged to represent the backbone of the future quantum internet.

A Novel Trust-Aware and Energy-Aware Clustering Method That Uses Stochastic Fractal Search in IoT-Enabled Wireless Sensor Networks

Wireless sensor network (WSN) technology is considered to be an integral part of large-scale and efficient deployment of Internet-of-Things (IoT). More specifically, in mission-critical IoT applications, trust in the sensor data is becoming increasingly important. Sensor nodes have limited processing, storage, and communication capabilities, which make them susceptible to attacks and unreliable functioning. However, the limitations in the energy resources of the sensors are a major challenge in maximizing the network’s lifetime. Grouping the sensors into clusters was proposed to address such energy limitations. Many meta-heuristic clustering protocols have been proposed to maximize the network lifetime, which is an NP-hard problem. This problem is more complicated when considering the trust factor. The majority of existing clustering models were built to reduce the energy consumption in the network without considering the energy consumption required to detect untrusted nodes, and thus, it requires extra energy consumption to perform this task. This article proposes a clustering protocol with a trust model that detects the untrusted nodes through energy and data-trust. In addition, the proposed clustering protocol maximizes the network’s lifetime through the good characteristics of stochastic fractal search optimization. Finally, a novel fitness function is introduced to select the cluster-heads among the trusted nodes. The function is based on the following four parameters: 1) the remaining energy of the nodes; 2) the density of the nodes; 3) the distance between each node and the base-station; and 4) the network’s dissipated energy. When forming the clusters, the density of the cluster-heads is considered to balance the load of all of the cluster-heads. The experimental evaluation performed here affirms the efficacy of the proposed protocol in comparison with existing protocols.

A Universal Routing Algorithm Based on Intuitionistic Fuzzy Multi-Attribute Decision-Making in Opportunistic Social Networks

With the vigorous development of big data and the 5G era, in the process of communication, the number of information that needs to be forwarded is increasing. The traditional end-to-end communication mode has long been unable to meet the communication needs of modern people. Therefore, it is particularly important to improve the success rate of information forwarding under limited network resources. One method to improve the success rate of information forwarding in opportunistic social networks is to select appropriate relay nodes so as to reduce the number of hops and save network resources. However, the existing routing algorithms only consider how to select a more suitable relay node, but do not exclude untrusted nodes before choosing a suitable relay node. To select a more suitable relay node under the premise of saving network resources, a routing algorithm based on intuitionistic fuzzy decision-making model is proposed. By analyzing the real social scene, the algorithm innovatively proposes two universal measurement indexes of node attributes and quantifies the support degree and opposition degree of node social attributes to help node forward by constructing intuitionistic fuzzy decision-making matrix. The relay nodes are determined more accurately by using the multi-attribute decision-making method. Simulation results show that, in the best case, the forwarding success rate of IFMD algorithm is 0.93, and the average end-to-end delay, network load, and energy consumption are the lowest compared with Epidemic algorithm, Spray and Wait algorithm, NSFRE algorithm, and FCNS algorithm.

WITHDRAWN: DESD-CAT inspired algorithm for establishing trusted connection in energy efficient FoG-BAN networks

Abstract Advanced technology utilization in medical field is emerging filed to reduce workload and time by providing earlier disease diagnosis and provide quality treatment. In this field to establish trusted connection from the attackers and providing secure data transfer among the interconnected sensors are challenging tasks. To overcome these problems, an attack identification scheme is required in trustable intra Body Area Network. Existing Trust-BAN networks are framed based on residual energy, Nodes distance, Cooperative communication and nodes behavior strategy. In this category nearest sensor nodes gathered all such nature details, based on that untrusted nodes are identified. But this is not suitable always in realistic situations. So an intelligent adaptive solution is needed in FoG computing based Body Area environment to identify malignant nodes. Hence proposed trust-based model, trustable nodes are identified using proper handshaking techniques which are happened in internal wireless Body Area Nodes, based on node id, Sensor localization, Channel Id ,Residual Energy, Delay and original sensor informations. This work also explaining about trust based energy efficient model for classifying malicious nodes from authorized sensor nodes. After classifying malicious nodes the remaining nodes in the WBAN form a trusted-cluster in order to provide proper handshaking signals among them. In every group the cluster head is selected based on the CAT inspired intelligent algorithm. By utilizing a Chaos based encryption techniques and adaptive fitness functions biomedical datas are encrypted in FoG server for further analysis and maintaining Integrity of data. The experimental results clearly explains that the proposed work achieve good performance in terms of precision, recall, throughput ,delay and other network centric performance measures compare to the firefly algorithm.

Spooky action at a global distance: analysis of space-based entanglement distribution for the quantum internet

Recent experimental breakthroughs in satellite quantum communications have opened up the possibility of creating a global quantum internet using satellite links. This approach appears to be particularly viable in the near term, due to the lower attenuation of optical signals from satellite to ground, and due to the currently short coherence times of quantum memories. The latter prevents ground-based entanglement distribution using atmospheric or optical-fiber links at high rates over long distances. In this work, we propose a global-scale quantum internet consisting of a constellation of orbiting satellites that provides a continuous, on-demand entanglement distribution service to ground stations. The satellites can also function as untrusted nodes for the purpose of long-distance quantum-key distribution. We develop a technique for determining optimal satellite configurations with continuous coverage that balances both the total number of satellites and entanglement-distribution rates. Using this technique, we determine various optimal satellite configurations for a polar-orbit constellation, and we analyze the resulting satellite-to-ground loss and achievable entanglement-distribution rates for multiple ground station configurations. We also provide a comparison between these entanglement-distribution rates and the rates of ground-based quantum repeater schemes. Overall, our work provides the theoretical tools and the experimental guidance needed to make a satellite-based global quantum internet a reality.

A trusted behaviour measurement scheme based on feedback and control in trusted network

To solve the real-time trusted measurement of user behaviour in trusted networks, a new combination of dynamic and static, subjective and objective behaviour trusted measurement scheme is presented. The scheme analyses the credibility of the real-time user state and the direct trusted measurement value of the user behaviour, and finally controls the user behaviour by the feedback measurement of the user behaviour. The research results show that when the ratio of untrusted nodes is 15%, 30% and 50%, the trusted detection rate of this paper can reach more than 92%, and the untrusted node in trusted network can be identified with the increase of time. Compared with traditional measurement scheme, the scheme can be more accurate and reasonable to calculate the credibility of user behaviour, and can reflect the changes of the credibility of users' actual behaviour at all times, and ultimately implement the feedback control on user behaviour.

Dynamic Network Security Mechanism Based on Trust Management in Wireless Sensor Networks

Wireless sensor network is a key technology in Internet of Things. However, due to the large number of sensor nodes and limited security capability, aging nodes and malicious nodes increase. In order to detect the untrusted nodes in the network quickly and effectively and ensure the reliable operation of the network, this paper proposes a dynamic network security mechanism. Firstly, the direct trust value of the node is established based on its behavior in the regional information interaction. Then, the comprehensive trust value is calculated according to the trust recommendation value and energy evaluation value of other high‐trust nodes. Finally, node reliability and management nodes are updated periodically. Malicious nodes are detected and isolated according to the credibility to ensure the dynamic, safe, and reliable operation of the network. Simulation results and analysis show that the node trust value calculated by this mechanism can reflect its credibility truly and accurately. In terms of reliable network operation, the mechanism can effectively detect malicious nodes, with higher detection rate, avoid the risk of malicious nodes as management nodes, reduce the energy consumption of nodes, and also play a defensive role in DOS attacks in wireless sensor networks.

Blockchain for smart grid security: applications, trends, and challenges

The electric power grid is the world's largest engineering system, and its secure and reliable operation is vital to human activities. The introduction of intelligence in the electrical power grid through smart grids imposes challenges that require new techniques and approaches to provide cyber-physical security. In this article, we discuss the use of blockchain to provide security and reliability to smart grids. Blockchain allows untrusted nodes to correctly and verifiably interact with each other in a distributed peer-to-peer network, without any reliable intermediary. We explore smart contracts, codes resident in blockchain that automate multi-step processes, as a way to automatically trade electric energy. We also discuss initiatives, challenges, and research opportunities of blockchain technologies in the electrical sector.

NOMA in Cooperative Communication Systems With Energy-Harvesting Nodes and Wireless Secure Transmission

In this paper, non-orthogonal multiple access (NOMA) in cooperative relay system is considered, where a source node communicates with a pair of energy harvesting (EH) user equipments through a multiple antennas relay node. A hybrid protocol is adopted at the relay, in which if the relay can successfully decode the signals, decode-and-forward (DF) protocol will be adopted to forward the signals to the users. Otherwise, amplify-and-forward (AF) protocol will be implemented. Assuming that the users adopt maximal ratio combining (MRC) to combine the received signals in the two cooperative phases, new explicit analytical expressions for the average sum-rate are derived when the relay works in, 1) AF mode, and 2) DF mode, in two scenarios when one user is the stronger in both cooperation phases, and when an alternative user is stronger in each phase. Then, the investigation is extended to the case where the relay is an untrusted node, and cooperative jamming technique is proposed to degrade the ability of the relay to decode the signals and enforce the relay to operate always in AF mode. For the untrusted relay scenario, new analytical expression for the average secrecy rate is derived. Monte Carlo simulations are provided to validate the analysis. The simulation results reveal that the location of the relay is the key parameter to achieve the best performance.

An Authenticated Enrolment Scheme of Nodes using Blockchain and Prevention of Collaborative Blackhole Attack in WSN

Security is indispensable concern part of the WSN. The reliable mechanisms and routing schemes are facing different set of encounters in the era of authentic status quo and it is also very knotty. Problem is identified in the recognition of untrusted nodes and routes followed from source to destination along with the restraint of battery status in WSN. No effective technique is there to avert the vindictive node attack. The current research article provides an algorithm of the nodes by employing the blockchain technology as far as solution to the other persisting drawbacks like identification of untrusted nodes and untrusted routes were tackled out by the help of secure AODV using blockchain. The outcomes of this research article by performing the simulation and experimental validation of the existing systems denotes the successful identification and occurrence of malicious nodes, end-to-end delay, packet delivery ratio and through put performance evaluation. The registration of the nodes in blockchain database and behaviour of black hole attack in AODV protocol was also simulated using NS2 blockchain algorithm.

A Challenge-Response Assisted Authorisation Scheme for Data Access in Permissioned Blockchains.

Permissioned blockchains can be applied for sharing data among permitted users to authorise the data access requests in a permissioned blockchain. A consensus network constructed using pre-selected nodes should verify a data requester’s credentials to determine if he or she have the correct permissions to access the queried data. However, current studies do not consider how to protect users’ privacy for data authorisation if the pre-selected nodes become untrusted, e.g., the pre-selected nodes are manipulated by attackers. When a user’s credentials are exposed to pre-selected nodes in the consensus network during authorisation, the untrusted (or even malicious) pre-selected nodes may collect a user’s credentials and other private information without the user’s right to know. Therefore, the private data exposed to the consensus network should be tightly restricted. In this paper, we propose a challenge-response based authorisation scheme for permissioned blockchain networks named Challenge-Response Assisted Access Authorisation (CRA3) to protect users’ credentials during authorisation. In CRA3, the pre-selected nodes in the consensus network do not require users’ credentials to authorise data access requests to prevent privacy leakage when these nodes are compromised or manipulated by attackers. Furthermore, the computational burden on the consensus network for authorisation is reduced because the major computing work of the authorisation is executed by the data requester and provider in CRA3.

Securing Cyber-Physical Systems from Hardware Trojan Collusion

Hardware Trojans, which are malicious modifications made to circuits, may cause severe security issues in Cyber-Physical Systems (CPS). CPS are usually composed of multiple untrusted nodes and a trusted server, with each node connecting to the server wirelessly in a multi-hop manner. A Trojan in one node may broadcast messages with triggers secretly embedded to simultaneously activate multiple Trojans in other nodes, causing system-wide catastrophe. To prevent hardware Trojan collusion in CPS, this paper presents a collaborative defensive framework. When deploying the network, a security requirement of vendor diversity is enforced between neighboring nodes, thus precluding collusion between neighboring nodes and allowing them to monitor each other's behavior. At runtime, a mutual auditing protocol is utilized to check, for each message, whether it is correctly encrypted by the source node and whether its content is maliciously changed by any node on the routing path. This protocol ensures that any message embedded with hardware Trojan trigger is either muted or detected and abandoned, while the benign messages are thwarted. The experimental results show that the framework effectively prevents hardware Trojan collusion with low latency overhead and almost no impact on packet completion rate and network throughput.

Secrecy capacity analysis of untrusted relaying energy-harvesting systems with hardware impairments

In this paper, we study the impact of hardware impairments, which can act as one of the factors that cause degradation in the performance of communication systems, on the secrecy capacity of an untrusted relaying wireless energy-harvesting (WEH) system. In the system, the energy-constrained relay is an untrusted node which can overhear the source’s confidential signal while assisting the source-destination communication. The relay operates in the amplify-and-forward (AF) mode and uses the power-splitting (PS) protocol for harvesting energy. The destination sends an artificial noise (AN) signal during the source-relay communication. The AN signal acts as an additional energy source and an interference source at the relay. In our study, we derive an approximation of the average secrecy capacity (ASC) for the high-power-regime approximation in order to evaluate the secrecy performance of the proposed system, which is also the upper bound for the ASC. The analytical results are confirmed via Monte Carlo simulations. The numerical results provide valuable insights into the effect of the various system parameters, such as the power-splitting ratio, the relay’s location, the trade-off between the source’s power and the destination’s power, and the level of hardware impairments, on the secrecy performance.

Trust-Based Probabilistic Broadcast Scheme for Mobile Ad Hoc Networks

The overhead caused by broadcast schemes cannot be neglected in mobile ad hoc networks. It is known that the probabilistic broadcast scheme is an effective approach to reduce overhead, in which nodes forward packets with a probability to reduce redundant retransmissions. In hostile environments, malicious nodes degrade network efficiency, and they should be prevented from route discovery and data transmission. In this case, routing packets forwarded by malicious nodes are redundant. This paper presents a Trust-based Probabilistic Broadcast scheme (TPB) focusing on reducing overhead, especially caused by malicious nodes, in which rebroadcast probability is determined based on nodes’ trustworthiness. In order to obtain nodes’ trust level, a light-weight trust management model is designed based on direct and recommended trust evidence. According to nodes’ trust level, rebroadcast delay is calculated for rearranging the rebroadcast order of routing packets. Furthermore, a novel method based on nodes’ trustworthiness is proposed to calculate rebroadcast probability, which prevents untrusted nodes from route discovery. The proposed trust-based probabilistic broadcast scheme is incorporated with existing routing protocol and its performance is evaluated by simulations. The numerical results show that the proposed scheme can secure network communication and reduce the routing overhead.