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Due to advancements in the development of wireless medical sensing devices and wireless communication technologies, the wireless body area network (WBAN) has become an eminent part of e-healthcare systems. WBAN uses medical sensors to continuously monitor and collect the physiological parameters of a patient’s health and send them to a remote medical server through a portable digital assistance (PDA)/mobile. Due to limitations in communication, such as power, storage, and the computational capabilities of sensors, data aggregation techniques are used to reduce the communication overhead in real-time data transmission in WBAN. However, since the WBAN transmits sensitive health data, data security and data privacy are a major concern. In this paper, we propose a secure privacy-preserving data aggregation (SPPDA) scheme based on bilinear pairing for remote health monitoring systems to improve data aggregation efficiency and data privacy. Our proposed SPPDA scheme utilizes the homomorphic property of the bilinear ElGamal cryptosystem to perform privacy-preserving secure computation and combines it with the aggregate signature scheme, enabling data authenticity/integrity in the WBAN. The proposed SPPDA scheme is proved to be semantically secure under the decisional bilinear Diffie–Hellman assumption. Security analysis demonstrates that our proposed scheme preserves data confidentiality, data authenticity, and data privacy; it also resists passive eavesdropping and replay attacks. A performance evaluation based on simulation results and a comparison of computational cost with related schemes show that data aggregation and batch verification at the PDA significantly reduce communication and transmission overhead and support efficient computation at the remote server.

Roaming service in wireless networks is highly desirable to mobile users. In this service, security and privacy are among the main factors. Moreover, allowing access to only authenticated legal users is one of the main factors for network service providers. This work proposes a privacy-preserving authentication scheme (PPAS) for roaming in a wireless network. The PPAS provides strong user anonymity, user unlinkability, and an efficient approach for network service providers to allow access to only authenticated legal users. The strong user anonymity and user unlinkability are based on the group signature and authentication list. The authentication list contains tokens for only legal users while preserving their privacy. A session key agreement is employed in the scheme for integrity and confidentiality. The proposed PPAS effectively mitigates some of the existing limitations.

From the beginning of 21st century, most people, especially the young ones, used to share whatever they want from their stuff like photo, chats, opinion, interests, accomplishments, and so on, over the social network day after day. One of the quite popular debates is about that if the social network sites preserve the individual privacy or not. The anonymizing techniques are famous techniques which provide privacy preservation for the published structural data. The proposed method aims to preserve the individuals’ privacy in the weighted social network network. This research proposes a (K, X)-isomorphism method, which is an anonymizing technique that produces for every subgraph a K -1 candidate subgraph. A (K X)-isomorphism depends on a range of methods that will help to make for every subgraph a ${K-1}$ similar subgraphs, like weighted community detection, graph density, weighted maximum common subgraph and bi-clustering methods. This research improves an MPD\_V method which is a maximum common subgraph, where this improvement makes MPD\_V more fitting to find the similarly weighted subgraphs.

Preserving privacy of the electronic health records of the patients has been a fundamental issue in the healthcare domain. Several techniques have been employed to maintain privacy of the sensitive information such as controlling access to the medical records. While acting as a first line of defense against illegitimate access, traditional access control schemes fall short of defending against misbehavior of the already authenticated and authorized users; a risk that can harbor devastating consequences upon potential data release or leak. Several approaches can be implemented to overcome this risk such as establishing the notion of trustworthiness of the system users, which makes the access control scheme more dynamic and adaptable. In effect, as opposed to rigidly denying an access request, an access control model becomes more tolerable towards risky access requests by employing risk mitigation strategies. This paper introduces a novel risk mitigation strategy, for the healthcare domain, through which the risk associated with an access request is evaluated against the privacy preferences of the patient undergoing the medical procedure. The proposed strategy, which is HIPAA compliant, decides the set of data objects that can be safely exposed to the healthcare service provider such that unnecessarily repeated tests and procedures can be avoided and the privacy preferences of the patient are preserved.

Homomorphic encryption has become a popular research topic since the cloud computing paradigm emerged. This paper discusses the design of a GPU-assisted homomorphic cryptograph for matrix operation. Our proposed scheme is based on an n*n matrix multiplication which are computationally homomorphic. We use more efficient GPU programming scheme with the extension of DGHV homomorphism, which prove the result of verification does not leak any information about the inputs or the output during the encryption and decryption. The performance results are obtained from the executions on a machine equipped with a GeForce GTX 765M GPU. We use three basic parallel algorithms to form efficient solutions which accelerate the speed of encryption and evaluation. Although fully homomorphic encryption is still not practical for real world applications in current stage, this work shows the possibility to improve the performance of homomorphic encryption and achieve this target one step closer.

Future Wireless Sensor Networks (WSNs) will be composed of a large number of densely deployed sensors. A key feature of such networks is that their nodes are untethered and unattended. Distributed techniques are expected in WSNs. Computing Connected Dominating Sets (CDSs) have been widely used for virtual backbone construction in WSNs to control topology, facilitate routing, and extend network lifetime. This paper proposes a new distributed algorithm for CDS construction in WSNs. The algorithm is intended to construct a CDS with the smallest ratio when compared to its centralized version. Moreover, this paper proposes a localized algorithm that efficiently maintains the backbone when some backbone nodes decide to enter the energy saving sleep mode. We attempt to prolong the lifetime of the constructed CDS by allowing nodes with higher residual energy to have more chances to be part of the constructed and maintained backbone. Simulation shows that our distributed approach has a maximum ratio of 1.53 to the centralized approach, and it satisfies all of the geometrical properties of its canalized version. Based on this ratio, this distributed algorithm has an approximation factor of 7.65 to the optimal CDS. To the best of our knowledge, this approximation is the smallest among all existing distributed CDS construction algorithms.

Future Wireless Sensor Networks (WSNs) will be composed of a large number of densely deployed sensors. A key feature of such networks is that their nodes are untethered and unattended. Distributed techniques are expected in WSNs. Connected Dominating Sets (CDSs) have been widely used for virtual backbone construction in WSNs to control topology, facilitate routing, and extend network lifetime. This paper proposes a new distributed algorithm for CDS construction in WSNs. The algorithm represents an extension for our previously proposed centralized algorithm. The algorithm is intended to construct a CDS with the smallest ratio when compared to its centralized version. Simulation shows that our distributed approach has a maximum ratio of 1.53 to the centralized approach in term of CDS size, and it satisfies all of the geometrical properties of its canalized version. Based on this ratio, this distributed algorithm has an approximation factor of 7.65 to the optimal CDS. This approximation outperforms the existing distributed CDS construction algorithms.

A mobile ad hoc network is a collection of wireless mobile devices communicating with each other and forming a temporary network, without any pre-deployed infrastructure. Security in MANET is a main and important element for the basic functions of a network. One of the security technologies is intrusion detection system which provides a second line of defense. In this paper, we propose an efficient defense system based on a cooperative scheme to deal with intrusions in clustered ad hoc networks. Our proposed system provides security against all network attacks that can be detected by any node in the network, in particular detects the actor. It is simple, reliable, effective and its performance not affected by status of channel.

Sandstorms are serious natural disasters, which are commonly seen in the Middle East, Northern Africa, and Northern China.In these regions, sandstorms have caused massive damages to the natural environment, national economy, and human health. To avoid such damages, it is necessary to effectively monitor the origin and development of sandstorms. To this end, wireless sensor networks (WSNs) can be deployed in the regions where sandstorms generally originate so that sensor nodes can collaboratively perform sandstorm monitoring and rapidly convey the observations to remote administration center. Despite the potential advantages, the deployment of WSNs in the vicinity of sandstorms faces many unique challenges, such as the temporally buried sensors and increased path loss during sandstorms. Consequently, the WSNs may experience frequent disconnections during the sandstorms. This further leads to dynamically changing topology. In this paper, a topology analysis of the WSNs for sandstorm monitoring is performed. Four types of channels a sensor can utilize during sandstorms are analyzed, which include air-to-air channel, air-to-sand channel, sand-to-air channel, and sand-to-sand channel. Based on the channel model solutions, a percolation-based connectivity analysis is performed. It is shown that if the sensors are buried in low depth, allowing sensor to use multiple types of channels improves network connectivity. Accordingly, much smaller sensor density is required compared to the case, where only terrestrial air channels are used. Through this topology analysis a WSN architecture can be deployed for very efficient sandstorm monitoring.

On-demand routing protocols used in mobile ad hoc networks suffer from transmitting a huge number of control packets which increases the overhead. In this new algorithm (ERDA), we try to improve the route discovery algorithm by reducing the routing overhead in the presence of random traffic. ERDA broadcasts any route request travelling within their source node’s neighbourhood region according to the routing algorithm used. However, propagation of the route request is deliberately delayed outside this region to provide the associated chase packet with an opportunity to stop the fulfilled route request and minimise network congestion. The algorithm is adaptive and continuously updates the boundary of each source node’s neighbourhood to improve performance. We provide detailed performance evaluation using simulation modelling. Our result shows that ERDA improves the performance by minimizing the average end-to-end delay as well as the network overhead and congestion level.