Jenq-Shiou Leu

Energy Efficient Clustering Scheme for Prolonging the Lifetime of Wireless Sensor Network With Isolated Nodes

A suitable clustering algorithm for grouping sensor nodes can increase the energy efficiency of WSNs. However, clustering requires additional overhead, such as cluster head selection and assignment, and cluster construction. This paper proposes a new regional energy aware clustering method using isolated nodes for WSNs, called Regional Energy Aware Clustering with Isolated Nodes (REAC-IN). In REAC-IN, CHs are selected based on weight. Weight is determined according to the residual energy of each sensor and the regional average energy of all sensors in each cluster. Improperly designed distributed clustering algorithms can cause nodes to become isolated from CHs. Such isolated nodes communicate with the sink by consuming excess amount of energy. To prolong network lifetime, the regional average energy and the distance between sensors and the sink are used to determine whether the isolated node sends its data to a CH node in the previous round or to the sink. The simulation results of the current study revealed that REAC-IN outperforms other clustering algorithms.

Efficient and secure dynamic ID-based remote user authentication scheme for distributed systems using smart cards

In a distributed environment, a fundamental concern is authentication of local and remote users in insecure communication networks. Absolutely, legitimate users are more powerful attackers, since they possess internal system information not available to an intruder. Therefore many remote user authentication schemes for distributed systems have been proposed. These schemes claimed that they could resist various attacks. However, they were found to have some weaknesses later. Lee et al . proposed a secure dynamic ID-based remote user authentication scheme for the multi-server environment using smart cards and claimed that their scheme could protect against masquerade attacks, server spoofing attack, registration server spoofing attack and insider attack. In this study, the authors show that Lee et al .s scheme is still vulnerable to password guessing attack, server spoofing attack and masquerade attack. To propose a viable authentication scheme for distributed systems, we remedy the flaws of Lee et al .s scheme and propose an efficient improvement over Lee et al .s scheme. Furthermore, we compare the proposed scheme with related ones to prove that the computation cost, security and efficiency of the proposed scheme are well suitable for practical applications in a distributed system.

Anonymous authentication protocol based on elliptic curve Diffie–Hellman for wireless access networks

Anonymous channel tickets have been proposed as a way to provide user anonymity and to reduce the overhead of re-authentication for authentication in wireless environments. Chen et al. proposed a secure and efficient protocol, based on a protocol proposed by Yang et al., which is resistant to guessing attacks on networks from which users’ secret keys are easy to obtain. However, their scheme is time-consuming in the phases of ticket issuing and authentication. Furthermore, a malicious attacker can utilize the expired time, Texp, to launch a denial of authentication (DoA) attack, which is a type of denial of service attack. Because Texp is exposed to any user, it would be easy to launch a DoA attack that could make the scheme impractical. To resist against DoAs that the scheme of Chen et al. might suffer, we propose an improved scheme based on elliptic curve cryptography in this paper. Our scheme not only reduces time cost but also enhances security. The basis of the proposed scheme is the elliptic curve discrete logarithm problem. The operations of points of an elliptic curve are faster and use fewer bits to achieve the same level of security. Therefore, our scheme is more suitable for mobile devices, which have limited computing power and storage. Copyright

Improving Heterogeneous SOA-Based IoT Message Stability by Shortest Processing Time Scheduling

An Internet of Things (IoT) system features integration information from heterogeneous sensor devices, allowing them to deliver a variety of sensed information through networks. An IoT broker in the system acts as an information exchange center, relaying periodic messages from heterogeneous sensor devices to IoT clients. As more devices participate in the IoT system, the service scale of entire system increases. To overcome the limitation of the number of direct links to an single working element, the whole IoT system should be divided into many subsystems, called IoT units, to form the system hierarchy. Furthermore, applying the service-oriented architecture (SOA) concept to realize the IoT service can facilitate to adapt the future-proof devices to the IoT system. Normally, a web-based message visualization can unify the client interface in a SOA-based system. However, a large volume of web-based messages with various sizes are not easy to be stably displayed at the client side. This paper proposes an IoT system skeleton and a shortest processing time (SPT) algorithm for scheduling web-based IoT messages. The implemented scheduling scheme supported by a priority queue model can effectively stablize the response messages from the scattered IoT sensors per each client request.

Exploiting hash functions to intensify the remote user authentication scheme

Nowadays, the client-server model plays an important part in the Internet architecture. The procedure that a server authenticates a remote user securely has become a significant issue. Hence, many remote user authentication schemes are proposed. Hsiang and Shih pointed out the weaknesses of Yoon et al.s scheme and proposed an improved scheme not only preserving original merits but also mending the weaknesses. The scheme protects against masquerading attacks, offline password guessing attacks and parallel session attacks. However, He et al. found that Hsiang et al.s scheme is still vulnerable to password guessing attack, masquerading server attack and masquerading attack. Furthermore, we also found Hsiang-Shihs scheme could be threatened by a malicious insider that can originate an infringed account attack and a resembling account attack. In this paper, we first describe how a malicious insider carries out an infringed account attack and then present a resembling account attack on Hsiang-Shihs scheme. After that, we propose an improvement assisted by hashing functions to enhance Hsiang-Shihs scheme.

Design of a time and location based One-Time Password authentication scheme

As the mobile networks are springing up, mobile devices become a must gadget in our daily life. People can easily access Internet application services anytime and anywhere via the hand-carried mobile devices. Most of modern mobile devices are equipped with a GPS module, which can help get the real-time location of the mobile device. In this paper, we propose a novel authentication scheme which exploits volatile passwords - One-Time Passwords (OTPs) based on the time and location information of the mobile device to transparently and securely authenticate users while accessing Internet services, such as online banking services and e-commerce transactions. Compared to a permanent password base scheme, an OTP based one can prevent users from being eavesdropped. In addition to a memoryless feature, the scheme restricts the validness of the OTP password not only in a certain time period but also in a tolerant geometric region to increase the security protection. However, if a legitimate user is not in the anticipated tolerant region, the user may fail to be authenticated. Hence, a Short Message Service (SMS) based mutual authentication mechanism is also proposed in the article to supplement the unexpected misjudgement. The proposed method with a volatile time/location-based password features more secure and more convenient for user authentication.

Running cellular/PWLAN services: practical considerations for cellular/PWLAN architecture supporting interoperator roaming

To offer wireless data access services that are more efficient than GPRS or UMTS networks, public WLANs are in a predominant position to embrace the wireless broadband era. Reusing the existing mechanisms for user authentication, access control, billing, and roaming handling procedures in mobile territory to construct a complementary network, public WLAN (PWLAN) has drawn the attention of cellular operators such as Vodafone and T-Mobile. In this article we aim to investigate a practical end-to-end PWLAN architecture capable of using GPRS/UMTS SIM-based authentication for current mobile users and carrying out Web-based authentication for occasional users without SIM modules simultaneously. Additionally, we consider a confederation of various PWLAN service providers by a RADIUS-based roaming mechanism to leverage the existing resources of cellular operators. The proposed considerations and guidelines provide a baseline skeleton to build an extendable environment and successfully construct a flexible cellular/PWLAN hotspot in mobeeLAN service.

An anonymous mobile user authentication protocol using self-certified public keys based on multi-server architectures

As a smart phone becomes a daily necessity, mobile services are springing up. A mobile user should be authenticated and authorized before accessing these mobile services. Generally, mobile user authentication is a method which is used to validate the legitimacy of a mobile login user. As the rapid booming of computer networks, multi-server architecture has been pervasive in many network environments. Much recent research has been focused on proposing password-based remote user authentication protocols using smart cards for multi-server environments. To protect the privacy of users, many dynamic identity based remote user authentication protocols were proposed. In 2009, Hsiang and Shih claimed their protocol is efficient, secure, and suitable for the practical application environment. However, Sood et al. pointed out Hsiang et al.’s protocol is susceptible to replay attack, impersonation attack and stolen smart card attack. Moreover, the password change phase of Hsiang et al.’s protocol is incorrect. Thus, Sood et al. proposed an improved protocol claimed to be practical and computationally efficient. Nevertheless, Li et al. found that Sood et al.’s protocol is still vulnerable to leak-of-verifier attack, stolen smart card attack and impersonation attack and consequently proposed an improvement to remove the aforementioned weaknesses. In 2012, Liao et al. proposed a novel pairing-based remote user authentication protocol for multi-server environment, the scheme based on elliptic curve cryptosystem is more secure and efficient. However, through careful analyses, we find that Liao et al.’s protocol is still susceptible to the trace attack. Besides, Liao et al.’s protocol is inefficient since each service server has to update its ID table periodically. In this paper, we propose an improved protocol to solve these weaknesses. By enhancing the security, the improved protocol is well suited for the practical environment.

A fault-tolerant scheme for an autonomous local wireless sensor network

Typical wireless sensor network comprises sensors and a sink. The sink gathers and analyzes the data from sensors and then takes the corresponding action. Such architecture may have single-point of failure problem. Besides, when sensors have no direct link with the sink, they must deliver data by hopping scheme. The sink may take a longer time to collect data. Furthermore, faulty sensors and environment interference may cause an incorrect result. To overcome the mentioned problems, we propose a consensus problem based solution to make all sensors reach an agreement without the sink. It can conduct actions more quickly and directly.

Received Signal Strength Fingerprint and Footprint Assisted Indoor Positioning Based on Ambient Wi-Fi Signals

Positioning is a basis for providing location information to mobile users. With the GPS signal strength hindered by the structure, indoor users cannot obtain their positions through their handheld devices. Indoor positioning has recently been conducted based on received signal strength (RSS) fingerprint from indoor wireless access devices. Integrating indoor position information with Smartphone can provide more precise in-building information. In this paper, we propose a novel indoor positioning scheme assisted by a RSS fingerprint and footprint architecture. Smartphone users can get their position based on RSSs from ambient Wi-Fi access points surrounding them. With the assistance of collecting RSSs from ambient Wi-Fi signals, confining RSSs by directions, and filtering burst noises, our propose scheme can overcome the severe signal fluctuation problem in the building. Meanwhile, the proposed RSS fingerprint and footprint matching mechanism can raise the accuracy of location estimation. The experiment results show that our proposed scheme can achieve a certain level of accuracy in the indoor environments and outperform other solutions.