60 research outputs found

    Group Key Management in Wireless Ad-Hoc and Sensor Networks

    Get PDF
    A growing number of secure group applications in both civilian and military domains is being deployed in WAHNs. A Wireless Ad-hoc Network (WARN) is a collection of autonomous nodes or terminals that communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralized manner. A Mobile Ad-hoc Network (MANET) is a special type of WARN with mobile users. MANET nodes have limited communication, computational capabilities, and power. Wireless Sensor Networks (WSNs) are sensor networks with massive numbers of small, inexpensive devices pervasive throughout electrical and mechanical systems and ubiquitous throughout the environment that monitor and control most aspects of our physical world. In a WAHNs and WSNs with un-trusted nodes, nodes may falsify information, collude to disclose system keys, or even passively refuse to collaborate. Moreover, mobile adversaries might invade more than one node and try to reveal all system secret keys. Due to these special characteristics, key management is essential in securing such networks. Current protocols for secure group communications used in fixed networks tend to be inappropriate. The main objective of this research is to propose, design and evaluate a suitable key management approach for secure group communications to support WAHNs and WSNs applications. Key management is usually divided into key analysis, key assignment, key generation and key distribution. In this thesis, we tried to introduce key management schemes to provide secure group communications in both WAHNs and WSNs. Starting with WAHNs, we developed a key management scheme. A novel architecture for secure group communications was proposed. Our proposed scheme handles key distribution through Combinatorial Key Distribution Scheme (CKDS). We followed with key generation using Threshold-based Key Generation in WAHNs (TKGS). For key assignment, we proposed Combinatorial Key Assignment Scheme (CKAS), which assigns closer key strings to co-located nodes. We claim that our architecture can readily be populated with components to support objectives such as fault tolerance, full-distribution and scalability to mitigate WAHNs constraints. In our architecture, group management is integrated with multicast at the application layer. For key management in WSNs, we started with DCK, a modified scheme suitable for WSNs. In summary, the DCK achieves the following: (1) cluster leader nodes carry the major part of the key management overhead; (2) DCK consumes less than 50% of the energy consumed by SHELL in key management; (3) localizing key refreshment and handling node capture enhances the security by minimizing the amount of information known by each node about other portions of the network; and (4) since DCK does not involve the use of other clusters to maintain local cluster data, it scales better from a storage point of view with the network size represented by the number of clusters. We went further and proposed the use of key polynomials with DCK to enhance the resilience of multiple node capturing. Comparing our schemes to static and dynamic key management, our scheme was found to enhance network resilience at a smaller polynomial degree t and accordingly with less storage per node

    A Framework for Secure Group Key Management

    Get PDF
    The need for secure group communication is increasingly evident in a wide variety of governmental, commercial, and Internet communities. Secure group key management is concerned with the methods of issuing and distributing group keys, and the management of those keys over a period of time. To provide perfect secrecy, a central group key manager (GKM) has to perform group rekeying for every join or leave request. Fast rekeying is crucial to an application\u27s performance that has large group size, experiences frequent joins and leaves, or where the GKM is hosted by a group member. Examples of such applications are interactive military simulation, secure video and audio broadcasting, and secure peer-to-peer networks. Traditionally, the rekeying is performed periodically for the batch of requests accumulated during an inter-rekey period. The use of a logical key hierarchy (LKH) by a GKM has been introduced to provide scalable rekeying. If the GKM maintains a LKH of degree d and height h, such that the group size n ≤ dh, and the batch size is R requests, a rekeying requires the GKM to regenerate O(R × h) keys and to perform O(d × R × h) keys encryptions for the new keys distribution. The LKH approach provided a GKM rekeying cost that scales to the logarithm of the group size, however, the number of encryptions increases with increased LKH degree, LKH height, or the batch size. In this dissertation, we introduce a framework for scalable and efficient secure group key management that outperforms the original LKH approach. The framework has six components as follows. First, we present a software model for providing secure group key management that is independent of the application, the security mechanism, and the communication protocol. Second, we focus on a LKH-based GKM and introduce a secure key distribution technique, in which a rekeying requires the GKM to regenerate O( R × h) keys. Instead of encryption, we propose a novel XOR-based key distribution technique, namely XORBP, which performs an XOR operation between keys, and uses random byte patterns (BPs) to distribute the key material in the rekey message to guard against insider attacks. Our experiments show that the XORBP LKH approach substantially reduces a rekeying computation effort by more than 90%. Third, we propose two novel LKH batch rekeying protocols . The first protocol maintains a balanced LKH (B+-LKH) while the other maintains an unbalanced LKH (S-LKH). If a group experiences frequent leaves, keys are deleted form the LKH and maintaining a balanced LKH becomes crucial to the rekeying\u27s process performance. In our experiments, the use of a B+-LKH by a GKM, compared to a S-LKH, is shown to substantially reduce the number of LKH nodes (i.e., storage), and the number of regenerated keys per a rekeying by more than 50%. Moreover, the B +-LKH performance is shown to be bounded with increased group dynamics. Fourth, we introduce a generalized rekey policy that can be used to provide periodic rekeying as well as other versatile rekeying conditions. Fifth, to support distributed group key management, we identify four distributed group-rekeying protocols between a set of peer rekey agents. Finally, we discuss a group member and a GKM\u27s recovery after a short failure time

    A practical key management and distribution system for IPTV conditional access

    Get PDF
    Conditional Access (CA) is widely used by pay-television operators to restrict access to content to authorised subscribers. Commercial CA solutions are available for structured broadcast and Internet Protocol Television (IPTV) environments, as well as Internet-based video-on-demand services, however these solutions are mostly proprietary, often inefficient for use on IP networks, and frequently depend on smartcards for maintaining security. An efficient, exible, and open conditional access system that can be implemented practically by operators with large numbers of subscribers would be beneficial to those operators and Set-Top-Box manufacturers in terms of cost savings for royalties and production costs. Furthermore, organisations such as the South African Broadcasting Corporation that are transitioning to Digital-Terrestrial-Television could use an open Conditional Access System (CAS) to restrict content to viewing within national borders and to ensure that only valid TV licence holders are able to access content. To this end, a system was developed that draws from the area of group key management. Users are grouped according to their subscription selections and these groups are authorised for each selection's constituent services. Group keys are updated with a key-tree based approach that includes a novel method for growing full trees that outperforms the standard method. The relations that are created between key trees are used to establish a hierarchy of keys which allows exible selection of services whilst maintaining their cryptographic protection. Conditions for security without dependence on smartcards are defined, and the system is expandable to multi-home viewing scenarios. A prototype implementation was used to assess the proposed system. Total memory consumption of the key-server, bandwidth usage for transmission of key updates, and client processing and storage of keys were all demonstrated to be highly scalable with number of subscribers and number of services

    Efficient Security Protocols for Fast Handovers in Wireless Mesh Networks

    Get PDF
    Wireless mesh networks (WMNs) are gaining popularity as a flexible and inexpensive replacement for Ethernet-based infrastructures. As the use of mobile devices such as smart phones and tablets is becoming ubiquitous, mobile clients should be guaranteed uninterrupted connectivity and services as they move from one access point to another within a WMN or between networks. To that end, we propose a novel security framework that consists of a new architecture, trust models, and protocols to offer mobile clients seamless and fast handovers in WMNs. The framework provides a dynamic, flexible, resource-efficient, and secure platform for intra-network and inter-network handovers in order to support real-time mobile applications in WMNs. In particular, we propose solutions to the following problems: authentication, key management, and group key management. We propose (1) a suite of certificate-based authentication protocols that minimize the authentication delay during handovers from one access point to another within a network (intra-network authentication). (2) a suite of key distribution and authentication protocols that minimize the authentication delay during handovers from one network to another (inter-network authentication). (3) a new implementation of group key management at the data link layer in order to reduce the group key update latency from linear time (as currently done in IEEE 802.11 standards) to logarithmic time. This contributes towards minimizing the latency of the handover process for mobile members in a multicast or broadcast group

    Smart Wireless Sensor Networks

    Get PDF
    The recent development of communication and sensor technology results in the growth of a new attractive and challenging area - wireless sensor networks (WSNs). A wireless sensor network which consists of a large number of sensor nodes is deployed in environmental fields to serve various applications. Facilitated with the ability of wireless communication and intelligent computation, these nodes become smart sensors which do not only perceive ambient physical parameters but also be able to process information, cooperate with each other and self-organize into the network. These new features assist the sensor nodes as well as the network to operate more efficiently in terms of both data acquisition and energy consumption. Special purposes of the applications require design and operation of WSNs different from conventional networks such as the internet. The network design must take into account of the objectives of specific applications. The nature of deployed environment must be considered. The limited of sensor nodes� resources such as memory, computational ability, communication bandwidth and energy source are the challenges in network design. A smart wireless sensor network must be able to deal with these constraints as well as to guarantee the connectivity, coverage, reliability and security of network's operation for a maximized lifetime. This book discusses various aspects of designing such smart wireless sensor networks. Main topics includes: design methodologies, network protocols and algorithms, quality of service management, coverage optimization, time synchronization and security techniques for sensor networks

    Key management for wireless sensor network security

    Get PDF
    Wireless Sensor Networks (WSNs) have attracted great attention not only in industry but also in academia due to their enormous application potential and unique security challenges. A typical sensor network can be seen as a combination of a number of low-cost sensor nodes which have very limited computation and communication capability, memory space, and energy supply. The nodes are self-organized into a network to sense or monitor surrounding information in an unattended environment, while the self-organization property makes the networks vulnerable to various attacks.Many cryptographic mechanisms that solve network security problems rely directly on secure and efficient key management making key management a fundamental research topic in the field of WSNs security. Although key management for WSNs has been studied over the last years, the majority of the literature has focused on some assumed vulnerabilities along with corresponding countermeasures. Specific application, which is an important factor in determining the feasibility of the scheme, has been overlooked to a large extent in the existing literature.This thesis is an effort to develop a key management framework and specific schemes for WSNs by which different types of keys can be established and also can be distributed in a self-healing manner; explicit/ implicit authentication can be integrated according to the security requirements of expected applications. The proposed solutions would provide reliable and robust security infrastructure for facilitating secure communications in WSNs.There are five main parts in the thesis. In Part I, we begin with an introduction to the research background, problems definition and overview of existing solutions. From Part II to Part IV, we propose specific solutions, including purely Symmetric Key Cryptography based solutions, purely Public Key Cryptography based solutions, and a hybrid solution. While there is always a trade-off between security and performance, analysis and experimental results prove that each proposed solution can achieve the expected security aims with acceptable overheads for some specific applications. Finally, we recapitulate the main contribution of our work and identify future research directions in Part V
    • …
    corecore