Systematizing Decentralization and Privacy: Lessons from 15 Years of Research and Deployments

Decentralized systems are a subset of distributed systems where multiple authorities control different components and no authority is fully trusted by all. This implies that any component in a decentralized system is potentially adversarial. We revise fifteen years of research on decentralization and privacy, and provide an overview of key systems, as well as key insights for designers of future systems. We show that decentralized designs can enhance privacy, integrity, and availability but also require careful trade-offs in terms of system complexity, properties provided, and degree of decentralization. These trade-offs need to be understood and navigated by designers. We argue that a combination of insights from cryptography, distributed systems, and mechanism design, aligned with the development of adequate incentives, are necessary to build scalable and successful privacy-preserving decentralized systems

Efficient key management in wireless sensor network security

Wireless sensor network is a multi-hop ad hoc network formed by a large number of low-cost micro-sensor nodes which communicate through radio channels. It is widely used in many areas in modern society and attracts a lot of attention from researchers. This research is on wireless sensor network security and it focuses on key management in hierarchical wireless sensor networks. Through literature review, the drawback and weakness of existing key management schemes are analyzed from various aspects including key establishment, key distribution, key update, authentication and node operation mechanism. Assessment criteria for key management scheme are proposed under different requirements and constraints of wireless sensor networks. The security criteria cover keying model, key distribution, key update, node operation and resilience. For cluster based hierarchical wireless sensor networks, an assistant node is introduced in a cluster to deal with the situation of cluster head compromise and to keep the member nodes securely staying in the network. With introduction of assistant nodes, a complete secure efficient hierarchical key management scheme (SEHKM) for wireless sensor network is proposed. The scheme supports three types of keys and the big improvement over existing key management schemes is on group key update, which is based on pseudo-random numbers and group Diffie-Hellman. The analysis and evaluation have shown that that SEHKM offers strong security with efficient operation from energy consumption point of view

Adaptable Security in Wireless Sensor Networks by Using Reconfigurable ECC Hardware Coprocessors

Specific features of Wireless Sensor Networks (WSNs) like the open accessibility to nodes, or the easy observability of radio communications, lead to severe security challenges. The application of traditional security schemes on sensor nodes is limited due to the restricted computation capability, low-power availability, and the inherent low data rate. In order to avoid dependencies on a compromised level of security, a WSN node with a microcontroller and a Field Programmable Gate Array (FPGA) is used along this work to implement a state-of-the art solution based on ECC (Elliptic Curve Cryptography). In this paper it is described how the reconfiguration possibilities of the system can be used to adapt ECC parameters in order to increase or reduce the security level depending on the application scenario or the energy budget. Two setups have been created to compare the software- and hardware-supported approaches. According to the results, the FPGA-based ECC implementation requires three orders of magnitude less energy, compared with a low power microcontroller implementation, even considering the power consumption overhead introduced by the hardware reconfiguratio

Key management for wireless sensor network security

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

Polynomial Based Dynamic Key Management for Secure Cluster Communication in Wireless Mobile Sensor Network

For inter and intra cluster communication, member nodes jointly build a mutual session key called cluster key to allow secure communication. Most existing schemes for cluster key management use messages exchange among the member nodes within a cluster for the new cluster key establishment when a node leaves or joins a cluster. This causes significant communication and computation costs. Furthermore, the secure distribution of cluster keys among member nodes in frequently changing environments is a difficult task without encryption and decryption operations. For secure cluster key management, we utilized polynomial (P) to accomplish effective intra-cluster key management and produced polynomial for making an inter-cluster key distribution. The main contribution is to generate polynomials and broadcast to nodes whenever a change occurs in a network or demanding nodes for secure key management. The presented scheme supports scalability for an increasing number of nodes using polynomials. The proposed scheme increases the lifetime of the network by decreasing the key pool size

Sensor Data Encryption Protocol for Wireless Network Security

Wireless Sensor Network consisting of a large number of sensor nodes that connected through wireless media has emerged as a ground breaking technology that offers unprecedented ability to monitor the physical word accurately. The privacy preservation is an important issue in wireless sensor network. Developing effective security solutions for wireless sensor networks are not easy due to limited resources. In this paper we propose new techniques for the purpose of security in wireless sensor network called as SDEP sensor data encryption protocol. In the scheme we use the RC 6 method for the purpose of encryption and decryption. RC 6 provide best confusion and diffusion properties with the less computational overhead. In order to confirm effectiveness of SDEP, a comparative performance evaluation with AES and RC 5 algorithms are presented in terms of memory requirement and execution time criteria. Our proposed scheme provides better performance than AES and RC 5 in the term of execution time and total memory requirement. We also provide simulation results for proposed method in the term of overhead and energy according to this result SDEP is strong block cipher for wireless sensor networks

Lightweight Key Management Scheme Using Fuzzy Extractor for Wireless Mobile Sensor Network

The mature design of wireless mobile sensor network makes it to be used in vast verities of applications including from home used to the security surveillance. All such types of applications based on wireless mobile sensor network are generally using real time data, most of them are interested in real time communication directly from cluster head of cluster instead of a base station in cluster network. This would be possible if an external user allows to directly access real time data from the cluster head in cluster wireless mobile sensor network instead of accessing data from base station. But this leads to a serious security breach and degrades the performance of any security protocol available in this domain. Most existing schemes for authentication and cluster key management for external users, exchange a number of messages between cluster head and base station to allow external to access real time data from the base station instead of cluster head. This increase communication cost and delay in such real time access information. To handle this critical issue in cluster wireless mobile sensor network, we propose a lightweight authentication and key management scheme using a fuzzy extractor. In this scheme, any external user can access data directly from the cluster head of any cluster without the involvement of the base station. The proposed scheme only uses the one-way hash functions and bitwise XOR operations, apart from the fuzzy extractor method for the user biometric verification at the login phase. The presented scheme supports scalability for an increasing number of nodes using polynomials. The proposed scheme increases the life-time of the network by decreasing the key pool size