A Machine-Checked Formalization of the Generic Model and the Random Oracle Model

Most approaches to the formal analyses of cryptographic protocols make the perfect cryptography assumption, i.e. the hypothese that there is no way to obtain knowledge about the plaintext pertaining to a ciphertext without knowing the key. Ideally, one would prefer to rely on a weaker hypothesis on the computational cost of gaining information about the plaintext pertaining to a ciphertext without knowing the key. Such a view is permitted by the Generic Model and the Random Oracle Model which provide non-standard computational models in which one may reason about the computational cost of breaking a cryptographic scheme. Using the proof assistant Coq, we provide a machine-checked account of the Generic Model and the Random Oracle Mode

A Survey on Wireless Sensor Network Security

Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. This paper discusses the current state of the art in security mechanisms for WSNs. Various types of attacks are discussed and their countermeasures presented. A brief discussion on the future direction of research in WSN security is also included.Comment: 24 pages, 4 figures, 2 table

Key Management Building Blocks for Wireless Sensor Networks

Cryptography is the means to ensure data confidentiality, integrity and authentication in wireless sensor networks (WSNs). To use cryptography effectively however, the cryptographic keys need to be managed properly. First of all, the necessary keys need to be distributed to the nodes before the nodes are deployed in the field, in such a way that any two or more nodes that need to communicate securely can establish a session key. Then, the session keys need to be refreshed from time to time to prevent birthday attacks. Finally, in case any of the nodes is found to be compromised, the key ring of the compromised node needs to be revoked and some or all of the compromised keys might need to be replaced. These processes, together with the policies and techniques needed to support them, are called key management. The facts that WSNs (1) are generally not tamper-resistant; (2) operate unattended; (3) communicate in an open medium; (4) have no fixed infrastructure and pre-configured topology; (5) have severe hardware and resource constraints, present unique challenges to key management. In this article, we explore techniques for meeting these challenges. What distinguishes our approach from a routine literature survey is that, instead of comparing various known schemes, we set out to identify the basic cryptographic principles, or building blocks that will allow practitioners to set up their own key management framework using these building blocks