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With reference to a distributed architecture consisting of sensor nodes connected in a wireless network, we present a model of a protection system based on segments and applications. An application is the result of the joint activities of a set of cooperating nodes. A given node can access a segment stored in the primary memory of a different node only by presenting a gate for that segment. A gate is a form of pointer protected cryptographically, which references a segment and specifies a set of access rights for this segment. Gates can be freely transmitted between nodes, thereby granting the corresponding access permissions. Two special node functionalities are considered, segment servers and application servers. Segment servers are used for inter-application communication and information gathering. An application server is used in each application to support key management and rekeying. The rekey mechanism takes advantage of key naming to cope with losses of rekey messages. The total memory requirements for key and gate storage result to be a negligible fraction of the overall memory resources of the generic network node. [ABSTRACT FROM AUTHOR]

With reference to a network consisting of sensor nodes connected by wireless links, we approach the problem of the distribution of the cryptographic keys. We present a solution based on communication channels connecting sequences of adjacent nodes. All the nodes in a channel share the same key. This result is obtained by propagating the key connecting the first two nodes to all the other nodes in the channel. The key propagation mechanism is also used for key replacement, as is required, for instance, in group communication to support forms of forward and backward secrecy, when a node leaves a group or a new node is added to an existing group. [ABSTRACT FROM AUTHOR]

The IEEE 802.15.4 standard allows devices to access the medium not only in contention mode but also in a contention-free way, in order to support quality of service (QoS). In contention-free mode, devices access the medium according to the guaranteed time slot (GTS) mechanism, which is vulnerable to the selective jamming attack. This is a particularly insidious form of denial of service that allows an attacker to thwart QoS while limiting her own exposure at the minimum. In this paper, we present selective jamming resistant GTS , a solution against the GTS-based selective jamming. We also show that our solution is standard compliant and affordable for resource-scarce devices like Tmote Sky motes. [ABSTRACT FROM AUTHOR]

Abstract: Secure group management is an important issue in Wireless Sensor Networks (WSNs). The most of previous works consider the whole network as a single group managed by a central, powerful node (e.g., the base station) capable of supporting heavy communication, computation and storage cost. However, typical WSNs applications may benefit from being designed and implemented as a collection of multiple logical groups, each one is maintained by a sensor node (the group controller) with constrained resources. Furthermore, previous schemes require multicast support at the routing level to deliver rekeying messages. Unfortunately, multicast may cause a storage and communication overhead that are not a_ordable in a WSN. In order to go beyond these two limitations, we propose a new secure group management scheme with a lightweight re-keying process. The scheme allows multiple logical groups, each one is maintained and rekeyed separately by a resource-constrained sensor node without requiring multicast routing support. We prove that the scheme is secure and we evaluate its performance from several view points. Actually, we show that our scheme outperforms some previous well-known schemes such as LKH. [Copyright &y& Elsevier]

Group communication has proven a powerful paradigm for designing applications and services in Wireless Sensor Networks (WSNs). Given the tight interaction between WSNs and the physical world, a security infringement may translate into a safety infringement. Therefore, in order to fully exploit the group communication paradigm we need to secure it. Traditionally, this requirement has been formalized in terms of backward and forward security and fulfilled by means of rekeying. In WSNs, group rekeying becomes particularly a complex problem because communication takes place over an easily accessible wireless medium and because sensor nodes have severe limitations in terms of computing, storage, energy, and tamper-resistance capabilities for cost reasons. In this article we present a Lightweight Authenticated ReKeying (LARK) scheme for clustered WSNs. LARK guarantees backward and forward security, is scalable in terms of communication overhead, and efficient in terms of computing overhead for key authentiticy verification. LARK achieves security, efficiency, and scalability by exploiting two basic well-known mechanisms, namely key graph and key chain, and integrating them in an original way. LARK supports a general group model where groups can be hierachical and partially overlapping. In contrast to other WSN group rekeying schemes, LARK considers grouping a tool for designing and implementing applications and services rather than for network management. Consequently, LARK receives a group topology reflecting the application needs and manages rekeying at single-group level. In the article we describe LARK, formally argue that it meets the backward and forward security requirements, and, finally, evaluate its performance in terms of communication, computing, and storage overhead in limited-resources sensor nodes. [ABSTRACT FROM AUTHOR]