A Key Establishment Scheme for Mobile Wireless Sensor Networks Using Post-Deployment Knowledge

Establishment of pairwise keys between sensor nodes in a sensor network is a difficult problem due to resource limitations of sensor nodes as well as vulnerability to physical captures of sensor nodes by the enemy. Public-key cryptosystems are not much suited for most resource-constrained sensor networks. Recently, elliptic curve cryptographic techniques show that public key cryptosystem is also feasible for resource-constrained sensor networks. However, most researchers accept that the symmetric key cryptosystems are viable options for resource-constrained sensor networks. In this paper, we first develop a basic principle to address the key pre-distribution problem in mobile sensor networks. Then, using this developed basic principle, we propose a scheme which takes the advantage of the post-deployment knowledge. Our scheme is a modified version of the key prioritization technique proposed by Liu and Ning. Our improved scheme provides reasonable network connectivity and security. Moreover, the proposed scheme works for any deployment topology.Comment: Published in International Journal of Computer Networks & Communications (IJCNC) Vol.3, No.4, July 201

Complexity of increasing the secure connectivity in wireless ad hoc networks

We consider the problem of maximizing the secure connectivity in wireless ad hoc networks, and analyze complexity of the post-deployment key establishment process constrained by physical layer properties such as connectivity, energy consumption and interference. Two approaches, based on graph augmentation problems with nonlinear edge costs, are formulated. The first one is based on establishing a secret key using only the links that are already secured by shared keys. This problem is in NP-hard and does not accept polynomial time approximation scheme PTAS since minimum cutsets to be augmented do not admit constant costs. The second one extends the first problem by increasing the power level between a pair of nodes that has a secret key to enable them physically connect. This problem can be formulated as the optimal key establishment problem with interference constraints with bi-objectives: (i) maximizing the concurrent key establishment flow, (ii) minimizing the cost. We prove that both problems are NP-hard and MAX-SNP with a reduction to MAX3SAT problem

Асимптотические соотношения для вероятностей числа нескомпрометированных ключей в схемах распределения ключей, построенных на основе блочных кодов

It is considered the probabilistic model of the correspondents compromising process in some broadcast key distribution schemes, built on base of orthogonal arrays of strength 1 or 2. As a result, we obtain proper bounds for binomial moments and asymptotic expressions of probability of the number non-compromising keys in these schemes under condition of random equiprobable t- subset correspondents compromising.Рассматривается вероятностная модель процесса компрометаций корреспондентов в определенных схемах широковещательного распределения ключей, построенных на основе ортогональных таблиц силы 1 или 2. Получены точные оценки биномиальных моментов и асимптотические выражения вероятностей числа нескомпрометированных ключей в этих схемах после компрометации случайного равновероятного t-подмножества корреспондентов