Efficient Key Distribution Schemes for Wireless Sensor Networks Using LDU′ Composition of Symmetric Matrices

Wireless sensor network (WSNs) is highly vulnerable to attacks because it consists of various resource-constrained sensor nodes which communicates among themselves via wireless links. Establishment of pairwise keys between sensor nodes is used to realize many of the security services for wireless sensor networks. Hence, securely distributing keys among sensor nodes is a fundamental challenge for providing security services in WSNs. Even though the random key pre-distribution approach is suitable for low power and resource constrained sensor nodes, a shared key between a pair of nodes is not guaranteed and thus, they may not be able to communicate with each other. Matrix based scheme for key pre-distribution essentially use

LU

decomposition of matrix which can provide keys between any pair of nodes but are quite vulnerable to attack. This paper proposes a new robust key pre-distribution schemes based on

LDU

′ composition of matrices. In the first scheme, we use integer as elements of symmetric matrices and in the second scheme we use polynomials over finite fields as elements of the symmetric matrices. The existing approach use decomposition of matrices which is compute intensive but our proposed scheme uses composition of matrices. The analysis shows that the proposed scheme allows almost 100% connectivity regardless of the number of keys and provides 100% resilience against node capture.