Efficient and scalable public key infrastructure for wireless sensor networks

Ensuring security is essential in wireless sensor networks (WSNs) since a variety of applications of WSNs, including military, medical and industrial sectors, require several kinds of security services such as confidentiality, authentication, and integrity. However, ensuring security is not trivial in WSNs because of the limited resources of the sensor nodes. This has led a lot of researchers to focus on a symmetric key cryptography which is computationally lightweight, but requires a shared key between the sensor nodes. Public key cryptography (PKC) not only solves this problem gracefully, but also provides enhanced security services such as non-repudiation and digital signatures. To take advantage of PKC, each node must have a public key of the corresponding node via an authenticated method. The most widely used way is to use digital signatures signed by a certificate authority which is a part of a public key infrastructure (PKI). Since traditional PKI requires a huge amount of computations and communications, it can be heavy burden to WSNs. In this paper, we propose our own energy efficient and scalable PKI for WSNs. This is accomplished by taking advantage of heterogeneous sensor networks and elliptic curve cryptography. Our proposed PKI is analyzed in terms of security, energy efficiency, and scalability. As you will see later, our PKI is secure, energy efficient, and scalable.