Phase-assisted NOMA based key distribution for IoT networks

Internet of Things (IoT) technology has recently been adopted in different fields and applications. An IoT network allows for a large set of physical objects (or devices) with various technologies to work together and exchange a large amount of information. This, however, raises different security and privacy concerns, including the confidentiality of the exchanged data. Usually, data confidentiality is maintained in wireless networks utilizing data encryption using a pre-shared secret key. Thus, protecting the key distribution process is essential to maintaining a secure network. However, due to the typically large size of IoT networks, conventional secret key distribution schemes are unsuitable and lead to resource inefficiency. Therefore, in this paper, an efficient key distribution scheme is proposed by using physical-layer security concepts. Specifically, non-orthogonal multiple access (NOMA) is utilized to distribute the key to multiple nodes in a resource-efficient manner. Moreover, the instantaneous channel phase is also used to attain a secure distribution in which each node can obtain its own key only. The performance of the proposed scheme is analyzed in terms of the key error rate at both a legitimate node and an eavesdropper under different channel fading models, where closed form mathematical expressions are derived and verified via simulation results.