Scalable Group Secret Key Generation over Wireless Channels

TL;DR

This paper introduces scalable physical layer group key generation methods for wireless networks that enable multiple users to securely generate shared keys simultaneously, improving efficiency and scalability over traditional pairwise approaches.

Contribution

It proposes novel half-duplex and full-duplex schemes leveraging prime numbers for simultaneous multi-user key generation, reducing communication complexity.

Findings

Half-duplex model reduces communication to linear scale.

Full-duplex model achieves constant scale complexity.

Methods enhance scalability of physical layer key generation.

Abstract

In this paper, we consider the problem of secret key generation for multiple parties. Multi-user networks usually require a trusted party to efficiently distribute keys to the legitimate users and this process is a weakness against eavesdroppers. With the help of the physical layer security techniques, users can securely decide on a secret key without a trusted party by exploiting the unique properties of the channel. In this context, we develop a physical layer group key generation scheme that is also based on the ideas of the analog function computation studies. We firstly consider the key generation as a function to be computed over the wireless channel and propose two novel methods depending on the users transmission capability (i.e. half-duplex and full-duplex transmissions). Secondly, we exploit the uniqueness of the prime integers in order to enable the simultaneous transmission of the users for key generation. As a result, our approach contributes to the scalability of the existing physical layer key generation algorithms since all users transmit simultaneously rather than using pairwise communications. We prove that our half-duplex network model reduces the required number of communications for group key generation down to a linear scale. Furthermore, the full-duplex network model reduces to a constant scale.