Securing the Inter-Spacecraft Links: Doppler Frequency Shift based Physical Layer Key Generation

TL;DR

This paper introduces a new physical layer key generation method for inter-spacecraft communication that leverages Doppler frequency shifts, providing a secure and practical solution validated through theoretical and numerical analysis.

Contribution

It presents a novel Doppler shift-based key generation technique with derived expressions for key disagreement rate, enhancing security for spacecraft links.

Findings

Derived closed-form expressions for key disagreement rate.

Numerical validation confirms the accuracy of theoretical approximations.

Method demonstrates practicality and security for inter-spacecraft communication.

Abstract

We propose a novel physical layer secret key generation method for the inter-spacecraft communication links. By exploiting the Doppler frequency shifts of the reciprocal spacecraft links as a unique secrecy source, spacecrafts aim to obtain identical secret keys from their individual observations. We obtain theoretical expressions for the key disagreement rate (KDR). Using generalized Gauss-Laguerre quadrature, we derive closed form expressions for the KDR. Through numerical studies, the tightness of the provided approximations are shown. Both the theoretical and numerical results demonstrate the validity and the practicality of the presented physical layer key generation procedure considering the security of the communication links of spacecrafts.