Advanced security framework for low Earth orbit satellites in space information network

Recently, low Earth orbit (LEO) satellites have emerged as key players in space information network (SIN) due to their ability to provide global coverage. However, they remain susceptible to threats such as denial of service (DoS), man-in-the-middle (MITM), and spoofing attacks. In this paper, we propose a cross-layer security framework (CLSF) to address these vulnerabilities. Our approach begins by employing a physically unclonable function (PUF) at the upper layer to establish mutual authentication between legitimate satellites and ground stations, while also securely exchanging frequency seeds for the next phase. Following this, dynamic seed frequency hopping (DSFH) is applied at the physical layer to counter DoS, MITM, and spoofing attacks. Additionally, the frequency transitions of malicious satellites are modeled using a Markov chain. Our results demonstrate that the proposed CLSF, which integrates PUF and DSFH, delivers strong security performance.