StarCast: A Secure and Spectrum-Efficient Group Communication Scheme for LEO Satellite Networks

TL;DR

StarCast is a novel encryption scheme for LEO satellite group communication that ensures security, fine-grained access control, and spectrum efficiency, addressing key management challenges in massive connectivity scenarios.

Contribution

It introduces a ciphertext-policy attribute-based encryption scheme tailored for LEO satellite networks, enhancing security and spectrum efficiency over traditional methods.

Findings

Maintains spectrum efficiency while providing secure group communication.

Reduces key management overhead compared to conventional encryption.

Ensures only authorized users access transmitted data.

Abstract

Low Earth Orbit (LEO) satellite networks serve as a cornerstone infrastructure for providing ubiquitous connectivity in areas where terrestrial infrastructure is unavailable. With the emergence of Direct-to-Cell (DTC) satellites, these networks can provide direct access to mobile phones and IoT devices without relying on terrestrial base stations, leading to a surge in massive connectivity demands for the serving satellite. To address this issue, group communication is an effective paradigm that enables simultaneous content delivery to multiple users and thus optimizes bandwidth reuse. Although extensive research has been conducted to improve group communication performance, securing this communication without compromising its inherent spectrum efficiency remains a critical challenge. To address this, we introduce StarCast, a secure group encryption scheme for LEO satellite networks. Our solution leverages ciphertext-policy attribute-based encryption (CP-ABE) to implement fine-grained access control by embedding access policies directly within the ciphertext. Unlike standard secure communication approaches that require dedicated per-user channels and significantly deplete limited satellite spectrum resources, StarCast maintains efficient spectrum reuse within user groups while ensuring that only authorized users can access transmitted data. Additionally, it significantly reduces the costly key management overhead associated with conventional encryption schemes.