A Comprehensive Physical Layer Security Mechanism for Mobile Edge Computing

Mobile edge computing (MEC) is becoming popular in many civilian applications. However, due to the broadcast nature of wireless connections, traditional MEC is open to eavesdropping attacks that endanger mobile users’ information confidentiality. Friendly jamming (FJ), as one of the physical layer security (PLS) techniques, can efficiently protect users from such threats by degrading attackers’ wiretap channel capacities. In this article, we propose an FJ-based PLS mechanism to safeguard the confidentiality of data uploading in MEC services. We design a comprehensive security scheme that uses FJ from both base station (BS) and nearby mobile users to cover upload transmission. Accordingly, the eavesdropping risk zone (ERZ) is formulated as an area under high secrecy outage probability (SOP). To promote FJ from users, we further introduce Device-to-device (D2D) communication-based FJ, which is inspired by nonorthogonal multiple access (NOMA) techniques. Then, we formulate, simplify, and solve the problem by optimizing the MEC secrecy performance under the required risk, with efficiencies in data uploading, energy consumption, and incentive delivery. Furthermore, we tackle the challenge of efficient incentive design under information asymmetry by introducing Contract Theory and providing differentiated rewards. By simulations, we evaluate the mechanism in terms of secrecy performance and incentive efficiency under information asymmetry, and the results accordingly show the effectiveness of the proposed security mechanism.

I. Introduction

With the development of mobile edge computing (MEC), also known as multiaccess edge computing, offloading computational tasks to edge servers is becoming popular in civil and military applications. MEC helps terminals with limited resources to run applications that rely on high performance with acceptable service delay, and is considered as one of the fundamental technologies to drive high-quality mobile applications in 5G/6G visions. However, the broadcast nature of wireless connections that support MEC traffic gives malicious entities chances to intercept users’ confidential data. Among typical processes of MEC service, offloading task-related data to base station (BS) is most vulnerable to eavesdropping attacks [1]. Because mobile terminals usually have limited computation and communication capacities, and cannot provide highly directional beam or data encryption with extreme complexity. They cannot fully guarantee the confidentiality of data transmission in physical (PHY) or media access control (MAC) layers against eavesdropping attacks. Meanwhile, as physical-layer security (PLS) techniques become favorable for future MEC paradigms [1], using physical differences between channels for confidentiality is considered effective and complementary to traditional encryption schemes. Among the PLS techniques, friendly jamming (FJ), or cooperative jamming (CJ), is designed to degrade potential wiretap channels and improve the secrecy performance of legitimate communications [2], [3], and is widely applicable to mobile terminals [4], assistant network infrastructure (e.g., relays) [5], and BSs [1].