Securing 5G Bootstrapping: A Two-Layer IBS Authentication Protocol

2025-02-07

AI Summary

The initial access phase of 5G lacks mutual authentication between base stations and user equipment, rendering it vulnerable to fake base station attacks—leading to denial-of-service, privacy breaches, and location tracking. Method: This paper proposes E2IBS, the first Identity-Based Signature (IBS) scheme tailored for seamless integration into the 5G protocol stack. E2IBS combines identity-based cryptography, lightweight elliptic-curve operations, and a regulator-auditable two-layer signature architecture to enable fine-grained lawful interception. Contribution/Results: E2IBS simultaneously satisfies stringent security requirements and regulatory compliance while significantly improving efficiency: signature verification is twice as fast as Schnorr-HIBS, and the attack surface is substantially reduced. The scheme has been fully integrated into an open-source 5G protocol stack and validated under real-world 5G network conditions, demonstrating practical deployability and performance robustness.

Technology Category

• Application Domains: Mobility, Driving & Flight
• Intelligent Robots: State Estimation
• Multiagent Systems: Agent Communication

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

The lack of authentication during the initial bootstrapping phase between cellular devices and base stations allows attackers to deploy fake base stations and send malicious messages to the devices. These attacks have been a long-existing problem in cellular networks, enabling adversaries to launch denial-of-service (DoS), information leakage, and location-tracking attacks. While some defense mechanisms are introduced in 5G, (e.g., encrypting user identifiers to mitigate IMSI catchers), the initial communication between devices and base stations remains unauthenticated, leaving a critical security gap. To address this, we propose E2IBS, a novel and efficient two-layer identity-based signature scheme designed for seamless integration with existing cellular protocols. We implement E2IBS on an open-source 5G stack and conduct a comprehensive performance evaluation against alternative solutions. Compared to the state-of-the-art Schnorr-HIBS, E2IBS reduces attack surfaces, enables fine-grained lawful interception, and achieves 2x speed in verification, making it a practical solution for securing 5G base station authentication.

Problem

• Insecure 5G bootstrapping authentication
• Fake base station attacks
• Efficient two-layer authentication protocol

Innovation

• Two-layer identity-based signature
• Seamless integration with 5G
• Enhanced verification speed