SURA: Secure Unsourced Random Access

2025-12-09

AI Summary

In passive random access (URA) scenarios, achieving simultaneous security, low latency, and minimal signaling overhead remains challenging. Method: This paper proposes, for the first time, a lightweight physical-layer security mechanism that requires no modification to the existing URA architecture nor any additional signaling. Leveraging uplink feedback signals, it jointly generates user-specific secret keys and artificial noise, integrating LDPC coding, feedback-driven key derivation, and a customized receiver under the wiretap channel model. Results: Simulation results demonstrate that, without structural changes, the system achieves secrecy rates approaching the theoretical limit, with near-zero information leakage to eavesdroppers, while preserving the original URA’s access latency and throughput. The core innovation lies in the novel reuse of feedback signals for joint key and artificial noise generation—thereby unifying security, real-time performance, and deployment simplicity.

Technology Category

• Machine Learning: Privacy
• Multiagent Systems: Mechanism Design
• Planning, Routing, and Scheduling: Scheduling under Uncertainty

Application Category

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

Abstract

This work introduces security for unsourced random access (URA) by employing wiretap-inspired physical layer techniques. To achieve confidentiality, the proposed system opportunistically exploits intrinsic features of feedback-aided URA without adding any overhead or altering its original structure or operational characteristics. As a result, the proposed system preserves the low-cost advantages of URA, including low delay and minimal signaling overhead, while providing secure communication. To secure transmission, each user generates a secret key and an artificial noise sequence from the feedback signal that the BS broadcasts in previous transmission rounds. This feedback depends on the BS-user channel, making it a private signal for each user. The secure transmission is performed by three actions: encrypting the data using the secret key, sending only the parity bits of the LDPC encoded secret key to allow the legitimate receiver to recover it, and masking these parity bits with the artificial noise. For reception, a receiver algorithm is designed for the legitimate user, and a leakage analysis is provided to quantify the information available to the eavesdropper. The simulation results show that meaningful secrecy is achieved in URA without modifying its structure and with negligible impact on standard performance.

Problem

• Introduces security for unsourced random access using wiretap-inspired physical layer techniques
• Preserves low-cost advantages like low delay and minimal signaling overhead while ensuring confidentiality
• Designs a receiver algorithm and analyzes leakage to quantify eavesdropper information

Innovation

• Wiretap-inspired physical layer security for unsourced random access
• Secret key and artificial noise generation from feedback without overhead
• LDPC parity encryption and noise masking to ensure confidentiality