Privacy-preserving Identifier Checking in 5G Networks Maintains Device Integrity with Homomorphic Encryption

Protecting user privacy in modern mobile networks presents a significant challenge, particularly when verifying device integrity through identifiers like the International Mobile Equipment Identity. Marcel D. S. K. Gräfenstein, Stefan Köpsell, and Maryam Zarezadeh, from Technische Universität Dresden and the Barkhausen Institut Dresden, address this issue with a new privacy-preserving method for identifier checking in 5G networks. Their research introduces a protocol that allows mobile networks to verify a device’s identity against blacklists or greylists without actually revealing the identifier itself, thereby mitigating long-term tracking risks. By adapting existing cryptographic techniques, specifically the PEPSI protocol and homomorphic encryption, the team demonstrates a system capable of performing this verification online within seconds, and with manageable communication overhead. This achievement represents a crucial step towards building scalable and compliant verification systems, not only for current 5G deployments but also for the future development of 6G networks, and establishes a pathway for balancing network security with individual privacy rights. Their research introduces a protocol that allows mobile networks to verify a device’s identity against blacklists or greylists without revealing the identifier itself. This is achieved by adapting existing cryptographic techniques, specifically the PEPSI protocol and homomorphic encryption, which enable computations on encrypted data without decryption.

The team engineered a protocol based on homomorphically encrypted Private Set Membership (PSM), adapting the PEPSI protocol and implementing the Brakerski, Fan, Vercauteren (BFV) scheme using Microsoft SEAL 4. This allows devices to prove their identifier is not on an operator’s blacklist or greylist without revealing the IMEI to the network. The system employs encrypted equality checks on IMEIs, ensuring the MNO only learns the verification outcome, Not-Listed, Listed, or Non-Evaluable, and nothing about the identifier itself. Scientists developed a bounded randomization mechanism to enhance statistical privacy and prevent ciphertext overflow during large-scale evaluations, maintaining accuracy while protecting user data. To balance privacy with accountability, the team incorporated a controlled Law Enforcement (LE) hook, enabling authorized deanonymization under specific legal circumstances. This is achieved by modifying a Private Set Membership (PSM) protocol and utilizing the Brakerski, Fan, Vercauteren (BFV) homomorphic encryption scheme, enabling encrypted equality checks on IMEIs. Experiments demonstrate the system can perform online verification within five seconds, requiring approximately 15 to 16 MB of communication per session, confirming its practicality for post-quantum security standards. The protocol incorporates a controlled Law Enforcement (LE) hook, allowing authorized deanonymization of devices on the greylist while preserving privacy by default, achieved through an additional encrypted ciphertext provided by the User Equipment (UE). Researchers implemented the system using Microsoft SEAL 4. 2 and conducted a comprehensive evaluation, analyzing runtime, communication overhead, and noise-budget trade-offs. The findings demonstrate the feasibility of homomorphic identifier verification at 5G scale, with a bounded randomization mechanism ensuring reliable homomorphic masking without ciphertext overflow during large set evaluations.,. Privacy Verification for 5G Networks Achieved This work demonstrates a privacy-preserving method for verifying device identifiers in 5G networks, addressing concerns about long-term tracking linked to sharing identifiers with mobile network operators. Researchers developed a protocol that allows operators to check if a device’s identifier is on a blacklist or greylist without actually learning the identifier itself, using a modified version of the PEPSI protocol and homomorphic encryption. The system incorporates a controlled mechanism for authorized law enforcement access, balancing privacy with accountability requirements. Implementation results confirm the practicality of the approach, with online verification completed within five seconds and communication overhead of approximately 16 MB. While the system operates within 5G latency constraints, the authors acknowledge limitations including communication overhead, increased ciphertext size, and minor statistical leakage. Future work may focus on mitigating these limitations to further enhance privacy and efficiency. The findings lay a foundation for scalable and compliant identifier verification systems, potentially extending to future 6G networks. 👉 More information 🗞 Privacy-Preserving Identifier Checking in 5G 🧠 ArXiv: https://arxiv.org/abs/2512.08310 Tags: Rohail T. As a quantum scientist exploring the frontiers of physics and technology. My work focuses on uncovering how quantum mechanics, computing, and emerging technologies are transforming our understanding of reality. I share research-driven insights that make complex ideas in quantum science clear, engaging, and relevant to the modern world. Latest Posts by Rohail T.: Document Parser Benchmarking Achieves 0.78 Correlation with Human Evaluation of Mathematical Formula Extraction from PDFs December 12, 2025 Token Expand-Merge: Training-Free Compression Accelerates Billion-Parameter Vision-Language-Action Model Inference December 12, 2025 Quantum Error Correction: Stabilizer Simulation Accurately Models Thermal-Relaxation Noise for Codes with ≤ 0.5 Amplitude December 12, 2025