Document Type : Original Research Paper

Author

• Arash Kosari

Department of Electrical Engineering and Information Technology, Iranian Research Organization for Science & Technology (IROST), Tehran, Iran.

Abstract

Background and Objectives: Quantum Key Distribution (QKD) ensures secure communication through quantum mechanics, but real-world implementations face vulnerabilities from detector blinding, time-shift, and side-channel attacks. While Measurement-Device-Independent QKD (MDI-QKD) mitigates detector vulnerabilities, it lacks real-time attack monitoring and struggles with finite-key limitations. This study presents an MDI ack QKD protocol that integrates deterministic acknowledgment pulses and multi-intensity decoy states to achieve robust, device-independent security with real-time attack detection.
Methods: The proposed protocol combines MDI-QKD’s device-independent framework with interleaved deterministic acknowledgment pulses and four-level decoy intensities. Alice and Bob generate weak coherent pulses with randomized phases, embedding acknowledgment pulses with probability ( Pd = 0.1 ) to probe channel integrity. An untrusted relay performs Bell-state measurements using superconducting nanowire single-photon detectors (SNSPDs). Multi-intensity decoy statistics enable finite-key parameter estimation, while integrated photonic platforms ensure scalability. Security is analyzed using the universally composable framework, with simulations and preliminary experiments conducted over metropolitan fiber distances.
Results: Numerical simulations demonstrate secure key rates exceeding 10 Mbps at 50 km and ~1 Mbps at 100 km under realistic conditions (0.2 dB/km fiber loss, 85% detector efficiency, 1 GHz pulse rate). Experimental tests on an integrated photonic chip at 1550 nm achieved raw key rates of 1.1 Mbps at 50 km with decoy accuracy within ±7%. Deterministic acknowledgments detected blinding attacks with high sensitivity, and multi-intensity decoys provided tight finite-key bounds, maintaining composable security against collective and coherent attacks.
Conclusion: The MDI ack QKD protocol achieves high-rate, device-independent quantum key distribution with real-time attack monitoring, offering a scalable solution for metropolitan quantum networks. Its compatibility with integrated photonics enables compact, stable implementations, while deterministic acknowledgments and multi-intensity decoys ensure robust security against evolving threats. This approach paves the way for practical, unconditionally secure communication systems, with potential for satellite-ground and multi-node network extensions.

Keywords

• MDI-QKD
• Detector Blinding
• Integrated Photonics
• Finite-Key Security
• Side-Channel Attacks

Open Access

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit: http://creativecommons.org/licenses/by/4.0/

 

Publisher’s Note

JECEI Publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

 

Publisher

Shahid Rajaee Teacher Training University