https://doi.org/10.1140/epjqt/s40507-026-00498-8
Research
Enhancing Quantum Key Distribution via McEliece-based hybrid PQC-QKD architecture
1
Department of Mathematical and Computational Sciences, National Institute of Technology Karnataka, Surathkal, India
2
Department of Computer Science and Engineering, Indian Institute of Technology, Kharagpur, India
3
Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, India
a
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Received:
28
October
2025
Accepted:
6
March
2026
Published online:
24
March
2026
Abstract
Quantum Key Distribution (QKD) offers information-theoretic security; however, its practicality is limited by an inherently low secret key rate. In this work, we propose a cryptographic enhancement of QKD by incorporating post-quantum public key encryption, namely Classic McEliece. We propose a novel hybrid PQC-QKD protocol named BBM that employs QC-LDPC based McEliece cryptosystem to encrypt the basis string in QKD, thereby skipping the sifting step and consequently improving the secret key rate. We only need to assume the short-term security of the McEliece cryptosystem during the protocol run to achieve the everlasting security of the distilled keys. Our analysis demonstrates that this integration not only enhances the achievable secret key rate by 
in the BB84 protocol but also provides resistance against photon number splitting attack, and inherits a fallback mechanism in its design. This marks a significant improvement in terms of efficiency, security, and reliability over conventional BB84-like QKD protocols.
Key words: Quantum Key Distribution / Post-Quantum Cryptography / Classic McEliece cryptosystem / Hybrid PQC-QKD / Secret Key Rate
Veeresh R. Maned, Satyabrat Rath and Jothi Ramalingam contributed equally to this work.
© The Author(s) 2026
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