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Q: Fachverband Quantenoptik und Photonik

Q 67: Poster – Quantum Information

Q 67.18: Poster

Thursday, March 5, 2026, 17:00–19:00, Philo 2. OG

Recent advances in the implementation of a post-processing pipeline for a star-shaped quantum key hub — •Tobias Liebmann and Thomas Walther — TU Darmstadt, Institute of Applied Physics, 64289 Darmstadt

Quantum computing threatens the security of widely used public-key cryptographic schemes such as the Rivest-Shamir-Adleman (RSA) protocol. As a countermeasure, quantum key distribution (QKD) enables the generation of symmetric keys with information-theoretic security, making it suitable for one-time-pad encryption. However, distilling secure keys from raw quantum measurement data requires a complex classical post-processing pipeline. We present recent advances in the post-processing system of our QKD network, with a focus on error correction, authentication, and privacy amplification. In particular, we employ protograph-based LDPC codes for error correction, allowing the code length and rate to be adapted to different links in our network. For authentication of the classical channel we use a Wegman-Carter scheme, and Toeplitz hashing for privacy amplification. We analyze these components with respect to common performance metrics and benchmark them against our previous implementations as well as other published approaches.

Keywords: Post-processing; Quantum key distribution; BBM 92; Network