Vatshal Srivastava

Quantum key distribution (QKD) brings the promise of communication with information-theoretic security, but is limited in practice due to its susceptibility to noise, losses, and difficulty in accounting for device imperfections. To address these challenges, we propose a robust high-dimensional (HD) \textit{one-sided} device-independent QKD (1sDI-QKD) protocol whose security is certified \mm{via detection/demonstration of steering}. Motivated by recent demonstrations of steering in high-dimensional systems with enhanced robustness to noise and loss [PhysRevX.12.041023], we present a systematic security analysis of HD 1sDI-QKD protocols leveraging quantum steering to certify security. We analyze the achievable secret key rates for protocols with different measurement configurations and system dimensions, combined with a reverse reconciliation scheme, which leads to significant improvements in secret key rates. Our results demonstrate two main advantages: (i) the protocols offer enhanced robustness of the key rates against noise and loss in comparison to fully device-independent QKD, and (ii) the key rate performance shows favorable scaling with increasing dimensions. Finally, we characterize the noise-loss trade-off, highlighting the feasibility of HD 1sDI-QKD in practical scenarios. We further demonstrate progress towards a proof-of-concept experimental implementation of HD 1sDI-QKD by exploring multi-outcome projective measurements across all mutually unbiased bases up to dimension 11. We observe steering violations demonstrating advantages for QKD up to dimension 7 under the fair-sampling assumption. Finally, we discuss perspectives towards a loophole-free implementation of 1sDI-QKD.