Adaptive Error Correction with Dynamic Initial Block Size in Quantum Cryptographic Key Distribution Protocols

We present an extension to the error correction facility that is at the core of classical quantum cryptographic key exchange in the spirit of the BB84 protocol. The Cascade error correction scheme proposed along with the experimental implementation of BB84 can significantly be improved by endowing it with an adaptive initial block size selection strategy that takes into account information from past protocol executions. Additionally, our model comes with learning capabilities enabling the protocol to adapt itself not only according to its past, but also to different environmental conditions which the link is subject to. At the same time, the procedure can widely be automated and can be implemented using known algorithms. We demonstrate the feasibility and efficiency of our proposal using experiments, comparing the classical approach to the dynamic extension, showing a significant efficiency benefit that we gain from an adaptive initial block size choice.