Information-Theoretic Security in BB84 QKD

This paper demonstrates ways to improve the post-processing phase of BB84-based Quantum Key Distribution (QKD) while maintaining Information-Theoretic security. Maximum entropy in the distilled bits can be achieved provided that we follow certain rules on which bits are sacrificed based on the properties of the generator matrix. We use standard decoder techniques to distill bits and establish Information-Theoretic security and provide insights into how those techniques can be adapted to provide greater bit throughput. Finally, we compare popular coding schemes in BB84 post-processing as a basis for code selection and discover at low initial Bit Error Rates (BER), a Polar 4/5 or Hamming* give the best performance and for higher initial BER, the LDPC 3/4 and Hamming* (a modified Hamming code) give the best performance [1] [2] [9] [10].