Key Reconciliation for High Performance Quantum Key Distribution

Abstract

Quantum Key Distribution is carving its place among the tools used to secure communications. While a difficult technology, it enjoys benefits that set it apart from the rest, the most prominent is its provable security based on the laws of physics. QKD requires not only the mastering of signals at the quantum level, but also a classical processing to extract a secret-key from them. This postprocessing has been customarily studied in terms of the efficiency, a figure of merit that offers a biased view of the performance of real devices. Here we argue that it is the throughput the significant magnitude in practical QKD, specially in the case of high speed devices, where the differences are more marked, and give some examples contrasting the usual postprocessing schemes with new ones from modern coding theory. A good understanding of its implications is very important for the design of modern QKD devices.

High-bit-rate continuous-variable quantum key distribution

“…These results only hold for large lengths; recently explicit fundamental one-way limits have been stressed in [12] as a function of the length and the target frame error rate (FER). However, a combination of error correcting codes with a few rounds of interactivity allows us to bypass these limitations while maintaining a high throughput [13].…”

Efficient Information Reconciliation for Energy-Time Entanglement Quantum Key Distribution

“…In particular, in [3], layered coding based on splitting the joint channel into channels for each bit layer, according to the chain rule of mutual information, offers a key rate higher than that of joint coding (treating the concatenation of bits as the bit-stream). Avoiding high latency to keep pace with the speed at which raw key is generated has become increasingly more important, see, e.g., [5], [6]. Layered coding is computationally challenging in the finite-length regime, especially when the number of bits per symbol increases, due to the dependencies between layers and the unexplored discrepancy between the asymptotic analysis and the finite-length code construction [7].…”

A fast and versatile quantum key distribution system with hardware key distillation and wavelength multiplexing

“…Recently, the need for faster systems has stimulated the development of dedicated hardware engines for quantum key distillation, e.g. [17][18][19].…”