Beyond the Limits of Shannon’s Information in Quantum Key Distribution

Abstract

We present a new post-processing method for Quantum Key Distribution (QKD) that raise cubically the secret key rate in the number of double matching detection events. In Shannon’s communication model information is prepared at Alice’s side then it is intended to pass it over a noisy channel. In our approach, secret bits do not rely in Alice’s transmitted quantum bits but in Bob’s basis measurement choices. Therefore measured bits are publicly revealed while bases selections remain secret. Our method implements sifting, reconciliation and amplification in a unique process, it just require a round iteration, no redundancy bits are sent and there is no limit in the correctable error percentage. Moreover, this method can be implemented as a post processing software into QKD technologies already in use.

Perfect Reconciliation in Quantum Key Distribution with Order-Two Frames

“…Not all the frames are converted into secret bits. In [23] we derived the throughput as 1 4 1 2 (1 − e) + 1 6 e that reaches a maximum gain of 1 8 n 2 when e = 0. Taking into account Table 2, we arrive to the throughput Equation 1 of frame reconciliation T .…”

“…This property gives immunity to the quantum key distribution protocol when it relies on double detection event as the vehicle to transmit a secret bit. Let us briefly summarize why the frame-based QKD is immune to the PNS and IR attack (other attack as the basis choice is described in [23]).…”

“…We published in [22,23] a new reconciliation algorithm that takes advantage of the characteristics of quantum communication, which, simply put, is equivalent to having two classical communication channels, one in the quantum X basis and the other in the Z basis. By means of a reverse reconciliation process, Bob sends parity information from these two channels so that Alice is able to recognize Bob's chosen bases on which the secret information is encoded as depicted in Figure 1.…”