# Advanced post-processing procedure for industrial quantum key distribution systems

Great attention to quantum key distribution (QKD) systems is related to the fact of breaking of public-key encryption algorithms using quantum computing. Security of public-key exchange schemes can be justified on the basis of the complexity of several mathematical problems. Nevertheless, the Shor’s algorithm allows solving these problems in a polynomial time. Absence of efficient classical (non-quantum) algorithms breaking public-key cryptosystems still remains unproved.

In this contribution, we report about the joint research project, which is aimed on a design of an industrial fiber based QKD system in Russia. The QKD engine is based on the decoy states BB84 protocol. We present the developed post-processing procedure for sifted quantum keys (i.e., keys after reconciliations), which consists of error correction, parameter estimation, and privacy amplification. Communications over public channel are authenticated.

The post-processing procedure works as follows [1]. Sifted keys go through the error correction that is adjusted on the current value of QBER. After accumulation of necessary number of blocks they input to the parameter estimation (together with their versions before the error correction).

[1] Kiktenko E. et. al. Post-processing procedure for industrial quantum key distribution systems, arXiv:1603.08387.