Accelerated key generation and distribution using polarization scrambling in optical fiber.

Abstract

The physical-layer properties of the classical optical fiber channel provide an inherent, unique, random and reciprocal source for secure key generation and distribution (SKGD). However, the key generation rate (KGR) is generally less than kbit/s in the reported SKGD schemes. In this paper, an accelerated SKGD scheme based on active polarization scrambling is proposed in the classical optical fiber channel. A combination of unique birefringence distribution of optical fiber channel and active scrambling of instant state of polarization (SOP) enables a fast and random SOP fluctuation to be securely shared between the legitimate users for accelerated SKGD. The proposed SKGD scheme is experimentally demonstrated over 24-km standard single-mode fiber (SSMF), where a KGR of 200-kbit/s with an error-free operation is achieved after the post-processing procedure. Moreover, the possible fiber-tapping attacks are theoretically and experimentally analyzed for the security robustness of the proposed scheme. The results imply that a faster SKGD scheme could be achieved by incorporating an active polarization scrambling mechanism into the random properties of the fiber channel.