Physical-layer key distribution is an area of active research due to vulnerabilities in current digital encryption methods, which rely on computational security. We propose and demonstrate a high-speed physical-layer key generation and distribution method based on random mode mixing in multimode optical fibers. We refer to this method as random-channel cryptography (RCC). In RCC, a key is extracted from the channel state of a shared multidimensional reciprocal channel. Projection operators reduce the signal to a single degree of freedom (DOF) for the legitimate users, while the signal is spread over many DOFs anywhere accessible to eavesdroppers. This produces a large asymmetry between the eavesdroppers' and legitimate users' measurement complexities. Furthermore, signal-to-noise ratio analysis reveals that RCC is information-theoretically secure under certain attacks. However, initial demonstrations of RCC offered very low key rate-distance products. A nine orders-of-magnitude increase in the key rate-distance product was demonstrated using techniques from traditional telecommunications, such as high-speed modulation, wavelength-division multiplexing, and advanced modulation formats. Compared to other physical-layer key distribution methods, RCC is easy-to-implement, robust, and offers high security.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2649 |
| Date | 01 January 2023 |
| Creators | Sampson, Rachel |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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