Lee, Min Soo Woo, Min Ki Jung, Jisung Kim, Yong-Su Han, Sang-Wook Moon, Sung 2024-01-20T01:32:02Z 2024-01-20T01:32:02Z 2021-09-01 2017-05-15 1094-4087 https://pubs.kist.re.kr/handle/201004/122733 We develop a way to hack free-space quantum key distribution (QKD) systems by changing the wavelength of the quantum signal laser using an external laser. Most free-space QKD systems use four distinct lasers for each polarization, thereby making the characteristics of each laser indistinguishable. We also discover a side-channel that can distinguish the lasers by using an external laser. Our hacking scheme identifies the lasers by automatically applying the external laser to each signal laser at different intensities and detecting the wavelength variation according to the amount of incident external laser power. We conduct a proof-of-principle experiment to verify the proposed hacking structure and confirm that the wavelength varies by several gigahertzes to several nanometers, depending on the intensity of the external laser. The risk of hacking is successfully proven through the experimental results. Methods for prevention are also suggested. (C) 2017 Optical Society of America English OPTICAL SOC AMER QUANTUM KEY DISTRIBUTION INDUCED DAMAGE CRYPTOGRAPHY PLUG BAND COMMUNICATION DAYLIGHT Free-space QKD system hacking by wavelength control using an external laser Article 10.1364/OE.25.011124 1 OPTICS EXPRESS, v.25, no.10, pp.11124 - 11131 OPTICS EXPRESS 25 10 11124 11131 scie scopus 000402733200036 2-s2.0-85019258952 Optics Optics Article QUANTUM KEY DISTRIBUTION INDUCED DAMAGE CRYPTOGRAPHY PLUG BAND COMMUNICATION DAYLIGHT Quantum hacking Free-Space QKD