Contributed Talk 4b
contributed
Thu, 17 Aug 2023, 12:15 - 12:35
- Satellite-Based Quantum Key Distribution in the Presence of Bypass ChannelsMasoud Ghalaii (University of Leeds); Sima Bahrani (University of Bristol); Carlo Liorni (University of Dusseldorf); Federico Grasselli (University of Dusseldorf); Hermann Kampermann (University of Dusseldorf); Lewis Wooltorton (University of Bristol); Rupesh Kumar (University of York); Stefano Pirandola (University of York); Timothy Spiller (University of York); Alexander Ling (National University of Singapore); Bruno Huttner (ID Quantique); Mohsen Razavi (University of Leeds)[abstract]Abstract: The security of prepare-and-measure satellite-based quantum key distribution (QKD), under restricted eavesdropping scenarios, is addressed. We particularly consider cases where the eavesdropper, Eve, has limited access to the transmitted signal by Alice, and/or Bob’s receiver station. For instance, Eve can only receive an attenuated version of the transmitted signals. This results in settings where an uncharacterized bypass channel, inaccessible to Eve, can also carry signals to Bob. We obtain generic bounds on the key rate in the presence of bypass channels and apply them to continuous-variable QKD protocols with Gaussian encoding as well as to the family of BB84 protocols. We find regimes of operation in which the above restrictions on Eve can considerably improve system performance. Our work opens up new security frameworks for spaceborne quantum communications systems.