Continuous-variable source-device-independent quantum key distribution against general attacks

Abstract

The continuous-variable quantum key distribution with entanglement in the middle, a semi-deviceindependent protocol, places the source in the untrusted third party between Alice and Bob, and thus has the advantage of high levels of security with the purpose of eliminating the assumptions about the source device. However, previous works considered the collective-attack analysis, which inevitably assumes that the states of the source has an identical and independently distributed (i.i.d) structure, and limits the application of the protocol. To solve this problem, we modify the original protocol by exploiting an energy test to monitor the potential high energy attacks an adversary may use. Our analysis removes the assumptions of the light source and the modified protocol can therefore be called source-device-independent protocol. Moreover, we analyze the security of the continuousvariable source-device-independent quantum key distribution protocol with a homodyne-homodyne structure against general coherent attacks by adapting a state-independent entropic uncertainty relation. The simulation results indicate that, in the universal composable security framework, the protocol can still achieve high key rates against coherent attacks under the condition of achievable block lengths.

Overview of device-independent continuous-variable quantum key distribution

“…Although certain countermeasures have been proposed in each case, in order to completely eliminate such attacks, it is necessary to deal with the problem at the root. Referring to recent advances in the field of MDI QKD, alternative practical schemes have been proposed that are resistant to loopholes in detection, thus protecting against all the above-mentioned attacks in QKD systems [4,27].…”

A modified practical homodyne detector model for continuous-variable quantum key distribution: detailed security analysis and improvement by the phase-sensitive amplifier

“…Continuous variable (CV) QKD [3,4] which is developed slightly posterior to discrete variable QKD, is now going through a booming period. Many kinds of CV-QKD protocols with specific purposes are proposed and analyzed: measurement-deviceindependent CV-QKD protocols can defense arbitrary attacks against the detector [5][6][7], while source-device-independent CV-QKD protocols are intrinsically secure against the malicious source [8,9]. Discrete modulation CV-QKD protocols can effectively reduce the modulation complexity [10][11][12], and passive state preparation CV-QKD protocols use the thermal source to generate quantum states which can reduce the difficulty of the state preparation [13,14].…”

Unidimensional Continuous-Variable Quantum Key Distribution with Untrusted Detection under Realistic Conditions

“…Nevertheless, DI protocols need a loophole-free Bell test [ 41 ] which is an experimental challenge. To compromise between practical protocols and full DI protocols, semi-device-independent (semi-DI) protocols are proposed, e.g., measurement-device-independent (MDI) [ 42 , 43 , 44 ], source-device-independent [ 45 , 46 ], and one-sided device-independent (1sDI) [ 47 , 48 ] QKD protocols, to consider both the security of some devices and the performance of a protocol. In semi-DI protocols, some devices can be assumed to be fully controlled by the adversary while the others should be well characterized.…”

“…In semi-DI protocols, some devices can be assumed to be fully controlled by the adversary while the others should be well characterized. The investigations on the security analysis of semi-DI protocols develop very fast in recent years, such as CV-MDI [ 49 , 50 , 51 ], source-device-independent [ 46 ] and CV-1sDI protocols [ 47 , 52 , 53 ], which extend the application of such protocols.…”