Secure quantum key distribution with a subset of malicious devices

Abstract

The malicious manipulation of quantum key distribution (QKD) hardware is a serious threat to its security, as, typically, neither end users nor QKD manufacturers can validate the integrity of every component of their QKD system in practice. One possible approach to re-establish the security of QKD is to use a redundant number of devices. Following this idea, we address various corruption models of the possibly malicious devices and show that, compared to the most conservative model of active and collaborative corrupted devices, natural assumptions allow to significantly enhance the secret key rate or considerably reduce the necessary resources. Furthermore, we show that, for most practical situations, the resulting finite-size secret key rate is similar to that of the standard scenario assuming trusted devices.

Practical Long‐Distance Measurement‐Device‐Independent Quantum Key Distribution By Four‐Intensity Protocol

“…[42,43,76] Recently, the performance of the four-intensity protocol was studied with leaky sources and also with a subset of malicious sources. [45,77] For a longer distance or higher key rate, one may refer to the twin-field (TF) QKD [78] and its variants, for example, the sendingor-not-sending (SNS) protocol, [79] the TF* protocol, [80] the CAL protocol, [81] and the NPP protocol. [82] The SNS protocol [79] and CAL protocol [81] are secure under general attacks and robust to misalignment errors and finite data size.…”

“…[ 42,43,76 ] Recently, the performance of the four‐intensity protocol was studied with leaky sources and also with a subset of malicious sources. [ 45,77 ]…”

Security of device-independent quantum key distribution protocols: a review

“…That being said, DI-QKD may also be feasible even if quantum theory were to be superseded by another physical theory that respects the nosignalling principle (Barrett et al, 2005). As quantum theory's validity remains unchallenged today, it shall 12 When considering DI-QKD implementation with multiple pairs of devices, it was shown in (Curty and Lo, 2019;Zapatero and Curty, 2021) that DI-QKD can still be secure with the aid of secret sharing if some but not all of the devices are malicious.…”

Security of quantum key distribution with intensity correlations

“…Also, let p d (δ A ) stand for the dark count probability of each of Bob's photo-detectors (polarization misalignment occurring in the channel). The model is [15,26] Z a,N…”