We consider quantum key distribution in the device-independent scenario, i.e., where the legitimate parties do not know (or trust) the exact specification of their apparatus. We show how secure key distribution can be realized against the most general attacks by a quantum adversary under the condition that measurements on different subsystems by the honest parties commute.

In this paper, we present three generalized quantum key distribution protocols between two groups, which consist of k and l members respectively. In these protocols two groups retrieve the secure key string, only if all members should cooperate with one another in each group. We show that if there is an eavesdropper between two groups then their cheating or eavesdropping cannot be accomplished.

In a typical optical implementation of the Bennett-Brassard 1984 (so-called BB84) quantum key distribution protocol, the sender uses an active source to produce the required signal states. While active state preparation of BB84 signals is a simple and elegant solution in principle, in practice passive state preparation might be desirable in some scenarios, for instance, in those experimental se...

A.S. Trushechkin, 2, 3 E.O. Kiktenko, 4 and A.K. Fedorov 5, 6 Steklov Mathematical Institute of Russian Academy of Sciences, Moscow 119991, Russia National Research Nuclear University MEPhI, Moscow 115409, Russia Department of Mathematics and Russian Quantum Center, National University of Science and Technology MISiS, Moscow 119049, Russia Bauman Moscow State Technical University, Moscow 105005...

This work is intended as an introduction to cryptographic security and a motivation for the widely used Quantum Key Distribution (QKD) security definition. We review the notion of security necessary for a protocol to be usable in a larger cryptographic context, i.e., for it to remain secure when composed with other secure protocols. We then derive the corresponding security criterion for QKD. W...

Recent advances in quantum key distribution (QKD) have given rise to systems that operate at transmission periods significantly shorter than the dead times of their component single-photon detectors. As systems continue to increase in transmission rate, security concerns associated with detector dead times can limit the production rate of sifted bits. We present a model of highspeed QKD in this...

It is often claimed that the security of quantum key distribution (QKD) is guaranteed by the laws of physics. However, this claim is content-free if the underlying theoretical definition of QKD is not actually compatible with the laws of physics. This paper observes that (1) the laws of physics pose serious obstacles to the security of QKD and (2) the same laws are ignored in all QKD “security ...

In our continuous variable quantum key distribution (QKD) scheme, the homodyne detection set-up requires balancing the intensity of an incident beam between two photodiodes. Realistic lens systems are insufficient to provide a spatially stable focus in the presence of large spatial beam-jitter caused by atmospheric transmission. We therefore present an improved geometry for optical tapers which...