Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution (Cho 2005),(Palmer 2007), (Kish 2006), (Mingesz 2013),(Kish 2009),(Mingesz 2008),(Kish 2006b), is a classical physical scheme that is a potential alternative to quantum key distribution. It is also sometimes loosely referred to as the Kish cipher, however, it is a hardware-based scheme for securely distributing cipher keys, and is not a...

Proving the unconditional security of quantum key distribution (QKD) is a highly challenging task as one needs to determine the most efficient attack compatible with experimental data. This task is even more demanding for continuous-variable QKD as the Hilbert space where the protocol is described is infinite dimensional. A possible strategy to address this problem is to make an extensive use o...

This paper provides an exposition of methods by which a trusted authority can distribute keys and/or broadcast a message over a network , so that each member of a privileged subset of users can compute a speciied key or decrypt the broadcast message. Moreover, this is done in such a way that no coalition is able to recover any information on a key or broadcast message they are not supposed to k...

In this paper, the systematisation and classification of modern quantum technologies of information security against cyber-terrorist attack are carried out. The characteristic of the basic directions of quantum cryptography from the viewpoint of the quantum technologies used is given. A qualitative analysis of the advantages and disadvantages of concrete quantum protocols is made. The current s...

Existing experimental implementations of continuous-variable quantum key distribution require shot-noise limited operation, achieved with shot-noise limited lasers. However, loosening this requirement on the laser source would allow for cheaper, potentially integrated systems. Here, we implement a theoretically proposed prepare-and-measure continuous-variable protocol and experimentally demonst...

We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and timebin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We...

A free-space quantum key distribution system that operates at a wavelength of 850 nm is presented. The system is designed to implement the B92 protocol at high transmission rates between two locations in urban areas. OCIS codes: (270.5568) Quantum cryptography; (060.2605) Free-space optical communication

This paper analyzes the information-theoretical security of the Differential Phase Shift (DPS) Quantum Key Distribution (QKD) protocol, using efficient computational information geometric algorithms. The DPS QKD protocol was introduced for practical reasons, since the earlier QKD schemes were too complicated to implement in practice. The DPS QKD protocol can be an integrated part of current net...

O. Gittsovich, N. J. Beaudry, 2 V. Narasimhachar, R. Romero Alvarez, 3 T. Moroder, 4 and N. Lütkenhaus Institute for Quantum Computing & Department of Physics and Astronomy, University of Waterloo, Waterloo ON Canada N2L 3G1 Institute for Theoretical Physics, ETH Zürich, 8093 Zürich, Switzerland Department of Physics, University of Toronto, Toronto ON Canada M5S 1A7 4 Naturwissenschaftlich-Tech...

We construct a new quantum key distribution scheme and prove its security against the most general type of attacks and the most general type of noises allowed by quantum physics. The novel technique we use is reduction from a quantum scheme to a classical scheme. We first show that, rather surprisingly, the proof of security of our quantum key distribution in the error-free case can be reduced ...