Nanowerk November 1, 2021 A key element for achieving discrete-variable QKD is a single-photon detector. Researchers in China heterogeneously integrated, superconducting silicon-photonic chip. Harnessing the unique high-speed feature of the optical waveguide-integrated superconducting detector, they performed optimal Bell-state measurement (BSM) of time-bin encoded qubits generated from two independent lasers. The optimal BSM enables an increased key rate of measurement-device-independent QKD (MDI-QKD), which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays. Together with the time-multiplexed technique, they enhanced the sifted key rate by almost one order of magnitude. […]
Tag Archives: Secure communication
Using quantum Parrondo’s random walks for encryption
Phys.org October 15, 2021 Quantum game theory has stimulated some interest in recent years with the advancement of quantum information theory. This interest has led to a resurgence of quantum Parrondo’s games. With two losing games combining to give a winning game, this paradoxical idea is known as Parrondo’s paradox. Researchers in Singapore used chaotic switching between the two losing quantum games, to show that it is possible to achieve Parrondo’s paradox involving a quantum walker playing two-sided quantum coin tossing games. They showed that the framework of chaotic switching in quantum coin tosses can be applied to encryption. This […]
New quantum transmission protocol has higher data transmission rate, robustness against interference
Phys.org September 22, 2021 One of the fundamental principles enabling entanglement-based quantum communication security is the fact that interfering with one photon will destroy entanglement and thus be detectable. However, this property is also the greatest obstacle. Random encounters of traveling photons, losses, and technical imperfections make noise an inevitable part of any quantum communication scheme, severely limiting distance, key rate, and environmental conditions in which quantum key distribution can be employed. Using photons entangled in their spatial degree of freedom, an international team of researchers (China, Austria, Canada, Czech Republic, Slovakia) has shown that the increased noise resistance of […]
Researchers propose the use of quantum cascade lasers to achieve private free-space communications
Phys.org June 22, 2021 An international team of researchers (France, Germany, USA – UCLA, University of New-Mexico) shows that two uni-directionally coupled quantum cascade lasers operating in the chaotic regime and the synchronization between them allow for the extraction of the information that has been camouflaged in the chaotic emission. This building block represents a key tool to implement a high degree of privacy directly on the physical layer. The team has built a proof-of-concept communication at a wavelength of 5.7 μm with a message encryption at a bit rate of 0.5 Mbit/s. Their demonstration of private free-space communication between […]
Quantum holds the key to secure conference calls
EurekAlert June 6, 2021 Traditional quantum communication protocols consume pair-wise entanglement, which is suboptimal for distributed tasks involving more than two users. An international team of researchers (UK, Germany) has demonstrated quantum conference key agreement leveraging multipartite entanglement to efficiently create identical keys between N users with up to N-1 rate advantage in constrained networks. They distributed four-photon Greenberger-Horne-Zeilinger (GHZ) states, generated by high-brightness telecom photon-pair sources over optical fiber with combined lengths of up to 50 km and performed multiuser error correction and privacy amplification. Under finite-key analysis, they established 1.5 × 106 bits of secure key, which were […]
Sharing a secret…the quantum way
Science Daily July 31, 2020 By taking advantage of the high‐dimensional Hilbert space for orbital angular momentum and using Perfect Vortex beams as their carriers, researchers in South Africa have presented a proof‐of‐principle implementation of a high‐dimensional quantum secret sharing scheme. This scheme is experimentally implemented with a fidelity of 93.4%, for 10 participants in =11 dimensions. The implementation can easily be scaled to higher dimensions and any number of participants, opening the way for securely distributing information across a network of nodes…read more. TECHNICAL ARTICLE
Physicist from Hannover develops new photon source for tap-proof communication
EurekAlert March 27, 2020 Sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors an international team of researchers (UK, Japan, Germany) has demonstrated two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications much more secure in the future….read more. Open Access TECHNICAL ARTICLE