A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs BB84 protocol with a strong reference to generate secure bits at rate of 16.5 kbit/s an error 0.5% over optical channel 10 dB loss, and 18 bits/s 0.75% 25 loss. To best our knowledge, these results represent highest loss reported for using approach. passive unidirectional scheme used compensate polarization dependence phase modulators in receiver module, resulted high...

Many quantum key distribution systems employ a laser followed by an optical attenuator to prepare weak coherent states in the source. Their mean photon number must be precalibrated guarantee security of distribution. Here we experimentally show that this calibration can broken with high-power attack. We test four fiber-optic types used systems, and find two them exhibit permanent decrease attenuation after damage. This results higher numbers prepared may allow eavesdropper compromise key.

A well-protected and characterized source in a quantum key distribution system is needed for its security. Unfortunately, the vulnerable to light-injection attacks, such as Trojan-horse, laser-seeding, laser-damage which an eavesdropper actively injects bright light hack unit. The hacking laser could be high-power one that can modify properties of components via attack also further help Trojan-horse other attacks. Here we propose countermeasure against consisting additional sacrificial...

Analysis of methods for utilizing by-products livestock farming allowed us to develop a promising concept accelerated technology processing litterless manure as part an organomineral mixture. The basis the is separation liquid and solid fractions already in barn and, accordingly, subsequent separate processing, disinfection introduction fractions. In this case, sterility fraction taken into account, therefore, its without processing. undergoes successive disinfection, mixing with fillers,...

We experimentally demonstrate that a single-photon detector ID210 commercially available from ID Quantique is vulnerable to blinding and can be fully controlled by bright illumination.In quantum key distribution, this vulnerability exploited an eavesdropper perform fakedstate attack giving her full knowledge of the without being noticed.We consider on standard BB84 protocol subcarrier-wave scheme, outline possible countermeasure.

Although quantum communication systems are being deployed on a global scale, their realistic security certification is not yet available. Here we present evaluation and improvement protocol for complete systems. The subdivides system by defining seven implementation sub-layers based hierarchical order of information flow; then it categorises the known imperfections hardness protection practical risk. Next, an initial analysis report lists all potential loopholes in its quantum-optical part....

We demonstrate qubit transmission via an optical cable in a metropolitan area network using quantum communications sidebands with record-setting system parameters for such systems mode. The sifted-key generation rate was 1.06 Mbits/s losses of 1.63 dB and error coefficient 1%.

We present a scheme of quantum repeater that uses entangled multimode coherent states are obtained by electro-optic modulation symmetric and antisymmetric Schr\"odinger cat states. Part the generated frequency modes is sent to beam splitter at central node, while remaining stored locally in memories. The between remote memories conditionally prepared photon-counting measurements output channels splitter. study how effects decoherence channel affect statistics photocounts and, for heralding...

Quantum cryptography allows distributing secure keys between two users so that any performed eavesdropping attempt would be immediately discovered. However, in practice an eavesdropper can obtain key information from multi-photon states when attenuated laser radiation is used as a source of quantum states. In order to prevent actions eavesdropper, it generally suggested implement special cryptographic protocols, like decoy or SARG04. this paper, we describe alternative method based on...

This article describes the current technical level of developments in field continuous-variable quantum key distribution (CV-QKD). Various classifications are described, criteria analyzed, and optimal protocol is selected. The analysis focused around device-dependent schemes with a theoretical emphasis, therefore, detailed device-independent CV-QKD side-channel attacks out scope work. However, latter, one way or another, taken into account when describing possible classifications. choice was...

We experimentally demonstrate quantum communication in 10 dB loss outdoor atmospheric channel with 5 kbit/s bitrate using subcarrier wave coding method. Free-space link was organized by telescoping system symmetric fiber-optic collimators.

We examine different methods to implement coherent detection in subcarrier wave quantum key distribution (SCW QKD) systems. For classical fields, we present the models describing homodyne-type and heterodyne-type schemes needed extract information from quadrature phase-coded multimode signals used SCW QKD. Practical feasibility of proposed is corroborated by experiments.

In this paper, we continue the study of quantum cryptographic GG02 protocol, performed using approach based on subcarrier waves. We modify scheme via heterodyne detection and perform security analysis for full trusted hardware noise model in presence collective attacks with finite-key effects. It is shown that system can potentially distribute key even if level losses channel above 9 dB. This result consistent general technical comply modern standards practical CV-QKD systems. Finally, under...

In this paper we report a continuous-variable quantum key distribution protocol using multimode coherent states generated on subcarrier frequencies of the optical spectrum. To detect quadrature components bosonic field propose detection scheme where power from carrier wave is used as local oscillator. We compose mathematical model proposed and perform its security analysis in finite-size regime fully asymptotic equipartition property technique. calculate lower bound secret rate for system...

Theoretical research and numerical simulation of the noise influence caused by spontaneous Raman scattering, four-wave mixing, linear channel cross talk on performances quantum key distribution (QKD) systems were conducted. Three types QKD considered: a coherent one-way protocol, subcarrier-wave system, continuous-variable integrated with classical dense wavelength division multiplexing (DWDM) channels. We calculate secure generation rate for mentioned addressing different allocation schemes...

It is shown that the action of a nanosecond pulse laser radiation with wavelengths 0.53 and 1.06 μm on glass waveguide layer contains silver ions causes nanoparticles to be formed surface glass. The are fixed by dielectric components A mechanism proposed for formation when acts.

Vulnerabilities of components used in quantum key distribution (QKD) systems affect its implementation security and must be taken into consideration during system development analysis. In this paper, we investigated transmission fiber optical elements, which are commonly QKD for designing countermeasures against Trojan-horse attacks, 1500-2100 nm range. As a result, found loopholes their spectra open possibilities eavesdropping. We also suggested simple passive countermeasure based on...

In this paper we investigate the chromatic dispersion impact on quantum key distribution system based multi-mode weak coherent phase-coded states. We provide an asymptotic secure rate estimation, taking into account error detection probability due to dispersion. demonstrate numerically and experimentally that effect of in optical fiber without any compensation hinders secret at a distance more than 53 km. Finally, propose modification considered communication order mitigate influence its performance.

We discuss a method for revealing photon-number-splitting (PNS) attack in quantum key distribution (QKD) system, which is based on analyzing the statistical of photon numbers detected each time interval. A relation estimating difference between expected photon-number and one appearing course PNS derived. An equation defining minimum number counts necessary with desired probability given. Formulas calculating amount raw keys known to an illegitimate user due are obtained depending system's...

Subject of study. Two-way continuous-variable quantum key distribution schemes are studied. Aim. This study aims to prove the security plug-and-play system in context model trusted noise from legitimate users. Method. Based on an analog well-known implementation format, performance such a operating under GG02 protocol is evaluated. The evaluation conducted presence collective attacks, considering finite-key effects. Main results. A secure that satisfies composability criteria can be...

This paper introduces a model of Grover's algorithm suitable for implementation in linear photonic chip. We compare two known realizations its main components, two-qubit CZ gates, order to define optimal chip architecture. The operation is simulated considering directional coupler imperfection influence on the scheme parameters. also determined tolerance boundaries distortions dimensions.