40 results about "Decoy state" patented technology

Embodiments of a present disclosure relate to communication systems and more particularly to a system and a method for a point-to-point decoy differential phase shift (DPS) Quantum Key Distribution (QKD). The system includes a source QKD device and a destination QKD device. The source QKD device generates and transmits one or more quantum states comprising a series of N coherent pulses with one or more phases to the destination QKD device. The destination QKD device receives, and records time information and corresponding detector units associated with each photon detection event in the received quantum states. The source and destination QKD devices use decoy states to detect and prevent attacks, such as Photon-Number-Splitting (PNS) attacks. The system allows for the secure generation of a secret key between the source and destination QKD devices.

The invention belongs to the technical field of quantum communication, and particularly relates to a quantum key distribution method and system based on mode pairing and a passive decoy state. In order to overcome the defect that the problem of side channel information leakage possibly exists due to the fact that an active decoy state method is adopted in an existing quantum key distribution method based on mode pairing, the invention adopts the following technical scheme that the quantum key distribution method based on mode pairing and passive decoy state comprises the following steps: two parties respectively generate a pair of entangled photons; the two parties respectively carry out information coding on signal photons through a signal path and a decoy path to obtain a coherent quantum state, and randomly send a modulated signal state or decoy state to Charlie; the Charlie performs single-photon interference measurement on the coherent quantum states sent by the two parties and publishes a measurement result; repeating for N rounds and then carrying out mode pairing; screening basis vectors; key mapping; estimating parameters; and key extraction. The method has the beneficial effects that the security is improved while a relatively high key generation rate is ensured.

The invention provides a Bayesian-based parameter optimization method and system for quantum key distribution, relates to the technical field of quantum information processing, and aims to solve the problems that in the prior art, the calculation amount is large, the efficiency is low, and real-time parameter optimization of a high-speed quantum key distribution system and the optimal configuration requirement of large quantum communication network resources are difficult to realize. The method comprises the following steps: acquiring system parameters, a sending probability in an MDI-QKD protocol, and intensities of a signal state and a decoy state; the obtained data is preprocessed; according to the preprocessed data, a parameter optimal model based on Bayesian optimization is constructed, training and testing are carried out, and a trained model is obtained; and inputting to-be-predicted system parameters and the sending probability, signal state and decoy state intensity data in the MDI-QKD protocol into the trained model, and outputting optimal parameters. According to the method, the to-be-optimized system parameters can be accurately predicted, the system parameter optimization efficiency is improved, the time cost is reduced, and the key generation rate is greatly improved.

The invention belongs to the technical field of optical secret communication, and discloses a quantum key distribution coding module, a sending end and a system network, the coding module comprises a circulator, a stable polarization modulation module and an optical path selection module; the polarization stabilization modulation module is used for carrying out stable polarization modulation on an input optical signal; the optical path selection module is used for enabling the optical signal to select two transmission paths, one path enables the polarization of the optical signal to be unchanged so as to realize discrete variable polarization coding, and the other path only passes through a specific linear polarization component so as to realize continuous variable Gaussian modulation coding, and the invention further discloses a quantum key distribution sending end and a system network. Compared with the prior art, polarization coding or Gaussian modulation coding can be realized, and decoy state modulation or pulse generation can also be realized, so that discrete variable coding and continuous variable coding are integrated in one transmitting end, and flexible reconstruction is realized; and different protocols can be better compatible in application, and the on-site deployment cost is reduced.

The invention discloses a quantum secure direct communication method and system based on a passive decoy state, an information receiver uses two coherent pulses with random phases, and the two coherent pulses are interfered and attenuated through a beam splitter to generate weak coherent pulse beams with random intensity. And the information receiver randomly encodes the weak coherent pulse and sends the weak coherent pulse to the information sender. And the information sender carries out information coding and then sends the photon pulse to the information receiver. And the information receiver decodes according to the pulse information initially sent by the information receiver and restores the information sent by the information sender. The method does not need to actively modulate the intensity of the light source, can realize a passive decoy state, can be realized by using a linear optical device, simplifies the experiment operation, resists the side channel attack of a third-party eavesdropper to the light source modulator, and can enhance the security of quantum secure direct communication.

The present invention belongs to the field of optical secure communication technology and discloses a plug-and-play time-phase coded quantum key distribution network. The central node includes a multi-wavelength laser, three beam splitters, a wavelength division multiplexer, and two single-photon detection units. Each user node includes an adjustable attenuator and a reflective intensity modulation module. The reflective intensity modulation module is used to modulate the intensity of two sub-pulses arriving at the user node through beam splitting-reflection-interference, thereby randomly generating two time-coded states in the Z basis and one phase-coded state in the X basis, as well as corresponding decoy states, while simultaneously rotating the polarization states of the two sub-pulses by 90 degrees. Compared with the prior art, the present invention adopts a round-trip architecture. Each user node uses the reflective intensity modulation module to implement three-state time-phase coding. This not only enables automatic polarization and phase compensation, but also enables polarization-independent quantum state preparation and decoy state preparation.

The application discloses a photon intensity control method and device of a BB84 decoy state quantum key distribution system, and relates to the technical field of quantum communication photon intensity control. The photon intensity control method comprises the following steps: detecting the photon intensity of the photon state of a first beam splitting ratio after beam splitting; determining the average photon number ratio of the photon state according to the photon intensity of the photon state and the trigger number of the photon state; determining the control signal of the photon state according to the average photon number ratio of the photon state; and controlling the photon intensity of the photon state of a second beam splitting ratio after beam splitting in response to the control signal of the photon state, so as to control the photon intensity of the photon state of the second beam splitting ratio of the BB84 decoy state quantum key distribution system. The photon intensity control method can accurately control the photon intensity of the signal state, the photon intensity of the decoy state and the photon intensity of the vacuum state, and improve the feedback control precision.

The application provides a method and device for quantitatively characterizing and classifying security parameters of a quantum key distribution device. The method provided by the application defines a security parameter set of the quantum key distribution device by using a weak randomness model; the security parameter set comprises a weak randomness security parameter, a light intensity fluctuation security parameter and a coding and decoding error security parameter; the weak randomness security parameter comprises an encoding weak randomness security parameter ε s1 of a sending end, a basis vector weak randomness security parameter ε s2 of the sending end, a decoy state weak randomness security parameter ε d of the sending end and a basis vector weak randomness security parameter ε r of a receiving end; the light intensity fluctuation security parameter refers to a light intensity fluctuation security parameter ε i of the sending end; and the coding and decoding error security parameter comprises a modulation error security parameter ε en of the sending end and a demodulation error security parameter ε de of the receiving end.

Embodiments of a present disclosure relate to communication systems and more particularly to a system and a method for detecting a Photon-Number-Splitting (PNS) attack in a secure quantum communication channel during Quantum Key Distribution (QKD). The system comprises source Quantum Key Distribution (QKD) device that transmits quantum states comprising signal and decoy states to destination QKD device through pre-authenticated classical communication channel. The destination QKD device records measurable parameters and sends them back to source QKD device through pre-authenticated classical communication channel. A source security analysis unit in source QKD device analyzes security parameters and detects Photon-Number-Splitting (PNS) attacks using a differential statistical analysis technique. A source key generation unit and source key management unit perform actions for secret key generation based on detected PNS attack. The destination QKD device generates secret key based on the transmitted measurable parameters.

The invention relates to the technical field of quantum information, in particular to a passive decoy state-based reference system independent quantum key distribution method. A reference frame independent quantum key distribution (RFI-QKD) protocol may still generate a secure key when the reference frame has a slow and unknown drift. In order to solve the potential side information leakage loophole in the active decoy state modulation process, the RFI-QKD protocol based on the passive decoy state is invented. Two beams of weak coherent light are subjected to interference in the beam splitter, and the signal light at the output end is divided into two types of photon number distribution according to the response result of the detector end, so that the risk caused by active modulation of light intensity can be avoided. Considering that single photon avalanche detectors (SPAD) of a transmitting end and a receiving end have inevitable post-pulse effects, a post-pulse compatible analysis model is constructed. A simulation result shows that the method is good in performance in an actual application scene.

The invention discloses a transmitting end and a method capable of weakening QKD decoy state spectral resolution, which adopt a technical concept of weakening the QKD decoy state spectral resolution by controlling modulation voltages at weak light positions among pulses, and enable the modulation voltages corresponding to different state positions to have rising edges and / or falling edges with the same slope. And the frequency shift amount and the frequency shift direction of the weak light before and after different state positions are consistent, so that the distinguishability between different state spectrums is weakened, and a spectrum side channel attack defense function such as frequency shift attack and the like can be provided in a simple and extremely low-cost manner.

The invention discloses a photon intensity control method and device of a BB84 decoy state quantum key distribution system, and relates to the technical field of quantum communication photon intensity control. The photon intensity control method comprises the following steps: detecting the photon intensity of a photon state of a first beam splitting ratio after beam splitting by a beam splitter; determining an average photon number ratio of the photon states according to the photon intensity of the photon states and the respective triggering number of the photon states; determining respective control signals of the photon states according to the average photon number ratio of the photon states; and in response to respective control signals of the photon states, controlling the photon intensity of the photon state of the second beam splitting ratio after beam splitting by the beam splitter so as to control the BB84 decoy state quantum key distribution system according to the photon intensity of the photon state of the second beam splitting ratio. According to the photon intensity control method, the photon intensity of a signal state, the photon intensity of a decoy state and the photon intensity of a vacuum state can be accurately controlled, and the feedback control precision is improved.

The present invention belongs to the field of quantum communication technology, and specifically relates to a quantum key distribution method and system based on mode pairing and passive decoy state. In view of the shortcomings of the existing quantum key distribution method based on mode pairing using the active decoy state method, which may have the problem of side channel information leakage, the present invention adopts the following technical solution: a quantum key distribution method based on mode pairing and passive decoy state, including: both parties generate a pair of entangled photons; both parties encode information on the signal photons through the signal path and the decoy path respectively to obtain a coherent quantum state, and randomly send the modulated signal state or decoy state to Charlie; Charlie performs single-photon interferometry on the coherent quantum states sent by both parties and publishes the measurement results; repeats mode pairing after N rounds; basis vector screening; key mapping; parameter estimation; key extraction. The beneficial effects of the present invention are: ensuring a high key generation rate while improving security.

The invention discloses a quantum secure direct communication method based on a symmetric all-passive light source, and the method comprises the steps: an information receiver uses four coherent pulses with random phases, generates weak coherent pulse beams with random intensity and random quantum states through the interference, beam combination and attenuation of a beam splitter and a polarization beam splitter, and transmits the weak coherent pulse beams to an information transmitter; and the information sender sends the photon pulse to the information receiver after coding. And the information receiver decodes according to the pulse information initially sent by the information receiver and restores the information sent by the information sender. According to the method, the intensity of the light source and the quantum state do not need to be actively modulated, the passive decoy state and the passive coding can be realized at the same time, the experimental operation can be simplified, the side channel attack of a third-party eavesdropper on the light source modulator can be resisted, and the security of quantum secure direct communication is enhanced.

The invention relates to the field of quantum key distribution, and discloses a key distribution anti-attack method and system based on decoy state coding and an irrelevant protocol, and the method comprises the steps: Alice generates a signal state quantum pulse and a three-intensity decoy state quantum pulse in a mixed manner, and transmits and monitors channel parameters in real time through a quantum channel; bob randomly selects a measurement base for measurement, records original data and delays to obtain a state type identifier; the Charlie transmits a random test state, collects Bell inequality verification parameters, and implements equipment-independent security verification; the two parties screen matched data through base comparison, evaluate channel security and correct a signal state bit error rate by using a decoy state bit error rate; and based on the screened keys, a Toeplitz matrix negotiation protocol is adopted for compression to generate a final key, 10% of the keys are randomly extracted for cross validation, and after the cross validation is passed, the keys are stored, and the decoy state strength and the measurement base group parameters are updated. According to the method, an Alice, Bob and Charlie three-party system is constructed to form an iterative security closed loop, attack is comprehensively resisted, and a security key is generated.

The invention belongs to the technical field of secret communication, and discloses a chip quantum key distribution system, which is characterized in that a sending end comprises an intensity modulation module and an encoding chip of an adjustable attenuation module; the intensity modulation module is used for chopping an optical pulse signal into two sub-pulses with a time difference of T and performing intensity modulation on the two sub-pulses to generate a signal state and a decoy state of a time phase coding quantum state, the adjustable attenuation module is used for attenuating the time phase coding quantum state to a single photon magnitude, and the receiving end comprises a decoding chip; the time delay difference of the cross-polarization time delay module included in the decoding chip for the TM polarization mode and the TE polarization mode is T. Compared with the prior art, the method has the advantages that the light pulse is chopped into the two sub-pulses, and the intensity modulation is respectively carried out, so that the time phase coding can be realized, and the complexity of a transmitting end is reduced; and the decoding chip adopts an unequal-arm interferometer with passive base selection and a symmetrical structure, and meanwhile, polarization-independent receiving decoding can be realized, so that the stability of the system is improved.

The present invention discloses a modulation device for a decoy state quantum key distribution system, comprising: a first beam splitting unit configured to receive an incident optical pulse and split the incident optical pulse into a first pulse and a second pulse; a first modulation unit coupled to the first beam splitting unit and configured to receive the first pulse and generate a first interference pulse after modulation; a second modulation unit coupled to the first beam splitting unit and configured to receive the second pulse and generate a second interference pulse after modulation; and a third modulation unit coupled to the first modulation unit and the second modulation unit and configured to receive the first interference pulse and the second interference pulse and generate a third interference pulse after modulation. The modulation device for a decoy state quantum key distribution system provided by the present invention and the encoding method for preparing a stable intensity state using the same can effectively suppress the encoding memory effect (pattern effect) between adjacent optical pulses and ensure the independence between the encoded pulses.

The invention discloses a dynamic user phase coding quantum communication system, and the system is characterized in that a laser LD generates a pulse optical signal, the pulse optical signal enters a first SC device for initial phase modulation, and then enters a polarization modulation module for phase loading and polarization state adjustment; a pulse light signal is modulated into a signal state or decoy state pulse through an intensity modulator IM, the signal state or decoy state pulse is attenuated into a single photon level through an attenuator ATT, then the single photon level enters a selected user side Bob in each period, and the single photon level enters an original path after being modulated at the user side Bob; and after returning, interference is generated at the 50: 50 beam splitter BS, and finally the light is emitted to the detection unit for detection. The phase encoder and the N (N is greater than or equal to 2) polarization encoders are arranged, so that the strong anti-interference capability is improved; a plurality of polarization encoders are utilized to adjust the pulse optical signal into a polarization state to select a user, so that different users can perform independent communication on the same quantum channel, and the flexibility of user selection is greatly improved.

This invention discloses a quantum key distribution device, method, and key rate estimation method based on a labeled source combined with light source monitoring. In the transmitting end of the device, a first optical switch and a second optical switch simultaneously and randomly select a period of time to send a second signal light to the light source monitoring module and a first idle light to the same module, respectively. The idle light passes through a polarization rotator to obtain a second idle light with the same polarization state as the second signal light. The second signal light and the second idle light pass through a beam splitter and then enter a single-photon detector to measure the coincidence count and calculate the HOM interference visibility, thus achieving light source monitoring. This invention improves the security and confidentiality of quantum key transmission by using a labeled single-photon source combined with a three-intensity decoy state scheme and a light source monitoring scheme. By measuring the HOM interference visibility, the amount of information that may be leaked at the source end can be characterized, thereby more accurately estimating the key rate that can be extracted at the measurement end.

The application discloses a kind of full passive quantum key distribution device, method and its key rate estimation method, arbitrary quantum state of sending end arbitrary quantum coherent state on Bloch sphere is generated by passive generation module, first reflection light after first beam splitter is used to carry out polarization direction measurement and quantum state post-selection, first transmission light after first beam splitter enters the local detection response module;In local detection response module, the transmission light of second beam splitter enters receiving end, and reflection light is divided into two single-photon detectors by beam splitting, and the corresponding photon number distribution model is established using the response and non-response events of single-photon detector;According to polarization direction, photon number distribution model and the measurement result of receiving end, the secure key of receiving end is obtained.The application avoids the intensity detection error caused by signal state and decoy state distinction.Can realize higher security key rate.

The invention provides an intensity modulation device for a QKD, and relates to the technical field of quantum communication, the intensity modulation device comprises a beam splitter, a beam combiner and an intensity modulation basic unit, when signal light and vacuum state pulse signals are modulated, the influence of a code pattern effect on output light intensity and relevance is greatly reduced, and the intensity of the output light intensity is modulated based on the construction of the basic intensity modulation unit. The intensity modulation device can limit the influence of the small change of the voltage on the output intensity within a small range when the intensity output is maximum, realizes modulation of a signal state, a decoy state and a vacuum state based on the intensity modulation device, limits the ratio of the light intensity change caused by the code pattern effect to the output light intensity within a small range, and improves the light intensity modulation efficiency. Side channels on a time domain are reduced, and modulation of a signal state, a decoy state and a vacuum state is realized.

The invention discloses a QKD decoy state and error correction code rate joint optimization method based on machine learning, and belongs to the technical field of quantum communication, and the method comprises the steps: collecting or generating key data under QBER fluctuation, carrying out the processing to obtain an original key feature extraction value, inputting a machine learning model for training, and carrying out the optimization of a QKD decoy state and an error correction code rate by taking the minimization of a loss function as a target. And iteratively adjusting parameters to obtain a machine learning predictor. Optimizing a decoy state and an error correction code rate by using a predictor; initializing a QKD system, and optimizing a signal state and the decoy state according to an initial QBER predicted value; secret key distribution is carried out, and original secret key data are collected and preprocessed to select an optimal error correction code; generating an expansion key, performing error correction coding, and obtaining a statistical distribution value sequence; and inputting the QBER prediction value into a machine learning predictor to obtain a QBER prediction value, and performing joint optimization on a decoy state and an error correction code rate of the system by using the QBER prediction value. The QBER prediction is introduced in the information coordination process, the QBER prediction value is used for decoy state optimization, and the security key rate of the QKD system is improved.

This invention provides a novel and efficient quantum joint signature method based on entanglement measurement. After the signer performs multiple measurements on the qubits in the sequence and generates different sequences multiple times, under the action of the verifier, different sequences are generated by inserting decoy states. The signer then measures and compares the different sequences. After comparing the measurement results of the signers, the verifier combines the different sequences to form a signature. By comparing whether the values ​​of the superimposed sequences from different signers are the same, the validity of the joint signature is determined.

The invention provides a novel efficient quantum joint signature method based on entanglement measurement, which comprises the following steps: after a signer measures quantum bits in a sequence for multiple times, generating different sequences for multiple times, and under the action of a verifier, generating different sequences by inserting a decoy state; according to the method and the device, a signer measures and compares different sequences, a verifier compares the measurement results of the signer and superposes the different sequences to form a signature, and whether the combined signature of the signer is valid or not is judged by comparing whether the superposed values of the different sequences of different signers are the same or not.

The invention relates to the technical field of key distribution, and provides a delay parameter adjusting method and device and a decoy state modulation method.The delay parameter adjusting method comprises the steps that a single-photon negative feedback optical signal is obtained, then a detection counting signal is obtained, the detection counting signal is obtained according to the single-photon negative feedback optical signal, a first ratio is calculated based on the detection counting signal, and a second ratio is calculated based on the first ratio; the first ratio is a ratio parameter of the signal state and the decoy state, and if the first ratio is greater than or equal to a first ratio threshold, obtaining a first target parameter and a second target parameter through a counting rule or a ratio rule, the ratio of the signal state to the decoy state is smaller than a first ratio threshold value in optical signals correspondingly output by a first electric signal output by the first time delay chip according to the first target parameter and a second electric signal output by the second time delay chip according to the second target parameter. According to the method, by adjusting the proportion of the signal state and the decoy state in real time, the problem that the preparation safety of the decoy state is low can be solved.

The invention provides a high-dimensional quantum key distribution performance estimation method for orbital angular momentum coding, and the method comprises the steps: obtaining OAM light beam characteristic parameters through employing a Laguerre-Gaussian mode as an orthogonal mode base set, and carrying out the estimation of the high-dimensional quantum key distribution performance of orbital angular momentum coding based on the OAM light beam characteristic parameters; respectively calculating the probability of receiving the correct OAM state under the influence of the pointing error and the probability of receiving the correct OAM state under the influence of the atmospheric turbulence; and according to the probability of receiving the correct OAM state under the influence of the pointing error and the atmospheric turbulence, carrying out decoy state OAM coding HD-QKD key estimation, and finally carrying out decoy state OAM coding HD-QKD finite length security key estimation to obtain the finite length security key rate of the HD-QKD system. According to the method, the high-dimensional quantum key distribution performance can be accurately estimated, the effective long security key rate of the HD-QKD system is obtained, and detection efficiency mismatch and system security vulnerabilities are avoided.

This invention discloses a secure authentication method and system for power grid operators based on quantum communication, relating to the field of quantum secure authentication technology. The method includes: a power grid control center and a power grid operator generating a Bell state sequence based on a binary key sequence and dividing it to obtain a first sequence and a second sequence; introducing decoy particles into the first sequence to form an extended first sequence, which is then transmitted via a quantum channel; a security center performing decoy state detection, permutation, and decoy state introduction on the extended first sequence to generate a new first sequence, which is then transmitted; the power grid control center and the power grid operator removing the decoy states from the new first sequence to restore the original first sequence; performing Pauli operations and Bell measurements on the second sequence to obtain measurement results; and exchanging the measurement results using classical communication channels to verify identity and achieve secure authentication of the power grid operator. This invention effectively prevents advanced persistent threats (APTs) and other potential security risks.

The present invention belongs to the field of quantum secure communication technology, and discloses a method and a device for generating an arbitrary passive decoy state for quantum key distribution, wherein the device includes a laser, a time-delay interferometer, a photodetector, an analog-to-digital conversion module, and a data processing module, wherein the data processing module is used to divide a digital signal into M light intensity intervals arranged in ascending order, and obtain the light intensity distribution of each light intensity interval, and the present invention also discloses a method for distributing an arbitrary passive decoy state for quantum key distribution. Compared with the prior art, the present invention uses a time-delay interferometer to convert the random phase of the spontaneous radiation of the laser into a random light intensity, and divides the light intensity distribution into an arbitrary number of light intensity intervals after real-time measurement, so as to realize the passive generation of an arbitrary number of decoy states, and reduce the influence of light intensity fluctuations on the system. And an arbitrary number of decoy states can be selected to improve the parameter estimation accuracy, thereby improving the security key rate.

The application belongs to the technical field of secret communication, and discloses a chipped quantum key distribution system, wherein a sending end comprises an encoding chip of a strength modulation module and an adjustable attenuation module; the strength modulation module is used for chopping an optical pulse signal into two sub-pulses with a time difference of T, and respectively performing intensity modulation on the two sub-pulses to generate a signal state and a decoy state of a time-phase encoding quantum state; the adjustable attenuation module is used for attenuating the time-phase encoding quantum state to a single-photon level; and a receiving end comprises a decoding chip; the decoding chip comprises a quadrature polarization delay module, and a delay difference of TM and TE polarization modes is T. Compared with the prior art, the application can realize time-phase encoding, and reduce the complexity of the sending end by respectively performing intensity modulation on two sub-pulses after chopping an optical pulse into the two sub-pulses; the decoding chip adopts a passive basis selection and a non-equal arm interferometer with a symmetrical structure, and simultaneously realizes polarization-independent receiving and decoding, thereby improving the stability of the system.

The invention discloses an electric power optical fiber communication safety enhancement system based on quantum key distribution, and relates to the technical field of electric power optical fiber communication, and the system comprises a lever coefficient calculation module which is used for calculating a basic structure lever coefficient based on a hinge side unbalance loading pressing belt of a connector box and a tray layer number of a target optical fiber in the connector box; the residual calculation module is used for calculating the actual measurement detection probability of the strong signal state and the actual measurement detection probability of the weak decoy state, and calculating a one-way consistency residual based on the actual measurement detection probability of the strong signal state and the actual measurement detection probability of the weak decoy state; and the secret key quantity calculation module is used for calculating an accepted secret key quantity according to the basic structure lever coefficient, the one-way consistency residual error and the initial secret key quantity of the statistical window. According to the method, the practicability and the anti-attack capability of the quantum key in electric power optical fiber communication are improved.