22 results about "Decoy state" patented technology

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 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.

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 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.

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 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.

The application discloses a quantum secure direct communication method based on a symmetric passive light source, wherein information receivers use four phase random coherent pulses to generate weak coherent pulse beams with random intensity and quantum state through beam splitters and polarization beam splitters interference, beam combination and attenuation, and send the beams to information senders. The information senders send the photon pulses back to the information receivers after encoding. The information receivers decode the information sent by the information senders according to the initial pulse information sent by the information receivers. The method does not need to actively modulate the intensity and quantum state of the light source, can simultaneously realize passive decoy states and passive encoding, can simplify experimental operation, can resist side channel attacks of a light source modulator by a third-party eavesdropper, and can enhance the security of quantum secure direct communication.

The application discloses a quantum signal encoding method and a quantum key extraction method suitable for quantum key distribution, wherein the quantum key extraction method comprises the following steps: using a polarizing plate and a polarizing beam splitter to randomly select a horizontal, vertical, positive 45-degree or negative 45-degree base vector to project and measure the polarization state of an encoded optical pulse signal sent by a sending terminal; randomly inputting the projection measurement result into a first detector or a second detector with asymmetric performance parameters to obtain a measurement result; reserving the measurement result of the measurement base vector consistent with the base vector disclosed by the sending terminal; estimating channel parameters by using a decoy state, and calculating the size of a key rate by using the estimated channel parameters; and extracting a final key from the reserved measurement result according to the size of the key rate. The application can improve the key coding rate and improve the practicability of the quantum key distribution system.

The invention relates to the technical field of quantum communication, in particular to an underwater decoy state quantum key distribution system and method based on Time-bin coding, and the system is characterized in that a control end comprises an FPGA (Field Programmable Gate Array) board and an upper computer; the transmitting end comprises a continuous coherent light source module, a signal module, a receiving module, an interference delay module, a light path beam combining module and an intensity modulation module, the output end of the continuous coherent light source module is connected with the input end of the interference delay module, and the output end of the signal module is connected with the light path beam combining module; and the receiving end comprises a wavelength division multiplexing module, a classic detection module, a base selection module, a non-equal arm interference module, a single photon detection module and a classic laser. The problem of photon polarization state and reference system drift caused by stability difference of transmitting and receiving equipment or water channel characteristics in the existing polarization coding technology is fundamentally avoided, and the error rate of the system is remarkably reduced.

The application discloses a quantum secure direct communication method and system based on passive decoy state, wherein an information receiver uses two phase random coherent pulses, the two coherent pulses are interfered and attenuated through a beam splitter to generate a weak coherent pulse light beam with random intensity; the information receiver further randomly encodes the weak coherent pulse and sends the same to an information sender; the information sender sends the photon pulse back to the information receiver after information encoding; and the information receiver decodes the information sent by the information sender according to the initial pulse information sent by the information receiver. The method does not need to actively modulate the intensity of a light source, can realize passive decoy state, can be realized by using linear optical devices, simplifies experimental operation, can resist side channel attacks of a light source modulator by a third-party eavesdropper and can enhance the security of quantum secure direct communication.

The invention discloses a measurement equipment irrelevant entanglement witness method based on a decoy state light source, and the method comprises the steps: obtaining a preset number of weak coherent pulse light sources with preset intensity prepared by a first local verification party and a second local verification party, and carrying out the coding, and obtaining a corresponding quantum state; performing non-destructive measurement based on quantum teleportation on all the quantum states to obtain a single photon state, and performing Bell state measurement on the single photon state and the to-be-verified particle to obtain a measurement result; obtaining the gain of the target detector according to the measurement result, and calculating the upper bound and the lower bound of the single photon response probability; and decomposing a pre-selected witness operator to all the quantum states to obtain a witness operator irrelevant to the measurement equipment, calculating an entanglement criterion to obtain an entanglement criterion calculation result, and verifying whether the particle to be verified has entanglement according to the entanglement criterion calculation result. According to the invention, the entanglement state in the to-be-verified particle can be accurately discriminated.

This invention relates to the field of quantum communication technology and discloses an anti-interference quantum key distribution protocol optimization method, comprising: acquiring the single-photon counter count statistics output by the measurement end during the key screening stage, including signal state, decoy state, and vacuum state count values; calculating the instantaneous variance of the vacuum state count value and determining a counting correction parameter based on the ratio of the variance to the signal state count value; using the parameter to correct the gain deviation of the single-photon counter count statistics; extracting the polarization deviation feature vector from the corrected statistics and determining the bit offset parameter; and performing bit-level logic remapping on the key screening sequence based on the bit offset parameter to compensate for channel disturbances when the polarization control voltage at the measurement end is constant. This invention converts the basis vector deflection into an address offset through protocol layer logic mapping, eliminates the occupation of the link by hardware calibration, ensures the continuity of key generation under environmental disturbances, avoids background noise introduced by strong light pilots, and improves quantum key distribution efficiency.

The invention relates to a quantum state encoder, in particular to a high-precision quantum state encoder based on a nested interferometer, which is characterized in that an unbalanced Mach-Zehnder interferometer is positioned on an anticlockwise path of a Sagnac interferometer and consists of a second beam splitter BS2 and a third beam splitter BS3, and two arms of the interferometer have unbalanced optical paths and are used for introducing fixed time delay; dividing a single light pulse into a morning time bin and a evening time bin in a time domain; the at least one phase modulator is located in the Sagnac interferometer, under the driving of the integrated control system, independent phase modulation is carried out on the passing light pulses, a target quantum state is directly synthesized by designing modulation phase combinations, and meanwhile a decoy state is formed; the integrated control system is used for generating a voltage pulse with a corresponding time sequence and amplitude according to a target quantum state to be generated and a decoy level in each pulse period, and directly driving the phase modulator; according to the method, the defects of discrete structure, high quantum bit error rate and poor expandability can be overcome.

The application discloses a kind of based on the method and system of quantum random number generation of decoy state of ubiquitous light source, the method can be applied in quantum random number generator system not depending on specific light source distribution.This method is prepared by party Alice, and the received optical pulse is randomly modulated into signal state, decoy state and vacuum state, then the modulated optical pulse is randomly prepared into one of four different encoding states, and is sent to measuring party Bob;Measuring party Bob randomly selects base vector to project the encoding state sent to carry out measurement, and obtains output result;Gain under corresponding optical pulse intensity is calculated, and channel parameters and randomness size are estimated based on the calculated gain using decoy state method;According to the randomness size, random number is extracted in measurement result.The application does not depend on specific light source distribution, and has universality.

The utility model discloses a dynamic user phase coding quantum communication system, and the system is characterized in that a laser LD generates a pulse optical signal which 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. According to the utility model, the phase encoder and the plurality of 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 quantum network user selection is greatly improved.