CN114338018B - Double-field quantum key distribution method and system for safety of actual signal source - Google Patents
Double-field quantum key distribution method and system for safety of actual signal source Download PDFInfo
- Publication number
- CN114338018B CN114338018B CN202210217737.3A CN202210217737A CN114338018B CN 114338018 B CN114338018 B CN 114338018B CN 202210217737 A CN202210217737 A CN 202210217737A CN 114338018 B CN114338018 B CN 114338018B
- Authority
- CN
- China
- Prior art keywords
- sending end
- basis vector
- under
- coherent light
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Optical Communication System (AREA)
Abstract
The invention discloses a method and a system for distributing a double-field quantum key for the safety of an actual signal source, wherein the quantum key distribution only needs to use weak coherent light pulses, and meanwhile, an intermediate measuring equipment end only needs to carry out interference operation. Based on the advantages, the key transmission distance is increased, and a higher code rate can be obtained under the condition of transmitting the quantum key at a long distance; simultaneously, based on above-mentioned advantage, this scheme has high suitability and stronger practicality to actual operation.
Description
Technical Field
The invention relates to the technical field of quantum key distribution, in particular to a method and a system for distributing a double-field quantum key which is safe to an actual signal source.
Background
The quantum key distribution can provide absolutely safe two-party communication based on the quantum mechanics basic principle, and the security vulnerability that the classical key distribution is easy to crack based on the calculation complexity is solved. Quantum key distribution has now made extensive research progress both theoretically and experimentally. Part of quantum key distribution protocols have entered the field of practical use. Although quantum key distribution has achieved some tentative results in the field of practical application, it is not considered that there is a larger hole from the actual practical application. The most important of these is the gap between the actual transmitting measurement device and the theoretical assumption. In theoretical security analysis of a quantum key distribution protocol, a sending measurement device end is often required to meet some ideal assumptions, for example, a sending end can accurately prepare a sent signal state while a side channel effect is not generated in the whole quantum key distribution project. In addition, trojan horse attacks are not always considered in security analysis of preparation-measurement quantum key distribution, which also leads to information leakage in practical situations.
To protect against all information leakage at the measuring end, 2011 quantum key distribution independent of the measuring device was proposed (phys. rev. lett. 108, 130503). Although the information leakage of all measuring ends can be resisted, the method is still influenced by a leak caused by the imperfection of a transmitting end. Meanwhile, another solution to solve the actual device vulnerability is device-independent quantum key distribution (phys. rev. lett. 98, 230501) proposed in 2007, which is based on the principle of quantum theory to guarantee theoretical security. But device independent quantum key distribution is far from practical use due to low coding rate. Meanwhile, one theoretical work in 2021 questioned the security of the current standard device independent quantum key distribution, putting the security of the device independent quantum key distribution into debate (phys. rev. lett. 127, 050503).
On the basis of an original measurement equipment independent quantum key distribution framework, a scheme can also solve information leakage caused by equipment imperfection of a sending end, and the specific method is to completely represent various information leakage possibly existing at the sending end in security analysis so as to bring the information leakage into a code rate forming formula. In 2019, a Marcos Curty group at Weigo university in Spain works in cooperation with a Kiyoshi Tamaki group at Fushan university in Japan (npj Quantum Inf 5, 62) by using a loss-tolerant method (loss-tolerant method) and simultaneously representing the security vulnerability existing at a sending end, so that the code forming rate of the distribution of the tri-state Quantum key which is not perfect for signal state preparation and still safe under the side channel effect and Trojan horse attack is given; in 2020, they consider the security hole of the correlation between the signal states of adjacent time series existing in the process of preparing the signal state by the transmitting end, and theoretically prove that the correlation effect can be regarded as a side channel effect to characterize (Science Advances, 6, 37, eaaz 4487). In the next 2021, they propose that security holes (phys. rev. Applied 15, 034072) of the transmitting end which can be considered at present can be comprehensively characterized by using only one parameter, and meanwhile, the requirement of actual security can be met by adopting a framework of a quantum key distribution protocol which is irrelevant to the measuring equipment. Although the work of the users represents the security loophole of the sending end relatively completely, the problem of low encoding rate still exists. Under actual equipment conditions, the protocol of the method is difficult to meet the practical code rate requirement; meanwhile, a teacher team of the university of Qinghua proposes a quantum key distribution protocol (physics, Rev, Applied 12, 054034, SNS-QKD for short) of sending-or-not-sending, and proves that the protocol can resist side channel attacks theoretically, but the protocol still has disputes in security and also has the problem of low code rate.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a method and a system for distributing a double-field quantum key which are safe to an actual signal source, and solves the problems of low code rate or low safety of the existing quantum key distribution protocol under the actual equipment condition. In the process of security analysis, the invention adopts a basic framework that the measuring equipment does not have the relation with quantum key distribution, uses a unique protocol implementation process, represents the existing actual loophole of a sending end, can meet the requirement of actual security, and does not need to monitor a transmission channel; meanwhile, the invention further improves the transmission noise immunity of the key, and the key becomes code rate and transmission distance.
The technical scheme is as follows: the invention relates to a double-field quantum key distribution method for safety of an actual signal source, which comprises the following steps:
(1) the method comprises the steps that a first sending end and a second sending end respectively prepare weak coherent light pulses as signal states, respectively carry out coding phase modulation on the prepared signal states, and simultaneously record coding information and basis vector information under the phase modulation; then, the signal states prepared by the first sending end and the second sending end are sent to the intermediate measuring equipment end, meanwhile, the first sending end and the second sending end need to monitor the light intensity and the phase of the signal states sent by the first sending end and the second sending end in real time, and the light intensity and the phase change of the signal states sent each time are recorded;
(2) the intermediate measuring equipment performs interference measurement on signal states from the first sending end and the second sending end, selects the moment when only one of the first detector and the second detector responds as an effective moment, and records the responding detector and the response occurrence moment;
(3) repeating the step (1) and the step (2) for multiple times, after distribution is completed, publishing response detectors and response occurrence time recorded by the effective time of the middle measuring equipment by the middle measuring equipment, and then respectively publishing base vector information of signal states under phase modulation at each response occurrence time by the first sending end and the second sending end; the first sending end and the second sending end form original key strings under respective basis vectors under the condition of taking the same basis vector according to the data published by the intermediate measuring equipment end and the basis vector information published by the intermediate measuring equipment end;
(4) the first sending end and the second sending end estimate the gain and the quantum bit error rate, if the estimated gain and the quantum bit error rate meet the requirement of the code rate, the protocol is continued; otherwise, abandoning the protocol and repeating the steps (1) to (3);
(5) the first sending end and the second sending end carry out error correction and privacy amplification and generate a final security key;
the specific process of performing the encoding phase modulation in the step (1) is as follows:
the phase modulation is selected as
In which the phase is modulated
Defined as the X basis vector, phase modulationSystem for making
Defined as Y basis vector, the first transmitting terminal and the second transmitting terminal respectively have probability
Selecting the X basis vector and the Y basis vector,
(ii) a The first sending end and the second sending end select phase options under the basis vector at equal probability under the selected basis vector to modulate the signal state; simultaneously recording the coding information and the basis vector information of the time by the first sending end and the second sending end;
the basis vector information is: selecting a basis vector and selecting a phase option of modulation under the basis vector;
the coded information is: when the phase modulation is 0 under the X basis vector, the corresponding code information is 0, and the phase modulation is
When the corresponding code is 1; when at the Y basis vector, the phase modulation is
When the corresponding code information is 1, the phase modulation is
The corresponding encoded information is 0;
the specific process of estimating the gain and the quantum bit error rate in the step (4) is as follows:
the first sending end and the second sending end completely publish the coding information and the monitoring information under the Y basis vector, and the bit error rate under the Y basis vector is calculated according to the coding information and the monitoring information under the Y basis vector
Then the first transmitting terminal and the second transmitting terminal publish partial coding information and monitoring under X basis vectorAccording to the coding information and the monitoring information under the X basis vector, the gain under the X basis vector is calculated
Bit error rate with X basis vector
；
At this time, the phase dislocation ratio under the X-base vector
Comprises the following steps:
wherein the content of the first and second substances,
for the physical quantity related to information leakage, the formula is
，
Is the gain at the basis X vector;
is the total actual signal state fidelity under different basis vectors.
Further, the first detector in step (2) responds when detecting that the phase difference of the signal states from the first transmitting terminal and the second transmitting terminal is 0; the second detector is used for detecting the phase difference of the signal states from the first transmitting end and the second transmitting end
Is responded to.
Further, the step (3) further comprises: when the intermediate measurement equipment terminal publishes the response detector recorded at the effective moment as a second detector, the second sending terminal can turn over the coding information under the basis vector at the corresponding moment.
Further, the
The method is the total actual signal state fidelity under different basis vectors, and is calculated according to quantum entanglement states of two sending ends, and the specific process is as follows:
when the transmitting end is in an ideal condition, the ideal signal state transmitted under the X basis vector is
The ideal signal state transmitted under the Y basis vector is
In which
Is the intensity of the light,
is expressed in imaginary units; then, according to the corresponding coding information, an ideal signal state based on quantum entanglement under different basis vectors is constructed under X basis vectors
Under the Y base vector
；
In practical situations, let the first sending end be a, the second sending end be B, and the entangled states under different basis vectors are written as
In which
To characterize different transmitters;
to obtain finally
。
Further, the formula of the coding rate in step (4) is:
wherein the content of the first and second substances,
is Shannon entropy, and the expression is
，
To the efficiency of error correction;
if the code forming rate is greater than 0, continuing the process; and (4) if the encoding rate is less than 0, abandoning the protocol and carrying out the steps (1) to (3) again.
The invention also comprises a double-field quantum key distribution system which is safe to the actual signal source, comprising a first sending end, a second sending end and a middle measuring equipment end, wherein the first sending end and the second sending end respectively comprise a coherent light preparation module, a modulation module and a monitoring module; wherein the coherent light preparation module is used for generating coherent light pulses; the modulation module is used for carrying out coding phase modulation on the coherent light pulse and attenuating the coherent light pulse into weak coherent light pulse; the monitoring module is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the transmitted weak coherent light pulse;
the intermediate measuring equipment end comprises a measuring module, and the measuring module is used for realizing interference measurement on the received weak coherent light pulse and carrying out corresponding response on the result of the interference measurement.
Further, the coherent light preparation module comprises a coherent light source for generating coherent light pulses; the modulation module comprises a phase modulation unit and an optical attenuation unit, wherein the phase modulation unit is used for carrying out coding phase modulation on coherent light pulses, and the optical attenuation unit is used for attenuating the coherent light pulses into weak coherent light pulses; the monitoring module comprises a second beam splitter and a third detector and is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the transmitted weak coherent light pulse;
the measuring module comprises a first beam splitter, a first detector and a second detector, the first beam splitter performs interference measurement of the weak coherent light pulses by interference of the two weak coherent light pulses, and the first detector and the second detector are respectively used for detecting photon detection responses of the two corresponding ports.
The invention has the beneficial effects that:
(1) the safety condition of the actual signal source is met: in the invention, the requirement of idealization on the weak coherent light pulse sent by the sending end is not needed, and the safe bit rate under the monitoring condition can be generated only by monitoring and recording the condition of the sent weak coherent light pulse and substituting the condition into the calculation of the bit rate;
(2) no spoofed state needs to be sent: the method optimizes the used safety analysis, removes the condition of using the decoy state, and simplifies the requirement of experimental equipment of the experimental transmitting end;
(3) noise immunity is improved: the invention estimates the information obtained by the eavesdropper in the generation process of the key, and is irrelevant to any condition of the weak coherent light pulse in the transmission process;
(4) the measuring equipment is irrelevant: the key generation process of the invention is irrelevant to the credibility of the intermediate measurement equipment end, and the safety of the invention can be ensured by setting the intermediate measurement equipment end as an eavesdropper;
(5) improving transmission distance and coding rate: based on the advantages, compared with the original protocol, the method also improves the distance of key transmission, and can obtain higher code rate under the condition of transmitting the quantum key in a long distance;
(6) the invention has simple and practical equipment, and has extremely high adaptability and strong practicability to actual operation.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention;
FIG. 2 is a schematic diagram of an embodiment of the present invention;
FIG. 3 is a graph showing the effect of the simulation result of the present invention.
Detailed Description
The invention is further described below with reference to the following figures and examples:
as shown in fig. 1 to fig. 3, the present invention provides a method for distributing a two-field quantum key that is secure to an actual signal source, including the following steps:
(1) the method comprises the steps that a first sending end and a second sending end respectively prepare weak coherent light pulses as signal states, respectively carry out coding phase modulation on the prepared signal states, and simultaneously record coding information and basis vector information under the phase modulation;
the specific process of performing the encoding phase modulation is as follows: the phase modulation is selected as
In the method there is a choice of basis vectors, where the phase modulation
Defined as the X basis vector, phase modulation
Defined as Y basis vector, the first transmitting terminal and the second transmitting terminal respectively have probability
Selecting the X basis vector and the Y basis vector,
(ii) a The first sending end and the second sending end select phase options under the basis vector at equal probability under the selected basis vector to modulate the signal state; simultaneously recording the coding information and the basis vector information of the time by the first sending end and the second sending end;
the basis vector information is: selecting a basis vector and selecting a phase option for modulation under the basis vector;
the coded information is: when in useUnder the X basis vector, when the phase modulation is 0, the corresponding coding information is 0, and the phase modulation is
When the corresponding code is 1; when at the Y basis vector, the phase modulation is
When the corresponding code information is 1, the phase modulation is
The corresponding encoded information is 0;
then, the signal states prepared by the first sending end and the second sending end are sent to the intermediate measuring equipment end, meanwhile, the first sending end and the second sending end need to monitor the light intensity and the phase of the signal states sent by the first sending end and the second sending end in real time, and the light intensity and the phase change of the signal states sent each time are recorded;
for the signal states prepared by the two sending ends, the invention allows the deviation of the light intensity and the phase generated in the preparation process, can ensure the safety of the signal states even if a certain deviation exists, and the two sending ends need to monitor the light intensity and the phase of the signal states.
(2) The intermediate measuring equipment performs interference measurement on signal states from the first sending end and the second sending end, selects the moment when only one of the first detector and the second detector responds as an effective moment, and records the responding detector and the response occurrence moment;
the first detector responds when detecting that the phase difference of the signal states from the first transmitting end and the second transmitting end is 0; the second detector is used for detecting the phase difference of the signal states from the first transmitting end and the second transmitting end
Is responded to.
Therefore, the intermediate measuring equipment terminal interferes the signal states of the two transmitting terminals to measure whether the phase difference of the signal states from the two transmitting terminals received at a certain time is 0 or not
Respectively, corresponding to the response of different detectors. And taking the moment when only one detector responds as the effective moment by the intermediate measuring equipment, and recording the responding detector and the response occurrence moment. The method is irrelevant to the measuring equipment, namely the middle measuring equipment end is not required to be set as a credible party except for the sending end, or the middle measuring equipment end can be considered as an eavesdropper.
(3) Repeating the step (1) and the step (2) for multiple times, after distribution is completed, publishing response detectors and response occurrence time recorded by the effective time of the middle measuring equipment by the middle measuring equipment, and then respectively publishing base vector information of signal states under phase modulation at each response occurrence time by the first sending end and the second sending end; the first sending end and the second sending end form an original key string under the basis vector under the condition of taking the same basis vector according to the data published by the intermediate measuring equipment end and the basis vector information published by the first sending end and the second sending end respectively, namely form respective original key strings under an X basis vector and a Y basis vector; when the intermediate measuring equipment terminal publishes the response detector recorded at the effective moment as a second detector, the second sending terminal can turn over the coding information under the corresponding moment basis vector.
(4) The first sending end and the second sending end carry out estimation of gain and quantum bit error rate, and the specific process is as follows:
the first sending end and the second sending end completely publish coding information and monitoring information under the Y-base vector, the monitoring information refers to the fact that signal state light intensity and phase sent by the first sending end and the second sending end are monitored in real time in the step (1), data of signal state light intensity and phase change sent each time are recorded, and the bit error rate under the Y-base vector is calculated according to the coding information and the monitoring information under the Y-base vector
Then the first transmitting end and the second transmitting end publish partial coding information and monitoring information under X basis vector, and gain under X basis vector is calculated according to the coding information and the monitoring information under X basis vector
Bit error rate with X basis vector
；
At the same time
Can be used to estimate the information on the original key available to an eavesdropper, which has a bit rate lower than the X-base vector
To characterize, the phase dislocation rate under X-base vector
The formula is as follows:
wherein the content of the first and second substances,
for the physical quantity related to information leakage, the formula is
，
Is the gain at the basis X vector;
the total actual signal state fidelity under different basis vectors;
when the transmitting end is in an ideal condition, the ideal signal state transmitted under the X basis vector is
The ideal signal state transmitted under the Y basis vector is
Wherein
Is the intensity of the light,
is expressed in imaginary units; then, according to the corresponding coding information, an ideal signal state based on quantum entanglement under different basis vectors is constructed under X basis vectors
Under the Y base vector
；
In practical cases, for the convenience of expression of theoretical formulas, we do not assume a symmetric situation, that is, the deviation of the light intensity phase modulation of two transmitting ends for different signal states is the same, and we assume that the four signal states are actually the same
(ii) a When considering the side channel effect, taking the side channel effect of the polarization space as an example, the four signal states can be written as
In the experiment we only takeThe condition of H polarization is used as a signal state of the code, a polarization-maintaining optical fiber can be used for limiting a polarized side channel in specific operation, and the polarization-maintaining degree of the polarization-maintaining optical fiber can be obtained by calibrating the polarization-maintaining degree of the polarization-maintaining optical fiber in advance
A value of (d); the invention emphasizes that other side signal conditions can be used for modeling the transmitted signal state according to the method and calculating the final code rate formula; meanwhile, the invention can also characterize the signal state association of the actual phase modulation of the transmitting terminal equipment, specifically, the state association can be used as a side channel to model according to the result of the literature (Science Advances, 6, 37, eaaz 4487), and the state association parameter is set as
Signal state
Can be written as
Wherein
Characterization and
orthogonal signal states, which we do not need to describe in detail, while we consider the worst case, which is orthogonal to all but itself; the remaining signal states are written to generate new signal states.
After that, let the first sending end be A, the second sending end be B, and the entanglement statuses under different basis vectors are written as
In which
To characterize different transmitters;
carry-in calculation to finally obtain
。
If the estimated gain and the quantum bit error rate meet the requirement of the code rate, continuing the protocol; otherwise, abandoning the protocol and repeating the steps (1) to (3);
the formula of the code rate is as follows:
wherein the content of the first and second substances,
is Shannon entropy, and the expression is
，
To the efficiency of error correction;
if the code forming rate is greater than 0, continuing the process; and (4) if the encoding rate is less than 0, abandoning the protocol and carrying out the steps (1) to (3) again.
According to the formula, it can be found that the signal state sent by the sending end under actual monitoring can also be brought into the estimation of the security code rate, but the estimation is irrelevant to the situation of the signal state in the transmission process.
(5) And the first sending end and the second sending end carry out error correction and privacy amplification and generate a final security key.
In order to simplify the calculation process, under the condition that an ideal signal state is considered to be symmetrical to two transmitting ends, the safe code rate of the invention is simulated, and the code rates under the condition of the same parameters as those of the reference 1Phys. Rev. Applied 15, 034072 and the reference 2Phys. Rev. Applied 12, 054034 are shown in FIG. 3, wherein the adopted parameters are as follows:
As can be seen from fig. 3, the present invention is advantageous in terms of the coding rate.
As shown in fig. 1, the present invention further includes a dual-field quantum key distribution system that is secure to an actual signal source, including a first transmitting end, a second transmitting end, and an intermediate measuring device end, where the first transmitting end and the second transmitting end both include a coherent light preparation module, a modulation module, and a monitoring module; wherein the coherent light preparation module is used for generating coherent light pulses; the modulation module is used for carrying out coding phase modulation on the coherent light pulse and attenuating the coherent light pulse into weak coherent light pulse; the monitoring module is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the transmitted weak coherent light pulse;
the intermediate measuring equipment end comprises a measuring module, and the measuring module is used for realizing interference measurement on the received weak coherent light pulse and carrying out corresponding response on the result of the interference measurement.
As shown in fig. 2, the present invention further includes a dual-field quantum key distribution system that is safe for an actual signal source, including a first transmitting end, a second transmitting end and a middle measuring device end, where the first transmitting end and the second transmitting end both include a coherent light preparation module, a modulation module and a monitoring module; the coherent light preparation module comprises a coherent light source, and the coherent light source is used for generating coherent light pulses; the modulation module comprises a phase modulation unit and an optical attenuation unit, wherein the phase modulation unit is used for carrying out coding phase modulation on coherent light pulses, and the optical attenuation unit is used for attenuating the coherent light pulses into weak coherent light pulses; the monitoring module comprises a second beam splitter and a third detector and is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the transmitted weak coherent light pulse;
the intermediate measurement equipment end comprises a measurement module, the measurement module comprises a first beam splitter, a first detector and a second detector, the first beam splitter is used for carrying out interference measurement on weak coherent light pulses by interference of the two weak coherent light pulses, and the first detector and the second detector are respectively used for detecting photon detection responses corresponding to the two ports.
In summary, the technical solution of the present invention requires strict requirements on the signal state sent by the sending end, and can ensure the security of the code formation while maintaining the monitoring, and meanwhile, the present invention removes the condition that the decoy state needs to be used, and simplifies the requirements of the experimental equipment of the experimental sending end. In addition, the key generation process of the invention has no relation between the estimation of the information acquired by the eavesdropper and any situation of the signal state in the transmission process, removes the requirement of channel monitoring and greatly improves the noise immunity of the system. In addition, the key generation process of the invention is irrelevant to the credibility of the middle measuring equipment end, and the measuring equipment end, namely an eavesdropper, can be set to possibly ensure the safety of the scheme. Based on the advantages, the invention improves the distance of key transmission and can obtain higher code rate under the condition of transmitting the quantum key at a long distance. Simultaneously, based on above-mentioned advantage, this scheme has high suitability and stronger practicality to actual operation.
Claims (5)
1. A double-field quantum key distribution method for safety of an actual signal source is characterized by comprising the following steps:
(1) the method comprises the steps that a first sending end and a second sending end respectively prepare weak coherent light pulses as signal states, respectively carry out coding phase modulation on the prepared signal states, and simultaneously record coding information and basis vector information under the phase modulation; then, the signal states prepared by the first sending end and the second sending end are sent to the intermediate measuring equipment end, meanwhile, the first sending end and the second sending end need to monitor the light intensity and the phase of the signal states sent by the first sending end and the second sending end in real time, and the light intensity and the phase change of the signal states sent each time are recorded;
(2) the intermediate measuring equipment performs interference measurement on signal states from the first sending end and the second sending end, selects the moment when only one of the first detector and the second detector responds as an effective moment, and records the responding detector and the response occurrence moment;
(3) repeating the step (1) and the step (2) for multiple times, after distribution is completed, publishing response detectors and response occurrence time recorded by the effective time of the middle measuring equipment by the middle measuring equipment, and then respectively publishing base vector information of signal states under phase modulation at each response occurrence time by the first sending end and the second sending end; the first sending end and the second sending end form original key strings under respective basis vectors under the condition of taking the same basis vector according to the data published by the intermediate measuring equipment end and the basis vector information published by the intermediate measuring equipment end;
(4) the first sending end and the second sending end estimate the gain and the quantum bit error rate, if the estimated gain and the quantum bit error rate meet the requirement of the code rate, the protocol is continued; otherwise, abandoning the protocol and repeating the steps (1) to (3);
(5) the first sending end and the second sending end carry out error correction and privacy amplification and generate a final security key;
the specific process of performing the encoding phase modulation in the step (1) is as follows:
the phase modulation is selected as
In which the phase is modulated
Defined as X basis vector, phase modulation
Defined as Y basis vector, the first transmitting terminal and the second transmitting terminal respectively have probability
Selecting the X basis vector and the Y basis vector,
(ii) a The first sending end and the second sending end select phase options under the basis vector at equal probability under the selected basis vector to modulate the signal state; simultaneously recording the coding information and the basis vector information of the time by the first sending end and the second sending end;
the basis vector information is: selecting a basis vector and selecting a phase option for modulation under the basis vector;
the coded information is: when the phase modulation is 0 under the X basis vector, the corresponding code information is 0, and the phase modulation is
When the corresponding code is 1; when at the Y basis vector, the phase is modulated as
When the corresponding code information is 1, the phase modulation is
The corresponding encoding information is 0;
the specific process of estimating the gain and the quantum bit error rate in the step (4) is as follows:
the first sending end and the second sending end completely publish the coding information and the monitoring information under the Y basis vector, and the bit error rate under the Y basis vector is calculated according to the coding information and the monitoring information under the Y basis vector
Then the first transmitting end and the second transmitting end publish partial coding information and monitoring information under X basis vector, and gain under X basis vector is calculated according to the coding information and the monitoring information under X basis vector
Bit error rate with X basis vector
；
At this time, the phase dislocation ratio under the X basis vector
Comprises the following steps:
wherein the content of the first and second substances,
for the physical quantity related to information leakage, the formula is
，
Is the gain at the basis X vector;
the total actual signal state fidelity under different basis vectors;
the above-mentioned
The method is the total actual signal state fidelity under different basis vectors, and is calculated according to quantum entanglement states of two sending ends, and the specific process is as follows:
when the transmitting end is in an ideal condition, the ideal signal state transmitted under the X basis vector is
The ideal signal state transmitted under the Y basis vector is
Wherein
Is the intensity of the light,
is expressed in imaginary units; then, according to the corresponding coding information, an ideal signal state based on quantum entanglement under different basis vectors is constructed under X basis vectors
Under the Y base vector
；
In practical situation, let the first sending end be A, the second sending end be B, and the entanglement statuses under different basis vectors are written as
Wherein
To characterize different transmitters;
to obtain finally
；
The formula of the code rate in the step (4) is as follows:
wherein the content of the first and second substances,
is Shannon entropy, and the expression is
，
To the efficiency of error correction;
if the code forming rate is greater than 0, continuing the process; and (4) if the encoding rate is less than 0, abandoning the protocol and carrying out the steps (1) to (3) again.
2. The method of claim 1, wherein the method comprises the following steps: the first detector in the step (2) responds when detecting that the phase difference of the signal states from the first transmitting end and the second transmitting end is 0; the second detector is used for detecting the phase difference of the signal states from the first transmitting end and the second transmitting end
Is responded to.
3. The method of claim 2, wherein the method comprises: the step (3) further comprises: when the intermediate measuring equipment terminal publishes the response detector recorded at the effective moment as a second detector, the second sending terminal can turn over the coding information under the corresponding moment basis vector.
4. A system of the two-field quantum key distribution method for securing to actual signal source according to any of claims 1 to 3, comprising a first transmitting end, a second transmitting end and an intermediate measuring device end, characterized in that: the first sending end and the second sending end both comprise a coherent light preparation module, a modulation module and a monitoring module; wherein the coherent light preparation module is used for generating coherent light pulses; the modulation module is used for carrying out coding phase modulation on the coherent light pulse and attenuating the coherent light pulse into weak coherent light pulse; the monitoring module is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the transmitted weak coherent light pulse;
the intermediate measuring equipment end comprises a measuring module, and the measuring module is used for realizing interference measurement on the received weak coherent light pulse and carrying out corresponding response on the result of the interference measurement.
5. The system of the method for two-field quantum key distribution secured to actual signal sources of claim 4, wherein: the coherent light preparation module comprises a coherent light source, and the coherent light source is used for generating coherent light pulses; the modulation module comprises a phase modulation unit and an optical attenuation unit, wherein the phase modulation unit is used for carrying out coding phase modulation on coherent light pulses, and the optical attenuation unit is used for attenuating the coherent light pulses into weak coherent light pulses; the monitoring module comprises a second beam splitter and a third detector and is used for monitoring the light intensity and the phase of the weak coherent light pulse in real time and recording the light intensity and the phase change of the sent weak coherent light pulse;
the measuring module comprises a first beam splitter, a first detector and a second detector, the first beam splitter performs interference measurement of the weak coherent light pulses by interference of the two weak coherent light pulses, and the first detector and the second detector are respectively used for detecting photon detection responses of the two corresponding ports.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210217737.3A CN114338018B (en) | 2022-03-08 | 2022-03-08 | Double-field quantum key distribution method and system for safety of actual signal source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210217737.3A CN114338018B (en) | 2022-03-08 | 2022-03-08 | Double-field quantum key distribution method and system for safety of actual signal source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114338018A CN114338018A (en) | 2022-04-12 |
| CN114338018B true CN114338018B (en) | 2022-07-12 |
Family
ID=81031524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210217737.3A Active CN114338018B (en) | 2022-03-08 | 2022-03-08 | Double-field quantum key distribution method and system for safety of actual signal source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114338018B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115276988B (en) * | 2022-09-27 | 2022-12-09 | 南京大学 | Four-strength measuring equipment independent key distribution method |
| CN115549908B (en) * | 2022-11-28 | 2023-03-14 | 南京大学 | Quantum secret sharing method and system based on phase coding |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112929161A (en) * | 2021-01-22 | 2021-06-08 | 西安电子科技大学 | Plug-and-play type reference system-independent double-field quantum key distribution protocol implementation method |
| CN113259104A (en) * | 2021-06-21 | 2021-08-13 | 南京大学 | High-noise-resistance four-state modulation homodyne measurement quantum key distribution method and system |
| CN113300762A (en) * | 2021-05-26 | 2021-08-24 | 南京邮电大学 | Passive light source monitoring method suitable for double-field protocol |
| CN113438076A (en) * | 2021-07-08 | 2021-09-24 | 南京大学 | Side-channel-free quantum key distribution method and system |
| CN114124379A (en) * | 2021-11-30 | 2022-03-01 | 南京大学 | Double-field quantum key distribution method based on single photon pair |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2021010429A1 (en) * | 2019-07-15 | 2021-01-21 | ||
| US20220014362A1 (en) * | 2020-07-13 | 2022-01-13 | The University Of Arizona, Tech Launch Arizona | Joint twin-field quantum key distribution cryptosystem |
| CN112702164B (en) * | 2020-12-29 | 2024-04-26 | 广东尤科泊得科技发展有限公司 | Multi-user double-field QKD network system and method based on orbital angular momentum |
-
2022
- 2022-03-08 CN CN202210217737.3A patent/CN114338018B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112929161A (en) * | 2021-01-22 | 2021-06-08 | 西安电子科技大学 | Plug-and-play type reference system-independent double-field quantum key distribution protocol implementation method |
| CN113300762A (en) * | 2021-05-26 | 2021-08-24 | 南京邮电大学 | Passive light source monitoring method suitable for double-field protocol |
| CN113259104A (en) * | 2021-06-21 | 2021-08-13 | 南京大学 | High-noise-resistance four-state modulation homodyne measurement quantum key distribution method and system |
| CN113438076A (en) * | 2021-07-08 | 2021-09-24 | 南京大学 | Side-channel-free quantum key distribution method and system |
| CN114124379A (en) * | 2021-11-30 | 2022-03-01 | 南京大学 | Double-field quantum key distribution method based on single photon pair |
Non-Patent Citations (4)
| Title |
|---|
| "Detector-decoy quantum key distribution without monitoring signal disturbance";Hua-Lei Yin et al.;《PHYSICAL REVIEW A》;American Physical Society;20160223;全文 * |
| "Homodyne Detection Quadrature Phase Shift Keying Continuous-Variable Quantum key Distribution with High Excess Noise Tolerance";Wen-Bo Liu et al.;《PRX Quantum 2》;American Physical Society;20211112;全文 * |
| "新型量子密钥分发协议的安全性分析";王荣;《中国优秀博硕士学位论文全文数据库(博士)基础科学辑》;20210915;全文 * |
| "超过404km的测量设备无关量子密钥分发实验";尹华磊 等;《信息安全研究》;20170131;第3卷(第1期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114338018A (en) | 2022-04-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112929161B (en) | Plug-and-play type reference system-independent double-field quantum key distribution protocol implementation method | |
| CN114338018B (en) | Double-field quantum key distribution method and system for safety of actual signal source | |
| US8082443B2 (en) | Pedigrees for quantum cryptography | |
| US9294272B2 (en) | System and method for quantum key distribution | |
| CN108650088B (en) | Quantum communication device and method comprising at least three parties | |
| CN108365953A (en) | Adaptive differential phase shift quantum key dissemination system based on deep neural network and its implementation | |
| CN113141252B (en) | Quantum key distribution method, quantum communication method, device and system | |
| CN112511303B (en) | Quantum secret sharing method and system without monitoring channel | |
| Fung et al. | Security proof of a three-state quantum-key-distribution protocol without rotational symmetry | |
| Lydersen et al. | Security of quantum key distribution with bit and basis dependent detector flaws | |
| JP2022126611A (en) | Long-distance quantum key distribution | |
| CN113438076B (en) | Side-channel-free quantum key distribution method and system | |
| Acín et al. | Secrecy properties of quantum channels | |
| CN115276988B (en) | Four-strength measuring equipment independent key distribution method | |
| Zhou et al. | Twin-field quantum key distribution with partial phase postselection | |
| Salas | Security of plug-and-play QKD arrangements with finite resources | |
| Zhou et al. | Twin-field quantum key distribution with three mutually unbiased bases | |
| CN115361118A (en) | Loss tolerant reference frame and measuring device independent quantum key distribution method | |
| Anghel | New eavesdropper detection method in quantum cryptography | |
| Anghel | Research, development and simulation of quantum cryptographic protocols | |
| Rebola et al. | Moment generating function for the rigorous performance assessment of direct-detection baseband OFDM communication systems | |
| CN115102819B (en) | Orthogonal time-frequency space safety transmission method, device and equipment based on unitary matrix transformation | |
| Ma | Security of quantum key distribution with realistic devices | |
| CN115549908B (en) | Quantum secret sharing method and system based on phase coding | |
| CN115378480B (en) | Precoding design method for constraint of discrete symbol input on safe interruption probability |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |