CN206117683U - Quantum key distribution system - Google Patents
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Abstract
The utility model provides a quantum key distribution system, include: dispensing device and receiving arrangement, dispensing device sends three kinds of quantum states of making an appointment and the measurement of each quantum state of sending base information to receiving arrangement at random, parameter estimation is carried out to each quantum state and the basic information of received measurement according to sending, obtains the bit error rate, be not more than when presetting the threshold value when the bit error rate, carry out the error correction and carry out the privacy and amplify, obtain the key, receiving arrangement uses a set of base of measuring in two sets of measurement bases to measure the quantum state of receiving at random, obtains measuring result, give receiving arrangement with the measurement base message routing who uses to measure basic information according to measuring result and received and carry out parameter estimation, obtain the bit error rate, be not more than when presetting the threshold value when the bit error rate, carry out the error correction and carry out the privacy and amplify, obtain the key. Use the utility model discloses can only need to use three kinds of quantum states can carry out safe quantum key distribution, reduce equipment cost, improve the key rate.
Description
Technical field
The utility model is related to quantum information technology field, more particularly to a kind of quantum key distribution system.
Background technology
With flourishing for Internet technology, the importance of communication security grows with each passing day.Under numerous occasions, communication is double
Fang Xiwang carries out secure communication in the case of using common signal channel.For example, when user submits account and password to Web bank
When, user wishes that these information are secrecy in transmittance process, i.e., any third party cannot eavesdrop.Currently extensively make
Encryption method is public key encryption algorithm.Algorithm complex of such algorithm based on some mathematical problems, with sending out for science and technology
Exhibition, their security is on the hazard.Therefore, we need the more safe and reliable encryption method of exploitation badly.
It, based on the brand-new cipher key distribution scheme of quantum mechanics characteristic, is quantum information technology that quantum key distribution technology is
In most have one of technology of application prospect.The technology borrow common signal channel cause to be shared between communication two party safety with secret
Key.With reference to the encryption method of one-time pad, shared random key can be used to be encrypted the information in communication, so as to protect
Card communication security.The security of quantum key distribution is based on basic physics theory, therefore is Information theoretical secure.
At present, some commercial quantum key distribution systems are had been provided in prior art, these system major part bases
In BB84 agreements.System is divided into dispensing device and reception device.In BB84 agreements, the quantum signal source for transmitting key is
Single photon, the key information of transmission needed for it is coding in the polarization state (or polarised direction) of single photon.Dispensing device will
Information is encoded in four kinds of different quantum states | and 0>、|1>、|+>、|->On.On hardware view, above-mentioned four kinds of quantum states can be by
The different frees degree of photon are encoding realization.For example, when using polarization encoder, can select in the horizontal direction, vertical direction,
The single photon of the linear polarization in 45 ° and 135 ° directions as quantum information carrier, in the polarization shape in above-mentioned four kinds of directions
The single photon of state can be used respectively | and 0>、|1>、|+>、|->Represent Deng four quantum states；In the same manner, when using phase code,
Four kinds of quantum states can be represented with four phase values between two coherent wave bags of photon | 0>、|1>、|+>、|->.
Wherein, in four kinds of above-mentioned quantum states, | 0>With | 1>It is mutually orthogonal, therefore one group of measurement base can be constituted, referred to as
For straight measurement base (abbreviation Z bases, similarly hereinafter), | 0>State and | 1>State is two eigenstates of Z bases；|+>With |->Also it is mutually orthogonal, because
This can constitute another group of measurement base, referred to as oblique measurement base (abbreviation X bases, similarly hereinafter), |+>State and |->State is two of X bases intrinsic
State.
Relation between four kinds of above-mentioned quantum states is as follows：
In order to transmit classical information, BB84 agreements prepare a photon on four above-mentioned quantum states, and arrange every
Coding information representated by individual quantum state.For example, in BB84 agreements, by the polarization of light, so as to encode to photon, with
Equiprobability random coded is on Z bases and X bases.Sender randomly generates a string number strings being made up of 0,1 bit, when selection is in Z bases
Under when being encoded, sender is encoded into 0 | 0>, 1 is encoded into | 1>；And when selecting to be encoded under X bases, sender
0 is encoded into |+>, 1 is encoded into |->.Then, above-mentioned quantum state is sent to recipient by sender by quantum channel,
The quantum state that recipient is sent using X bases or the measurement of Z bases with equiprobability from sender；Then, sender and recipient are being reflected
The selected measurement base for using when each leisure is encoded or measured is announced in fixed classical channel, is selected so as to filter out both sides
Coded data when identical measurement base is encoded or measured, as the key information for being transmitted.
Therefore, when above-mentioned BB84 agreements are performed, dispensing device needs to launch above-mentioned four kinds of quantum states at random.For
This, hardware realizes typically there are two methods：One kind be using a laser instrument, and the light that it is emitted carry out (polarization,
The frees degree such as phase place) fast modulation；Another kind is to use four laser instruments (as shown in Figure 1), and every laser instrument is fixed and sends one
Quantum state is planted, the recovery of four tunnels is used on one channel with unification photoswitch.
One important performance characteristic of practical key distribution system is the emission rate of dispensing device.In general, launch
Speed is higher, and the final key rate of system is higher.However, quantum key distribution system of the prior art needs random four kinds of transmission
Quantum state.As previously shown, if dispensing device using a laser instrument scheme, system required the modulation rate of modulating part
It is higher；If using the scheme of multi-station laser, system is higher to the rate requirement of number of lasers and photoswitch.Therefore can
Know, in above two method of the prior art, due to having used four kinds of quantum states, therefore transmitting terminal relatively costly, system
Final key rate is relatively low.
Utility model content
In view of this, the utility model provides a kind of quantum key distribution system, so as to need to only use three kinds of quantum states
Safe quantum key distribution can be carried out, reduce equipment cost, improve key rate.
What the technical solution of the utility model was specifically realized in：
A kind of quantum key distribution system, the system includes：Dispensing device and reception device；
The dispensing device and reception device are connected by transmission channel；
The dispensing device, for sending make an appointment three kinds of quantum states at random to reception device；It is additionally operable to send out
Each quantum state preparation base information sent is sent to reception device；It is additionally operable to according to each quantum state for being sent and receives
Measurement base information carry out parameter Estimation, obtain the bit error rate；When the bit error rate is not more than predetermined threshold value, carries out error correction and carry out hidden
Private is amplified, and obtains key；
Wherein, the three kinds of quantum states made an appointment are any in four kinds of quantum states for be subordinated to two groups of different measuring bases
The three kinds of quantum states for selecting, and selected three kinds of quantum states are encoded in advance, and in selected three kinds of quantum states,
It is using the coding corresponding to two quantum states for belonging to same group of measurement base as primary key information, another quantum state institute is right
The coding answered is used as parameter Estimation information；
The reception device, for being carried out to the quantum state for being received using one group of measurement base in two groups of measurement bases at random
Measurement, obtains measurement result；The measurement base information for being additionally operable to be used the quantum state to being received is sent to reception device, and
Parameter Estimation is carried out according to measurement result and the measurement base information for receiving, the bit error rate is obtained；When the no more than default threshold of the bit error rate
During value, carry out error correction and carry out privacy amplification, obtain key.
Preferably, the dispensing device includes：First controller, laser instrument and modulator；
The reception device includes：Single photon detection unit and second controller；
The signal output part of first controller is connected with laser instrument；The output end of the laser instrument connects with modulator
Connect；The output end of the modulator is connected by transmission channel with single photon detection unit；The single photon detection unit it is defeated
Go out end to be connected with second controller；The synchronizing signal end of first controller is connected with the synchronizing signal end of second controller；
First controller controls laser instrument output single photon by sending control signal；It is additionally operable to send out modulator
Each quantum state preparation base information sent is sent to second controller；It is additionally operable to each quantum state sent according to modulator
Parameter Estimation is carried out with the measurement base information for receiving, the bit error rate is obtained；When the bit error rate is not more than predetermined threshold value, error correction is carried out
And privacy amplification is carried out, obtain key；
The laser instrument is used to export single photon to the modulator according to control signal；
The modulator is used for the single photon Stochastic Modulation for receiving into the three kinds of quantum states made an appointment, and will modulation
Quantum state afterwards gives single photon detection unit by transmission channel, and while the quantum state for being sent is sent to into the first control
Device processed；
The single photon detection unit is entered at random using one group of measurement base in two groups of measurement bases to the quantum state for being received
Row measurement, obtains measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to into the
Two controllers；
The second controller, for the measurement base used the quantum state for being received information to be sent to into the first control
Device, is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, and obtains the bit error rate；When the bit error rate it is little
When predetermined threshold value, carry out error correction and carry out privacy amplification, obtain key.
Preferably, the dispensing device includes：First controller, first laser device, second laser, the 3rd laser instrument and
Modulator；
The reception device includes：Single photon detection unit and second controller；
The signal output part of first controller connects respectively with first laser device, second laser and the 3rd laser instrument
Connect；The output end of the first laser device, second laser and the 3rd laser instrument is connected with modulator；The modulator it is defeated
Go out end to be connected with single photon detection unit by transmission channel；The output end of the single photon detection unit connects with second controller
Connect；The synchronizing signal end of first controller is connected with the synchronizing signal end of second controller；
First controller is defeated by sending control signal control first laser device, second laser or the 3rd laser instrument
Go out there is the single photon for determining quantum state；Each quantum state preparation base information for being additionally operable to be sent modulator is sent to
Two controllers；The measurement base information for being additionally operable to each quantum state sent according to modulator and receiving carries out parameter Estimation,
Obtain the bit error rate；When the bit error rate is not more than predetermined threshold value, carries out error correction and carry out privacy amplification, obtain key；
The first laser device, second laser and the 3rd laser instrument are exported respectively according to control signal to the modulator
Single photon with the first quantum state, the second quantum state and the 3rd quantum state for determining；Wherein, first quantum state, second
Quantum state and the 3rd quantum state are the three kinds of quantum states made an appointment；
The modulator is used to randomly choose a kind of quantum state from three kinds of received quantum states, and will be selected
Quantum state gives single photon detection unit by transmission channel, and while the quantum state for being sent is sent to into the first control
Device；
The single photon detection unit is entered at random using one group of measurement base in two groups of measurement bases to the quantum state for being received
Row measurement, obtains measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to into the
Two controllers；
The second controller, for the measurement base used the quantum state for being received information to be sent to into the first control
Device, is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, and obtains the bit error rate；When the bit error rate it is little
When predetermined threshold value, carry out error correction and carry out privacy amplification, obtain key.
Preferably, the modulator is photoswitch.
Preferably, the modulator is electrooptic modulator EOM.
Preferably, the transmission channel is optical fiber or free space.
As seen from the above technical solution, in quantum key distribution system of the present utility model, because dispensing device is only needed
Using three kinds of quantum states without using four kinds of quantum states key can be transmitted to reception device, the distribution of quantum key is completed,
Therefore, compared with prior art, the technical solution of the utility model only need to can ensure security using less quantum state
On the premise of carry out safe quantum key distribution, such that it is able to be effectively reduced equipment cost, improve key rate.
Description of the drawings
Fig. 1 is the structural representation of quantum key distribution system of the prior art.
Fig. 2 is the overall structure diagram of the quantum key distribution system in the utility model embodiment.
Fig. 3 is the structural representation of the quantum key distribution system in specific embodiment of the utility model one.
Fig. 4 is the structural representation of the quantum key distribution system in specific embodiment of the utility model two.
Specific embodiment
To make the technical solution of the utility model and advantage become more apparent, below in conjunction with drawings and the specific embodiments,
The utility model is described in further detail.
Fig. 2 is the structural representation of the quantum key distribution system in the utility model embodiment.As shown in Fig. 2 this reality
Included with the quantum key distribution system in new embodiment：Dispensing device 31 and reception device 32；
The dispensing device 31 and reception device 32 are connected by transmission channel 33；
The dispensing device 31, for sending three kinds of quantum states at random to reception device 32；It is additionally operable to each by what is sent
Individual quantum state preparation base information is sent to reception device 32；It is additionally operable to according to each quantum state for being sent and the survey for receiving
Amount base information carries out parameter Estimation, obtains the bit error rate；When the bit error rate is not more than predetermined threshold value, error correction is carried out and carries out privacy to put
Greatly, key is obtained；
Wherein, three kinds of quantum states are optional three kinds in four kinds of quantum states for be subordinated to two groups of different measuring bases
Quantum state, and in advance selected three kinds of quantum states are encoded, and in selected three kinds of quantum states, will belong to same
Coding corresponding to two quantum states of group measurement base makees the coding corresponding to another quantum state as primary key information
For parameter Estimation information；
The reception device 32, for being entered to the quantum state for being received using one group of measurement base in two groups of measurement bases at random
Row measurement, obtains measurement result；The measurement base information for being additionally operable to be used the quantum state to being received is sent to reception device
31, and parameter Estimation is carried out according to measurement result and the measurement base information for receiving, obtain the bit error rate；When the bit error rate is not more than in advance
If during threshold value, carrying out error correction and carrying out privacy amplification, key is obtained.
By above-mentioned quantum key distribution system, dispensing device 31 can be passed using three kinds of quantum states to reception device 32
Defeated key, completes the distribution of quantum key.
Preferably, in specific embodiment of the utility model, the transmission channel 33 is optical fiber or free space.
Preferably, in specific embodiment of the utility model, when two groups of different measuring bases are selected, described two groups different
Measurement base can be above-mentioned straight measurement base (Z yls) and oblique measurement base (X yls).Then, can be from above-mentioned Z bases and four kinds of amounts of X bases
Sub- state | 0>、|1>、|+>、|->In, arbitrarily select three kinds of quantum states.
For example, preferably, in specific embodiment of the utility model, selected three kinds of quantum states can be | 0>、|1
>、|+>, or：|0>、|1>、|->, or：|+>、|->、|0>；Can also be：|+>、|->、|1>.
After it have selected three kinds of quantum states, you can selected three kinds of quantum states are encoded.
For example, preferably, in specific embodiment of the utility model, when selected three kinds of quantum states are：|0>、|1
>、|+>When, 0 can be encoded into | 0>, 1 is encoded into | 1>.
In addition, in the technical solution of the utility model, two quantum belonging to same group of measurement base of also making an appointment
Coding corresponding to state as primary key information, and using the coding corresponding to another quantum state as parameter Estimation information.
For example, preferably, in specific embodiment of the utility model, when selected three kinds of quantum states are：|0>、|1
>、|+>When, can be by quantum state | 0>、|1>Corresponding coding as primary key information, and by quantum state |+>Corresponding
Coding is used as parameter Estimation information.
Below all it is to be with selected three kinds of quantum states：|0>、|1>、|+>As a example by and the description that carries out.When selected
When three kinds of quantum states are other selection modes, by that analogy, therefore can repeat no more.
In addition, in the technical solution of the utility model, can there are ways to realize above-mentioned dispensing device.Below
The technical solution of the utility model will be introduced by taking two kinds of specific implementations therein as an example.
A laser instrument is only provided with specific embodiment one, dispensing device.
For example, preferably, in specific embodiment of the utility model, Fig. 3 is specific embodiment of the utility model one
In quantum key distribution system structural representation, as shown in figure 3, the dispensing device 31 includes：First controller 311,
Laser instrument 312 and modulator 313；The reception device 32 includes：Single photon detection unit 321 and second controller 322；
The signal output part of first controller 311 is connected with laser instrument 312；The output end of the laser instrument 312 with
Modulator 313 connects；The output end of the modulator 313 is connected by transmission channel 33 with single photon detection unit 321；It is described
The output end of single photon detection unit 321 is connected with second controller 322；The synchronizing signal end of first controller 311 with
The synchronizing signal end connection of second controller 322；
First controller 311 controls the output single photon of laser instrument 312 by sending control signal；It is additionally operable to modulate
Each quantum state preparation base information that device 313 is sent is sent to second controller 322；It is additionally operable to according to the institute of modulator 313
Each quantum state for sending and the measurement base information for receiving carry out parameter Estimation, obtain the bit error rate；When the bit error rate is not more than in advance
If during threshold value, carrying out error correction and carrying out privacy amplification, key is obtained；
The laser instrument 312 is used to export single photon to the modulator 313 according to control signal；
The modulator 313 is used for the single photon Stochastic Modulation for receiving into the three kinds of quantum states made an appointment, and will
Quantum state after modulation is transferred to single photon detection unit 321 by transmission channel 33, and while the quantum state for being sent is sent out
The first controller 311 is given, so that the first controller 311 can know each quantum state and each quantum state for being sent
The measurement base for being used；
Wherein, the three kinds of quantum states made an appointment are any in four kinds of quantum states for be subordinated to two groups of different measuring bases
The three kinds of quantum states for selecting, and selected three kinds of quantum states are encoded in advance, and in selected three kinds of quantum states,
It is using the coding corresponding to two quantum states for belonging to same group of measurement base as primary key information, another quantum state institute is right
The coding answered is used as parameter Estimation information；
The single photon detection unit 321 it is random using one group of measurement base in two groups of measurement bases to the quantum state that received
Measure, obtain measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to
Second controller 322；
The second controller 322, for the measurement base used the quantum state for being received information to be sent to into first
Controller 311, is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, and obtains the bit error rate；When by mistake
When code check is not more than predetermined threshold value, carries out error correction and carry out privacy amplification, obtain key.
By above-mentioned quantum key distribution system, dispensing device can be transmitted close using three kinds of quantum states to reception device
Key, completes the distribution of quantum key.
Three laser instruments are provided with specific embodiment two, dispensing device.
For example, preferably, in specific embodiment of the utility model, Fig. 4 is specific embodiment of the utility model two
In quantum key distribution system structural representation, as shown in figure 4, the dispensing device 31 includes：First controller 41,
One laser instrument 42, second laser 43, the 3rd laser instrument 44 and modulator 45；The reception device 31 includes：Single photon detection
Unit 321 and second controller 322；
The signal output part of first controller 41 respectively with first laser device 42, the laser of second laser 43 and the 3rd
Device 44 connects；The first laser device 42, the output end of the laser instrument 44 of second laser 43 and the 3rd are connected with modulator 45；
The output end of the modulator 45 is connected by transmission channel 33 with single photon detection unit 321；The single photon detection unit
321 output end is connected with second controller 322；The synchronizing signal end of first controller 41 and second controller 322
Synchronizing signal end connects；
First controller 41 is swashed by sending control signal control first laser device 42, second laser 43 or the 3rd
The output of light device 44 has the single photon for determining quantum state；It is additionally operable to each quantum state preparation base letter for being sent modulator 45
Breath is sent to second controller 322；It is additionally operable to each quantum state sent according to modulator 45 and the measurement base letter for receiving
Breath carries out parameter Estimation, obtains the bit error rate；When the bit error rate is not more than predetermined threshold value, carries out error correction and carry out privacy amplification, obtain
To key；
The first laser device 42, the laser instrument 44 of second laser 43 and the 3rd are respectively according to control signal to the modulation
The output of device 45 has the single photon of the first quantum state, the second quantum state and the 3rd quantum state that determine；Wherein, first quantum
State, the second quantum state and the 3rd quantum state are the three kinds of quantum states made an appointment；
The three kinds of quantum states made an appointment are arbitrarily to select in four kinds of quantum states for be subordinated to two groups of different measuring bases
Three kinds of quantum states, and in advance selected three kinds of quantum states are encoded, and in selected three kinds of quantum states, will belong to
The coding corresponding to two quantum states in same group of measurement base as primary key information, by corresponding to another quantum state
Coding is used as parameter Estimation information；
The modulator 45 is used to randomly choose a kind of quantum state from three kinds of received quantum states, and will be selected
Quantum state single photon detection unit 321 is transferred to by transmission channel 33, and while the quantum state for being sent is sent to into
One controller 41, so that the first controller 41 can know what each quantum state for being sent and each quantum state were used
Measurement base；
The single photon detection unit 321 it is random using one group of measurement base in two groups of measurement bases to the quantum state that received
Measure, obtain measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to
Second controller 322；
The second controller 322, for the measurement base used the quantum state for being received information to be sent to into first
Controller 41, is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, and obtains the bit error rate；Work as error code
When rate is not more than predetermined threshold value, carries out error correction and carry out privacy amplification, obtain key.
In addition, preferably, in specific embodiment of the utility model, the modulator 45 can be photoswitch.For example,
In one of the present utility model concrete preferred embodiment, when using multi-station laser, then photoswitch can be used as tune
Device processed 45.
For example, preferably, in specific embodiment of the utility model, the modulator 45 can be electrooptic modulator
(EOM).For example, in one of the present utility model concrete preferred embodiment, when a laser instrument is only used, then can use
EOM is used as modulator 45.
In addition, preferably, in specific embodiment of the utility model, the single photon detection unit 321 can also enter one
Step includes：Measurement base selector and single-photon detector；
The measurement base selector is arranged on before the single-photon detector；
The measurement base selector, for randomly selecting one group of measurement base from two groups of measurement bases；
The single-photon detector, for being measured to the quantum state for being received according to selected measurement base, obtains
Measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to into second controller 322.
In addition, preferably, in specific embodiment of the utility model, the measurement base selector can be modulator,
For example, photoswitch or electrooptic modulator (EOM).The modulator can be by way of dynamic modulation photon (polarization) come from two groups
One group of measurement base is randomly selected in measurement base.
Preferably, in specific embodiment of the utility model, the measurement base selector can also be beam splitter (BS).
Two outlets of the beam splitter can respectively connect and connect a single-photon detector again after an optical module (such as polarizer).Cause
This, the beam splitter can be randomly selecting one group of measurement base using passive mode from two groups of measurement bases.
By above-mentioned quantum key distribution system, dispensing device can be transmitted close using three kinds of quantum states to reception device
Key, completes the distribution of quantum key.
For example, in the technical solution of the utility model, when using above-mentioned quantum key distribution system, can be by such as
Descend described mode to use three kinds of quantum states to transmit key to reception device, complete the distribution of quantum key：
Step 21, is subordinated in four kinds of quantum states of two groups of different measuring bases and arbitrarily select three kinds of quantum states, and right in advance
Selected three kinds of quantum states are encoded, and in selected three kinds of quantum states, will belong to two of same group of measurement base
Coding corresponding to quantum state is believed as primary key information using the coding corresponding to another quantum state as parameter Estimation
Breath.
For example, preferably, in specific embodiment of the utility model, can first select two groups of different measuring bases.It is described
Two groups of different measuring bases can be above-mentioned straight measurement base (Z yls) and oblique measurement base (X yls).Then, can be from above-mentioned Z bases and X bases
Four kinds of quantum states | 0>、|1>、|+>、|->In, arbitrarily select three kinds of quantum states.
For example, preferably, in specific embodiment of the utility model, selected three kinds of quantum states can be | 0>、|1
>、|+>, or：|0>、|1>、|->, or：|+>、|->、|0>；Can also be：|+>、|->、|1>.
For the ease of description, below will (i.e. selected three kinds of quantum states be with a kind of selection mode therein：|0>、|1
>、|+>) as a example by, clear and detailed introduction is carried out to the technical solution of the utility model.
After it have selected three kinds of quantum states, you can selected three kinds of quantum states are encoded.
For example, preferably, in specific embodiment of the utility model, when selected three kinds of quantum states are：|0>、|1
>、|+>When, 0 can be encoded into | 0>, 1 is encoded into | 1>.
In addition, in the technical solution of the utility model, two quantum belonging to same group of measurement base of also making an appointment
Coding corresponding to state as primary key information, and using the coding corresponding to another quantum state as parameter Estimation information.
For example, preferably, in specific embodiment of the utility model, when selected three kinds of quantum states are：|0>、|1
>、|+>When, can be by quantum state | 0>、|1>Corresponding coding as primary key information, and by quantum state |+>Corresponding
Coding is used as parameter Estimation information.
Below all it is to be with selected three kinds of quantum states：|0>、|1>、|+>As a example by and the description that carries out.When selected
When three kinds of quantum states are other selection modes, by that analogy, therefore can repeat no more.
Step 22, dispensing device to reception device sends at random three kinds of quantum states.
In the technical solution of the utility model, after it have selected above-mentioned three kinds of quantum states, transmitting terminal can be using upper
State selected three kinds of quantum states and send described three at random to reception device to reception device transmission random information, i.e. dispensing device
Plant quantum state.
Step 23, reception device is surveyed at random using one group of measurement base in two groups of measurement bases to the quantum state for being received
Amount, obtains measurement result；
For example, when the two groups of measurement bases for being used are respectively straight measurement base and oblique measurement base, reception device can be random
The quantum state for being received is measured using straight measurement base or oblique measurement base, obtains corresponding measurement result.
Each quantum state preparation base information (i.e. basic vector information) for being sent is sent to reception by step 24, dispensing device
Device；The measurement base information used the quantum state for being received is sent to dispensing device by reception device.
For example, preferably, in specific embodiment of the utility model, when selected three kinds of quantum states are：|0>、|1
>、|+>, and dispensing device is respectively to the quantum state that reception device sends：|0>、|+>、|1>、|0>、|+>、|1>, then in this step
In rapid, dispensing device is sent to the measurement base information of reception device and will be respectively：Z bases, X bases, Z bases, Z bases, X bases, Z bases.
Because by appointment belongs to coding corresponding to two quantum states of same group of measurement base as primary key
Information, and using the coding corresponding to another quantum state as parameter Estimation information, therefore, when selected three kinds of quantum states
For：|0>、|1>、|+>When, dispensing device and reception device all can be by quantum states | and 0>、|1>Corresponding coding is used as original close
Key information, and by quantum state |+>Corresponding coding as parameter Estimation information, for carrying out parameter Estimation.
Step 25, dispensing device and reception device carry out parameter Estimation, obtain the bit error rate；If the bit error rate is more than default threshold
Value then terminates whole flow process；Otherwise, execution step 26.
In the technical solution of the utility model, which quantum should be used because dispensing device and reception device are all known
Coding corresponding to state as parameter Estimation information, therefore, dispensing device and reception device can be according to the parameter Estimation information
Parameter Estimation is carried out, so as to obtain the corresponding bit error rate.In the utility model, it is possible to use conventional method for parameter estimation is obtained
To the above-mentioned bit error rate, will not be described here.
After the above-mentioned bit error rate is obtained, you can judge the bit error rate whether more than predetermined threshold value.If the bit error rate is big
In predetermined threshold value, then illustrate that error code is too many, it is necessary to abandon resulting key information, therefore whole flow process will be terminated.If should
The bit error rate is more than predetermined threshold value, then illustrate the bit error rate within the acceptable range, such that it is able to carry out performing following steps 26,
To obtain final key.
Step 26, dispensing device and reception device carry out error correction.
In the technical solution of the utility model, it is possible to use conventional error correction method is believed received primary key
Breath carry out error correction, so as to obtain error correction after key information, therefore, specific error correction method will not be described here.
Step 27, dispensing device and reception device carry out privacy amplification, obtain key.
In the technical solution of the utility model, it is possible to use conventional privacy amplification method is to the key information after error correction
Privacy amplification is carried out, so as to obtain final key, therefore, specific privacy amplification method will not be described here.
By above-mentioned step 21～27, can transmission key between dispensing device and reception device.
In the technical solution of the utility model, because dispensing device only need to be using three kinds of quantum states without using four kinds
Quantum state can transmit key to reception device, complete the distribution of quantum key, thus the utility model only need to use it is less
Quantum state can ensure security on the premise of carry out safe quantum key distribution, such that it is able to be effectively reduced equipment into
This, improves key rate.
In sum, in the technical solution of the utility model, because dispensing device only need to be using three kinds of quantum states not
Key must can be transmitted to reception device using four kinds of quantum states, complete the distribution of quantum key, therefore, with prior art phase
Than the technical solution of the utility model only can need to be carried out safe using less quantum state on the premise of security is ensured
Quantum key distribution, such that it is able to be effectively reduced equipment cost, improves key rate.
In addition, in the technical solution of the utility model, dispensing device can use a laser instrument, it is also possible to use three
Platform laser instrument, can according to practical application scene need voluntarily select.In addition, the technical solution of the utility model can be used
Various Physical realizations of the quantum states such as polarization encoder, phase code are specifically repeated no more realizing.
Additionally, the technical solution of the utility model is used directly for, based on the key distribution system of single-photon source, also may be used
State technology is inveigled to use for the system based on weak coherent light source to combine.
Preferred embodiment of the present utility model is the foregoing is only, it is all at this not to limit the utility model
Within the spirit and principle of utility model, any modification, equivalent substitution and improvements done etc. should be included in the utility model
Within the scope of protection.
Claims (6)
1. a kind of quantum key distribution system, it is characterised in that the system includes：Dispensing device and reception device；
The dispensing device and reception device are connected by transmission channel；
The dispensing device, for sending make an appointment three kinds of quantum states at random to reception device；It is additionally operable to be sent
Each quantum state preparation base information is sent to reception device；It is additionally operable to according to each quantum state for being sent and the survey for receiving
Amount base information carries out parameter Estimation, obtains the bit error rate；When the bit error rate is not more than predetermined threshold value, error correction is carried out and carries out privacy to put
Greatly, key is obtained；
Wherein, the three kinds of quantum states made an appointment are arbitrarily to select in four kinds of quantum states for be subordinated to two groups of different measuring bases
Three kinds of quantum states, and in advance selected three kinds of quantum states are encoded, and in selected three kinds of quantum states, will belong to
The coding corresponding to two quantum states in same group of measurement base as primary key information, by corresponding to another quantum state
Coding is used as parameter Estimation information；
The reception device, for being surveyed to the quantum state for being received using one group of measurement base in two groups of measurement bases at random
Amount, obtains measurement result；The measurement base information for being additionally operable to be used the quantum state to being received is sent to reception device, and root
Parameter Estimation is carried out according to measurement result and the measurement base information for receiving, the bit error rate is obtained；When the bit error rate is not more than predetermined threshold value
When, carry out error correction and carry out privacy amplification, obtain key.
2. system according to claim 1, it is characterised in that
The dispensing device includes：First controller, laser instrument and modulator；
The reception device includes：Single photon detection unit and second controller；
The signal output part of first controller is connected with laser instrument；The output end of the laser instrument is connected with modulator；Institute
The output end for stating modulator is connected by transmission channel with single photon detection unit；The output end of the single photon detection unit with
Second controller connects；The synchronizing signal end of first controller is connected with the synchronizing signal end of second controller；
First controller controls laser instrument output single photon by sending control signal；It is additionally operable to sent modulator
Each quantum state preparation base information is sent to second controller；It is additionally operable to each quantum state for being sent according to modulator and connects
The measurement base information for receiving carries out parameter Estimation, obtains the bit error rate；When the bit error rate is not more than predetermined threshold value, carries out error correction and go forward side by side
Row privacy is amplified, and obtains key；
The laser instrument is used to export single photon to the modulator according to control signal；
The modulator is used for the single photon Stochastic Modulation for receiving into the three kinds of quantum states made an appointment, and by after modulation
Quantum state gives single photon detection unit by transmission channel, and while the quantum state for being sent is sent to into the first control
Device；
The single photon detection unit is surveyed at random using one group of measurement base in two groups of measurement bases to the quantum state for being received
Amount, obtains measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to into the second control
Device processed；
The second controller, for the measurement base used the quantum state for being received information to be sent to into the first controller,
It is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, obtains the bit error rate；When the bit error rate is not more than
During predetermined threshold value, carry out error correction and carry out privacy amplification, obtain key.
3. system according to claim 1, it is characterised in that
The dispensing device includes：First controller, first laser device, second laser, the 3rd laser instrument and modulator；
The reception device includes：Single photon detection unit and second controller；
The signal output part of first controller is connected respectively with first laser device, second laser and the 3rd laser instrument；Institute
The output end for stating first laser device, second laser and the 3rd laser instrument is connected with modulator；The output end of the modulator
It is connected with single photon detection unit by transmission channel；The output end of the single photon detection unit is connected with second controller；
The synchronizing signal end of first controller is connected with the synchronizing signal end of second controller；
First controller controls first laser device, second laser or the 3rd laser instrument output tool by sending control signal
There is the single photon for determining quantum state；Each quantum state preparation base information for being additionally operable to be sent modulator is sent to the second control
Device processed；The measurement base information for being additionally operable to each quantum state sent according to modulator and receiving carries out parameter Estimation, obtains
The bit error rate；When the bit error rate is not more than predetermined threshold value, carries out error correction and carry out privacy amplification, obtain key；
The first laser device, second laser and the 3rd laser instrument have respectively according to control signal to modulator output
It is determined that the first quantum state, the second quantum state and the 3rd quantum state single photon；Wherein, first quantum state, the second quantum
State and the 3rd quantum state are the three kinds of quantum states made an appointment；
The modulator is used to randomly choose a kind of quantum state from three kinds of received quantum states, and by selected quantum
State gives single photon detection unit by transmission channel, and while the quantum state for being sent is sent to into the first controller；
The single photon detection unit is surveyed at random using one group of measurement base in two groups of measurement bases to the quantum state for being received
Amount, obtains measurement result, and the measurement base information that measurement result and quantum state to being received are used is sent to into the second control
Device processed；
The second controller, for the measurement base used the quantum state for being received information to be sent to into the first controller,
It is additionally operable to carry out parameter Estimation according to measurement result and the measurement base information for receiving, obtains the bit error rate；When the bit error rate is not more than
During predetermined threshold value, carry out error correction and carry out privacy amplification, obtain key.
4. system according to claim 3, it is characterised in that：
The modulator is photoswitch.
5. system according to claim 2, it is characterised in that：
The modulator is electrooptic modulator EOM.
6. system according to claim 1, it is characterised in that：
The transmission channel is optical fiber or free space.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106254072A (en) * | 2016-10-18 | 2016-12-21 | 清华大学 | A kind of quantum key distribution system and method |
| CN114598457A (en) * | 2020-12-03 | 2022-06-07 | 科大国盾量子技术股份有限公司 | Secret key generation method and device applied to quantum communication |
-
2016
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106254072A (en) * | 2016-10-18 | 2016-12-21 | 清华大学 | A kind of quantum key distribution system and method |
| CN106254072B (en) * | 2016-10-18 | 2022-11-25 | 清华大学 | Quantum key distribution method |
| CN114598457A (en) * | 2020-12-03 | 2022-06-07 | 科大国盾量子技术股份有限公司 | Secret key generation method and device applied to quantum communication |
| CN114598457B (en) * | 2020-12-03 | 2024-01-30 | 科大国盾量子技术股份有限公司 | Key generation method, device, medium and equipment applied to quantum communication |
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