CN106254072B - Quantum key distribution method - Google Patents
Quantum key distribution method Download PDFInfo
- Publication number
- CN106254072B CN106254072B CN201610902950.2A CN201610902950A CN106254072B CN 106254072 B CN106254072 B CN 106254072B CN 201610902950 A CN201610902950 A CN 201610902950A CN 106254072 B CN106254072 B CN 106254072B
- Authority
- CN
- China
- Prior art keywords
- quantum
- receiving device
- measurement
- quantum states
- information
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0852—Quantum cryptography
- H04L9/0858—Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding
Abstract
The invention provides a quantum key distribution system and a quantum key distribution method. The method comprises the following steps: the transmitting device randomly transmits three quantum states belonging to two groups of different measurement bases to the receiving device; the receiving device randomly uses one of the two groups of measurement bases to measure the received quantum state to obtain a measurement result; the transmitting device transmits the transmitted measurement base information of each quantum state to the receiving device; the receiving device sends the measurement base information used by the received quantum state to the sending device; the transmitting device and the receiving device carry out parameter estimation to obtain an error rate; if the error rate is larger than a preset threshold value, the whole process is terminated; otherwise, the transmitting device and the receiving device carry out error correction and privacy amplification to obtain the secret key. The invention can distribute the quantum key safely only by using three quantum states, thereby reducing the equipment cost and improving the key rate.
Description
Technical Field
The invention relates to the technical field of quantum information, in particular to a quantum key distribution system and a quantum key distribution method.
Background
With the vigorous development of internet technology, the importance of communication security is increasing day by day. In many situations, both parties desire to communicate securely using a common channel. For example, when a user submits an account number and a password to internet banking, the user wants the information to be confidential during the transmission process, i.e., the information cannot be intercepted by any third party. A widely used encryption method at present is a public key encryption algorithm. Such algorithms are based on the algorithm complexity of some mathematical problems, and as science and technology develops, their security is threatened. Therefore, there is a need to develop a more secure and reliable encryption method.
The quantum key distribution technology is a brand new key distribution scheme based on quantum mechanical characteristics, and is one of the technologies with the most application prospects in the quantum information technology. The technology borrows a public channel to ensure that a safe random secret key is shared between two communication parties. And in combination with a one-time pad encryption method, the shared random key can be used for encrypting information in communication, so that the communication safety is ensured. The security of quantum key distribution is based on physics rationale and is therefore information-theoretic secure.
Currently, some commercial quantum key distribution systems are already provided in the prior art, and the systems are mostly based on the BB84 protocol. The system is divided into a transmitting device and a receiving device. In the BB84 protocol, the quantum signal source used for transmitting the key is a single photon, and the key information to be transmitted is encoded in the polarization state (or polarization direction) of the single photon. The transmitting device encodes information in four different quantum states |0>, |1>, | + >, and | - >. On the hardware level, the four quantum states can be encoded by different degrees of freedom of photons. For example, when polarization encoding is used, single photons of linear polarization in the horizontal direction, the vertical direction, the 45 ° direction and the 135 ° direction can be selected as carriers of quantum information, and the single photons in the polarization states in the above four directions can be represented by four quantum states of |0>, |1>, | + >, and | - >; similarly, when phase encoding is used, four quantum states |0>, |1>, | + >, and | - >, can be represented by four phase values between two coherent wave packets of photons.
Wherein, in the above four quantum states, |0> and |1> are orthogonal to each other, so that a group of measurement bases can be formed, which are called as straight measurement bases (abbreviated as Z base, the same below), and |0> state and |1> state are two eigenstates of the Z base; the two states are also orthogonal, so that another set of measurement bases can be formed, called diagonal measurement bases (X base, the same applies below), and the states of | + > and | - > are two eigenstates of the X base.
The relationship between the four quantum states described above is as follows:
in order to transmit classical information, the BB84 protocol prepares one photon on the above four quantum states and contracts the encoded information represented by each quantum state. For example, in the BB84 protocol, photons are encoded by polarization of light, and are randomly encoded on the Z basis and the X basis with equal probability. A sender randomly generates a string consisting of 0 and 1 bits, and when the coding is selected under the Z base, the sender codes 0 into |0> and 1 into |1>; when the encoding is selected under the X base, the sender encodes 0 into | + >, and encodes 1 into | - >. Then, the sender sends the quantum state to the receiver through a quantum channel, and the receiver measures the quantum state sent from the sender by using an X base or a Z base with equal probability; then, the sender and the receiver publish the measurement bases selected for use in encoding or measuring respectively in the authenticated classical channel, and thereby screen out encoded data when both select the same measurement base for encoding or measuring as the transmitted key information.
Therefore, in executing the BB84 protocol, the transmitting device needs to randomly transmit the four quantum states. For this reason, there are generally two methods for hardware implementation: one is to adopt a laser and rapidly modulate the emitted light (with the freedom degrees of polarization, phase and the like); the other is to use four lasers (as shown in fig. 1), each of which fixedly transmits a quantum state, and an optical switch is used to multiplex four paths of light onto one channel.
An important performance parameter of a practical key distribution system is the transmission rate of the sending device. In general, the higher the transmission rate, the higher the system final key rate. However, the quantum key distribution system in the prior art requires four quantum states to be randomly transmitted. As shown above, if the transmitting apparatus uses a laser, the system has a high requirement on the modulation rate of the modulation component; if a scheme of multiple lasers is used, the system has higher requirements on the number of lasers and the speed of an optical switch. Therefore, it can be seen that, in the two methods in the prior art, since four quantum states are used, the cost of the transmitting end is high, and the final key rate of the system is low.
Disclosure of Invention
In view of this, the present invention provides a quantum key distribution system and method, so that only three quantum states are needed to perform secure quantum key distribution, thereby reducing the equipment cost and improving the key rate.
The technical scheme of the invention is realized in the following way:
a quantum key distribution method, the method comprising the steps of:
A. randomly selecting three quantum states from four quantum states belonging to two groups of different measurement bases, and coding the selected three quantum states in advance, wherein in the selected three quantum states, codes corresponding to two quantum states belonging to the same group of measurement bases are used as original key information, and codes corresponding to the other quantum state are used as parameter estimation information;
B. the transmitting device randomly transmits the three quantum states to the receiving device;
C. the receiving device randomly uses one of the two groups of measurement bases to measure the received quantum state to obtain a measurement result;
D. the transmitting device transmits the transmitted measurement base information of each quantum state to the receiving device; the receiving device sends the measurement base information used by the received quantum state to the sending device;
E. the transmitting device and the receiving device carry out parameter estimation to obtain an error rate; if the error rate is larger than a preset threshold value, the whole process is terminated; otherwise, executing step F;
F. the transmitting device and the receiving device carry out error correction;
G. the transmitting device and the receiving device carry out privacy amplification to obtain a secret key.
Preferably, the two different measurement bases are a direct measurement base and an oblique measurement base.
Preferably, the three selected quantum states are:
|0>、|1>、|+>；
or |0>, |1>, | - >;
or | + >, | - >, and |0>;
or | + >, | - >, |1>.
Preferably, when the three selected quantum states are: i0 >, |1>, | + >:
encoding 0 into |0> and 1 into |1>;
the codes corresponding to the quantum states |0>, |1> are used as original key information, and the code corresponding to the quantum state | + > is used as parameter estimation information.
The invention also provides a quantum key distribution system, which comprises: a transmitting device and a receiving device;
the transmitting device and the receiving device are connected through a transmission channel;
the transmitting device is used for randomly transmitting three quantum states agreed in advance to the receiving device; the device is also used for sending the sent measurement base information of each quantum state to the receiving device; the device is also used for carrying out parameter estimation according to each transmitted quantum state and the received measurement basis information to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and carrying out privacy amplification to obtain a secret key;
the three pre-agreed quantum states are three quantum states randomly selected from four quantum states belonging to two groups of different measurement bases, the three selected quantum states are encoded in advance, codes corresponding to the two quantum states belonging to the same group of measurement bases in the three selected quantum states are used as original key information, and codes corresponding to the other quantum states are used as parameter estimation information;
the receiving device is used for measuring the received quantum state by using one of the two groups of measuring bases at random to obtain a measuring result; the device is also used for sending the measurement base information used for the received quantum state to the receiving device, and carrying out parameter estimation according to the measurement result and the received measurement base information to obtain the error rate; and when the error rate is not greater than the preset threshold value, correcting the error and carrying out privacy amplification to obtain a secret key.
Preferably, the transmitting device includes: a first controller, a laser, and a modulator;
the receiving apparatus includes: the single photon detection unit and the second controller;
the signal output end of the first controller is connected with the laser; the output end of the laser is connected with the modulator; the output end of the modulator is connected with the single photon detection unit through a transmission channel; the output end of the single photon detection unit is connected with the second controller; the synchronous signal end of the first controller is connected with the synchronous signal end of the second controller;
the first controller controls the laser to output single photons by sending a control signal; the modulator is also used for sending the measurement base information of each quantum state sent by the modulator to the second controller; the modulator is also used for carrying out parameter estimation according to each quantum state sent by the modulator and the received measurement basis information to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and carrying out privacy amplification to obtain a secret key;
the laser is used for outputting single photons to the modulator according to a control signal;
the modulator is used for randomly modulating the received single photons into three predetermined quantum states, transmitting the modulated quantum states to the single photon detection unit through a transmission channel, and simultaneously transmitting the transmitted quantum states to the first controller;
the single photon detection unit randomly uses one of the two groups of measurement bases to measure the received quantum state to obtain a measurement result, and sends the measurement result and information of the measurement base used for the received quantum state to the second controller;
the second controller is used for sending the received measurement base information used by the quantum state to the first controller and is also used for carrying out parameter estimation according to the measurement result and the received measurement base information to obtain an error rate; and when the error rate is not greater than the preset threshold value, carrying out error correction and privacy amplification to obtain a secret key.
Preferably, the transmitting device includes: the laser system comprises a first controller, a first laser, a second laser, a third laser and a modulator;
the receiving apparatus includes: the single photon detection unit and the second controller;
the signal output end of the first controller is respectively connected with the first laser, the second laser and the third laser; the output ends of the first laser, the second laser and the third laser are connected with the modulator; the output end of the modulator is connected with the single photon detection unit through a transmission channel; the output end of the single photon detection unit is connected with a second controller; the synchronous signal end of the first controller is connected with the synchronous signal end of the second controller;
the first controller controls the first laser, the second laser or the third laser to output single photons with determined quantum states by sending control signals; the modulator is also used for sending the measurement base information of each quantum state sent by the modulator to the second controller; the modulator is also used for carrying out parameter estimation according to each quantum state sent by the modulator and the received measurement basis information to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and carrying out privacy amplification to obtain a secret key;
the first laser, the second laser and the third laser respectively output single photons with a determined first quantum state, a determined second quantum state and a determined third quantum state to the modulator according to control signals; wherein the first quantum state, the second quantum state and the third quantum state are three predetermined quantum states;
the modulator is used for randomly selecting one quantum state from the received three quantum states, transmitting the selected quantum state to the single photon detection unit through the transmission channel, and simultaneously transmitting the transmitted quantum state to the first controller;
the single photon detection unit randomly uses one of the two groups of measurement bases to measure the received quantum state to obtain a measurement result, and sends the measurement result and information of the measurement base used for the received quantum state to the second controller;
the second controller is used for sending the received measurement base information used by the quantum state to the first controller and also used for carrying out parameter estimation according to the measurement result and the received measurement base information to obtain the bit error rate; and when the error rate is not greater than the preset threshold value, correcting the error and carrying out privacy amplification to obtain a secret key.
Preferably, the modulator is an optical switch.
Preferably, the modulator is an electro-optical modulator (EOM).
Preferably, the transmission channel is an optical fiber or a free space.
It can be seen from the above technical solutions that, in the quantum key distribution system and method of the present invention, since the sending device can transmit the key to the receiving device only using three quantum states instead of four quantum states, and thus, the distribution of the quantum key is completed, compared with the prior art, the technical solution of the present invention can perform the secure quantum key distribution on the premise of ensuring the security only using fewer quantum states, thereby effectively reducing the equipment cost and improving the key rate.
Drawings
Fig. 1 is a schematic structural diagram of a quantum key distribution system in the prior art.
Fig. 2 is a schematic flow chart of a quantum key distribution method in the embodiment of the present invention.
Fig. 3 is a schematic diagram of an overall structure of a quantum key distribution system in the embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a quantum key distribution system in a first embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a quantum key distribution system in a second embodiment of the present invention.
Detailed Description
In order to make the technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and specific embodiments.
Fig. 2 is a schematic flowchart of a quantum key distribution method in the embodiment of the present invention. As shown in fig. 2, the quantum key distribution method in the embodiment of the present invention includes:
and 21, randomly selecting three quantum states from four quantum states belonging to two groups of different measurement bases, encoding the three selected quantum states in advance, and taking the codes corresponding to the two quantum states belonging to the same group of measurement bases as original key information and the code corresponding to the other quantum state as parameter estimation information in the three selected quantum states.
For example, in an embodiment of the present invention, two different sets of measurement bases may be selected. The two different sets of measurement bases may be the straight measurement base (Z base) and the oblique measurement base (X base) described above. Then, from the four quantum states |0>, |1>, | + >, and | - > of the Z group and the X group, three quantum states can be arbitrarily selected.
For example, in the embodiment of the present invention, the selected three quantum states may be |0>, |1>, | + >, or may be: i 0>, |1>, | - >, may be: | + >, | - >, and |0>; the method can also be as follows: i + >, | - >, and |1>.
For convenience of description, the technical solution of the present invention will be clearly and specifically described below by taking one of the selection modes (i.e. the selected three quantum states are: |0>, |1>, | + >) as an example.
After the three quantum states are selected, the three selected quantum states can be encoded.
For example, preferably, in the embodiment of the present invention, when the three selected quantum states are: if |0>, |1>, | + >, 0 may be encoded as |0> and 1 may be encoded as |1>.
In addition, in the technical solution of the present invention, the codes corresponding to two quantum states that are agreed in advance to belong to the same group of measurement bases are used as the original key information, and the code corresponding to another quantum state is used as the parameter estimation information.
For example, preferably, in the embodiment of the present invention, when the three selected quantum states are: if |0>, |1>, | + >, the code corresponding to quantum state |0>, |1> can be used as the original key information, and the code corresponding to quantum state | + > can be used as the parameter estimation information.
All of the above are selected three quantum states: the description of |0>, |1>, | + > is given as an example. When the three selected quantum states are other selection modes, the analogy can be carried out, and therefore, the description is omitted.
In the technical scheme of the invention, after the three quantum states are selected, the transmitting terminal can use the selected three quantum states to send random information to the receiving device, namely, the transmitting device sends the three quantum states to the receiving device randomly.
for example, when the two measurement bases are a direct measurement base and an oblique measurement base, respectively, the receiving device may randomly use the direct measurement base or the oblique measurement base to measure the received quantum state, and obtain a corresponding measurement result.
For example, preferably, in the embodiment of the present invention, when the three selected quantum states are: l 0>, |1>, | + >, and the quantum states transmitted by the transmitting device to the receiving device are respectively: if 0>, | plus >, |1>, |0>, | plus >, |1>, then in this step, the measurement base information sent by the sending device to the receiving device will be: z group, X group, Z group, X group, Z group.
Because the codes corresponding to two quantum states belonging to the same group of measurement bases have been agreed in advance as original key information, and the code corresponding to another quantum state is used as parameter estimation information, when the three selected quantum states are: when |0>, |1>, | + >, both the transmitting device and the receiving device will use the codes corresponding to the quantum states |0>, |1> as the original key information, and use the codes corresponding to the quantum state | + > as the parameter estimation information for parameter estimation.
In the technical solution of the present invention, since both the transmitting device and the receiving device know which quantum state corresponding code should be used as the parameter estimation information, both the transmitting device and the receiving device can perform parameter estimation according to the parameter estimation information, thereby obtaining the corresponding bit error rate. In the present invention, the above-mentioned error rate can be obtained by using a common parameter estimation method, which is not described herein again.
After the error rate is obtained, whether the error rate is greater than a preset threshold value can be judged. If the error rate is greater than the preset threshold, it indicates that there are too many errors, and the obtained key information must be discarded, so the whole process will be terminated. If the error rate is greater than the predetermined threshold, it is an indication that the error rate is within an acceptable range, so that step 26, described below, may be performed to obtain the final key.
In the technical solution of the present invention, a common error correction method may be used to correct errors in the received original key information, so as to obtain the corrected key information, and therefore, the specific error correction method is not described herein again.
And 27, the transmitting device and the receiving device carry out privacy amplification to obtain a secret key.
In the technical scheme of the invention, the corrected key information can be subjected to privacy amplification by using a common privacy amplification method so as to obtain a final key, and therefore, the specific privacy amplification method is not described herein again.
Through the above steps 21 to 27, the key can be transmitted between the transmitting apparatus and the receiving apparatus.
In the technical scheme of the invention, as the sending device can transmit the key to the receiving device only by using three quantum states without using four quantum states to complete the distribution of the quantum key, the invention can carry out safe quantum key distribution on the premise of ensuring the safety by using fewer quantum states, thereby effectively reducing the equipment cost and improving the key rate.
In addition, according to the quantum key distribution method provided by the present invention, the present invention further provides a corresponding quantum key distribution system, specifically please refer to fig. 2.
Fig. 3 is a schematic structural diagram of a quantum key distribution system in the embodiment of the present invention. As shown in fig. 3, the quantum key distribution system in the embodiment of the present invention includes: a transmitting device 31 and a receiving device 32;
the transmitting device 31 and the receiving device 32 are connected by a transmission channel 33;
the transmitting device 31 is configured to randomly transmit three quantum states to the receiving device 32; and is further configured to send the transmitted measurement base information of each quantum state to the receiving device 32; the device is also used for carrying out parameter estimation according to each transmitted quantum state and the received measurement basis information to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and privacy amplification to obtain a secret key;
the three quantum states are any three selected from four quantum states belonging to two groups of different measurement bases, the three selected quantum states are encoded in advance, codes corresponding to the two quantum states belonging to the same group of measurement bases in the three selected quantum states are used as original key information, and codes corresponding to the other quantum states are used as parameter estimation information;
the receiving device 32 is configured to measure the received quantum state by using one of the two sets of measurement bases at random to obtain a measurement result; the device is further configured to send measurement base information used for the received quantum state to the receiving device 31, and perform parameter estimation according to the measurement result and the received measurement base information to obtain an error rate; and when the error rate is not greater than the preset threshold value, carrying out error correction and privacy amplification to obtain a secret key.
With the quantum key distribution system, the transmitting device 31 can transmit the key to the receiving device 32 using three quantum states, thereby completing the distribution of the quantum key.
Preferably, in the embodiment of the present invention, the transmission channel 33 is an optical fiber or a free space.
In addition, in the technical solution of the present invention, the above-described transmission apparatus may be implemented in various ways. The following will describe the technical solution of the present invention by taking two specific implementation manners as examples.
In the first embodiment, only one laser is provided in the transmitting device.
For example, in an embodiment of the present invention, preferably, fig. 4 is a schematic structural diagram of a quantum key distribution system in a first embodiment of the present invention, as shown in fig. 4, the sending device 31 includes: a first controller 311, a laser 312, and a modulator 313; the receiving device 32 includes: a single photon detection unit 321 and a second controller 322;
the signal output end of the first controller 311 is connected with the laser 312; the output end of the laser 312 is connected with a modulator 313; the output end of the modulator 313 is connected with the single photon detection unit 321 through a transmission channel 33; the output end of the single photon detection unit 321 is connected with the second controller 322; the synchronization signal terminal of the first controller 311 is connected with the synchronization signal terminal of the second controller 322;
the first controller 311 controls the laser 312 to output a single photon by sending a control signal; and is further configured to send the measurement base information of each quantum state sent by the modulator 313 to the second controller 322; the modulator 313 is further configured to perform parameter estimation according to each quantum state sent by the modulator 313 and the received measurement basis information to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and carrying out privacy amplification to obtain a secret key;
the laser 312 is configured to output a single photon to the modulator 313 according to a control signal;
the modulator 313 is configured to randomly modulate the received single photon into three predetermined quantum states, transmit the modulated quantum states to the single photon detection unit 321 through the transmission channel 33, and simultaneously transmit the transmitted quantum states to the first controller 311, so that the first controller 311 can know the transmitted quantum states and measurement bases used by the quantum states;
the three pre-agreed quantum states are three quantum states randomly selected from four quantum states belonging to two groups of different measurement bases, the three selected quantum states are encoded in advance, codes corresponding to the two quantum states belonging to the same group of measurement bases in the three selected quantum states are used as original key information, and codes corresponding to the other quantum states are used as parameter estimation information;
the single-photon detection unit 321 measures the received quantum state by using one of the two measurement bases at random to obtain a measurement result, and sends the measurement result and information of the measurement base used for the received quantum state to the second controller 322;
the second controller 322 is configured to send the measurement basis information used for the received quantum state to the first controller 311, and is further configured to perform parameter estimation according to the measurement result and the received measurement basis information to obtain an error rate; and when the error rate is not greater than the preset threshold value, carrying out error correction and privacy amplification to obtain a secret key.
Through the quantum key distribution system, the sending device can transmit the key to the receiving device by using three quantum states, and the distribution of the quantum key is completed.
In the second embodiment, three lasers are provided in the transmitting device.
For example, in an embodiment of the present invention, preferably, fig. 5 is a schematic structural diagram of a quantum key distribution system in a second embodiment of the present invention, as shown in fig. 5, the sending device 31 includes: a first controller 41, a first laser 42, a second laser 43, a third laser 44, and a modulator 45; the receiving device 31 includes: a single photon detection unit 321 and a second controller 322;
the signal output end of the first controller 41 is respectively connected with the first laser 42, the second laser 43 and the third laser 44; the output ends of the first laser 42, the second laser 43 and the third laser 44 are all connected with a modulator 45; the output end of the modulator 45 is connected with the single photon detection unit 321 through the transmission channel 33; the output end of the single photon detection unit 321 is connected with the second controller 322; the synchronous signal terminal of the first controller 41 is connected with the synchronous signal terminal of the second controller 322;
the first controller 41 sends a control signal to control the first laser 42, the second laser 43 or the third laser 44 to output single photons with determined quantum states; and is further configured to send the measurement base information of each quantum state sent by the modulator 45 to the second controller 322; the modulator 45 is further configured to perform parameter estimation according to each quantum state sent by the modulator 45 and the received measurement basis information, so as to obtain an error rate; when the error rate is not greater than a preset threshold value, carrying out error correction and privacy amplification to obtain a secret key;
the first laser 42, the second laser 43 and the third laser 44 respectively output single photons with determined first quantum state, second quantum state and third quantum state to the modulator 45 according to control signals; wherein the first quantum state, the second quantum state and the third quantum state are three predetermined quantum states;
the three pre-agreed quantum states are three quantum states randomly selected from four quantum states belonging to two groups of different measurement bases, the three selected quantum states are encoded in advance, and in the three selected quantum states, the codes corresponding to the two quantum states belonging to the same group of measurement bases are used as original key information, and the code corresponding to the other quantum state is used as parameter estimation information;
the modulator 45 is configured to randomly select one quantum state from the received three quantum states, transmit the selected quantum state to the single-photon detection unit 321 through the transmission channel 33, and simultaneously transmit the transmitted quantum state to the first controller 41, so that the first controller 41 can know the transmitted quantum states and measurement bases used by the quantum states;
the single-photon detection unit 321 measures the received quantum state by using one of the two measurement bases at random to obtain a measurement result, and sends the measurement result and information of the measurement base used for the received quantum state to the second controller 322;
the second controller 322 is configured to send the measurement basis information used for the received quantum state to the first controller 41, and is further configured to perform parameter estimation according to the measurement result and the received measurement basis information to obtain an error rate; and when the error rate is not greater than the preset threshold value, correcting the error and carrying out privacy amplification to obtain a secret key.
In addition, preferably, in the embodiment of the present invention, the modulator 45 may be an optical switch. For example, in a particularly preferred embodiment of the present invention, when multiple lasers are used, an optical switch may be used as modulator 45.
For example, in an embodiment of the present invention, the modulator 45 may be an electro-optical modulator (EOM). For example, in a particularly preferred embodiment of the present invention, when only one laser is used, the EOM may be used as modulator 45.
In addition, preferably, in an embodiment of the present invention, the single photon detection unit 321 may further include: a measurement basis selector and a single photon detector;
the measurement base selector is arranged in front of the single-photon detector;
the measuring base selector is used for randomly selecting one group of measuring bases from the two groups of measuring bases;
the single photon detector is configured to measure the received quantum state according to the selected measurement basis to obtain a measurement result, and send the measurement result and information of the measurement basis used for the received quantum state to the second controller 322.
In addition, preferably, in the embodiment of the present invention, the measurement basis selector may be a modulator, such as an optical switch or an electro-optical modulator (EOM). The modulator can randomly select one group of measuring bases from two groups of measuring bases by dynamically modulating photons (polarization).
Preferably, in an embodiment of the present invention, the measurement-based selector may also be a Beam Splitter (BS). The two outlets of the beam splitter can be respectively connected with an optical component (such as a polaroid) and then connected with a single photon detector. Thus, the beam splitter can use a passive approach to randomly select one of the two sets of measurement bases.
Through the quantum key distribution system, the sending device can transmit the key to the receiving device by using three quantum states, and the distribution of the quantum key is completed.
In summary, in the technical solution of the present invention, since the sending device can transmit the secret key to the receiving device only using three quantum states without using four quantum states, and complete the distribution of the quantum secret key, compared with the prior art, the technical solution of the present invention can perform the secure quantum secret key distribution on the premise of ensuring the security only using fewer quantum states, thereby effectively reducing the equipment cost and improving the secret key rate.
In addition, in the technical scheme of the invention, one laser can be used as the sending device, and three lasers can also be used, and the sending device can be selected according to the requirements of practical application scenes. In addition, the technical scheme of the invention can be realized by using various physical implementation modes of quantum states such as polarization coding, phase coding and the like, and details are not repeated.
In addition, the technical scheme of the invention can be directly used for a key distribution system based on a single photon source, and can also be used for a system based on a weak coherent light source by combining a decoy state technology.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (4)
1. A quantum key distribution method, comprising the steps of:
A. randomly selecting three quantum states from four quantum states belonging to two groups of different measurement bases, and coding the selected three quantum states in advance, wherein in the selected three quantum states, codes corresponding to two quantum states belonging to the same group of measurement bases are used as original key information, and codes corresponding to the other quantum state are used as parameter estimation information;
B. the transmitting device randomly transmits the three quantum states to the receiving device;
C. the receiving device randomly uses one of the two groups of measurement bases to measure the received quantum state to obtain a measurement result;
D. the transmitting device transmits the transmitted measurement base information of each quantum state to the receiving device; the receiving device sends the measurement base information used by the received quantum state to the sending device;
E. the transmitting device and the receiving device carry out parameter estimation to obtain an error rate; if the error rate is larger than a preset threshold value, the whole process is terminated; otherwise, executing step F;
F. the transmitting device and the receiving device carry out error correction;
G. the transmitting device and the receiving device carry out privacy amplification to obtain a secret key.
2. The method of claim 1, wherein:
the two groups of different measuring bases are a straight measuring base and an inclined measuring base.
3. The method of claim 2, wherein the three selected quantum states are:
|0>、|1>、|+>；
or |0>, |1>, | - >;
or | + >, | - >, and |0>;
or | + >, | - >, |1>.
4. The method of claim 3, wherein when the three selected quantum states are: i0 >, |1>, | + >:
encoding 0 into |0> and 1 into |1>;
the codes corresponding to the quantum states |0>, |1> are used as original key information, and the code corresponding to the quantum state | + > is used as parameter estimation information.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610902950.2A CN106254072B (en) | 2016-10-18 | 2016-10-18 | Quantum key distribution method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610902950.2A CN106254072B (en) | 2016-10-18 | 2016-10-18 | Quantum key distribution method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106254072A CN106254072A (en) | 2016-12-21 |
| CN106254072B true CN106254072B (en) | 2022-11-25 |
Family
ID=57612650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610902950.2A Active CN106254072B (en) | 2016-10-18 | 2016-10-18 | Quantum key distribution method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106254072B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107070643B (en) * | 2016-12-26 | 2023-04-25 | 清华大学 | Quantum key distribution device and method |
| CN106708470B (en) * | 2016-12-28 | 2023-04-07 | 清华大学 | Quantum random number generator and quantum random number generation method |
| CN106789020B (en) * | 2016-12-28 | 2022-11-25 | 清华大学 | Decoy state quantum key distribution system and method |
| CN106878006B (en) * | 2016-12-31 | 2019-11-05 | 北京邮电大学 | Quantum key channel transmission method and system based on Optical Time Division Multiplexing |
| CN109428708A (en) * | 2017-08-21 | 2019-03-05 | 熊英 | A kind of quantum secret communication method of functionization |
| CN108306733A (en) * | 2018-05-04 | 2018-07-20 | 北京邮电大学 | A kind of post-processing approach in discrete modulation continuous variable quantum key distribution |
| CN108574577A (en) * | 2018-06-12 | 2018-09-25 | 清华大学 | A kind of quantum key distribution system and method |
| CN108712254B (en) * | 2018-06-20 | 2023-03-10 | 清华大学 | Quantum key distribution system and method |
| CN108712255B (en) * | 2018-06-29 | 2024-01-02 | 清华大学 | Quantum key distribution system and method |
| CN113225184A (en) * | 2021-05-11 | 2021-08-06 | 中国人民解放军空军工程大学 | Passive decoy state modulation reference system-independent quantum key distribution system and method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6801626B1 (en) * | 1999-05-12 | 2004-10-05 | Nec Corporation | Cryptographic key distribution using light pulses of three macroscopic quantum states |
| CN101697512A (en) * | 2009-11-09 | 2010-04-21 | 中国电子科技集团公司第三十研究所 | Method and system for anti-interference quantum secure direct communication |
| CN102185693A (en) * | 2011-04-25 | 2011-09-14 | 安徽量子通信技术有限公司 | Quantum cryptography teaching system based on BB84 protocol and communication method thereof |
| WO2012074369A1 (en) * | 2010-12-02 | 2012-06-07 | Mimos Berhad | A system and method for exchangeable quantum key distribution |
| CN104954122A (en) * | 2015-06-18 | 2015-09-30 | 清华大学 | Quantum key distribution post-processing method and quantum key distribution post-processing system under condition of mixed base vectors |
| CN206117683U (en) * | 2016-10-18 | 2017-04-19 | 清华大学 | Quantum key distribution system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4838166B2 (en) * | 2007-02-19 | 2011-12-14 | ソニー株式会社 | Quantum cryptographic communication device and communication terminal |
-
2016
- 2016-10-18 CN CN201610902950.2A patent/CN106254072B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6801626B1 (en) * | 1999-05-12 | 2004-10-05 | Nec Corporation | Cryptographic key distribution using light pulses of three macroscopic quantum states |
| CN101697512A (en) * | 2009-11-09 | 2010-04-21 | 中国电子科技集团公司第三十研究所 | Method and system for anti-interference quantum secure direct communication |
| WO2012074369A1 (en) * | 2010-12-02 | 2012-06-07 | Mimos Berhad | A system and method for exchangeable quantum key distribution |
| CN102185693A (en) * | 2011-04-25 | 2011-09-14 | 安徽量子通信技术有限公司 | Quantum cryptography teaching system based on BB84 protocol and communication method thereof |
| CN104954122A (en) * | 2015-06-18 | 2015-09-30 | 清华大学 | Quantum key distribution post-processing method and quantum key distribution post-processing system under condition of mixed base vectors |
| CN206117683U (en) * | 2016-10-18 | 2017-04-19 | 清华大学 | Quantum key distribution system |
Non-Patent Citations (1)
| Title |
|---|
| 联合噪声下确定的安全量子通信;顾斌等;《中国科学:物理学 力学 天文学》;20100215(第02期);第177-182页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106254072A (en) | 2016-12-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106254072B (en) | Quantum key distribution method | |
| Djordjevic | Physical-layer security and quantum key distribution | |
| KR102485797B1 (en) | Method and system for detecting eavesdropping during data transmission | |
| CN107113169B (en) | Permanent secure communications from short-term secure encrypted quantum communications | |
| US7333611B1 (en) | Ultra-secure, ultra-efficient cryptographic system | |
| US9160529B2 (en) | Secret communication system and method for generating shared secret information | |
| CN108650088B (en) | Quantum communication device and method comprising at least three parties | |
| US11930106B2 (en) | Quantum communication system that switches between quantum key distribution (QKD) protocols and associated methods | |
| US8867742B2 (en) | Optical transmission device and reception device for Yuen encryption, optical transmission method and reception method for Yuen encryption, and encrypted communication system | |
| CN111404672B (en) | Quantum key distribution method and device | |
| EP1653654A1 (en) | Method and system for generating shared information | |
| WO2007036013A1 (en) | Any-point-to-any-point ('ap2ap') quantum key distribution protocol for optical ring network | |
| JP2023502349A (en) | quantum key distribution protocol | |
| CN113141252B (en) | Quantum key distribution method, quantum communication method, device and system | |
| Sun et al. | Design and implementation of a practical quantum secure direct communication system | |
| JP2010114662A (en) | Optical transmission device and method | |
| JP2018037904A (en) | Quantum key delivery system | |
| CN108712254B (en) | Quantum key distribution system and method | |
| CN111934785B (en) | Local area network terminal quantum communication method and system based on router | |
| CN212660171U (en) | Quantum key distribution system applied to mobile communication network | |
| CN106789020B (en) | Decoy state quantum key distribution system and method | |
| CN206117683U (en) | Quantum key distribution system | |
| CN115361118A (en) | Loss tolerant reference frame and measuring device independent quantum key distribution method | |
| JP5540743B2 (en) | Signal processing system, quantum cryptography system, signal processing method, and quantum cryptography method | |
| CN111917537B (en) | Base station-based mobile communication terminal quantum communication method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |