CN114374503A - A Long-distance Key Distribution System Based on Chaos Synchronization - Google Patents

Abstract

The invention belongs to the technical field of secret optical communication, in particular to a long-distance key distribution system based on chaotic synchronization, which solves the technical problems in the background technology and comprises a one-drive-two communication structure consisting of a driving part and two communication parties or a two-drive-two communication structure consisting of two driving parts and two communication parties which are respectively connected. The invention uses digital optical signal as drive signal, and responds the synchronous state of the laser output signal by the phase regulation of the key-controlled injection light, in the process, the digital signal is used as drive signal for long-distance transmission, and the digital signal is less influenced by noise in the link, thereby improving the synchronous quality, further increasing the key distribution distance, being applicable to longer-distance transmission and improving the long-distance synchronous quality.

Description

A Long-distance Key Distribution System Based on Chaos Synchronization

technical field

This application is a divisional application of the patent application with application number 202110508221.X. The application date of the original application is May 11, 2021. The name of the invention-creation of the original application is a long-distance key distribution system based on chaos synchronization.

The invention belongs to the technical field of secure optical communication, in particular to a long-distance key distribution system based on chaotic synchronization.

Background technique

Confidential communications are related to national stability, social security, privacy protection and many other aspects. In today's era, secure communication is developing in the direction of large capacity and long distance. Confidential communication is mainly divided into two categories: encryption of the channel and encryption of information. The security of information encryption depends on the security of the key. The existing secure communication distance is limited by the key distribution distance. Therefore, safe and long-distance key distribution to legitimate communication parties is an important research content to realize long-distance secure communication.

The existing key distribution scheme based on chaotic synchronization is that the legitimate user uses the synchronized chaotic laser as the relevant signal source and uses the independent random private key to key the transceiver, and finally extracts a password by filtering the chaotic timing modulated by the same private key. key for key distribution. In 2016, Porte et al. realized back-to-back key distribution using mutual coupling synchronization experiments ( Optics letters 41.12 (2016): 2871-2874.), but in this scheme, the chaotic carrier is exposed to the public channel, and the security is low. In 2012, Yoshimura of Japan's NTT Communication Laboratory proposed a chaotic co-drive synchronization key generation scheme ( Physical review letters 108.7 (2012): 070602.), and the experiment achieved key distribution at a distance of 120km. However, limited by the synchronization quality, it is difficult to increase the key distribution distance.

To sum up, the existing key distribution schemes have problems of low security or short distribution distance, and the existing key distribution schemes usually use analog signals as the driving source, but the analog signals are easily affected by noise, so it is necessary to A key distribution technology with strong anti-interference ability, security and long-distance transmission is invented.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problems that the existing key distribution scheme has low security or short distribution distance, and uses an analog signal as a driving source, so it is easily affected by noise. Long-distance key distribution system based on chaos synchronization with distance transmission.

The first technical means adopted by the present invention to solve the technical problem is: a long-distance key distribution system based on chaotic synchronization, including party A, party B and a driving part, and the driving part serves as the driving part of party A and party B at the same time The source forms a "one-drive-two" structure, and the driving part includes a narrow linewidth laser, a first polarization controller, a first erbium-doped fiber amplifier, an intensity modulator, an isolator, and a first fiber coupler, which are connected in sequence. The first fiber coupler The device includes an input end and two output ends. The other input end of the intensity modulator, which is not connected to the first erbium-doped fiber amplifier, is connected with a first arbitrary waveform generator, and the digital signal output by the first arbitrary waveform generator is determined by the intensity The modulator modulates the optical signal emitted by the narrow linewidth laser to form a digital optical signal; the A-side and the B-side respectively include an A-side optical attenuator and a B-side optical attenuator, and the two output ends of the first fiber coupler are respectively connected to A-side optical attenuator and B-side optical attenuator; A-side long-distance optical fiber is arranged between the first fiber coupler and A-side optical attenuator, and B-side optical attenuator is arranged between the first fiber coupler and B-side optical attenuator Long-distance fiber; the output end of the A-side optical attenuator is sequentially connected with the A-side phase modulator, the second A-side polarization controller, the A-side 1×2 fiber coupler, and the A-side semiconductor laser. The other input terminal that is not connected to the A-party optical attenuator is connected to a second A-party arbitrary waveform generator, and the A-party phase modulator uses the 01 random sequence sent by the second A-party arbitrary waveform generator to key the digital optical signal. Phase, the 01 random sequence of the second A-party arbitrary waveform generator used to control the phase of the digital optical signal is the A-party private key, and the other output end of the A-party 1×2 fiber coupler that is not connected to the A-party semiconductor laser A-side photodetector is connected, and the output end of A-side photodetector is also connected with A-side analog-to-digital converter and A-side memory in turn. After the digital optical signal is transmitted to the A-side semiconductor laser, the A-side semiconductor laser emits a chaotic signal. , the chaotic signal is converted into an electrical signal after being processed by the A-side photodetector, and the electrical signal is then processed by the A-side analog-to-digital converter and then converted into binary code and stored in the A-side memory. The output of the second A-side arbitrary waveform generator It is connected to the memory of party A to send the private key of party A to the memory of party A for storage; the output end of the optical attenuator of party B is connected with the phase modulator of party B, the second polarization controller of party B, the 1× 2. The fiber coupler and the B-side semiconductor laser, the other input end of the B-side phase modulator that is not connected to the B-side optical attenuator is connected with a second B-side arbitrary waveform generator, and the B-side phase modulator passes through the second B-side The arbitrary waveform generator sends 01 random sequence to key the phase of the digital optical signal, and the 01 random sequence of the second B-party arbitrary waveform generator used to control the phase of the digital optical signal is the B-party private key, and the B-party 1×2 fiber The other output end of the coupler that is not connected with the B-side semiconductor laser is connected with a B-side photodetector, and the output of the B-side photodetector is also connected with a B-side analog-to-digital converter and a B-side memory in turn, and the digital optical signal is transmitted. After reaching the B-side semiconductor laser, the B-side semiconductor laser emits The chaotic signal is generated. The chaotic signal is converted into an electrical signal after being processed by the B-side photodetector. The electrical signal is then processed by the B-side analog-to-digital converter and then converted into binary code and stored in the B-side memory. The second B-side arbitrary waveform generator The output end of the device is connected to the party B's memory to send the private key of party B to the memory of party B for storage; a public channel for exchanging the private key of party A and the private key of party B is connected between the memory of party A and the memory of party B. Party A and Party B both compare their own private key, namely the 01 random sequence, with the private key of the other party, and select the corresponding binary code when the phases are consistent as the consensus key of both parties A and B.

Party A and Party B are both parties of the communication. In order to achieve signal synchronization, the structural composition of the A party and the B party and the parameters set by each part should be consistent, which is well known to those skilled in the art. The digital signal has only two states, 0 and 1. The mean value is denoted as 0, and the above value is denoted as 1. Even if other interfering signals are mixed in, the original signal can be reproduced as long as the value of the interfering signal does not exceed the threshold range. Even if a bit error occurs because the value of the interference signal exceeds the threshold range, the bit error can be detected and corrected as long as a certain coding technique is used, such as an error correction code technique (ECC/FEC/RS). Therefore, compared with the analog signal, the digital signal has better anti-interference ability and smaller distortion amplitude during the transmission process, and has the potential for long-distance transmission. Using the digital signal as the driving signal in the present invention can improve the quality of chaotic synchronization. The phase of the injected light is keyed by the private key in response to the synchronization state of the output signal of the semiconductor laser. When the private keys of both parties are the same, chaos synchronization can be achieved; when the private keys of the two parties are different, the two parties are not synchronized. The A-side long-distance optical fiber is located between the first fiber coupler and the A-side optical attenuator, and the B-side long-distance optical fiber is located between the first optical fiber coupler and the B-side optical attenuator. In this process, the digital optical signal is used as the driving signal. Distance transmission, while digital signals are less affected by noise in the link, which improves synchronization quality and increases key distribution distance.

Preferably, a second A-side erbium-doped fiber amplifier is further arranged between the A-side optical attenuator and the A-side long-distance optical fiber, and a second B-side erbium-doped fiber amplifier is also arranged between the B-side optical attenuator and the B-side long-distance optical fiber. optical fiber amplifier. Setting the second A-side erbium-doped fiber amplifier and the second B-side erbium-doped fiber amplifier can increase the security of signal transmission.

The second technical means adopted by the present invention to solve the technical problem is: including A side, B side, a first arbitrary waveform generator, and a first driving part and a second driving part with the same structure, the first and second driving parts are divided into As the driving source of the A side and the B side to form a "two-drive-two" structure, the first and second driving parts each include a narrow linewidth laser, a first polarization controller, a first erbium-doped fiber amplifier, an intensity modulator, The isolator and the first fiber coupler, the first fiber coupler includes an input end and an output end, and the two output ends of the first arbitrary waveform generator are respectively connected to the intensity modulation in the first and second driving parts through long-distance optical fibers The other input end of the device that is not connected to the first erbium-doped fiber amplifier, the digital signal output by the first arbitrary waveform generator is transmitted over a long distance and then modulated by the intensity modulator to the optical signal emitted by the respective narrow linewidth lasers A digital optical signal is formed; the A-side and the B-side respectively include the A-side optical attenuator and the B-side optical attenuator, and the output ends of the first fiber couplers in the first and second driving parts are respectively connected with the A-side optical attenuator and the B-side optical attenuator. The optical attenuator is connected, and the output end of the A-side optical attenuator is also connected with the A-side phase modulator, the second A-side polarization controller, the A-side 1×2 fiber coupler, the A-side semiconductor laser, and the A-side phase modulator. The other input end of the optical attenuator that is not connected to the A-party optical attenuator is connected with a second A-party arbitrary waveform generator, and the A-party phase modulator keyes the digital optical signal through the 01 random sequence sent by the second A-party arbitrary waveform generator. The 01 random sequence of the second A-party arbitrary waveform generator used to control the phase of the digital optical signal is the A-party private key, and the other output of the A-party 1×2 fiber coupler that is not connected to the A-party semiconductor laser The A-side photodetector is connected to the end, and the output end of the A-side photodetector is also connected to the A-side analog-to-digital converter and the A-side memory in turn. After the digital optical signal is transmitted to the A-side semiconductor laser, the A-side semiconductor laser emits chaos. Signal, the chaotic signal is converted into an electrical signal after being processed by the A-side photodetector, and the electrical signal is converted into a binary code after being processed by the A-side analog-to-digital converter and stored in the A-side memory. The output of the second A-side arbitrary waveform generator The terminal is connected to the memory of party A, and the second party A arbitrary waveform generator sends the private key of party A to the memory of party A for storage; the output end of the optical attenuator of party B is also connected with the phase modulator of party B, the second party B Square polarization controller, B-side 1×2 fiber coupler and B-side semiconductor laser, the other input end of B-side phase modulator not connected with B-side optical attenuator is connected with a second B-side arbitrary waveform generator, B-side The square phase modulator uses the 01 random sequence sent by the second B-party arbitrary waveform generator to key the phase of the digital optical signal, and the 01 random sequence of the second B-party arbitrary waveform generator used to control the phase of the digital optical signal is B The private key of the party, the other output end of the 1×2 fiber coupler of party B that is not connected to the semiconductor laser of party B is connected with the photodetector of party B, and the output end of the photodetector of party B is also connected with the analog-to-digital conversion of party B in turn. device and B-side memory, the digital optical signal is transmitted to the B-side semiconductor laser After the optical device, the B-side semiconductor laser emits a chaotic signal. The chaotic signal is converted into an electrical signal after being processed by the B-side photodetector. The electrical signal is then processed by the B-side analog-to-digital converter and then converted into binary code and stored in the B-side memory. , the output of the second party B arbitrary waveform generator is connected to the memory of party B, and the second party B arbitrary waveform generator sends the private key of party B to the memory of party B for storage; the connection between the memory of party A and the memory of party B There is a public channel for exchanging the private key of Party A and Party B's private key. Both Party A and Party B compare their own private key, namely the 01 random sequence, with the private key of the other party, and select the corresponding binary code when the phases are consistent as A, The consensus key of both parties of B. In this structure, the two-drive-two structure is adopted, and the driving and the response are together, so the first driving part and the A party are collectively referred to as the A communication party, and the second driving part and the B party are collectively referred to as the B communication party. Between the intensity modulator and the first arbitrary waveform generator, in this process, the digital signal is transmitted as a driving signal for a long distance, and the driving signal is not transmitted in a common channel, so the security is higher, and the digital signal is affected by the link. The impact of noise is low, the synchronization quality is improved, and the key distribution distance is increased. In order to achieve signal synchronization, the structural composition of the A communication party and the B communication party and the parameters set by each part should be consistent, which is well known to those skilled in the art.

The beneficial effects of the present invention are: using the digital optical signal as the driving signal, and responding to the synchronous state of the laser output signal through the phase control of the keyed injected light, in this process, the digital signal is used as the driving signal for long-distance transmission, and the digital signal is received in the link. The influence of noise is low, the synchronization quality is improved, and the key distribution distance is increased, which can be used for longer-distance transmission and improve the long-distance synchronization quality.

Description of drawings

FIG. 1 is a schematic structural diagram of a long-distance key distribution system based on chaotic synchronization described in Embodiment 1 of the present invention.

FIG. 2 is a schematic structural diagram of a long-distance key distribution system based on chaotic synchronization described in Embodiment 2 of the present invention.

In the figure: 1-narrow linewidth laser; 2-first polarization controller; 3-first erbium-doped fiber amplifier; 4-intensity modulator; 5-isolator; 6-first fiber coupler; 7-first Arbitrary waveform generator; 8a-A square optical attenuator; 9a-A square long-distance fiber; 10a-A square phase modulator; 11a-second A square polarization controller; 12a-A square 1×2 fiber coupler; 13a-A-Side Semiconductor Laser; 14a-Second A-Side Arbitrary Waveform Generator; 15a-A-Side Photodetector; 16a-A-Side Analog-to-Digital Converter; 17a-A-Side Memory; 18a-Second A-Side Erbium-Doped Fiber Amplifier; 8b-B-side optical attenuator; 9b-B-side long-distance fiber; 10b-B-side phase modulator; 11b-Second B-side polarization controller; 12b-B-side 1×2 fiber coupler; 13b-B square semiconductor laser; 14b-second B-square arbitrary waveform generator; 15b-B-square photodetector; 16b-B-square analog-to-digital converter; 17b-B-square memory; 18b-second B-square erbium-doped fiber amplifier; 19 - common channel; 20 - long-distance fiber.

Detailed ways

1 and 2, a long-distance key distribution system based on chaotic synchronization according to the present invention will be described in detail.

Embodiment 1: A long-distance key distribution system based on chaotic synchronization, as shown in Figure 1, includes party A, party B and a driving part, and the driving part acts as the driving source of party A and party B at the same time to form a "one-drive system". 2" structure, the driving part includes a narrow linewidth laser 1, a first polarization controller 2, a first erbium-doped fiber amplifier 3, an intensity modulator 4, an isolator 5 and a first fiber coupler 6, which are connected in sequence. The coupler 6 includes an input end and two output ends, and another input end of the intensity modulator 4 that is not connected with the first erbium-doped fiber amplifier 3 is connected with a first arbitrary waveform generator 7, the first arbitrary waveform generator 7 The output digital signal is modulated by the intensity modulator 4 to the optical signal emitted by the narrow linewidth laser 1 to form a digital optical signal; The two output ends of the coupler 6 are respectively connected to the A-side optical attenuator 8a and the B-side optical attenuator 8b; an A-side long-distance optical fiber 9a is arranged between the first fiber coupler 6 and the A-side optical attenuator 8a. A B-side long-distance optical fiber 9b is arranged between an optical fiber coupler 6 and a B-side optical attenuator 8b; the output end of the A-side optical attenuator 8a is sequentially connected with an A-side phase modulator 10a and a second A-side polarization controller 11a, A-side 1×2 fiber coupler 12a and A-side semiconductor laser 13a, the other input end of A-side phase modulator 10a not connected to A-side optical attenuator 8a is connected with a second A-side arbitrary waveform generator 14a , the A-side phase modulator 10a uses the 01 random sequence sent by the second A-side arbitrary waveform generator 14a to key the phase of the digital optical signal, and the second A-side arbitrary waveform generator 14a uses 01 to control the phase of the digital optical signal The random sequence is the private key of the party A. The other output end of the 1×2 fiber coupler 12a of the party A, which is not connected to the semiconductor laser 13a of the party A, is connected to the photodetector 15a of the party A, and the output end of the photodetector 15a of the party A is connected. A-side analog-to-digital converter 16a and A-side memory 17a are also connected in turn. After the digital optical signal is transmitted to the A-side semiconductor laser 13a, the A-side semiconductor laser 13a emits a chaotic signal, and the chaotic signal is processed by the A-side photodetector 15a. Converted into an electrical signal, the electrical signal is then processed by the A-side analog-to-digital converter 16a and then converted into a binary code and stored in the A-side memory 17a. The output end of the second A-side arbitrary waveform generator 14a is connected to the A-side memory 17a for Send the private key of the A-party to the A-party memory 17a for storage; the output of the B-party optical attenuator 8b is sequentially connected with the B-party phase modulator 10b, the second B-party polarization controller 11b, and the B-party 1×2 fiber coupling The other input end of the B-side phase modulator 10b that is not connected to the B-side optical attenuator 8b is connected to a second B-side arbitrary waveform generator 14b, and the B-side phase modulator 10b is passed through the second B-side arbitrary waveform generator 14b. The second B-side arbitrary waveform generator 14b sends a 01 random sequence to key the phase of the digital optical signal, and the second B-side arbitrary waveform generator 14b The 01 random sequence used to control the phase of the digital optical signal is the private key of the party B. The other output end of the 1×2 fiber coupler 12b of the party B, which is not connected to the semiconductor laser 13b of the party B, is connected to the photodetector 15b of the party B. The output end of the B-side photodetector 15b is also connected to the B-side analog-to-digital converter 16b and the B-side memory 17b in sequence. After the digital optical signal is transmitted to the B-side semiconductor laser 13b, the B-side semiconductor laser 13b emits a chaotic signal, and the chaotic signal After being processed by the B-side photodetector 15b, it is converted into an electrical signal, and the electrical signal is then processed by the B-side analog-to-digital converter 16b and then converted into a binary code and stored in the B-side memory 17b. The output of the second B-side arbitrary waveform generator 14b The terminal is connected with the B-party memory 17b to send the B-party private key to the B-party memory 17b for storage; the A-party memory 17a and the B-party memory 17b are connected with a public key for exchanging the A-party private key and the B-party private key. In channel 19, Party A and Party B both compare their own private key, namely the 01 random sequence, with the private key of the other party, and select the corresponding binary code when the phases are consistent as the consensus key of both parties A and B.

Party A and Party B are both parties of the communication. In order to achieve signal synchronization, the structural composition of the A party and the B party and the parameters set by each part should be consistent, which is well known to those skilled in the art. The digital signal has only two states, 0 and 1. The mean value is denoted as 0, and the above value is denoted as 1. Even if other interfering signals are mixed in, the original signal can be reproduced as long as the value of the interfering signal does not exceed the threshold range. Even if a bit error occurs because the value of the interference signal exceeds the threshold range, the bit error can be detected and corrected as long as a certain coding technique, such as an error correction code technique, such as ECC/FEC/RS is adopted. Therefore, compared with the analog signal, the digital signal has better anti-interference ability and smaller distortion amplitude during the transmission process, and has the potential for long-distance transmission. Using the digital signal as the driving signal in the present invention can improve the quality of chaotic synchronization. The phase of the injected light is keyed by the private key in response to the synchronization state of the output signal of the semiconductor laser. When the private keys of both parties are the same, chaos synchronization can be achieved; when the private keys of the two parties are different, the two parties are not synchronized. The A-side long-distance optical fiber 9a is located between the first fiber coupler 6 and the A-side optical attenuator 8a, and the B-side long-distance optical fiber 9b is located between the first optical fiber coupler 6 and the B-side optical attenuator 8b. The optical signal is used as a driving signal for long-distance transmission, while the digital signal is less affected by the noise in the link, which improves the synchronization quality and further increases the key distribution distance.

Further, as a specific implementation of the long-distance key distribution system based on chaotic synchronization described in Embodiment 1, a second A-side optical attenuator 8a and the A-side long-distance optical fiber 9a are also provided. A second B-side erbium-doped fiber amplifier 18b is also arranged between the square erbium-doped fiber amplifier 18a, the B-side optical attenuator 8b and the B-side long-distance optical fiber 9b. Setting the second A-side erbium-doped fiber amplifier 18a and the second B-side erbium-doped fiber amplifier 18b can increase the security of signal transmission.

Further, as a specific implementation of the long-distance key distribution system based on chaotic synchronization described in Embodiment 1, the first fiber coupler 6, the A-side 1×2 fiber-optic coupler 12a, and the B-side 1× The coupling ratios of the two fiber couplers 12b are both 50:50.

Embodiment 2: A long-distance key distribution system based on chaotic synchronization, as shown in FIG. 2, including party A, party B, a first arbitrary waveform generator 7, and a first driving part and a second driving part with the same structure , the first and second driving parts are divided into the driving sources of the A side and the B side to form a "two driving two" structure. The first and second driving parts both include a narrow linewidth laser 1, a first polarization controller 2, The first erbium-doped fiber amplifier 3, the intensity modulator 4, the isolator 5 and the first fiber coupler 6, the first fiber coupler 6 includes an input end and an output end, and the two outputs of the first arbitrary waveform generator 7 The ends are respectively connected to the other input ends of the intensity modulator 4 in the first and second driving parts that are not connected to the first erbium-doped fiber amplifier 3 through the long-distance optical fiber 20, and the digital signal output by the first arbitrary waveform generator 7 passes through the long-distance optical fiber. After distance transmission, the intensity modulator 4 modulates the optical signal emitted by the respective narrow linewidth laser 1 to form a digital optical signal; The output ends of the first fiber coupler 6 in the first and second driving parts are respectively connected to the A-side optical attenuator 8a and the B-side optical attenuator 8b, and the output end of the A-side optical attenuator 8a is also connected to the A-side phase modulation device in sequence. 10a, the second A-side polarization controller 11a, the A-side 1×2 fiber coupler 12a, and the A-side semiconductor laser 13a, and the other input end of the A-side phase modulator 10a that is not connected to the A-side optical attenuator 8a is connected to There is a second A-party arbitrary waveform generator 14a, the A-party phase modulator 10a uses the 01 random sequence sent by the second A-party arbitrary waveform generator 14a to key the phase of the digital optical signal, and the second A-party arbitrary waveform generator 14a The 01 random sequence used to control the phase of the digital optical signal is the private key of the party A. The other output end of the 1×2 fiber coupler 12a of the party A, which is not connected to the semiconductor laser 13a of the party A, is connected to the photodetector 15a of the party A. , the output end of the A-side photodetector 15a is also connected with the A-side analog-to-digital converter 16a and the A-side memory 17a in turn. After the digital optical signal is transmitted to the A-side semiconductor laser 13a, the A-side semiconductor laser 13a emits a chaotic signal. The signal is converted into an electrical signal after being processed by the A-square photodetector 15a, and the electrical signal is converted into a binary code after being processed by the A-square analog-to-digital converter 16a and stored in the A-square memory 17a. The output end is connected to the A-party memory 17a, and the second A-party arbitrary waveform generator 14a sends the A-party private key to the A-party memory 17a for storage; the output end of the B-party optical attenuator 8b is also sequentially connected with the B-party phase modulation 10b, the second B-side polarization controller 11b, the B-side 1×2 fiber coupler 12b and the B-side semiconductor laser 13b, the other input end of the B-side phase modulator 10b that is not connected to the B-side optical attenuator 8b is connected There is a second B-party arbitrary waveform generator 14b, and the B-party phase modulator 10b sends 01 random sequence to key the phase of the digital optical signal, the 01 random sequence of the second B-party arbitrary waveform generator 14b used to control the phase of the digital optical signal is the B-party private key, and the B-party 1×2 fiber coupler 12b is not connected to The other output end connected to the B-side semiconductor laser 13b is connected to a B-side photodetector 15b, and the output end of the B-side photodetector 15b is also connected to a B-side analog-to-digital converter 16b and a B-side memory 17b in sequence. After reaching the B-side semiconductor laser 13b, the B-side semiconductor laser 13b emits a chaotic signal, the chaotic signal is converted into an electrical signal after being processed by the B-side photodetector 15b, and the electrical signal is processed by the B-side analog-to-digital converter 16b and then converted into binary. The code is stored in the B-party memory 17b, the output end of the second B-party arbitrary waveform generator 14b is connected to the B-party memory 17b, and the second B-party arbitrary waveform generator 14b sends the B-party private key to the B-party memory 17b for processing. Storage: A public channel 19 is connected between the A-party memory 17a and the B-party memory 17b for exchanging the private key of the A-party and the private key of the B-party. For comparison, select the corresponding binary code when the phases are consistent as the consensus key of both A and B. In this structure, the two-drive-two structure is adopted, and the driving and the response are together, that is, the first driving part and the A party are collectively referred to as the A communication party, the second driving part and the B party are collectively referred to as the B communication party, and the long-distance optical fiber 20 It is set between the intensity modulator 4 and the first arbitrary waveform generator 7. In this process, the digital signal is transmitted as a driving signal for a long distance, and the driving signal is not transmitted in the common channel 19, so the safety is higher, while the digital signal is transmitted over a long distance. It is less affected by the noise in the link, improves the synchronization quality, and further increases the key distribution distance.

Further, as a specific implementation of the long-distance key distribution system based on chaotic synchronization described in Embodiment 2, the first fiber coupler 6, the A-side 1×2 fiber-optic coupler 12a, and the B-side 1× The coupling ratios of the two fiber couplers 12b are both 50:50.

The above specific structure is a specific description of the preferred embodiment of the present invention, but the invention is not limited to the embodiment, and those skilled in the art can make various equivalents without departing from the spirit of the present invention. Modifications or substitutions, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present application.

Claims (2)

1. A long-distance key distribution system based on chaotic synchronization, characterized in that it includes a party A, a party B, a first arbitrary waveform generator (7), and a first driving part and a second driving part with the same structure; The first and second driving parts are divided into the driving sources of the A side and the B side to form a "two driving two" structure. The first and second driving parts both include a narrow linewidth laser (1), a first polarization controller (2) ), a first erbium-doped fiber amplifier (3), an intensity modulator (4), an isolator (5) and a first fiber coupler (6), the first fiber coupler (6) including an input end and an output end , the two output ends of the first arbitrary waveform generator (7) are respectively connected to the first and second erbium-doped fiber amplifiers (3) of the intensity modulator (4) in the first and second driving parts through long-distance optical fibers (20). The other input end that is connected, the digital signal output by the first arbitrary waveform generator (7) is transmitted over a long distance and then modulated by the intensity modulator (4) to the optical signal emitted by the respective narrow linewidth laser (1) to form Digital optical signal; the A-side and the B-side respectively include an A-side optical attenuator (8a) and a B-side optical attenuator (8b), and the output ends of the first fiber couplers (6) in the first and second driving parts are respectively connected to The A-side optical attenuator (8a) is connected to the B-side optical attenuator (8b), and the output end of the A-side optical attenuator (8a) is also connected to the A-side phase modulator (10a) and the second A-side polarization controller in sequence. (11a), A-side 1×2 fiber coupler (12a) and A-side semiconductor laser (13a), the other input end of A-side phase modulator (10a) not connected to A-side optical attenuator (8a) is connected There is a second A-party arbitrary waveform generator (14a), the A-party phase modulator (10a) uses the 01 random sequence sent by the second A-party arbitrary waveform generator (14a) to key the phase of the digital optical signal, the second A-party arbitrary waveform generator (14a) The 01 random sequence of the square arbitrary waveform generator (14a) used to control the phase of the digital optical signal is the private key of the A-side, and the A-side 1×2 fiber coupler (12a) is not connected to the A-side semiconductor laser (13a). The other output end is connected with the A-side photodetector (15a), and the output end of the A-side photodetector (15a) is also connected with the A-side analog-to-digital converter (16a) and the A-side memory (17a) in turn. After being emitted to the A-side semiconductor laser (13a), the A-side semiconductor laser (13a) emits a chaotic signal, and the chaotic signal is converted into an electrical signal after being processed by the A-side photodetector (15a), and the electrical signal is then converted by the A-side analog-to-digital conversion. The output terminal of the second A-party arbitrary waveform generator (14a) is connected to the A-party memory (17a), and the second A-party arbitrary waveform generates The device (14a) sends the private key of the A-party to the A-party memory (17a) for storage; the output of the B-party optical attenuator (8b) is also sequentially connected with the B-party phase modulator (10b), the second B-party polarization Controller (11b), B side 1×2 fiber coupler (1 2b) and the B-side semiconductor laser (13b), the other input end of the B-side phase modulator (10b) that is not connected to the B-side optical attenuator (8b) is connected with a second B-side arbitrary waveform generator (14b), The B-side phase modulator (10b) keys the phase of the digital optical signal through the 01 random sequence sent by the second B-side arbitrary waveform generator (14b), which is used to control the digital The 01 random sequence of the optical signal phase is the private key of party B, and the other output end of the 1×2 fiber coupler (12b) of party B, which is not connected to the semiconductor laser of party B (13b), is connected to the photodetector of party B (15b). ), the output end of the B-side photodetector (15b) is also connected to the B-side analog-to-digital converter (16b) and the B-side memory (17b) in turn. After the digital optical signal is transmitted to the B-side semiconductor laser (13b), the B-side The semiconductor laser (13b) emits a chaotic signal, and the chaotic signal is converted into an electrical signal after being processed by the B-square photodetector (15b), and the electrical signal is then processed by the B-square analog-to-digital converter (16b) and then converted into binary code and stored in B In the party memory (17b), the output end of the second party B arbitrary waveform generator (14b) is connected to the party B memory (17b), and the second party B arbitrary waveform generator (14b) sends the private key of party B to party B Stored in the memory (17b); the A-party memory (17a) and the B-party memory (17b) are connected with a public channel (19) for exchanging the private key of the A-party and the private key of the B-party. The private key of one's own party is compared with the private key of the other party, and the corresponding binary code when the phase is consistent is selected as the consensus key of both parties A and B. 2. A long-distance key distribution system based on chaotic synchronization according to claim 1, characterized in that the first fiber coupler (6), the A side 1×2 fiber coupler (12a) and the B side 1 The coupling ratios of the ×2 fiber couplers (12b) are all 50:50.

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