Secret communication system and method based on receiving chaos synchronization test adjustment

Abstract

The invention relates to the technical field of chaos secret communication, in particular to a secret communication system and method based on receiving chaos synchronization test adjusting.The secret communication system comprises a sending end, a transmission link and a receiving end, and chaos mixing superposed signals output by the sending end are evenly divided into two paths for transmission through a power divider unit; one path is used for generating a chaos synchronization signal through an open-loop chaos structure of a receiving end, and the other path is used as a ciphertext signal, so that chaos synchronization of a receiving end and a transmitting end is facilitated, the transmission process of the chaos synchronization signal in a public transmission link is avoided, and the confidentiality of the system is fundamentally ensured. And a receiving end adjusts the length of the optical fiber delay line through a delay test and feedback unit, so that the relative delay of two paths of signals output by the power divider unit is 0, and a chaotic signal synchronous with the sending end is quickly obtained. Therefore, the problems of difficulty in chaotic synchronization of the transmitting and receiving ends and poor transmission safety performance of the existing chaotic secure communication system are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of chaotic secure communication, and particularly to a secure communication system and method based on receiving chaotic synchronization test adjustment. Background Art

[0002] Under the background of the information age, network security risks are becoming increasingly prominent, and secure communication technology has attracted more and more attention. Chaotic secure communication has become a research hotspot in recent years due to its high bandwidth, signal characteristics similar to noise, high sensitivity to initial conditions, difficulty in being predicted, and good compatibility with existing communication systems.

[0003] Problems existing in traditional chaotic communication systems include: (1) When transmitting over a long distance, it is difficult to synchronize chaotic signals between the sending end and the receiving end; (2) During the transmission of chaotic signals between the sending end and the receiving end of the system through a common transmission link, the security of the system is relatively poor. Summary of the Invention

[0004] The purpose of the present invention is to provide a secure communication system and method based on receiving chaotic synchronization test adjustment, aiming to solve the problems of difficult chaotic synchronization between the sending and receiving ends and poor transmission security performance existing in existing chaotic secure communication systems.

[0005] To achieve the above object, in a first aspect, the present invention provides a secure communication system based on receiving chaotic synchronization test adjustment, including a sending end, a transmission link, and a receiving end, which are sequentially connected;

[0006] The sending end is used to superimpose the plaintext information to be transmitted with the chaotic signal modulated by the system for signal mixing encryption;

[0007] The transmission link is used to securely transmit the ciphertext signal superimposed with the chaotic carrier to the receiving end;

[0008] The receiving end is used to quickly obtain a chaotic signal synchronized with the sending end, and then recover the original plaintext information through differential demodulation.

[0009] Among them, the sending end includes a laser source unit, a chaotic modulation unit, a service unit, and a mixing and superimposing unit. The output port of the laser source unit is connected to the input port of the chaotic modulation unit, and the output ports of the chaotic modulation unit and the service unit are both connected to the input port of the mixing and superimposing unit;

[0010] The laser source unit is used to output laser to the chaotic modulation unit;

[0011] The chaotic modulation unit is used to generate a chaotic signal with complex dynamic characteristics;

[0012] The said service unit is used for the plaintext information to be transmitted;

[0013] The said mixing and superposition unit superimposes the modulated chaotic signal and the plaintext information to obtain an encrypted signal with chaotic carrier mixing and superposition.

[0014] Among them, the said chaotic modulation unit includes a modulator, an optical fiber delay line, a photodetector, and a radio frequency amplifier;

[0015] The said modulator is used for inducing the generation of chaotic oscillation;

[0016] The said optical fiber delay line is used for generating complex dynamic behaviors and increasing the chaotic dimension;

[0017] The said photodetector is used for performing optoelectronic conversion;

[0018] The said radio frequency amplifier is used for enhancing the degree of the electrical signal and then driving the modulator, so that the modulator shows nonlinearity under the condition of a large driving voltage.

[0019] Among them, the said receiving end includes a power splitter unit, a chaotic synchronization unit, a signal demodulation unit, a delay test unit, and a feedback unit;

[0020] The said power splitter unit is used for equally dividing the encrypted signal into two paths for parallel transmission;

[0021] The said chaotic synchronization unit is used for generating a chaotic signal synchronized with the sending end;

[0022] The said signal demodulation unit is used for performing differential demodulation on the ciphertext information transmitted by the sending end and the synchronized chaotic signal at the receiving end to recover the service information;

[0023] The said delay test unit is used for testing the relative delay of the two signals output by the power splitter unit to the demodulation unit;

[0024] The said feedback unit adjusts the length of the optical fiber delay line according to the delay test result.

[0025] In a second aspect, a secure communication method based on receiving chaotic synchronization test and adjustment is used for the secure communication system based on receiving chaotic synchronization test and adjustment described in the first aspect, and includes the following steps:

[0026] The sending end mixes and superimposes the service information to be transmitted with the chaotic signal to encrypt and protect the plaintext information;

[0027] The transmission link securely transmits the chaos-encrypted information to the receiving end;

[0028] The receiving end conducts a delay test on the system and performs feedback adjustment to quickly obtain a chaotic synchronization signal, and then performs differential demodulation with the encrypted signal to recover the service information transmitted by the sending end.

[0029] A secure communication system based on receiving chaos synchronization test adjustment according to the present invention includes a transmitting end, a transmission link, and a receiving end, which are connected in sequence; the transmitting end is used for superimposing the plaintext information to be transmitted with the chaos signal modulated by the system for signal mixing encryption; the transmission link is used for securely transmitting the ciphertext signal superimposed with the chaos carrier to the receiving end; the receiving end is used for quickly obtaining the chaos signal synchronized with the transmitting end, and then restoring the original plaintext information through differential demodulation. The chaos mixing superimposed signal output by the transmitting end of the present invention is evenly divided into two paths for transmission through a power divider unit. One path is used for generating a chaos synchronization signal through the open-loop chaos structure of the receiving end, and the other path is used as the ciphertext signal. In this way, it is easy to achieve chaos synchronization between the transmitting and receiving ends, and it also avoids the transmission process of the chaos synchronization signal on the common transmission link, fundamentally ensuring the confidentiality of the system. The receiving end adjusts the length of the optical fiber delay line through a delay test and a feedback unit, so that the relative delay of the two signals output by the power divider unit is 0, thereby quickly obtaining the chaos signal synchronized with the transmitting end. Thus, the problems of difficult chaos synchronization between the transmitting and receiving ends and poor transmission security performance existing in the existing chaos secure communication system are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic diagram of a secure communication system based on receiving chaos synchronization test adjustment provided by the present invention. In the figure, 4 represents an electric switch.

[0032] Figure 2 It is a schematic diagram of the principle of a secure communication system based on receiving chaos synchronization test adjustment. In the figure, 4 represents an electric switch; the dotted connecting line represents an optical signal connection; the solid connecting line represents an electric signal connection.

[0033] Figure 3 It is a schematic diagram of a chaos modulation unit.

[0034] Figure 4 It is a flowchart of a secure communication method based on receiving chaos synchronization test adjustment provided by the present invention.

[0035] In the figure: 1 - transmitting end, 2 - transmission link, 3 - receiving end, 11 - laser source unit, 12 - chaotic modulation unit, 13 - service unit, 14 - mixing and superposition unit, 121 - modulator, 122 - optical fiber delay line, 123 - photodetector, 124 - radio frequency amplifier, 31 - power splitter unit, 32 - chaotic synchronization unit, 33 - signal demodulation unit, 34 - delay test unit, 35 - feedback unit. Specific embodiments

[0036] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0037] Please refer to Figures 1 to 3 , in a first aspect, the present invention provides a secure communication system based on receiving chaotic synchronization test and adjustment, including a transmitting end 1, a transmission link 2, and a receiving end 3, where the transmitting end 1, the transmission link 2, and the receiving end 3 are connected in sequence;

[0038] The transmitting end 1 is used to superimpose the plaintext information to be transmitted with the chaotic signal modulated by the system for signal mixing encryption;

[0039] The transmission link 2 is used to securely transmit the ciphertext signal superimposed with the chaotic carrier to the receiving end 3;

[0040] The receiving end 3 is used to quickly obtain a chaotic signal synchronized with the transmitting end 1, and then restore the original plaintext information through differential demodulation.

[0041] In this embodiment, the transmitter 1 is configured to superimpose the plaintext information to be transmitted with the chaotic signal modulated by the system for signal mixing encryption; the transmission link 2 is configured to securely transmit the ciphertext signal superimposed with the chaotic carrier to the receiver 3; the receiver 3 is configured to quickly obtain the chaotic signal synchronized with the transmitter 1, and then restore the original plaintext information through differential demodulation. The chaotic mixing superimposed signal output by the transmitter 1 of the present invention is evenly divided into two paths for transmission through the power splitter unit 31. One path passes through the open-loop chaotic structure of the receiver 3 to generate a chaotic synchronization signal, and the other path serves as the ciphertext signal. This makes it easy for the transmitter and receiver to achieve chaotic synchronization and avoids transmitting the chaotic synchronization signal in the public transmission link 2, fundamentally ensuring the confidentiality of the system. The receiver 3 adjusts the length of the optical fiber delay line 122 through the delay test unit 34 and the feedback unit 35 so that the relative delay of the two signals output by the power splitter unit 31 is 0, thereby quickly obtaining the chaotic signal synchronized with the transmitter 1. This solves the problems of difficult chaotic synchronization between the transmitter and receiver and poor transmission security performance existing in the existing chaotic secure communication system.

[0042] Further, the transmitter 1 includes a laser source unit 11, a chaotic modulation unit 12, a service unit 13, and a mixing and superimposing unit 14. The output port of the laser source unit 11 is connected to the input port of the chaotic modulation unit 12, and the output ports of the chaotic modulation unit 12 and the service unit 13 are both connected to the input port of the mixing and superimposing unit 14;

[0043] The laser source unit 11 is configured to output laser to the chaotic modulation unit 12;

[0044] The chaotic modulation unit 12 is configured to generate a chaotic signal with complex dynamic characteristics;

[0045] The service unit 13 is configured to handle the plaintext information to be transmitted;

[0046] The mixing and superimposing unit 14 superimposes the modulated chaotic signal with the plaintext information to obtain an encrypted signal of chaotic carrier mixing and superimposing.

[0047] In this embodiment, the laser source unit 11 outputs laser, and the chaotic modulation unit 12 introduces a non-linear interaction to the optical signal output by the laser source to generate a chaotic signal with complex dynamic behavior, and superimposes it with the service signal to be transmitted, obtaining an encrypted chaotic carrier mixing and superimposing signal, achieving the purpose of encrypting the service signal to prevent eavesdropping, attacks and other behaviors from obtaining service information during the transmission process.

[0048] Further, the chaotic modulation unit 12 includes a modulator 121, an optical fiber delay line 122, a photodetector 123, and a radio frequency amplifier 124;

[0049] The modulator 121 is used to induce the generation of chaotic oscillations;

[0050] The optical fiber delay line 122 is used to generate complex dynamic behaviors and increase the chaotic dimension;

[0051] The photodetector 123 is used for photoelectric conversion;

[0052] The radio frequency amplifier 124 is used to enhance the level of the electrical signal and then drive the modulator, so that the modulator exhibits non-linearity under the condition of a large driving voltage.

[0053] In this embodiment, the light output by the laser source is transmitted to the optical input port of the Mach-Zehnder modulator 121 through an optical fiber connecting line. The optical output port of the Mach-Zehnder modulator 121 is connected to one end of the optical fiber delay line 122, and the other end of the optical fiber delay line 122 is connected to the input port of the photodetector 123. The output port P of the photodetector 123 is connected to the input port of the radio frequency amplifier 124 through a radio frequency line, and the output port of the radio frequency amplifier 124 is connected to the radio frequency input port of the Mach-Zehnder modulator 121 through a radio frequency line, thus forming a closed-loop structure for generating chaotic signals. The other output port N of the photodetector 123 is transmitted to the input end of the mixing and superposition unit 14 through a radio frequency line together with the service information for superposition, and the output end of the mixing and superposition unit 14 is connected to the signal transmission link 2.

[0054] Furthermore, the receiving end 3 includes a power splitter unit 31, a chaotic synchronization unit 32, a signal demodulation unit 33, a delay test unit 34, and a feedback unit 35. On the one hand, when the signal is transmitted confidentially, one output port of the power splitter unit 31 is connected to the chaotic synchronization unit 32 and the signal demodulation unit 33, and the other output port is directly connected to the signal demodulation unit 33. On the other hand, when the system delay is tested, the output port of the delay test unit 34 is connected to the input port of the power splitter unit 31 and is connected to the feedback unit 35. The feedback unit 35 is connected to the chaotic synchronization unit 32, and the input port of the delay test unit 34 is connected to the output ports of the chaotic synchronization unit 32 and the power splitter unit 31;

[0055] The power splitter unit 31 is used to equally divide the encrypted signal into two paths for parallel transmission;

[0056] The chaotic synchronization unit 32 is used to generate a chaotic signal synchronized with the sending end 1;

[0057] The signal demodulation unit 33 is used to perform differential demodulation on the ciphertext information transmitted by the sending end 1 and the synchronous chaotic signal of the receiving end 3 to recover the service information;

[0058] The delay test unit 34 is configured to test the relative delay of the two signals output by the power splitter unit 31 to the demodulation unit;

[0059] The feedback unit 35 adjusts the length of the optical fiber delay line 122 according to the delay test result.

[0060] In this embodiment, first, the output port of the delay test unit 34 is connected to the input port of the power splitter unit 31. The power splitter unit 31 outputs two signals. One of the signals enters the chaotic synchronization unit 32 and then returns to the signal input end of the delay test unit 34, and the other signal directly returns to the signal input end of the delay test unit 34. In this way, the delay time of the two signals can be measured, and the length of the optical fiber delay line 122 is adjusted in real time through the feedback control unit to make the relative delay of the two signals zero. Then, the input port of the power splitter unit 31 is connected to the transmission link 2. The power splitter unit 31 outputs two ciphertext signals. One of the signals obtains a chaotic signal synchronized with the sending end 1 through the chaotic synchronization unit 32, and then reaches the signal demodulation unit 33 through a radio frequency line. At this time, the other signal output by the power splitter unit 31 also reaches the signal demodulation unit 33 through a radio frequency line. The two signals recover the original service information of the sending end 1 through differential demodulation.

[0061] Please refer to Figure 4 , in a second aspect, a secure communication method based on receiving chaotic synchronization test adjustment, which is used for the secure communication system based on receiving chaotic synchronization test adjustment described in the first aspect, includes the following steps:

[0062] S1 The sending end 1 mixes and superimposes the service information to be transmitted with the chaotic signal to encrypt and protect the plaintext information;

[0063] Specifically, the output light source of the laser is connected to the optical input end of the Mach-Zehnder modulator 121 through an optical fiber connection line. The laser provides a light source for generating chaotic signals. By adjusting the bias voltage of the Mach-Zehnder modulator 121, a suitable operating point can be found. An appropriate bias voltage can make the Mach-Zehnder modulator 121 operate in the nonlinear region, making it easier to generate complex dynamic behaviors and providing a basis for the formation of a chaotic system. The optical output port of the Mach-Zehnder modulator 121 is connected to one end of the optical fiber delay line 122. The chaotic dimension can be effectively increased by adjusting the length of the optical fiber delay line 122, thereby enhancing the complexity of the chaotic behavior and making the dynamic characteristics of the system more difficult to predict and analyze. The other end of the optical fiber delay line 122 is connected to the input port of the photodetector 123 for optoelectronic conversion. The output electrical signal of the photodetector 123 is transmitted to the input port of the radio frequency amplifier 124 through a radio frequency line via port P. The output port of the radio frequency amplifier 124 is connected to the radio frequency input end of the Mach-Zehnder modulator 121 through a radio frequency line. By adjusting the gain of the radio frequency amplifier 124, the signal strength and the stability of the system can be enhanced. An appropriate gain setting can effectively control the chaotic state and prevent the system from entering an unstable or out-of-control state. At this time, a closed-loop structure is formed. When the output light of the laser passes through the Mach-Zehnder modulator 121, the nonlinear feedback mechanism adjusts the system parameters according to the intensity or phase of the optical signal, thereby inducing the generation of chaotic oscillations. The chaotic signal output from the other output port N of the photodetector 123 is superimposed on the service information to form a chaotic carrier mixing and superimposing signal, thereby completing the encryption of the service information.

[0064] The transmission link 2 of S2 securely transmits the chaotically encrypted information to the receiving end 3;

[0065] Specifically, the transmission link 2 carries the chaotic carrier mixing signal composed of the superposition of the chaotic signal and the service signal at the sending end 1 and transmits it to the receiving end 3 through a radio frequency line.

[0066] The receiving end 3 of S3 performs a delay test on the system and feedback adjusts to quickly obtain a chaotic synchronization signal, and then performs differential demodulation with the encrypted signal to recover the service information transmitted by the sending end 1.

[0067] Specifically, first, the output signal of the delay test unit 34 is equally divided into two paths by the power splitter unit 31. One path of the signal returns to the delay test unit 34 through the chaotic synchronization unit 32, and the other path of the signal directly returns to the delay test unit 34. Thus, the relative delay between the two paths of signals is measured, and the length of the optical fiber delay line 122 is adjusted in real time by the feedback control unit to make the relative delay zero. Then, the transmission link 2 is connected to the input end of the power splitter unit 31, and the power splitter unit 31 outputs two encrypted signals. One of the encrypted signals is filtered out the service information by the chaotic synchronization unit 32 to obtain a chaotic synchronization signal, and then the chaotic synchronization signal is differentially demodulated with the other encrypted signal to restore the original service information of the sending end 1.

[0068] The beneficial effects of the present invention are as follows:

[0069] (1) The chaotic mixing and superposition signal output by the sending end of the present invention is equally divided into two paths for transmission by the power splitter. One path passes through the open-loop chaotic structure of the receiving end to generate a chaotic synchronization signal, and the other path is used as the ciphertext signal. In this way, it is easy to achieve chaotic synchronization between the sending and receiving ends, and the transmission process of the chaotic synchronization signal in the public transmission link is avoided, fundamentally ensuring the confidentiality of the system.

[0070] (2) The receiving end of the present invention adjusts the length of the optical fiber delay line through the delay test and feedback unit to make the relative delay between the two paths of signals output by the power splitter zero, so as to quickly obtain a chaotic signal synchronized with the sending end.

[0071] (3) The structure of the present invention is simple, easy to build, and convenient for engineering application.

[0072] The above-disclosed is only a preferred embodiment of a secure communication system and method based on receiving chaotic synchronization test and adjustment of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A secure communication system based on receiving chaotic synchronization test adjustment, characterized in that, It includes a sending end, a transmission link, and a receiving end, which are connected in sequence; The sending end is used to superimpose the plaintext information to be transmitted with the chaotic signal modulated by the system for signal mixing encryption; The transmission link is used to securely transmit the ciphertext signal superimposed with the chaotic carrier to the receiving end; The receiving end is used to quickly obtain a chaotic signal synchronized with the sending end, and then recover the original plaintext information through differential demodulation.

2. The secure communication system based on received chaos synchronization test adjustment as claimed in claim 1, wherein The sending end includes a laser source unit, a chaos modulation unit, a service unit, and a mixing and superimposing unit. The output port of the laser source unit is connected to the input port of the chaos modulation unit, and the output ports of the chaos modulation unit and the service unit are both connected to the input port of the mixing and superimposing unit; The laser source unit is used to output laser to the chaos modulation unit; The chaos modulation unit is used to generate a chaotic signal with complex dynamic characteristics; The service unit is used to process the plaintext information to be transmitted; The mixing and superimposing unit superimposes the modulated chaotic signal with the plaintext information to obtain an encrypted signal with chaotic carrier mixing and superimposing.

3. The secure communication system based on received chaos synchronization test adjustment as claimed in claim 2, wherein The chaos modulation unit includes a modulator, an optical fiber delay line, a photodetector, and a radio frequency amplifier; The modulator is used to induce the generation of chaotic oscillation; The optical fiber delay line is used to generate complex dynamic behaviors and increase the chaos dimension; The photodetector is used for optoelectronic conversion; The radio frequency amplifier is used to enhance the electrical signal level and then drive the modulator, so that the modulator exhibits nonlinearity under the condition of a large driving voltage.

4. The secure communication system based on received chaos synchronization test adjustment as claimed in claim 1, wherein The receiving end includes a power splitter unit, a chaos synchronization unit, a signal demodulation unit, a delay test unit, and a feedback unit; The power splitter unit is used to equally divide the encrypted signal into two paths for parallel transmission; The chaos synchronization unit is used to generate a chaotic signal synchronized with the sending end; The signal demodulation unit is used to perform differential demodulation on the ciphertext information transmitted by the sending end and the synchronous chaotic signal at the receiving end to recover the service information; The delay test unit is used to test the relative delay of the two signals output by the power splitter unit to the demodulation unit; The feedback unit adjusts the length of the optical fiber delay line according to the delay test result.

5. A secure communication method based on received chaotic synchronization test adjustment, which is used for the secure communication system based on received chaotic synchronization test adjustment described in any one of claims 1-4, characterized in that It includes the following steps: The sending end mixes and superimposes the service information to be transmitted with the chaotic signal to encrypt and protect the plaintext information; The transmission link securely transmits the chaos-encrypted information to the receiving end; The receiving end performs delay testing and feedback adjustment on the system, quickly obtains the chaotic synchronization signal, and then performs differential demodulation with the encrypted signal to recover the service information transmitted by the sending end.

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