阅读说明：本技术 一种量子保密通信系统中感知及定位窃听装置及方法 (Sensing and positioning eavesdropping device and method in quantum secret communication system ) 是由 高震森 王云才 杨军 秦玉文 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种量子保密通信系统中感知及定位窃听装置及方法,装置包括发射端、接收端以及传输光纤,所述发射端发射量子保密通信信号和监控信号至传输光纤中,所述量子保密通信信号的波长和监控信号的波长不相等,所述传输光纤还与接收端连接,接收传输光纤中传输过来的信号,所述监控信号在传输光纤传输过程中产生的后向散射信号被发射端接收,发射端通过后向散射信号感知并定位窃听。本发明中,采用基于相位敏感光时域反射技术,在窃听者对量子保密通信系统实施窃听前,对其引起的光纤振动或扰动进行提前感知,并通过后向散射信号光,准确定位窃听者的窃听位置,有利于事前感知并定位窃听者,保障量子保密通信系统的安全性。(The invention discloses a device and a method for perceiving and positioning eavesdropping in a quantum secret communication system, wherein the device comprises a transmitting end, a receiving end and a transmission optical fiber, the transmitting end transmits a quantum secret communication signal and a monitoring signal to the transmission optical fiber, the wavelength of the quantum secret communication signal is not equal to that of the monitoring signal, the transmission optical fiber is also connected with the receiving end to receive the signal transmitted from the transmission optical fiber, a back scattering signal generated in the transmission process of the monitoring signal by the transmission optical fiber is received by the transmitting end, and the transmitting end perceives and positions eavesdropping through the back scattering signal. In the invention, a phase-sensitive optical time domain reflection technology is adopted, before eavesdropping is carried out on the quantum secret communication system by an eavesdropper, the eavesdropping position of the eavesdropper is accurately positioned through back-scattered signal light, the eavesdropper is favorably perceived and positioned in advance, and the safety of the quantum secret communication system is ensured.)

1. The device is characterized by comprising a transmitting end, a receiving end and a transmission optical fiber, wherein the transmitting end transmits a quantum secret communication signal and a monitoring signal to the transmission optical fiber, the wavelength of the quantum secret communication signal is not equal to that of the monitoring signal, the transmission optical fiber is also connected with the receiving end to receive the signal transmitted from the transmission optical fiber, a back scattering signal generated by the monitoring signal in the transmission process of the transmission optical fiber is received by the transmitting end, and the transmitting end senses and positions eavesdropping through the back scattering signal.

2. The device for perceiving and positioning eavesdropping in the quantum secure communication system according to claim 1, wherein the transmitting end comprises a quantum secure communication transmitting module and a phase sensitive optical time domain reflection measuring module, the quantum secure communication transmitting module outputs a quantum secure communication signal, and the phase sensitive optical time domain reflection measuring module outputs a monitoring signal and receives a back scattering signal returned by the monitoring signal in a transmission process of a transmission optical fiber.

3. The apparatus for perceiving and locating an eavesdropping in a quantum secure communication system according to claim 2, wherein the transmitting end further comprises a wavelength division multiplexer, an output end of the quantum secure communication transmitting module is connected to an input port corresponding to the wavelength division multiplexer, an output end of the phase-sensitive optical time domain reflection measuring module is connected to an input port corresponding to the wavelength division multiplexer, and an output port of the wavelength division multiplexer is connected to a transmission fiber.

4. The device for perceiving and locating eavesdropping in the quantum secure communication system according to claim 3, wherein the phase sensitive optical time domain reflectometry module comprises a narrow linewidth laser, a pulse modulator, an optical amplifier, an optical circulator, a photoelectric detection module, a signal acquisition module, a signal storage module and a signal processing module, wherein:

the output end of the narrow linewidth laser is connected with the input end of the pulse modulator;

the output end of the pulse modulator is connected with the input end of the optical amplifier;

the output end of the optical amplifier is connected with the first port of the optical circulator, the second port of the optical circulator is connected with the corresponding input port of the wavelength division multiplexer, and the third port of the optical circulator is connected with the input end of the photoelectric detection module;

the output end of the photoelectric detection module is connected with the input end of the signal acquisition module;

the output end of the signal acquisition module is respectively connected with the input end of the signal storage module and the input end of the signal processing module, and the signal processing module processes the returned back scattering signals to obtain whether eavesdropping behaviors exist or not and eavesdropping positions.

5. The apparatus for eavesdropping sensing and positioning in a quantum secure communication system as claimed in claim 4, wherein the wavelength channels of the quantum secure communication signal and the supervisory signal are multiplexed with a coarse wavelength multiplexing, and the coarse wavelength multiplexing is spaced at 20 nm.

6. The apparatus for perceiving and positioning eavesdropping in the quantum secure communication system as claimed in claim 5, wherein the receiving end comprises a wavelength division multiplexing demultiplexing module and a quantum secure communication receiving module, wherein:

the wavelength division multiplexing and demultiplexing module is connected with the transmission optical fiber and used for demultiplexing the quantum secret communication signals in the transmission optical fiber, and the wavelength division multiplexing and demultiplexing module is used for transmitting the demultiplexed quantum secret communication signals to the quantum secret communication receiving module.

7. A method for perceiving and locating eavesdropping in a quantum secure communication system, which is applied to the device for perceiving and locating eavesdropping in the quantum secure communication system as claimed in claims 1 to 6, comprising the steps of:

s1: pre-obtaining a reference backscattering curve without any disturbance;

s2: during communication, the transmitting end transmits a quantum secret communication signal and a monitoring signal to the transmission optical fiber for transmission;

s3: when the monitoring signal is transmitted by the transmission optical fiber, a backscattering signal returned by scattering is received by the transmitting end to form a backscattering curve, the backscattering curve and the reference backscattering curve are both curves taking the distance from the transmitting end as an abscissa and the signal power as an ordinate, and the round-trip time of backscattering signals at different distances is obtained;

s4: and performing subtraction operation on the backscatter reference signal and the reference scatter signal, and positioning the eavesdropping position through the length of the optical fiber and the round trip time.

Technical Field

The invention relates to the field of quantum communication, in particular to a sensing and positioning eavesdropping device and method in a quantum secret communication system.

Background

Quantum secret communication is a secret communication technology for guaranteeing information safe transmission by using a quantum mechanics principle, and has important application value in the fields of national defense, finance, government affairs and the like. The quantum secret communication technology is mainly based on the quantum mechanics inaccuracy measuring principle and the quantum unclonable law to realize quantum key distribution, namely, a quantum channel is used for transmitting a key, the key is used for encrypting classical information, and then the traditional classical channel is used for transmitting the encrypted information, so that the safety of a physical layer is provided for a communication network. Quantum secret communication combining quantum key distribution with modern optical fiber communication technology is a new secret communication technology capable of realizing safe and efficient transmission of a data physical layer.

The quantum key distribution is based on the basic principle of quantum physics, the quantum state of a single photon is used as an information carrier for encoding, transmission and detection, the key can be shared among users separated in space, and unconditional and safe key distribution is realized. Secure communications based on quantum key distribution are in principle absolutely secure and cannot be broken, since an eavesdropper cannot either copy the quantum states of a single photon to attempt to steal the secure data, or split a single photon to measure its quantum state. The photons, once measured, change their state and affect the bit error rate of the measurement, so that the presence of an eavesdropper is perceived by the sender. The quantum key distribution technology is realized regardless of the complexity of mathematical computation, and distributed keys cannot be broken even if the quantum key distribution technology has infinitely strong computing power. Therefore, quantum secure communication is considered as one of the important technical means for improving network information security in the future.

Although the quantum secure communication technology is a theoretically absolutely secure communication mode, the key problem of the quantum secure communication technology is that once an eavesdropper invades a quantum communication system and performs measurement eavesdropping of quantum states, the quantum states of photons are interfered, the bit error rate of key negotiation between two sending parties is increased, the sending party stops performing key distribution immediately, and all normal communication is stopped. The contradiction between the security and robustness of a system is an inherent problem that is difficult to solve. If an eavesdropper continues to eavesdrop maliciously, the quantum secure communication system will always be unable to make any communication, without any security and reliability. Therefore, it is highly desirable to develop a method for sensing and positioning an eavesdropper in advance in a quantum secure communication system, so that once the eavesdropper invades the quantum secure communication system, the existence of the eavesdropper can be quickly sensed and accurately positioned before the eavesdropper steals the secret information, thereby preventing illegal eavesdropping in time and ensuring the security and robustness of the quantum secure communication system.

Disclosure of Invention

The invention aims to provide a sensing and positioning eavesdropping device in a quantum secret communication system, which solves the problems of difficult eavesdropping positioning and low reliability of quantum communication.

It is a further object of the present invention to provide a method for perceiving and locating eavesdropping in a quantum secure communication system.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a perception and positioning eavesdropping device in a quantum secret communication system comprises a transmitting end, a receiving end and a transmission optical fiber, wherein the transmitting end transmits a quantum secret communication signal and a monitoring signal to the transmission optical fiber, the wavelength of the quantum secret communication signal is not equal to that of the monitoring signal, the transmission optical fiber is further connected with the receiving end to receive the signal transmitted from the transmission optical fiber, a back scattering signal generated in the transmission process of the monitoring signal by the transmission optical fiber is received by the transmitting end, and the transmitting end perceives and positions eavesdropping through the back scattering signal.

In the above scheme, the monitoring signal is coupled to the same optical fiber for optical fiber communication signal transmission through wavelength division multiplexing, the existing quantum secret communication system is kept unchanged, after the monitoring signal transmitted in the forward direction is transmitted through the optical fiber, due to the fact that the optical fiber is non-homogeneous, a backward Rayleigh scattering effect is caused, a backward scattering signal is generated and received by a transmitting end, when vibration or a micro disturbance event caused by eavesdropping is generated on the periphery of an optical fiber communication channel, the signal generated by the vibration or disturbance is transmitted through mechanical waves, vibration of the optical fiber is caused, optical fiber characteristics such as the length and the refractive index of the region are changed, and further the optical phase of the region is changed. Through the interference of the backward scattering light, the change of the phase position can cause the change of the power of the backward scattering light, thereby causing the change of the power of the backward scattering signal, determining the eavesdropping behavior and the eavesdropping position according to the change of the power of the backward scattering signal, realizing the distributed monitoring and positioning of the quantum secret communication system, needing no reflection device and having no limit to the communication wavelength.

Preferably, the transmitting end includes a quantum secure communication transmitting module and a phase sensitive optical time domain reflection measuring module, the quantum secure communication transmitting module outputs a quantum secure communication signal, and the phase sensitive optical time domain reflection measuring module outputs a monitoring signal and receives a back scattering signal returned by the monitoring signal in a transmission process of the transmission optical fiber.

Preferably, the transmitting terminal further includes a wavelength division multiplexer, an output terminal of the quantum secure communication transmitting module is connected to an input port corresponding to the wavelength division multiplexer, an output terminal of the phase-sensitive optical time domain reflection measuring module is connected to an input port corresponding to the wavelength division multiplexer, an output port of the wavelength division multiplexer is connected to the transmission optical fiber, and the monitoring signal of the phase-sensitive optical time domain reflection measuring module can be coupled to the transmission optical fiber link by adding a wavelength division multiplexer to the conventional quantum secure communication system.

Preferably, the phase-sensitive optical time domain reflectometry module includes a narrow linewidth laser, a pulse modulator, an optical amplifier, an optical circulator, a photoelectric detection module, a signal acquisition module, a signal storage module, and a signal processing module, wherein:

the output end of the narrow linewidth laser is connected with the input end of the pulse modulator;

the output end of the pulse modulator is connected with the input end of the optical amplifier;

the output end of the optical amplifier is connected with the first port of the optical circulator, the second port of the optical circulator is connected with the corresponding input port of the wavelength division multiplexer, and the third port of the optical circulator is connected with the input end of the photoelectric detection module;

the output end of the photoelectric detection module is connected with the input end of the signal acquisition module;

the output end of the signal acquisition module is respectively connected with the input end of the signal storage module and the input end of the signal processing module, and the signal processing module processes the returned back scattering signal to obtain whether eavesdropping behavior exists and an eavesdropping position;

the eavesdropping monitoring wavelength is generated by a narrow linewidth laser (about several GHz), a pulse detection optical signal is generated by a pulse modulator, and then the signal is amplified by an optical amplifier, enters a first port of an optical circulator and is output from a second port. The output monitoring signal is combined with the quantum secret communication signal and coupled to a transmission optical fiber link. After the monitoring signal of forward transmission transmits, can produce the backscatter, the light signal of scattering can backward pass back in the second port of optical circulator to export in the third port of follow optical circulator, enter into and carry out photoelectric conversion in the photoelectric detection module, the backscatter signal who will detect turns into the signal of telecommunication, and carry out data acquisition through signal acquisition module, the backscatter signal that gathers when will not have eavesdropper to invade quantum communication system simultaneously is saved in signal storage module as reference signal. The backscattering signals acquired by the data acquisition module are input into the signal processing module every time, the signal processing module performs subtraction operation according to backscattering reference signals and backscattering signals of the data acquisition module, and time information of optical signals is converted into optical fiber length information to sense and position eavesdropping behaviors in the quantum communication system.

Preferably, the wavelength channels of the quantum secret communication signal and the monitoring signal are multiplexed by coarse wavelength multiplexing, and the coarse wavelength multiplexing interval is 20nm, or the coarse wavelength multiplexing interval is dense wavelength division multiplexing (such as 0.8 nm).

Preferably, the receiving end includes a wavelength division multiplexing demultiplexing module and a quantum secure communication receiving module, wherein:

the wavelength division multiplexing and demultiplexing module is connected with the transmission optical fiber and used for demultiplexing the quantum secret communication signals in the transmission optical fiber, and the wavelength division multiplexing and demultiplexing module is used for transmitting the demultiplexed quantum secret communication signals to the quantum secret communication receiving module.

A perception and positioning eavesdropping method in a quantum secret communication system is applied to a perception and positioning eavesdropping device in the quantum secret communication system, and comprises the following steps:

s1: pre-obtaining a reference backscattering curve without any disturbance;

s2: during communication, the transmitting end transmits a quantum secret communication signal and a monitoring signal to the transmission optical fiber for transmission;

s3: when the monitoring signal is transmitted by the transmission optical fiber, a backscattering signal returned by scattering is received by the transmitting end to form a backscattering curve, the backscattering curve and the reference backscattering curve are both curves taking the distance from the transmitting end as an abscissa and the signal power as an ordinate, and the round-trip time of backscattering signals at different distances is obtained;

s4: and performing subtraction operation on the backscatter reference signal and the reference scatter signal, and positioning the eavesdropping position through the length of the optical fiber and the round trip time.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

the invention provides a device and a method for perceiving and positioning eavesdropping in a quantum secret communication system, which are used for improving the security of key distribution and enhancing the reliability of the quantum communication system. In the invention, a phase-sensitive optical time domain reflection technology is adopted, before eavesdropping is carried out on the quantum secret communication system by an eavesdropper, the eavesdropping position of the eavesdropper is accurately positioned through back-scattered signal light, the eavesdropping position is sensed and positioned in advance, and the safety of the quantum secret communication system is ensured. Meanwhile, through rapid sensing and positioning of the eavesdropper, eavesdropping measurement of the eavesdropper can be prevented in time, the defect that all normal communication is stopped once eavesdropping is found in a traditional quantum communication system is avoided, and the reliability of quantum secret communication is greatly improved.

Drawings

FIG. 1 is a schematic structural diagram of the apparatus of the present invention.

FIG. 2 is a schematic flow chart of the method of the present invention.

In the figure, 1 is a phase sensitive optical time domain reflection measurement module, 101 is a narrow linewidth laser, 102 is a pulse modulator, 103 is an optical amplifier, 104 is an optical circulator, 105 is a photoelectric detection module, 106 is a signal acquisition module, 107 is a signal storage module, 108 is a signal processing module, 2 is a quantum secure communication transmission module, 3 is a wavelength division multiplexer, 4 is a wavelength division multiplexing demultiplexing module, 5 is a quantum secure communication receiving module, and 6 is a transmission optical fiber.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent;

for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product;

it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.