Optical devices for quantum key distribution protection, quantum communication systems and communication methods

Abstract

The present disclosure provides a kind of quantum key distribution protection optical device, quantum communication system and communication method.The optical device includes: first optical channel, the first port of first optical channel is used to input signal photon;Resonant cavity, resonant cavity is resonated with photon, to couple signal photon from first optical channel to second optical channel;Second optical channel, the signal photon of resonant cavity coupling output is output from the first port of second optical channel;Wherein, in the case where detection photon is output at the second port of second optical channel or the second port of first optical channel, it is determined whether there is attacker to the first port of second optical channel input injection photon.

Description

Technical Field

[0001] This disclosure relates to the field of quantum communication technology, and more specifically, to an optical device for quantum key distribution protection against injection attacks, a quantum communication system for resisting injection attacks, and a quantum communication method for resisting injection attacks. Background Technology

[0002] Quantum Key Distribution (QKD) technology, leveraging the superposition and no-cloning principles of quantum mechanics and combined with the unconditionally secure "one-time pad" encryption method, can theoretically achieve absolutely secure key distribution. However, in practical applications, device defects may introduce security vulnerabilities, which attackers can exploit to launch attacks, leading to the risk of key leakage.

[0003] For example, injection attacks involve an attacker actively injecting light into the transmitter or receiver of a quantum key distribution system to steal the key. In a Trojan horse attack, the attacker injects strong light into the transmitter or receiver, analyzes the reflected light to obtain measurement basis information, and then uses a intercept-retransmission method to steal the key. In a strong light blinding attack, the attacker first injects strong continuous light into the receiver, causing the avalanche diode used at the receiver to generate additional photocurrent and operate in linear mode. The attacker then intercepts and randomly selects a basis to measure the signal photons emitted by the transmitter, and injects strong light of the corresponding state into the receiver based on the measurement results. At this point, the attacker can control the response of the receiver's detector without being detected. In an injection-locking attack, the attacker injects randomly polarized strong light into the transmitter. When the injected light matches the polarization selected by the transmitter, it enters the laser, creating an injection-locking effect, thereby controlling and shifting the wavelength of the emitted signal light. An eavesdropper can then use bandpass filtering to select the wavelength of the signal light to determine whether an injection-locking effect has occurred and obtain the polarization information of the signal light. Finally, the attacker can shift the wavelength of the signal light back to its original wavelength, ensuring the attack remains undetected. Furthermore, lithium niobate, a material widely used in the transmitting end, exhibits a photorefractive effect, which introduces potential security vulnerabilities. Peng Ye et al. proposed an attack method to steal keys by injecting weak light into the transmitting end to induce the photorefractive effect of lithium niobate devices. Therefore, resisting injection attacks is one of the key measures to ensure the security of quantum communication. Summary of the Invention

[0004] In view of this, embodiments of the present disclosure provide an optical device for quantum key distribution protection against injection attacks, a quantum communication system for resisting injection attacks, and a quantum communication method for resisting injection attacks.

[0005] One aspect of this disclosure provides an optical device for quantum key distribution protection against injection attacks, comprising:

[0006] The first optical channel, wherein the first port of the first optical channel is used to input signal photons;

[0007] A resonant cavity, wherein the resonant cavity resonates with the photons to couple the signal photons from the first optical channel to the second optical channel;

[0008] The signal photons coupled out from the resonant cavity of the aforementioned second optical channel are output from the first port of the aforementioned second optical channel;

[0009] Specifically, when a detection photon is output from the second port of the second optical channel or the second port of the first optical channel, it is determined whether an attacker has injected photons into the first port of the second optical channel.

[0010] According to embodiments of this disclosure, the detection photons are generated in the following manner:

[0011] If the attacker inputs the injected photon through the first port of the second optical channel, and the injected photon does not resonate with the resonant cavity, the second port of the second optical channel outputs the injected photon, wherein the injected photon output by the second port of the second optical channel represents the detection photon.

[0012] If the injected photons resonate with the resonant cavity, some of the injected photons enter the resonant cavity, causing the resonant frequency of the resonant cavity to change under the action of optical material effects. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

[0013] When the resonant frequency of the resonant cavity changes, some or all of the signal photons are output from the second port of the first optical channel, wherein the signal photons output from the second port of the first optical channel represent the detection photons.

[0014] According to embodiments of this disclosure, the first optical channel and the second optical channel are free-space optical paths, optical fibers, optical waveguides, or prisms made of a target medium, wherein light propagates in the target medium in a target propagation mode, wherein the target propagation mode includes at least one of direct propagation, reflection, and refraction, and the resonant cavity is an optical structure that allows light to oscillate continuously therein, wherein the resonant cavity includes a ring resonant cavity, a disk resonant cavity, a spherical resonant cavity, a Fabry-Pérot resonant cavity, and a photonic crystal cavity.

[0015] Another aspect of this disclosure provides a quantum communication system for resisting injection attacks, comprising:

[0016] The transmitting end is used to generate signal photons;

[0017] The first optical resonance device is made according to an optical device. The signal photon enters from the first port of the first optical channel in the first optical resonance device and resonates with the resonant cavity of the first optical resonance device. The resonant cavity of the first optical resonance device couples the signal photon to the second optical channel of the first optical resonance device.

[0018] The channel is used to transmit signal photons output from the first port of the second optical channel in the first optical resonance device described above;

[0019] The receiving end is used to analyze, decode, detect, and post-process the signal photons transmitted through the aforementioned channel to obtain the quantum key;

[0020] In the case where a first detection photon is output from the second port of the second optical channel in the first optical resonance device or the second port of the first optical channel, or when the quantum key generation rate changes, the operating state of the transmitter is controlled. The first detection photon is used to determine that an attacker is stealing the quantum key.

[0021] According to an embodiment of this disclosure, when the attacker sends a first attack photon to the transmitter using the channel, if the first attack photon does not resonate with the resonant cavity in the first optical resonant device, the second port of the second optical channel of the first optical resonant device outputs the first attack photon, wherein the first attack photon represents the first detection photon.

[0022] If the first attacking photon resonates with the resonant cavity of the first optical resonant device, some of the first attacking photon enters the resonant cavity of the first optical resonant device, causing the resonant frequency of the resonant cavity of the first optical resonant device to change under the action of optical material effects. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

[0023] When the resonant frequency of the resonant cavity of the first optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel in the first optical resonant device, wherein the signal photons output from the second port of the first optical channel represent the first detection photons.

[0024] According to embodiments of this disclosure, the quantum communication system further includes:

[0025] The second optical resonance device is made based on an optical device. The signal photon output from the channel enters from the first port of the first optical channel in the second optical resonance device and resonates with the resonant cavity of the second optical resonance device. The resonant cavity of the second optical resonance device couples the signal photon to the second optical channel of the second optical resonance device. The signal photon is output from the first port of the second optical channel of the second optical resonance device to the receiving end.

[0026] In the case where the second detection photon is output from the second port of the first optical channel in the second optical resonance device, or when the quantum key generation rate changes, the operating state of the transmitter is controlled. The second detection photon is used to determine that an attacker is stealing the quantum key.

[0027] According to an embodiment of this disclosure, when the attacker sends a second attack photon to the receiver using the channel, if the second attack photon does not resonate with the resonant cavity of the second optical resonant device, the second port of the first optical channel of the second optical resonant device outputs the second attack photon, wherein the second attack photon output by the second port of the first optical channel of the second optical resonant device represents the second detection photon.

[0028] If the second attack photon resonates with the resonant cavity of the second optical resonant device, the second attack photon enters the resonant cavity of the second optical resonant device and, under the effect of the optical material, causes the resonant frequency of the resonant cavity of the second optical resonant device to change. At the same time, some or all of the second attack photon are output from the first port of the second optical channel of the second optical resonant device.

[0029] When the resonant frequency of the resonant cavity of the second optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel of the second optical resonant device, wherein the signal photons output from the second port of the first optical channel of the second optical resonant device characterize the second detection photons.

[0030] According to embodiments of this disclosure, the quantum communication system further includes:

[0031] A first dispersion compensator is disposed between the transmitter and the first optical resonant device, or between the first optical resonant device and the channel. The first dispersion compensator is used to perform dispersion compensation processing on the signal photons to obtain dispersion-compensated signal photons, so as to input the dispersion-compensated signal photons into the first optical resonant device or the channel.

[0032] The second dispersion compensator is disposed between the second optical resonant device and the receiver, or between the channel and the second optical resonant device. The second dispersion compensator is used to perform dispersion compensation processing on the signal photons output by the second optical resonant device to obtain dispersion-compensated transmitted photons, so as to transmit the dispersion-compensated transmitted photons to the receiver or the second optical resonant device.

[0033] Another aspect of this disclosure provides a quantum communication method for resisting injection attacks, comprising:

[0034] Signal photons are generated using the transmitting end;

[0035] The signal photons are transmitted to the resonant cavity of the first optical resonant device through the first port of the first optical channel of the first optical resonant device, wherein the first optical resonant device is made based on an optical device;

[0036] When the aforementioned signal photon resonates with the resonant cavity of the aforementioned first optical resonant device, the signal photon is output through the first port of the second optical channel of the first optical resonant device;

[0037] The aforementioned signal photons are transmitted to the receiving end using a channel;

[0038] The quantum key is obtained by analyzing the aforementioned signal photons at the receiver.

[0039] In the case where the second port of the second optical channel in the first optical resonance device outputs a first detection photon, or when the quantum key generation rate changes, the operating state of the transmitter is controlled. The first detection photon is used to determine whether an attacker is injecting photons into the transmitter.

[0040] According to embodiments of this disclosure, the first detection photon is generated in the following manner:

[0041] In the case where the attacker sends a first attack photon to the transmitter using the channel, if the first attack photon does not resonate with the resonant cavity in the first optical resonant device, the second port of the second optical channel of the first optical resonant device outputs the first attack photon, wherein the first attack photon represents the first detection photon.

[0042] If the first attacking photon resonates with the resonant cavity of the first optical resonant device, some of the first attacking photon enters the resonant cavity of the first optical resonant device, causing the resonant frequency of the resonant cavity of the first optical resonant device to change under the action of optical material effects. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

[0043] When the resonant frequency of the resonant cavity of the first optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel in the first optical resonant device, wherein the signal photons output from the second port of the first optical channel represent the first detection photons.

[0044] According to embodiments of this disclosure, the quantum communication method further includes:

[0045] When the second detection photon is output from the second port of the first optical channel of the second optical resonator, the operating state of the transmitter is controlled. The second detection photon is used to determine that an attacker is injecting photons into the receiver. The first port of the second optical channel of the second optical resonator is connected to the receiver, and the first port of the first optical channel of the second optical resonator is connected to the channel.

[0046] According to embodiments of this disclosure, by controlling the signal photon and the resonant cavity to be in a resonant state, when no attacker steals the quantum key through injection attack, the signal photon can resonate with the resonant cavity to couple the signal photon in the first optical channel to the resonant cavity and output through the second optical channel. When an attacker steals the quantum key through injection attack, the second port of the second optical channel or the second port of the first optical channel in the optical device can output a detection photon indicating the presence of an attacker and automatically change the quantum key generation rate, thereby improving the information security in quantum key distribution and preventing attackers from stealing the quantum key through injection attack. Attached Figure Description

[0047] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0048] Figure 1 A schematic diagram of the structure of an optical device according to an embodiment of the present disclosure is shown.

[0049] Figure 2 A schematic diagram of the structure of an optical device according to another embodiment of the present disclosure is shown;

[0050] Figure 3 A schematic diagram of the structure of an optical device according to yet another embodiment of the present disclosure is shown;

[0051] Figure 4 A schematic diagram of the structure of an optical device according to another embodiment of the present disclosure is shown;

[0052] Figure 5 This schematic diagram illustrates the signal flow when a quantum communication system according to the first embodiment of this disclosure is attacked;

[0053] Figure 6 This schematic diagram illustrates the signal flow when a quantum communication system according to a second embodiment of the present disclosure is attacked.

[0054] Figure 7 This schematic diagram illustrates the signal flow when a quantum communication system according to a third embodiment of this disclosure is attacked;

[0055] Figure 8 This diagram illustrates the signal flow when a quantum communication system according to a fourth embodiment of the present disclosure is attacked.

[0056] Figure 9 A flowchart illustrating a quantum communication method according to an embodiment of the present disclosure is shown schematically. Detailed Implementation

[0057] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0058] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0059] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0060] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0061] To enhance the security of quantum communication in the face of injection attacks, the inventors noted a common optical structure: the optical resonant cavity, such as a ring resonant cavity, disk resonant cavity, spherical resonant cavity, Fabry-Pérot resonant cavity, and photonic crystal cavity, which has an optical filtering effect. The closer the frequency of the light input to the resonant cavity is to a certain resonant frequency of the cavity, the greater the proportion of light that can couple into the cavity. If the frequency of the input light differs significantly from the resonant frequency of the cavity, the input light will almost completely fail to couple into the cavity. If the frequency of the input light exactly matches a certain resonant frequency of the cavity (satisfying the resonance condition) and the cavity is in a critical coupling state with the external environment, then all the input light will couple into the cavity. Simultaneously, the light coupled into the cavity can affect the resonant frequency of the cavity through thermo-optical effects, thermal expansion effects, photorefractive effects, electro-optic effects, piezoelectric effects, photoelastic effects, Kerr effects, Faraday optical rotation effects, Kelton-Morton effects, and electrochromic effects.

[0062] In view of this, embodiments of the present disclosure provide an optical device, a quantum communication system, and a communication method for quantum key distribution protection. The optical device includes: a first optical channel, with a first port for inputting signal photons; a resonant cavity that resonates with the signal photons to couple them from the first optical channel to a second optical channel; and a second optical channel from which signal photons coupled from the resonant cavity are output from the first port. Specifically, when a detection photon is output from either the second port of the second optical channel or the second port of the first optical channel, it is determined whether an attacker has injected photons into the first port of the second optical channel.

[0063] Figure 1 A schematic diagram of the structure of an optical device 100 according to an embodiment of the present disclosure is shown.

[0064] like Figure 1 As shown, the optical device 100 for quantum key distribution protection against injection attacks includes:

[0065] The first optical channel 110, the first port 111 of the first optical channel 110 is used to input signal photons;

[0066] The resonant cavity 120 resonates with the signal photon to couple the signal photon from the first optical channel 110 to the second optical channel 130.

[0067] The signal photons coupled out of the resonant cavity 120 in the second optical channel 130 are output from the first port 131 of the second optical channel 130.

[0068] Specifically, when a detection photon is output from the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110, it is determined whether an attacker has injected photons into the first port 131 of the second optical channel 130 to obtain a quantum key.

[0069] According to embodiments of this disclosure, an optical channel is a structure composed of one or more media, in which light can propagate in various ways such as direct transmission, reflection, and refraction.

[0070] According to an embodiment of this disclosure, before quantum communication, the frequency of the signal photons input to the first optical channel 110 is first matched with a certain resonant frequency of the resonant cavity 120, and the first optical channel 110 and the resonant cavity 120 are in a critical coupling state. At this time, if there is no attacker, the signal photons enter the first optical channel 110 through the first port 111 of the first optical channel 110, and then all the signal photons are coupled from the first optical channel 110 into the resonant cavity 120 and output from the first port 131 of the second optical channel 130.

[0071] According to embodiments of this disclosure, when an attacker launches an injection attack, the attacker inputs injected photons from the first port 131 of the second optical channel 130. If there is a detection photon output at the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110, it can be proven that an attacker is stealing quantum keys through an injection attack.

[0072] According to embodiments of this disclosure, by controlling the signal photon and the resonant cavity to be in a resonant state, when no attacker steals the quantum key through injection attack, the signal photon can resonate with the resonant cavity to couple the signal photon in the first optical channel to the resonant cavity and output through the second optical channel. When an attacker steals the quantum key through injection attack, the second port of the second optical channel or the second port of the first optical channel in the optical device can output a detection photon indicating the presence of an attacker and automatically change the quantum key generation rate, thereby improving the information security in quantum key distribution and preventing attackers from stealing the quantum key through injection attack.

[0073] According to embodiments of this disclosure, the detection photons are generated in the following manner:

[0074] If an attacker inputs an injected photon through the first port 131 of the second optical channel 130, and the injected photon does not resonate with the resonant cavity 120, the second port 132 of the second optical channel 130 outputs the injected photon, wherein the injected photon output by the second port 132 of the second optical channel 130 represents the detection photon.

[0075] If the injected photons resonate with the resonant cavity 120, some of the injected photons enter the resonant cavity 120. Under the influence of optical material effects, the resonant frequency of the resonant cavity 120 changes. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

[0076] When the resonant frequency of the resonant cavity 120 changes, some or all of the signal photons are output from the second port 112 of the first optical channel 110, wherein the signal photons output from the second port 112 of the first optical channel 110 represent the detection photons.

[0077] According to embodiments of this disclosure, when an attacker launches an injection attack, the attacker inputs injected photons through the first port 131 of the second optical channel 130. The injected photons do not resonate with the resonant cavity 120. At this time, the injected photons propagate along the second optical channel 130, but because they cannot couple into the resonant cavity 120, they are directly output from the second port 132 of the second optical channel 130. A photodetector 900 can be placed at the second port 132 of the second optical channel 130 to detect the output injected photons. In this case, the injected photons cannot pass through the resonant cavity 120, thus preventing the injection attack. Simultaneously, the photodetector 900 detects an increase in light intensity output from the second port 132 of the second optical channel 130, thereby determining that an attacker may intend to launch an injection attack to steal quantum keys.

[0078] According to embodiments of this disclosure, when an attacker launches an injection attack, the injected photon approaches or exactly resonates with the resonant cavity 120. At this time, the injected photon propagates along the second optical channel 130 and is partially or completely coupled into the resonant cavity 120. In this case, the injected photon generates additional thermo-optical effects, thermal expansion effects, photorefractive effects, electro-optic effects, piezoelectric effects, photoelastic effects, Kerr effects, Faraday optical rotation effects, Kelton-Morton effects, electrochromic effects, etc., within the resonant cavity 120. This causes a change in the resonant frequency of the resonant cavity 120, reducing or eliminating the proportion of signal photons coupled from the first optical channel 110 into the resonant cavity 120. Consequently, the probability of signal photons being output from the first port 131 of the second optical channel 130 decreases or becomes zero, while the probability of outputting from the second port 132 of the second optical channel 130 increases. Therefore, the light intensity measured by the photodetector 900 located at the first port 131 of the second optical channel 130 increases, indicating a possible attacker intending to launch an injection attack to steal quantum keys.

[0079] Figure 2 A schematic diagram of the structure of an optical device 100 according to another embodiment of the present disclosure is shown. Figure 3 A schematic diagram of the structure of an optical device 100 according to yet another embodiment of the present disclosure is shown. Figure 4 A schematic diagram of the structure of an optical device 100 according to another embodiment of the present disclosure is shown.

[0080] According to embodiments of this disclosure, the first optical channel 110 and the second optical channel 130 are free-space optical paths, optical fibers, optical waveguides, or prisms made of a target medium, wherein light propagates in the target medium in a target propagation mode, wherein the target propagation mode includes at least one of direct propagation, reflection, and refraction, and the resonant cavity 120 is an optical structure that allows light to oscillate continuously therein, and the resonant cavity 120 includes a ring resonant cavity, a disk resonant cavity, a spherical resonant cavity, a Fabry-Pérot resonant cavity, and a photonic crystal cavity.

[0081] In one embodiment, such as Figure 2 As shown, the first optical channel 110 and the second optical channel 130 are both optical waveguides, and the resonant cavity 120 is a ring resonant cavity.

[0082] In another embodiment, such as Figure 3 As shown, both the first optical channel 110 and the second optical channel 130 are prisms, and the resonant cavity 120 is a whispering-gallery mode cavity. It should be noted that the resonant cavity 120 can also be a resonant cavity of other shapes, such as a ring resonant cavity, a disk resonant cavity, a spherical resonant cavity, etc.

[0083] According to embodiments of this disclosure, the resonant cavity 120 can be fabricated using a target medium made of materials such as silicon on insulator (SOI), silicon nitride, aluminum nitride, group III-IV element materials, and lithium niobate, thereby enabling the resonant cavity 120 to possess optical material effects such as thermo-optic effect, thermal expansion effect, photorefractive effect, electro-optic effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kelton-Morton effect, and electrochromic effect.

[0084] In another embodiment, such as Figure 4 As shown, the first optical channel 110 and the second optical channel 130 are both free-space optical paths, and the resonant cavity 120 is a Fabry-Pérot resonant cavity. Signal photons are incident on the Fabry-Pérot resonant cavity 120 from ports 111 and 112 of the first optical channel 110. The frequency of the signal photons is exactly matched with a certain resonant frequency of the Fabry-Pérot resonant cavity 120, so that they can be transmitted from the first port 131 and the second port 132 of the second optical channel 130 with a high probability. When injected photons are incident on the Fabry-Pérot resonant cavity 120 from the first port 131 and the second port 132 of the second optical channel 130, if the frequency of the injected photons does not match the resonant frequency of the Fabry-Pérot resonant cavity, they cannot pass through the Fabry-Pérot resonant cavity 120 or can only pass through with a very small transmittance (achieving the filtering of injected photons). If the frequency of the injected light matches a certain resonant frequency of the Fabry-Pérot resonant cavity 120, a large proportion of the injected photons can enter the Fabry-Pérot resonant cavity 120. The resulting thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kelton-Morton effect, electrochromic effect, etc., change the resonant frequency of the Fabry-Pérot resonant cavity 120, resulting in a decrease in the transmittance of signal photons, thereby indicating that there may be injected light between the two communicating parties (achieving the detection of injected light).

[0085] It should be noted that the Fabry-Pérot resonator 120 can be integrated into an optical fiber or on a chip, or the Fabry-Pérot resonator can be fabricated using materials whose refractive index is sensitive to temperature or materials with significant photorefractive effects, thereby enabling the detection of injection attacks.

[0086] Figure 5 The diagram illustrates the signal flow when a quantum communication system according to the first embodiment of this disclosure is attacked.

[0087] like Figure 5 As shown, a quantum communication system for resisting injection attacks includes:

[0088] Transmitter 200 is used to generate signal photons;

[0089] The first optical resonance device 300 is made according to the optical device 100. The signal photon enters from the first port 111 of the first optical channel 110 in the first optical resonance device 300 and resonates with the resonant cavity 120 of the first optical resonance device 300. The resonant cavity 120 of the first optical resonance device 300 couples the signal photon to the second optical channel 130 of the first optical resonance device 300.

[0090] Channel 400 is used to transmit signal photons output from the first port 131 of the second optical channel 130 in the first optical resonance device 300;

[0091] The receiver 500 is used to analyze the signal photons transmitted through the channel 400 to obtain the quantum key. The analysis may include operations such as decoding, detection and post-processing.

[0092] When the first detection photon is output from the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110 in the first optical resonance device 300, the working state of the transmitter 200 is controlled. The first detection photon is used to determine whether an attacker is injecting photons into the transmitter 200.

[0093] According to an embodiment of this disclosure, when there is no attacker attack, the signal photons generated by the transmitter 200 are input to the first optical resonant device 300 from port 111. Since the frequency of the signal photons matches a certain resonant frequency of the resonant cavity 120 and the first optical channel 110 and the resonant cavity 120 are in a critical coupling state, all the signal photons are coupled from the first optical channel 110 into the resonant cavity 120 and coupled out from the second optical channel 130, inputting into the channel 400 from the first port 131 of the second optical channel 130. No light or very little light is output from the second port 112 of the first optical channel 110 and the second port 132 of the second optical channel 130. The signal photons transmitted through the channel 400 are input to the receiver 500. In this case, quantum key distribution proceeds normally.

[0094] According to the embodiments of this disclosure, when an attacker injects attack photons from channel 400 toward transmitter 200, the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110 in the first optical resonance device 300 will output a first detection photon, at which point it can be determined that an attacker is stealing the quantum key.

[0095] According to embodiments of this disclosure, by adjusting the signal photon to be in a critical coupling state with the resonant cavity 120 of the first optical resonant device 300, when no attacker steals the quantum key through injection attack, the input signal photon can resonate with the resonant cavity 120 to couple the signal photon in the first optical channel 110 to the resonant cavity 120 and output through the second optical channel 130. When an attacker steals the quantum key through injection attack, the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110 in the first optical resonant device 300 can output a first detection photon indicating the presence of an attacker, thereby improving the information security in quantum key distribution and preventing attackers from stealing the quantum key through injection attack.

[0096] Figure 6 The diagram illustrates the signal flow when a quantum communication system according to a second embodiment of the present disclosure is attacked.

[0097] If the first attacking photon resonates with the resonant cavity 120 of the first optical resonance device 300, some of the first attacking photon enters the resonant cavity 120 of the first optical resonance device 300. Under the action of optical material effects, the resonant frequency of the resonant cavity 120 of the first optical resonance device 300 changes. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kelton-Morton effect, and electrochromic effect.

[0098] When the resonant frequency of the resonant cavity 120 of the first optical resonant device 300 changes, some or all of the signal photons are output from the second port 112 of the first optical channel 110 in the first optical resonant device 300, wherein the signal photons output from the second port 112 of the first optical channel 110 represent the first detection photons.

[0099] According to embodiments of this disclosure, such as Figure 5As shown, when an attacker launches an injection attack on transmitter 200, when the attacker injects a first attack photon from channel 400 towards transmitter 200, and the first attack photon does not resonate with the resonant cavity 120 of the first optical resonator 300, the first attack photon enters the first optical resonator 300 through the first port 131 of the second optical channel 130 and propagates along the second optical channel 130, but cannot couple into the resonant cavity 120 of the first optical resonator 300. It is directly output from the second port 132 of the second optical channel 130. At this time, a photodetector 900 can be used to detect this port. In this case, the first attack photon cannot enter transmitter 200, so an injection attack against transmitter 200 cannot be achieved. At the same time, when the light intensity measured by photodetector 900 increases, it can indicate to both communicating parties (transmitter 200 and receiver 500) that an attacker may intend to launch an injection attack against transmitter 200.

[0100] According to embodiments of this disclosure, such as Figure 6As shown, when an attacker launches an injection attack on the transmitter 200, when the attacker injects a first attack photon from the channel 400 toward the transmitter 200, and the first attack photon is close to or exactly in resonance with the resonant cavity 120 of the first optical resonant device 300, the first attack photon enters the first optical resonant device 300 from the first port 131 of the second optical channel 130 in the first optical resonant device 300, is transmitted along the second optical channel 130, and is partially or completely coupled into the resonant cavity 120 of the first optical resonant device 300. In this case, the first attack photon generates additional thermo-optical effects, thermal expansion effects, photorefractive effects, electro-optical effects, piezoelectric effects, photoelastic effects, Kerr effects, Faraday optical rotation effects, Kerr-Morton effects, electrochromic effects, etc., within the resonant cavity 120 of the first optical resonant device 300. This causes a change in the resonant frequency of the resonant cavity 120 of the first optical resonant device 300, reducing or eliminating the proportion of signal photons coupled from the first optical channel 110 into the resonant cavity 120 of the first optical resonant device 300. Consequently, the probability of signal photons being output from the first port 131 of the second optical channel 130 decreases or becomes zero, while the probability of outputting from the second port 112 of the first optical channel 110 increases. Therefore, the light intensity output from the second port 112 of the first optical channel 110 increases, the intensity of the signal photons received by the receiver 500 decreases or becomes zero, and the key rate generated by QKD decreases or becomes zero. When both communicating parties detect this phenomenon, it indicates that an attacker may intend to launch an injection attack on the transmitter 200, and that the first attack photon may be output from the first port 111 of the first optical channel 110 through the first optical resonator 300 and enter the transmitter 200. The communicating parties immediately stop QKD. In the case of the key rate becoming zero, this is equivalent to the quantum communication system of this disclosure automatically interrupting the QKD process. Furthermore, in this situation, some of the first attack photons may still be output from the second port 132 of the second optical channel 130, which also suggests that an attacker may intend to launch an injection attack on the transmitter 200.

[0101] Figure 7 The diagram illustrates the signal flow when a quantum communication system according to a third embodiment of this disclosure is attacked.

[0102] According to embodiments of this disclosure, the quantum communication system further includes:

[0103] The second optical resonance device 600 is made based on the optical device 100. The signal photons output from the channel 400 enter from the first port 111 of the first optical channel 110 in the second optical resonance device 600 and resonate with the resonant cavity 120 of the second optical resonance device 600. The resonant cavity 120 of the second optical resonance device 600 couples the signal photons to the second optical channel 130 of the second optical resonance device 600. The signal photons are output from the first port 131 of the second optical channel 130 of the second optical resonance device 600 to the receiving end 500.

[0104] In the case where the second detection photon is output from the second port 112 of the first optical channel 110 in the second optical resonance device 600, or when the quantum key generation rate changes, the working state of the transmitter 200 is controlled. The second detection photon is used to determine that an attacker is injecting photons into the receiver 500.

[0105] According to an embodiment of this disclosure, when there is no attacker, the signal photons generated by the transmitter 200 are input to the first optical resonant device 300 from port 111. Since the frequency of the signal photons matches a certain resonant frequency of the resonant cavity 120 and the first optical channel 110 is in a critical coupling state with the resonant cavity 120, all the signal photons are coupled from the first optical channel 110 into the resonant cavity 120 and coupled out from the second optical channel 130, inputting into the channel 400 from the first port 131 of the second optical channel 130. No light or very little light is output from the second port 112 of the first optical channel 110 and the second port 132 of the second optical channel 130. The signal photons transmitted through the channel 400 enter the second optical resonant device 600 from the first port 111 of the first optical channel 110. Because the frequency of the signal photon matches a certain resonant frequency of the resonant cavity 120 of the second optical resonator 600, and the first optical channel 110 and the resonant cavity 120 of the second optical resonator 600 are in a critical coupling state, all the signal photons are coupled from the first optical channel 110 into the resonant cavity 120 of the second optical resonator 600 and coupled out from the second optical channel 130 of the second optical resonator 600, and output to the receiver 500 through the first port 131 of the second optical channel 130 of the second optical resonator 600. No signal photons or very few signal photons are output from the second port 112 of the first optical channel 110 and the second port 132 of the second optical channel 130 of the second optical resonator 600. In this case, QKD proceeds normally.

[0106] According to embodiments of this disclosure, such as Figure 7As shown, when an attacker injects attack photons from channel 400 toward receiver 500, the second port 112 of the first optical channel 110 in the second optical resonance device 600 will output a second detection photon. At this time, it can be determined that an attacker is stealing the quantum key.

[0107] According to embodiments of this disclosure, when the signal photon is in a critical coupling state with the resonant cavity 120 of the second optical resonant device 600, the input signal photon can resonate with the resonant cavity 120 to couple the signal photon in the first optical channel 110 to the resonant cavity 120 and output through the second optical channel 130 when no attacker steals the quantum key through injection attack. When an attacker steals the quantum key through injection attack, the second port 112 of the first optical channel 110 in the second optical resonant device 600 can output a second detection photon indicating the presence of an attacker, thereby improving the information security in quantum key distribution and preventing attackers from stealing the quantum key through injection attack.

[0108] Figure 8 The diagram illustrates the signal flow when a quantum communication system according to a fourth embodiment of the present disclosure is attacked.

[0109] According to an embodiment of this disclosure, when an attacker sends a second attack photon to a receiver 500 using channel 400, if the second attack photon does not resonate with the resonant cavity 120 of the second optical resonant device 600, the second port 112 of the first optical channel 110 of the second optical resonant device 600 outputs the second attack photon, wherein the second attack photon output by the second port 112 of the first optical channel 110 of the second optical resonant device 600 represents the second detection photon.

[0110] If the second attack photon resonates with the resonant cavity 120 of the second optical resonant device 600, the second attack photon enters the resonant cavity 120 of the second optical resonant device 600 and, under the effect of the optical material, causes the resonant frequency of the resonant cavity 120 of the second optical resonant device 600 to change. At the same time, some or all of the second attack photon is output from the first port 131 of the second optical channel 130 of the second optical resonant device 600.

[0111] When the resonant frequency of the resonant cavity 120 of the second optical resonant device 600 changes, some or all of the signal photons are output from the second port 112 of the first optical channel 110 of the second optical resonant device 600, wherein the signal photons output from the second port 112 of the first optical channel 110 of the second optical resonant device 600 characterize the second detection photons.

[0112] According to embodiments of this disclosure, such as Figure 7As shown, when an attacker launches an injection attack on receiver 500, if the attacker injects a second attack photon from channel 400 towards receiver 500, and the second attack photon does not resonate with the resonant cavity 120 of the second optical resonator 600, the second attack photon enters the second optical resonator 600 through the first port 111 of the first optical channel 110 and propagates along the first optical channel 110, but cannot enter the resonant cavity 120 of the second optical resonator 600. It is directly output from the second port 112 of the first optical channel 110 of the second optical resonator 600. In this case, the second attack photon cannot enter receiver 500, thus preventing the injection attack on receiver 500 from being achieved. At the same time, the light intensity output from the second port 112 of the first optical channel 110 of the second optical resonator 600 increases, thereby indicating that there may be an attacker intending to launch an injection attack on receiver 500.

[0113] According to embodiments of this disclosure, such as Figure 8As shown, when an attacker launches an injection attack on receiver 500, when the attacker injects a second attack photon from channel 400 toward receiver 500, and the second attack photon resonates with the resonant cavity 120 of the second optical resonant device 600, the second attack photon enters the second optical resonant device 600 from the first port 111 of the first optical channel 110 of the second optical resonant device 600, is transmitted along the first optical channel 110, and is partially or completely coupled into the resonant cavity 120 of the second optical resonant device 600. In this case, the second attack photon generates additional thermo-optical effects, thermal expansion effects, photorefractive effects, electro-optic effects, piezoelectric effects, photoelastic effects, Kerr effects, Faraday optical rotation effects, Kerr-Morton effects, electrochromic effects, etc., within the resonant cavity 120 of the second optical resonant device 600. This causes a change in the resonant frequency of the resonant cavity 120 of the second optical resonant device 600, reducing the proportion of signal photons coupled into the resonant cavity 120 of the second optical resonant device 600 through the first optical channel 110. Consequently, the probability of signal photons being output from the first port 131 of the second optical channel 130 of the second optical resonant device 600 decreases, while the probability of being output from the second port 112 of the first optical channel 110 of the second optical resonant device 600 increases. At the same time, some injected light may also be output from the first port 131 of the second optical channel 130 of the second optical resonant device 600. Therefore, the input light intensity and counting rate of the receiver 500 change, and the key rate generated by QKD decreases or becomes zero. When both communicating parties detect this phenomenon, it indicates that an attacker may intend to launch an injection attack on the receiver 500, and that the second attack photon may be output from the first port 131 of the second optical channel 130 of the second optical resonator 600 and enter the receiver 500. Both communicating parties immediately stop QKD. The aforementioned key rate becoming zero is equivalent to the disclosed quantum communication system automatically interrupting the QKD process.

[0114] According to embodiments of this disclosure, the quantum communication system further includes:

[0115] The first dispersion compensator 700 is disposed between the transmitter 200 and the first optical resonance device 300. The first dispersion compensator 700 is used to perform dispersion compensation processing on the signal photon to obtain the compensated signal photon, so as to input the compensated signal photon into the first optical resonance device 300.

[0116] The second dispersion compensator 800 is disposed between the second optical resonance device 600 and the receiver 500. The second dispersion compensator 800 is used to perform dispersion compensation processing on the signal photons output by the second optical resonance device 600 to obtain compensated transmitted photons, so as to transmit the compensated transmitted photons to the receiver 500.

[0117] According to embodiments of this disclosure, the optical device 100 for quantum key distribution protection against injection attacks may introduce dispersion when processing signal photons. This causes the signal photons to be broadened, resulting in crosstalk between adjacent signal photons and thus increasing the bit error rate of QKD. A first dispersion compensator 700 and a second dispersion compensator 800 are used to compensate for the dispersion caused by the signal photons passing through the first optical resonance device 300 and the second optical resonance device 600, respectively, thereby eliminating the aforementioned adverse effects.

[0118] In low-speed QKD applications, the signal photon repetition frequency is low, and the inter-pulse crosstalk caused by dispersion and broadening is small, thus having little impact on the QKD bit error rate. In this case, the first dispersion compensator 700 and the second dispersion compensator 800 may not be set, or only one dispersion compensator may be set.

[0119] According to embodiments of this disclosure, the first dispersion compensator 700 and the second dispersion compensator 800 may be in the form of dispersion-shifting fiber, chirped fiber grating, prism pair, diffraction grating pair, Gires-Tournois interferometer, chirped mirror, or other devices or combinations thereof capable of achieving dispersion adjustment.

[0120] According to embodiments of this disclosure, the positions of the first dispersion compensator 700 and the first optical resonator 300 can be interchanged. Specifically, the transmitter 200 is connected to the first port 111 of the first optical channel 110 in the first optical resonator 300, the first port 131 of the second optical channel 130 in the first optical resonator 300 is connected to the first dispersion compensator 700, and the first dispersion compensator 700 is connected to the channel 400. Similarly, the positions of the second dispersion compensator 800 and the second optical resonator 600 can be interchanged. Specifically, the channel 400 is connected to the second dispersion compensator 800, the second dispersion compensator 800 is connected to the first port 111 of the first optical channel 110 in the second optical resonator 600, and the first port 131 of the second optical channel 130 in the second optical resonator 600 is connected to the receiver 500.

[0121] Figure 9 A flowchart illustrating a quantum communication method according to an embodiment of the present disclosure is shown schematically.

[0122] like Figure 9 As shown, the quantum communication method for resisting injection attacks includes operations S910 to S950.

[0123] When operating the S910, signal photons are generated using the transmitter 200.

[0124] In operation S920, signal photons are transmitted to the resonant cavity 120 of the first optical resonant device 300 via the first port 111 of the first optical channel 110 of the first optical resonant device 300, wherein the first optical resonant device 300 is made based on the optical device 100.

[0125] In operation S930, when the signal photon resonates with the resonant cavity 120 of the first optical resonant device 300, the signal photon is output through the first port 131 of the second optical channel 130 of the first optical resonant device 300, wherein the first optical channel 110 of the first optical resonant device 300 and the resonant cavity 120 are in a resonant state.

[0126] In operation of S940, signal photons are transmitted to receiver 500 using channel 400.

[0127] When operating the S950, the signal photons are analyzed using the receiver 500 to obtain the quantum key. The analysis includes decoding, detection, and post-processing.

[0128] In the case where the first detection photon is output from the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110 in the first optical resonance device 300, or when the quantum key generation rate changes, the working state of the transmitter 200 is controlled. The first detection photon is used to determine that an attacker is injecting photons into the transmitter 200.

[0129] It should be noted that the quantum communication method section in the embodiments of this disclosure corresponds to the quantum communication system section in the embodiments of this disclosure. The description of the quantum communication method section is specifically referred to in the quantum communication system section, and will not be repeated here.

[0130] According to embodiments of this disclosure, by controlling the signal photon to resonate with the resonant cavity 120 of the first optical resonant device 300, when no attacker steals the quantum key through injection attack, the input signal photon can resonate with the resonant cavity 120 to couple the signal photon in the first optical channel 110 to the resonant cavity 120 and output through the second optical channel 130. When an attacker steals the quantum key through injection attack, the second port 132 of the second optical channel 130 or the second port 112 of the first optical channel 110 in the first optical resonant device 300 can output a first detection photon indicating the presence of an attacker, thereby improving the information security in quantum key distribution and preventing attackers from stealing the quantum key through injection attack.

[0131] According to embodiments of this disclosure, the first detection photon is generated in the following manner:

[0132] When an attacker sends a first attack photon to a transmitter 200 using channel 400, if the first attack photon does not resonate with the resonant cavity 120 in the first optical resonant device 300, the second port 112 of the first optical channel 110 of the first optical resonant device 300 outputs the first attack photon, wherein the first attack photon represents the first detection photon.

[0133] If the first attacking photon resonates with the resonant cavity 120 of the first optical resonance device 300, and some or all of the first attacking photon enters the resonant cavity 120 of the first optical resonance device 300, the resonant frequency of the resonant cavity 120 of the first optical resonance device 300 will change under the action of optical material effects. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

[0134] When the resonant frequency of the resonant cavity 120 of the first optical resonant device 300 changes, some or all of the signal photons are output from the second port 112 of the first optical channel 110 in the first optical resonant device 300, wherein the signal photons output from the second port 112 of the first optical channel 110 represent the first detection photons.

[0135] According to embodiments of this disclosure, the quantum communication method further includes:

[0136] When the second detection photon is output from the second port 112 of the first optical channel 110 of the second optical resonance device 600, the operating state of the transmitter 200 is controlled. The second detection photon is used to determine the presence of an attacker stealing the quantum key. The first port 131 of the second optical channel 130 of the second optical resonance device 600 is connected to the receiver 500. The first port 121 of the first optical channel 120 of the second optical resonance device 600 is connected to the channel 400. The second port 112 of the first optical channel 110 of the second optical resonance device 600 can be connected to an external photodetector 900.

[0137] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An optical device for quantum key distribution protection against injection attacks, comprising: A first optical channel, wherein the first port of the first optical channel is used to input signal photons; A resonant cavity that resonates with the photon to couple the signal photon from the first optical channel to the second optical channel; The second optical channel, wherein the signal photons coupled out by the resonant cavity are output from the first port of the second optical channel; Specifically, if a detection photon is output from the second port of the second optical channel or the second port of the first optical channel, it is determined whether an attacker has injected photons into the first port of the second optical channel. The detection photons are generated in the following manner: If the attacker inputs the injected photon through the first port of the second optical channel, and the injected photon does not resonate with the resonant cavity, the second port of the second optical channel outputs the injected photon, wherein the injected photon output from the second port of the second optical channel represents the detection photon; If the injected photon resonates with the resonant cavity, some of the injected photon enters the resonant cavity, causing the resonant frequency of the resonant cavity to change under the effect of optical material; When the resonant frequency of the resonant cavity changes, some or all of the signal photons are output from the second port of the first optical channel, wherein the signal photons output from the second port of the first optical channel characterize the detection photons.

2. The optical device according to claim 1, wherein, The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect.

3. The optical device according to claim 1, wherein, The first optical channel and the second optical channel are free-space optical paths, optical fibers, optical waveguides or prisms made of the target medium, wherein light propagates in the target medium in a target propagation mode, wherein the target propagation mode includes at least one of direct, reflection and refraction, and the resonant cavity is an optical structure that allows light to oscillate continuously therein, wherein the resonant cavity includes a ring resonant cavity, a disk resonant cavity, a spherical resonant cavity, a Fabry-Pérot resonant cavity, and a photonic crystal cavity.

4. A quantum communication system for resisting injection attacks, comprising: The transmitting end is used to generate signal photons; A first optical resonance device, wherein the first optical resonance device is made of an optical device according to any one of claims 1 to 3, wherein the signal photon enters from the first port of the first optical channel in the first optical resonance device and resonates with the resonant cavity of the first optical resonance device, and the resonant cavity of the first optical resonance device couples the signal photon to the second optical channel of the first optical resonance device. The channel is used to transmit signal photons output from the first port of the second optical channel in the first optical resonance device; The receiving end is used to analyze the signal photons transmitted through the channel to obtain the quantum key; Specifically, when the second port of the second optical channel in the first optical resonance device outputs a first detection photon, or when the quantum key generation rate changes, the operating state of the transmitting end is controlled. The first detection photon is used to determine whether an attacker is stealing the quantum key.

5. The system according to claim 4, wherein, In the case where the attacker sends a first attack photon to the transmitter using the channel, if the first attack photon does not resonate with the resonant cavity in the first optical resonant device, the second port of the second optical channel of the first optical resonant device outputs the first attack photon, wherein the first attack photon represents the first detection photon; If the first attacking photon resonates with the resonant cavity of the first optical resonant device, some of the first attacking photon enters the resonant cavity of the first optical resonant device, causing the resonant frequency of the resonant cavity of the first optical resonant device to change under the action of optical material effects. The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kelton-Morton effect, and electrochromic effect. When the resonant frequency of the resonant cavity of the first optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel in the first optical resonant device, wherein the signal photons output from the second port of the first optical channel represent the first detection photons.

6. The system according to claim 4, further comprising: The second optical resonant device is made of an optical device according to any one of claims 1 to 3. The signal photon output from the channel enters from the first port of the first optical channel in the second optical resonant device and resonates with the resonant cavity of the second optical resonant device. The resonant cavity of the second optical resonant device couples the signal photon to the second optical channel of the second optical resonant device. The signal photon is output from the first port of the second optical channel of the second optical resonant device to the receiving end. In the case where a second detection photon is output from the second port of the first optical channel in the second optical resonance device, or when the quantum key generation rate changes, the operating state of the transmitting end is controlled, wherein the second detection photon is used to determine that an attacker is stealing the quantum key.

7. The system according to claim 6, wherein, In the case where the attacker sends a second attack photon to the receiver using the channel, if the second attack photon does not resonate with the resonant cavity of the second optical resonator, the second port of the first optical channel of the second optical resonator outputs the second attack photon, wherein the second attack photon output by the second port of the first optical channel of the second optical resonator represents the second detection photon; If the second attacking photon resonates with the resonant cavity of the second optical resonant device, the second attacking photon enters the resonant cavity of the second optical resonant device and, under the effect of the optical material, causes the resonant frequency of the resonant cavity of the second optical resonant device to change. At the same time, some or all of the second attacking photon is output from the first port of the second optical channel of the second optical resonant device. When the resonant frequency of the resonant cavity of the second optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel of the second optical resonant device, wherein the signal photons output from the second port of the first optical channel of the second optical resonant device characterize the second detection photon.

8. The system according to claim 6, further comprising: A first dispersion compensator is disposed between the transmitter and the first optical resonator, or between the first optical resonator and the channel. The first dispersion compensator is used to perform dispersion compensation processing on the signal photon to obtain a dispersion-compensated signal photon, so as to input the dispersion-compensated signal photon into the first optical resonator or the channel. The second dispersion compensator is disposed between the second optical resonant device and the receiving end, or between the channel and the second optical resonant device. The second dispersion compensator is used to perform dispersion compensation processing on the signal photons output by the second optical resonant device to obtain dispersion-compensated transmitted photons, so as to transmit the dispersion-compensated transmitted photons to the receiving end or the second optical resonant device.

9. A quantum communication method for resisting injection attacks, comprising: Signal photons are generated using the transmitting end; The signal photons are transmitted to the resonant cavity of the first optical resonant device through the first port of the first optical channel of the first optical resonant device, wherein the first optical resonant device is made of an optical device according to any one of claims 1 to 3; When the signal photon resonates with the resonant cavity of the first optical resonant device, the signal photon is output through the first port of the second optical channel of the first optical resonant device. The signal photons are transmitted to the receiving end using a channel; The quantum key is obtained by analyzing the signal photons at the receiving end; In the case where a first detection photon is output from the second port of the second optical channel in the first optical resonance device or the second port of the first optical channel, or when the quantum key generation rate changes, the working state of the transmitting end is controlled. The first detection photon is used to determine whether an attacker is injecting photons into the transmitting end. The first detection photon is generated in the following manner: In the case where the attacker sends a first attack photon to the transmitter using the channel, if the first attack photon does not resonate with the resonant cavity in the first optical resonant device, the second port of the second optical channel of the first optical resonant device outputs the first attack photon, wherein the first attack photon represents the first detection photon; If the first attacking photon resonates with the resonant cavity of the first optical resonant device, some of the first attacking photon enters the resonant cavity of the first optical resonant device, and under the effect of optical material, the resonant frequency of the resonant cavity of the first optical resonant device changes. When the resonant frequency of the resonant cavity of the first optical resonant device changes, some or all of the signal photons are output from the second port of the first optical channel in the first optical resonant device, wherein the signal photons output from the second port of the first optical channel represent the first detection photons.

10. The method according to claim 9, wherein, The optical material effects include at least one of the following: thermo-optical effect, thermal expansion effect, photorefractive effect, electro-optical effect, piezoelectric effect, photoelastic effect, Kerr effect, Faraday optical rotation effect, Kerr-Morton effect, and electrochromic effect; The method further includes: When the second detection photon is output from the second port of the first optical channel of the second optical resonator, the operating state of the transmitter is controlled. The second detection photon is used to determine that an attacker is injecting photons into the receiver. The first port of the second optical channel of the second optical resonator is connected to the receiver, and the first port of the first optical channel of the second optical resonator is connected to the channel.

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