Demonstration system for quantum channel eavesdropping attacks on quantum key distribution devices

Abstract

The present invention proposes a demonstration system for quantum channel eavesdropping attacks on a quantum key distribution device, comprising a quantum key distribution transmitting terminal Alice, a quantum key distribution eavesdropping terminal Eve, a quantum key distribution detecting terminal Bob, a transmission optical path, a control terminal, and a demonstration terminal, wherein: the Alice terminal is configured to output a single-photon signal; the Eve terminal and the Bob terminal are configured to detect the single-photon signal and output a detection electrical signal; the transmission optical path is configured to achieve an optical path connection between the Alice terminal and the Bob terminal or an optical path connection between the Alice terminal and the Eve terminal according to a control signal provided by the control terminal; and the demonstration terminal is configured to demonstrate the quantum channel eavesdropping attack according to detection results of the Bob terminal and / or the Eve terminal.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication, and in particular to a demonstration system for quantum channel eavesdropping attacks on quantum key distribution equipment. Background Art

[0002] Quantum key distribution (QKD) systems can theoretically and unconditionally securely generate consistent quantum keys for legitimate communicating parties. Currently, most attacks demonstrated against these systems are data-layer attacks, meaning attackers are unable to decipher data messages encrypted with quantum keys. Other attacks on quantum channels, designed to exploit system vulnerabilities, are more complex and intended to highlight potential security vulnerabilities in QKD systems, failing to demonstrate the secure key distribution capabilities of QKD systems. These existing systems fail to effectively demonstrate the single-quantum indivisibility property upon which QKD security is based. Summary of the Invention

[0003] In response to the above-mentioned problems existing in the prior art, the present invention proposes a demonstration system for quantum channel eavesdropping attacks on quantum key distribution devices, which includes a quantum key distribution transmitting end Alice, a quantum key distribution eavesdropping end Eve, a quantum key distribution detection end Bob, a transmission optical path, a control end and a demonstration end, wherein: the Alice end is configured to output a single photon signal; the Eve end and the Bob end are configured to detect the single photon signal and output a detection electrical signal; the transmission optical path is configured to achieve an optical path connection between the Alice end and the Bob end or an optical path connection between the Alice end and the Eve end according to a control signal provided by the control end; and the demonstration end is configured to demonstrate the quantum channel eavesdropping attack based on the detection results of the Bob end and / or the Eve end.

[0004] Preferably, the transmission optical path may include an optical switch, a first optical path A, a second optical path B, a beam splitting unit, and a beam combining unit. The optical switch may be configured to switch the optical path connection between the Alice end and the first optical path A or the second optical path B according to the control signal; the beam combining unit may be configured to combine and output optical signals input through the first optical path A and the second optical path B; and the beam splitting unit may be configured to split and output optical signals input through the second optical path B.

[0005] Furthermore, the Alice end is connected to the Bob end via the first optical path A and the beam combining unit; the Alice end is connected to the Eve end via the second optical path B and the beam splitting unit, and is connected to the Bob end via the second optical path B, the beam splitting unit and the beam combining unit.

[0006] Preferably, the beam combining unit may be a beam splitter, and / or the beam splitting unit may be a beam splitter or a clamp.

[0007] Preferably, the control end may include a first counter and a second counter, wherein the first counter is used to count the detection electrical signal output from the Bob end, and the second counter is used to count the detection electrical signal output from the Eve end. Furthermore, the control end may also include a third counter, a signal delay regulator and a coincidence gate unit, wherein the signal delay regulator is configured so that within one cycle, the detection electrical signal output from the Bob end and the detection electrical signal output from the Eve end arrive at the coincidence gate unit at the same time, the coincidence gate unit is configured to perform an AND gate operation on the detection electrical signal output from the Bob end and the detection electrical signal output from the Eve end, and the third counter is used to count the valid electrical signals output from the coincidence gate unit.

[0008] Preferably, the control end may further include a clock source for outputting a synchronous clock signal to the Alice end, the Bob end and the Eve end.

[0009] Preferably, the control end may further include a discriminator for discriminating and shaping the detection electrical signal output by the Bob end and / or the detection electrical signal output by the Eve end.

[0010] Preferably, the Alice end may have a low-frequency strong light emission mode and a high-frequency single-photon emission mode, and is configured to be able to switch between the low-frequency strong light emission mode and the high-frequency single-photon emission mode based on the control of the control end.

[0011] Preferably, the demonstration terminal may include an input interface and a display interface, wherein the input interface allows a user to input instructions to determine whether the demonstration system operates in normal mode or eavesdropping mode, and the display interface is used for system status demonstration. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The principle of the demonstration system for quantum channel eavesdropping attack on quantum key distribution device of the present invention is shown; and

[0013] Figure 2 An exemplary embodiment of a demonstration system for quantum channel eavesdropping attacks on quantum key distribution devices of the present invention is shown. DETAILED DESCRIPTION

[0014] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so as to fully convey the spirit of the present invention to those skilled in the art to which the present invention belongs. Therefore, the present invention is not limited to the embodiments disclosed herein.

[0015] Figure 1 It is used to illustrate the principle of the demonstration system for quantum channel eavesdropping attack on quantum key distribution equipment of the present invention. Figure 1 As shown, the demonstration system may include a quantum key distribution transmitting end (Alice), a quantum key distribution eavesdropping end (Eve), a quantum key distribution detecting end (Bob), a transmission optical path, a control end (not shown) and a demonstration end (not shown).

[0016] The quantum key distribution transmitter Alice emits a single photon signal to simulate the generation of a quantum key signal. As an example, the quantum key distribution transmitter can be any light source that can provide a single photon signal, or a light source based on a weak coherent laser source.

[0017] The quantum key distribution detection terminal Bob can receive and detect the presence of single-photon signals, simulating the reception of quantum key signals. The quantum key distribution eavesdropping terminal Eve can receive and detect the presence of single-photon signals, simulating an eavesdropper on the quantum key signals. In the present invention, the quantum key distribution detection terminal Bob and the quantum key distribution eavesdropping terminal Eve preferably have the same detection structure. As an example, Bob and Eve can include single-photon detectors, preferably avalanche detectors or superconducting detectors.

[0018] The transmission optical path realizes the optical path connection between Alice end and Bob end or Eve end according to the control signal provided by the control end.

[0019] Figure 1 The document also exemplifies an embodiment of a transmission optical path according to the present invention. As shown in the figure, the transmission optical path may include an optical switch, a first optical path A, a second optical path B, a beam splitting unit, and a beam combining unit. Alice's output is optically connected to the input of the optical switch. The first and second outputs of the optical switch are connected to the first optical path A and the second optical path B, respectively. This allows the optical switch to direct single-photon signals emitted by Alice into either the first optical path A or the second optical path B, depending on a control signal.

[0020] The beam combining unit includes a first / second input terminal and an output terminal, and is used to combine the optical signals input through the first and second input terminals and output them through the output terminal. As an example, the first input terminal of the beam combining unit can be optically connected to the first output terminal of the optical switch via the first optical path A, and the output terminal of the beam combining unit can be optically connected to the Bob terminal. As an example, the beam combining unit can be a beam splitter (BS), such as Figure 1 shown.

[0021] The beam splitting unit is provided on the second optical path B and includes an input end and a first / second output end, and is used to split the optical signal inputted through the input end and output the two split light beams through the first / second output end. As an example, the input end of the beam splitting unit can be optically connected to the second output end of the optical switch, the first output end of the beam splitting unit can be optically connected to the Eve end, and the second output end of the beam splitting unit can be connected to the second input end of the beam combining unit through the second optical path B. As an example, the beam splitting unit can be a beam splitter (BS) or a clamp, such as Figure 1 Those skilled in the art know that the clamp can split the light signal in the optical fiber by destroying the total reflection effect of the optical fiber without damaging the optical fiber.

[0022] In this structure, a single-photon signal is emitted by Alice, which passes through the optical switch and enters two paths, namely the first optical path A and the second optical path B. When the optical switch connects to the first optical path A, the single-photon signal emitted by Alice will be directly input to the Bob end, demonstrating the state of not being eavesdropped. When the optical switch connects to the second optical path B, the single-photon signal emitted by Alice will be transmitted toward the Eve / Bob end under the action of the beam splitting unit, demonstrating the state of being eavesdropped. It should be noted that due to the indivisible nature of single photons, the same single-photon signal from Alice cannot be detected by both Bob and Eve at the same time, thus proving that single-photon signals are used in the quantum key distribution system.

[0023] Figure 2 An exemplary embodiment of a demonstration system for quantum channel eavesdropping attacks on quantum key distribution devices is shown, which is used to specifically illustrate the structures of the control end and the demonstration end. Figure 2 As shown, a clock source may be provided in the control terminal, which outputs a clock signal to Alice terminal, Bob terminal and Eve terminal, so that the clocks of the three terminals are synchronized.

[0024] Alice generates and outputs a single-photon signal, which passes through an optical switch and enters two paths, namely, a first optical path A and a second optical path B. When the optical switch connects to the first optical path A, the single-photon signal emitted by Alice is directly input to the Bob end via a beam combining unit (such as BS). At the Bob end, the input single-photon signal is detected and a corresponding electrical signal is output. The detection electrical signal output by the Bob end is then input to the control end. In the control end of the present invention, a first discriminator can be preferably provided to discriminate and shape the input detection electrical signal, and then the shaped valid electrical signal is input to a first counter for counting and statistics, thereby recording the number of signals used in communication (not subject to eavesdropping).

[0025] When the optical switch connects to the second optical path B, the single-photon signal emitted by Alice will enter the second optical path B and reach the beam splitting unit (such as a clamp). Due to the indivisible nature of single-photon signals, the single-photon signal will, with a certain probability, directly reach Eve via the first output of the beam splitting unit or reach Bob via the second output of the beam splitting unit, the second input, and the output of the beam combiner.

[0026] When a single-photon signal enters the Eve terminal, it detects the input single-photon signal and outputs a corresponding electrical signal. The detection electrical signal output by the Eve terminal is then input to the control terminal. Similarly, the control terminal of the present invention can preferably be equipped with a second discriminator to discriminate and shape the input detection electrical signal. The shaped valid electrical signal is then input to a second counter for counting, thereby recording the number of signals that were not used for communication (i.e., were subject to eavesdropping).

[0027] The control terminal of the present invention also includes a signal delay regulator, which is used to ensure that the detection electrical signal output from the Bob terminal and the detection electrical signal output from the Eve terminal reach the coincidence gate unit simultaneously within a cycle. As an example, the signal delay regulator can be arranged between the second discriminator and the coincidence gate unit. The coincidence gate unit performs an "AND gate" operation on the input electrical signals, that is, when two signals are input simultaneously, it outputs a valid electrical signal. The valid electrical signals output by the coincidence gate unit are input into a third counter for counting, thereby recording the number of signals used for communication (and subject to eavesdropping).

[0028] The three counting results from the three counters are input to the control unit for processing and storage.

[0029] The demonstration terminal includes an input interface and a display interface. The input interface allows users to input commands, such as controlling an optical switch via the control terminal, to determine whether the system operates in normal mode or eavesdropping mode. The display interface is used to demonstrate system status, for example, by displaying the untappable nature of quantum communication based on the counts of three counters.

[0030] In the present invention, in order to ensure the correctness of the delay adjustment of the signal delay adjuster, the control end is configured to enable the Alice end to have two working modes, namely, low-frequency strong light emission mode and high-frequency single-photon emission mode.

[0031] The low-frequency, high-intensity light emission mode is used for debugging. For example, it can have a light emission frequency of 10kHz and an average photon count of ~10 per pulse. In this mode, since the line delay error cannot exceed one transmission cycle (for example, a 10kHz frequency corresponds to a 100µs time interval, which corresponds to a 10,000m cable length), the required delay value can be accurately found. The high-frequency, single-photon emission mode is used for operating conditions. For example, it can have a light emission frequency of 40MHz and an average photon count of ~0.5 per pulse. In this mode, the indivisibility of single photons can be demonstrated while maintaining a high count rate per second, ensuring a good demonstration effect.

[0032] The demonstration system of this invention solves the problem of demonstrating the single-photon indivisibility of quantum key distribution systems. By using a beam-splitting unit to attack the quantum key distribution system, combined with counting and statistics by a coincidence gate unit, it is intuitively demonstrated that the effectively coded single-photon signal between Alice and Bob cannot be captured by Eve. In other words, it is impossible for valid detection electrical signals to appear simultaneously on both Bob and Eve within a single cycle. This has significant implications for the popularization of technology and its application.

[0033] The above description is not intended to limit the present invention, nor is the present invention limited to the above examples. In addition, the above-mentioned various alternatives may be used in combination with each other unless there is any contradiction. Any changes, modifications, additions, or substitutions made by a person skilled in the art within the spirit and scope of the present invention shall also fall within the scope of protection of the present invention, and the scope of protection of the present invention shall be subject to the claims.

Claims

1. A demonstration system for quantum channel eavesdropping attacks on a quantum key distribution device, comprising a quantum key distribution transmitter Alice, a quantum key distribution eavesdropper Eve, a quantum key distribution detector Bob, a transmission optical path, a control terminal, and a demonstration terminal, wherein: The Alice terminal is configured to output a single photon signal; The Eve terminal and the Bob terminal are configured to detect the single photon signal and output a detection electrical signal; The transmission optical path is configured to realize an optical path connection between the Alice end and the Bob end or an optical path connection between the Alice end and the Eve end according to a control signal provided by the control end; as well as The demonstration end is configured to demonstrate a quantum channel eavesdropping attack based on the detection results of the Bob end and / or the Eve end; The transmission optical path includes an optical switch, a first optical path A, a second optical path B, a beam splitting unit, and a beam combining unit; the optical switch is configured to switch the optical path connection between the Alice end and the first optical path A or the second optical path B according to the control signal; the beam combining unit is configured to combine and output the optical signals input through the first optical path A and the second optical path B; the beam splitting unit is configured to split and output the optical signal input through the second optical path B; The Alice end is connected to the Bob end via the first optical path A and the beam combining unit; the Alice end is connected to the Eve end via the second optical path B and the beam splitting unit, and is connected to the Bob end via the second optical path B, the beam splitting unit and the beam combining unit.

2. The demonstration system according to claim 1, wherein: The beam combining unit is a beam splitter; and / or the beam splitting unit is a beam splitter or a clamp.

3. The demonstration system according to claim 1, wherein: The control end includes a first counter and a second counter; the first counter is used to count the detection electrical signal output by the Bob end, and the second counter is used to count the detection electrical signal output by the Eve end.

4. The demonstration system according to claim 3, wherein: The control end also includes a third counter, a signal delay adjuster and a coincidence gate unit. The signal delay adjuster is configured so that within one cycle, the detection electrical signal output by the Bob end and the detection electrical signal output by the Eve end reach the coincidence gate unit at the same time; the coincidence gate unit is configured to perform an AND gate operation on the detection electrical signal output by the Bob end and the detection electrical signal output by the Eve end; and the third counter is used to count the valid electrical signals output by the coincidence gate unit.

5. The demonstration system according to claim 3, wherein: The control end further includes a clock source for outputting a synchronous clock signal to the Alice end, the Bob end, and the Eve end.

6. The demonstration system according to claim 3, wherein: The control end further includes a discriminator for discriminating and shaping the detection electrical signal output by the Bob end and / or the detection electrical signal output by the Eve end.

7. The demonstration system according to any one of claims 1, 3-6, wherein: The Alice end has a low-frequency strong light emission mode and a high-frequency single-photon emission mode, and is configured to be able to switch between the low-frequency strong light emission mode and the high-frequency single-photon emission mode based on the control of the control end.

8. The demonstration system according to claim 1, wherein: The demonstration end includes an input interface and a display interface. The input interface allows a user to input instructions to determine whether the demonstration system operates in a normal mode or a wiretap mode. The display interface is used for system status demonstration.

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