A discrete-modulated continuous-variable quantum multicast network system and a communication method thereof

Abstract

The application discloses a discrete modulation continuous variable quantum multicast network system and a communication method thereof, and relates to the technical field of quantum communication. The method comprises the following steps: each source node generates a double-mode compressed light, i.e. signal light and probe light; each source node measures the signal light, monitors the light intensity of the probe light, and corrects the light intensity; each target node measures the corrected probe light; each source node performs quantum entanglement discrimination according to the measurement results of the signal light and the probe light, performs block modulation and encryption on the to-be-sent message when the quantum side channel is in an entangled state, sends the modulated message to each target node, and performs exclusive OR processing on the encrypted messages sent by all the source nodes and sends the processed messages to each target node; and each target node decodes the exclusive OR processed message according to the signal light and the modulated message to obtain the to-be-sent message of each source node. The method can improve the defense capability against optical injection attacks.

Description

Technical Field

[0001] This invention relates to the field of quantum communication technology, and in particular to a discrete modulation continuous variable quantum multicast network system and its communication method. Background Technology

[0002] Current continuous-variable quantum network coding (CVQNC) technology faces two fundamental technical bottlenecks in realizing quantum multicast communication, severely restricting the application of quantum communication networks in distributed systems. Firstly, traditional CVQNC systems, based on a point-to-point communication model, suffer from inherent limitations in multicast scenarios. Secondly, the topological structure restricts its use to single-source-single-target communication, failing to achieve true multi-source-multi-target multicast.

[0003] In existing technologies, multicast communication with multiple sources and multiple targets is usually achieved using typical multicast topologies such as butterfly networks. However, when facing optical injection attacks, existing multicast communication methods typically use protective devices such as optical isolators, circulators, optical power limiters and narrowband filters, or detect attacks through intensity monitors and photodetectors. However, their defense capabilities are insufficient in the face of complex and ever-changing attack scenarios. Summary of the Invention

[0004] Therefore, it is necessary to provide a discrete modulation continuous variable quantum multicast network system and its communication method to address the above-mentioned technical problems.

[0005] The present invention adopts the following technical solution:

[0006] This invention provides a communication method for a discrete-modulation continuous-variable quantum multicast network system. The method is applied to this system, which includes multiple source nodes, intermediate nodes, and multiple target nodes. The method includes:

[0007] Each source node generates a dual-mode compressed light; the dual-mode compressed light includes a signal light and a probe light; the signal light and the probe light are entangled dual-mode light fields with complementary orthogonal components;

[0008] Each source node measures the signal light to obtain the orthogonal component and conjugate orthogonal component of the signal light, and couples the probe light to the quantum side channel. The quantum side channel monitors the light intensity of the probe light during transmission and corrects the light intensity when the light intensity is greater than a multiple of the initial light intensity.

[0009] Each target node receives the corrected probe light through the quantum side channel, measures the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couples them to the quantum side channel; each source node performs quantum entanglement discrimination based on the orthogonal component and conjugate orthogonal component of the signal light and the probe light.

[0010] When the quantum entanglement discrimination result indicates that the quantum side channel is in an entangled state, each source node modulates and encrypts the message to be sent in blocks, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel. The intermediate node performs XOR processing on all the encrypted messages to be sent by the source nodes, and sends the XOR processed message to each target node.

[0011] Each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent from each source node.

[0012] Optionally, each source node includes a non-degenerate optical parametric amplifier and a polarization beam splitter; each source node generates dual-mode compressed light, including:

[0013] For any source node, a raw pulse is generated and injected into a non-degenerate optical parametric amplifier to obtain undivided two-mode compressed light;

[0014] The unsplittered dual-mode compressed light is split using a polarization beam splitter to obtain signal light and probe light.

[0015] Optionally, the method further includes:

[0016] When the light intensity is greater than a multiple of the initial light intensity, the intensity of the probe light is attenuated to a safe threshold.

[0017] Optionally, quantum entanglement is determined based on the orthogonal and conjugate orthogonal components of the signal and probe beams, including:

[0018] The criterion value is determined based on the orthogonal and conjugate orthogonal components of the signal light and the probe light;

[0019] If the criterion value is less than the preset entanglement critical threshold, then the quantum entanglement determination result is that the quantum side channel is in an entangled state; criterion value The calculation formula is:

[0020] ;

[0021] in, For variance, and These are the orthogonal components of the signal light and the probe light, respectively. and These are the orthogonal components and conjugate orthogonal components of the probe light, respectively. It indicates a desire for the expected value.

[0022] Optionally, the method further includes:

[0023] After determining that the quantum entanglement discrimination result indicates that the quantum side channel is in an entangled state, each source node encrypts the message to be sent using a key to obtain the encrypted message to be sent; the key is a pre-shared mask key among multiple source nodes.

[0024] Optionally, before sending the modulated message to each target node via the quantum side channel, the method further includes:

[0025] The variance, transmittance, and noise of the quantum side channel are corrected based on the orthogonal components of the signal and probe beams.

[0026] Optionally, variance correction includes:

[0027] ;

[0028] in, The corrected variance, To attack the light intensity scaling factor, For variance;

[0029] Transmittance correction includes:

[0030] ;

[0031] ;

[0032] in, This is the corrected transmittance. This is an estimate of the transmittance. For dynamic sample numbers, These are orthogonal measurements of the signal light from the source node. These are orthogonal measurements of the probe light at the target node;

[0033] Noise correction includes:

[0034] ;

[0035] ;

[0036] in, For the corrected noise, This represents excess noise in a quantum side channel.

[0037] Optionally, each source node performs block modulation on the message to be sent, including:

[0038] For any source node, the source node divides the message to be sent into segments of length [length missing]. The blocks are divided, and a detection bit and a parity bit are added to each block to generate a uniform sequence;

[0039] The discrete modulator in the source node modulates the uniform sequence and outputs a coherent sequence, i.e., the modulated message.

[0040] Optionally, each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent by each source node, including:

[0041] For any target node, the target node measures the signal light to obtain the orthogonal components;

[0042] The message modulated by any source node is recovered based on the orthogonal components to obtain the message to be sent by that source node;

[0043] By decoding the XOR-processed message from the source node's message to be sent, we can obtain the messages to be sent from other source nodes.

[0044] This invention provides a discrete-modulation continuous-variable quantum multicast network system, which includes multiple source nodes, intermediate nodes, and multiple target nodes;

[0045] Each source node is used to generate dual-mode compressed light; the dual-mode compressed light includes a signal light and a probe light; the signal light and the probe light are entangled dual-mode light fields with complementary orthogonal components; the signal light is measured to obtain the orthogonal components and conjugate orthogonal components of the signal light, and the probe light is coupled to the quantum side channel;

[0046] Quantum side channels are used to monitor the intensity of probe light during transmission and to correct the intensity when the intensity exceeds a multiple of the initial intensity.

[0047] Each target node is used to receive the corrected probe light through the quantum side channel, measure the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couple them to the quantum side channel;

[0048] Each source node is used to determine quantum entanglement based on the orthogonal and conjugate orthogonal components of the signal and probe beams. When the quantum entanglement determination result indicates that the quantum side channel is in an entangled state, each source node modulates and encrypts the message to be sent in blocks, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel. The key used by the source node to encrypt the message to be sent is a pre-shared mask key of multiple source nodes.

[0049] Intermediate nodes are used to perform XOR processing on the encrypted messages to be sent by all source nodes, and then send the XOR-processed messages to each target node.

[0050] Each target node is used to decode the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent from each source node.

[0051] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the communication method of the discrete-modulated continuous-variable quantum multicast network system described above.

[0052] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the communication method of the discrete-modulated continuous-variable quantum multicast network system described above.

[0053] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects:

[0054] Injection attacks typically disrupt legitimate quantum signals by injecting strong light into the channel, causing communication anomalies. In this invention, the intensity of the probe light in the quantum edge channel is monitored. When the light intensity exceeds a set threshold multiple of the initial light intensity, it is determined that an injection attack may have occurred, and light intensity correction is performed to maintain the channel light intensity within the range that can handle legitimate signals. This reduces the interference of the injected strong light on the transmission of quantum signals, thus resisting injection attacks at the physical transmission level. Then, security verification based on quantum entanglement discrimination is performed. If the attacker injects a non-entangled light signal, it is easy to destroy the originally maintained entanglement relationship. Therefore, anomalies can be identified through entanglement discrimination. Encrypted data transmission is performed when the quantum edge channel is in an entangled state, improving the defense effect against optical injection attacks in discrete modulation continuous variable quantum multicast network systems. Attached Figure Description

[0055] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0056] Figure 1 A schematic diagram of a communication method for a discrete-modulated continuous-variable quantum multicast network system provided by the present invention;

[0057] Figure 2 A schematic diagram of a communication method for another discrete-modulated continuous-variable quantum multicast network system provided by the present invention;

[0058] Figure 3This invention provides a schematic diagram of multicast CVQNC under a butterfly network architecture and a quantum side channel implementation architecture diagram;

[0059] Figure 4 A flowchart of message block uniform mapping and discrete modulation is provided for this invention;

[0060] Figure 5 A schematic diagram of an optical injection attack model provided by the present invention;

[0061] Figure 6 This invention provides a schematic diagram of modulation parameter offset and phase space distortion characteristics.

[0062] Figure 7 This invention provides a schematic diagram of message block uniformity effect;

[0063] Figure 8 A schematic diagram of entanglement degradation characteristics provided by the present invention;

[0064] Figure 9 A schematic diagram illustrating the performance comparison of effective information rate provided by this invention;

[0065] Figure 10 Another effective information rate performance comparison diagram provided by the present invention;

[0066] Figure 11 This invention provides a schematic diagram of a modulation variance optimization curve;

[0067] Figure 12 This invention provides a closed-loop topology diagram of the anti-attack implementation process for a discrete-modulation continuous-variable quantum multicast network system. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0069] Currently, in typical multicast topologies such as the Butterfly Network, the channel capacity utilization rate of bottleneck nodes is less than 40%; quantum channel resources cannot be efficiently shared among multiple users, resulting in low overall spectrum efficiency. Performance constraints on multi-hop transmission cause information transmission latency to increase exponentially. Inter-node coordination overhead accounts for over 30% of the effective bandwidth; it cannot meet the microsecond-level synchronization accuracy requirements of quantum sensor networks. Security bottlenecks include the need for multiple key distribution negotiations, increasing the risk of side-channel attacks; relay nodes become potential security vulnerabilities, expanding the attack surface. These shortcomings limit the application of traditional CVQNC systems in scenarios requiring efficient multicast support, such as quantum data center interconnection and distributed quantum computing. Experiments show that in an 8-node quantum sensor network, the positioning error of the traditional architecture is more than three times higher than that of the multicast scheme.

[0070] In the analysis of optical injection attack vulnerabilities, the physical layer security of quantum communication systems faces severe challenges, especially the highly covert and destructive nature of optical injection attacks on source devices. The attack mechanism involves the attacker (Eve) injecting a strong laser signal of a specific wavelength (1530-1565nm) into the source device. Attack locations: behind the isolator and before the modulator (approximately 5cm from the modulator). Attack vector: Attack parameters: Injection power adjustable from 1-100mW, modulation parameter offset range 0-2. System impacts include: modulation distortion, coherent state constellation point distortion, and an increase in the root mean square error vector magnitude (EVMRMS) of the 8PSK signal from 8% to 25%. This distortion manifests in phase space as an anomalous shift in the quantum state distribution. In the QPSK attack state, the phase shift is >25° (ideal value 90° → measured 115°). In the 8PSK attack state, there is a ring breakage plus a 30% amplitude fluctuation parameter shift. The modulation parameter shift increases linearly with the injected power. Entanglement degradation: The entanglement variance V increases from a safe value of 1.2 to a dangerous value of 2.5 (threshold V=2.0).

[0071] Light injection attack core model:

[0072] (1);

[0073] in, The attack light intensity scaling factor (measured range 1.0-3.0) is used. The original variance parameters are (0.5-1.5). This is the compression parameter (typical value 1.2-1.5). To coordinate efficiency, The amount of information available to Eve.

[0074] Analysis of the limitations of existing defense technologies: Wavelength isolation technology is implemented using an optical bandpass filter. Its main limitation is that it can only effectively defend against attacks of fixed wavelengths, and its protection against tunable laser attacks is weak (tunable laser attack penetration rate >85%). Security performance indicators: The attack success rate is 64.3%, indicating that more than half of attacks can successfully penetrate this defense measure. In light intensity monitoring technology, the implementation method is a real-time monitoring system based on photodiodes. Its main limitation is a response delay greater than 100 microseconds. This makes it ineffective against transient pulse attacks; security performance indicators: the attack success rate is as high as 77.2%, proving that the technology has limited protection against complex attacks. In the protocol authentication technology, the implementation method is: using the QKD handshake protocol for identity authentication; main limitation: it adds 300 milliseconds of communication latency (+300ms), making it unsuitable for systems with high real-time requirements; security performance indicators: the attack success rate is 58.9%, still failing to provide sufficient protection.

[0075] Based on this, the present invention provides a communication method for a discrete modulation continuous variable quantum multicast network system, which improves the defense capability against complex and ever-changing attack scenarios.

[0076] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0077] Figure 1 This is a schematic diagram of a communication method for a discrete-modulation continuous-variable quantum multicast network system according to the present invention. The method is applied to a discrete-modulation continuous-variable quantum multicast network system, which includes multiple source nodes, intermediate nodes, and multiple target nodes. The method specifically includes the following steps:

[0078] S101, each source node generates dual-mode compressed light; the dual-mode compressed light includes signal light and probe light; the signal light and probe light are entangled dual-mode light fields with complementary orthogonal components.

[0079] The source node is the end that needs to send messages in multicast communication, and the destination node is the end that receives messages in multicast communication.

[0080] Each source node includes a non-degenerate optical parametric amplifier (NOPA) and a polarizing beam splitter (PBS). Each source node generates dual-mode compressed light by: generating a raw pulse for any source node and injecting the raw pulse into the NOPA to obtain unsplit dual-mode compressed light; and splitting the unsplit dual-mode compressed light by the polarizing beam splitter to obtain signal light and probe light.

[0081] The source node can include two source nodes, S1 and S2. The optical path is split by a polarization beam splitter starting from a non-degenerate optical parametric amplifier inside the source node.

[0082] The non-degenerate optical parametric amplifier uses a type II periodically polarized lithium niobate waveguide (PPLN). Located inside the source node, the amplifier measures 10 × 0.5 × 30 mm³, has a pump wavelength of 1550 nm, a compression parameter r = 1.2 (7 dB compression), and a bandwidth of 100 MHz. Its function is to generate a two-mode compressed vacuum state (unsplit two-mode compressed light).

[0083] (2);

[0084] in, These represent compression and decompression operations, respectively. These are the initial orthogonal components. and These are the quantum noise of the input vacuum state in the position component and the quantum noise of the input vacuum state in the momentum component, respectively. and These are the orthogonal components of the signal light and the conjugate orthogonal components of the signal light.

[0085] The polarization beam splitter has a 50:50 split ratio and an insertion loss of less than 0.2 dB. It splits the dual-mode compressed vacuum state output by NOPA into two functional optical paths: a signal beam and a signal beam. (Retained on the source node delay line) and probe light (Direct connection to the target node).

[0086] The source node also includes a commercial continuous wave (CW) laser (1550nm wavelength, 10mW power), an amplitude modulator, and a 50:50 beam splitter (BS). Its function is to perform pre-processing optical steps for quantum state generation. Specifically, the CW laser outputs optical pulses, which are then modulated by the amplitude modulator to generate a pulse sequence. The 50:50 beam splitter then splits the pulses into a primary pulse and a reference pulse. The reference pulse is reflected by a Faraday mirror to a variable optical attenuator (VOA) to adjust its intensity. The primary pulse enters the NOPA to generate dual-mode compressed light. This step is a pre-processing step for quantum state generation, producing only unsegmented dual-mode compressed light (without differentiation). and The key point of this step is that the reference pulse does not enter the NOPA; it is only used for subsequent classical calibration. The reference pulse is the phase reference generator of the source node homodyne detection system. Through dynamic intensity adjustment (VOA) and time-domain synchronization (EOM), it ensures that the target node responds to the probe light. The orthogonal component measurement accuracy is achieved, and the original pulse is the only input for quantum state generation.

[0087] In the quantum resource preparation process, the original pulse enters NOPA to generate dual-mode compressed light. The generated unsegmented dual-mode compressed state is the result of the dual-mode compressed light being split into two states by PBS. The object of the process operation, signal light Preserve the source node (inheritance) and Characteristics), detection light Direct connection to target node (probe light) Inherit the orthogonal components of the probe light and (Properties of the conjugate orthogonal components of the probe light).

[0088] S102, each source node measures the signal light to obtain the orthogonal component and conjugate orthogonal component of the signal light, and couples the probe light to the quantum side channel. The quantum side channel monitors the light intensity of the probe light during transmission and corrects the light intensity when the light intensity is greater than a multiple of the initial light intensity. Each target node receives the corrected probe light through the quantum side channel, measures the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couples it to the quantum side channel.

[0089] Taking source node S1 as an example, S1 randomly selects the signal light. of m At each location, measure the orthogonal components. and conjugate orthogonal components And publish the location.

[0090] Each target node includes a zero-difference detection system and an orthogonal component measurement unit, which serves as the phase reference engine for achieving zero-difference detection. It is directly connected to the fiber optic coupler and... Difference frequency signals are generated by interference within the coupler. The parameters of the zero-difference detection system include: local oscillator power of 2 mW, quantum efficiency of 85%, and bandwidth of 12 GHz (supporting 10 Gbps transmission); the parameters of the quadrature component measurement unit include: sampling accuracy of 0.01 rad (phase) and 0.1 dB (amplitude).

[0091] Specifically, the target node uses a local oscillator to perform zero-difference detection on the probe light and measures the quadrature component and the conjugate quadrature component.

[0092] Taking the target node T1 as an example, T1 uses a zero-difference detection system and an orthogonal component measurement unit to detect the light. Measure the quadrature components of the probe light at the same location and conjugate orthogonal components .

[0093] in, and The correlation is spatial separation (source node and target node). and The correlations are mutually orthogonal and conjugate, constituting the core variables for entanglement verification.

[0094] It should be noted that during the transmission of the probe light in the quantum side channel, the intensity of the probe light is monitored throughout the entire process. When the intensity exceeds a multiple of the initial intensity, the intensity is corrected. The probe light received by the target node is then the intensity-corrected probe light, and the measurements are taken of its orthogonal and conjugate orthogonal components. When the intensity of the probe light is less than or equal to a multiple of the initial intensity, no intensity processing is performed.

[0095] When the light intensity is greater than a multiple of the initial light intensity, the intensity of the probe light is attenuated to a safe threshold.

[0096] Specifically, the intensity of the detected light Greater than a multiple of the initial light intensity When this occurs, an alarm is triggered, and the intensity of the probe light is attenuated to a safe threshold. k To defend against light injection attacks. Among them, , The initial light intensity, k To attack the light intensity scaling factor, k It can be 0.8.

[0097] After detecting that the light intensity is a multiple of the initial light intensity, before sending the modulated message to each target node through the quantum side channel, the variance, transmittance and noise of the quantum side channel are corrected according to the orthogonal components of the signal light and the probe light.

[0098] Specifically, the system also includes a light intensity monitoring unit, a light power limiter, and a parameter corrector. The light power limiter is an acrylic prism limiter, which is a physical layer defense module in the system. The light intensity monitoring unit detects the light intensity of the probe light transmitted in the quantum side channel in real time. If the light intensity If the initial light intensity exceeds a preset threshold, the optical power limiter is triggered, blocking the strong light through nonlinear scattering (damage threshold 50mW). After the optical power limiter blocks the attack, the parameter corrector updates the parameters of the quantum side channel to compensate for signal distortion. The parameters of the optical power limiter include: nonlinear coefficients. The damage threshold is 50mW (blocking attack light >10mW); the correction parameters of the parameter corrector include: variance correction, transmittance correction and noise correction.

[0099] Variance correction includes:

[0100] (3);

[0101] in, The corrected variance, To attack the light intensity scaling factor, Let Variance be the variance.

[0102] Transmittance is estimated using a maximum likelihood estimation algorithm, and then corrected. Transmittance correction includes:

[0103] (4);

[0104] (5);

[0105] in, This is the corrected transmittance. This is an estimate of the transmittance of the quantum side channel. For dynamic sample numbers, These are orthogonal measurements of the signal light from the source node. These are orthogonal measurements of the probe light at the target node. Based on a normal linear model, the orthogonal measurements of the source and target nodes are used to... and The transmittance T is derived using the maximum likelihood estimation method, which is performed during the target node parameter estimation stage to correct for transmittance shifts caused by attacks. This formula is used to correct channel parameters after an attack, eliminating estimation bias caused by optical injection attacks.

[0106] Noise correction:

[0107] (6);

[0108] (7);

[0109] in, The corrected noise. This represents the excess noise in a quantum side channel, a quantized value of channel distortion caused by an attack, measuring the additional noise introduced by eavesdropping attacks (such as optical injection attacks), exceeding the inherent noise (vacuum noise) of the quantum channel. Unit: linear scale (unitless). Its derivation process is as follows: calculate the sum of squares of the deviations between measured and theoretical values: (Quantization of received signal) Compared with theoretical value (Differences); Subtracting vacuum noise reference: Subtracting fixed constants (Vacuum noise variance) yields the pure attack noise: Its function is: 1. When When an optical injection or tampering attack is detected in the channel (e.g., ξ=0.05 indicates that the attack noise exceeds the limit by 5 times), the typical security threshold is... (Dynamic defense will be triggered if the threshold is exceeded).

[0110] Dynamic calibration engine: At the target node, parameter correction is triggered when the intensity of the probe light exceeds a threshold. It includes corrections for transmittance, noise, and variance, achieving dynamic balance of system parameters under attack through a shared attack light intensity scaling factor k. Maximum likelihood estimation of channel parameters is performed based on received data, along with transmittance estimation. Linkage and real-time correction of channel parameters: Noise suppression: (Noise is suppressed to a safe threshold). The k parameter in the parameter correction is the same as the k parameter in the light intensity monitoring to eliminate parameter offset caused by the attack. The correction frequency is 10 kHz.

[0111] The intensity of the probe light is monitored by an optical power limiter, and when the intensity of the probe light exceeds a multiple of the initial intensity, the intensity of the probe light is attenuated to a safe threshold.

[0112] When the light intensity exceeds a multiple of the initial light intensity, the modulation variance is dynamically adjusted. An optical power limiter (acrylic prism) scatters excessive attack light (damage threshold 50mW), and linked parameters are re-evaluated to ensure continuous communication stability. Specifically, the modulation signal light is dynamically adjusted. The variance of quantum state amplitude: , , . To attack the light intensity scaling factor, light injection attack simulation shows that when... QPSK error rate exceeds This refers to the optical injection attack scaling factor (range 1.0-3.0), located at the optical intensity monitoring unit (end-to-end). Its impact is on modulation variance correction. r (compression parameter): Meaning: Entanglement strength generated by NOPA (typically 1.2-1.5), Location: Source node NOPA. Impact: Entanglement verification (V is negatively correlated with r). Acrylic prism scatters excessive attack light, re-estimating channel parameters. T (Transmittance): Meaning: Channel transmission efficiency; Location: Target node parameter estimation; Impact: Maximum likelihood correction (…). ). (Excessive Noise): Meaning: Added noise to the channel; Location: Target node parameter estimation; Impact: Correction ( ). (Modulation variance): Meaning: Variance of the signal light; Location: Source node modulator; Impact: Dynamically adjusts to optimize the effective information rate.

[0113] System robustness guarantee: ensuring that the bit error rate remains less than [value missing] even under attack. This overcomes the vulnerability of traditional quantum communication. (Formula notation explanation:) Transmittance correction term: Transmittance estimate from formula (4) Eliminate signal attenuation and distortion caused by attacks. For dynamic sample numbers, hour, estimation error (To ensure accuracy). Vacuum noise compensation term: Subtracts inherent vacuum fluctuations in the quantum channel (omitting this term would result in overestimation). 50%. The source node sends a signal, which is then orthogonally modulated ( Alternating components). The target node receives the signal, and the technical requirement is zero-difference detection results (bandwidth > 100MHz).

[0114] S103, each source node performs quantum entanglement discrimination based on the orthogonal components and conjugate orthogonal components of the signal light and the probe light.

[0115] In one embodiment, quantum entanglement discrimination is performed based on the orthogonal and conjugate orthogonal components of the signal light and the probe light, including: determining a criterion value based on the orthogonal and conjugate orthogonal components of the signal light and the probe light; if the criterion value is less than a preset entanglement critical threshold, the quantum entanglement discrimination result is determined to be that the quantum side channel is in an entangled state; the criterion value... The calculation formula is:

[0116] V = (8);

[0117] in, For variance, and These are the orthogonal components of the signal light and the probe light, respectively. and These are the orthogonal components and conjugate orthogonal components of the probe light, respectively. It indicates a desire for the expected value.

[0118] The preset entanglement threshold can be 1.8, if the criterion is met ( <1.8 indicates that the quantum channel has not been eavesdropped on, and communication continues; if the criterion is not met ( If the value is below 1.8, the recalibration protocol is triggered: the criterion directly determines whether communication is interrupted, and if it is below 1.8, normal communication is maintained. This is derived from the analysis of entanglement degradation under attack. This verification ensures that quantum resources have not degraded. If the attack causes V ≥ 1.8, it indicates insecurity; if the attack causes scaling of orthogonal components (…), then… The complete solution needs to cover all orthogonal components (orthogonal components are used as an example here), and only when the light intensity monitoring unit detects... Scaling is performed when the value is greater than 1.0, and the scaling range covers all four orthogonal components. Perform synchronous scaling. Without scaling, the attack will distort the entanglement criterion V, leading to misjudgments. Location: Light injection attack analysis phase (used to assess attack impact). Authentication latency: <1 ms (meets the microsecond-level synchronization requirements of quantum data centers).

[0119] S104, when the quantum entanglement discrimination result indicates that the quantum side channel is in an entangled state, each source node performs block modulation and encryption on the message to be sent, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel. The intermediate node performs XOR processing on all the encrypted messages to be sent by the source nodes, and sends the XOR processed message to each target node.

[0120] In one embodiment, after determining that the quantum entanglement discrimination result indicates that the quantum side channel is in an entangled state, each source node encrypts the message to be sent using a key to obtain the encrypted message to be sent; the key is a pre-shared mask key among multiple source nodes.

[0121] Specifically, the source node also includes an AES-128 encryption module, whose parameters include a key generation rate of 10^64. 6 bits / s, computation latency less than 50 ns.

[0122] The intermediate node includes an XOR operation processor with a throughput of 20 Gbps.

[0123] The source nodes include S1 and S2, and the message to be sent by source node S1 is... The message to be sent by source node S2 is M is the pre-shared mask key, and the source node S1 uses M to... Encryption is performed to obtain the encrypted message to be sent. Source node S2 accesses M through Encryption is performed to obtain the encrypted message to be sent. Source node S1 will The signal is sent to the XOR processor via a classic channel, and the source node S2 will... The data is sent to the XOR processor via a classic channel, and the XOR processor executes the operation. and will The aggregated message is distributed to each target node. C2 distributes the aggregated message via the quantum side channel. Its core advantages are: reusing existing sub-channel resources to reduce deployment costs; using entangled optical synchronization to ensure accuracy of <100 ps; and using dynamic modulation (8PSK / 16APSK) to improve channel utilization to 77%. This design is a key innovation to break through the bottleneck of multicast networks, and C2 can be a relay processor.

[0124] Technical Specifications: Bottleneck node utilization: from 40% to 77%; Multi-source message synchronization error: <100 ps. Related Steps: Addresses the inherent bottlenecks of the butterfly network topology, providing efficient input for the synchronous decoding of the S105.

[0125] In one embodiment, each source node performs block modulation on the message to be sent, including: for any source node, the source node divides the message to be sent into blocks of length [missing information]. The source node modulates the uniform sequence by adding detection bits and parity bits to each block; the discrete modulator in the source node modulates the uniform sequence and outputs a coherent sequence, i.e., the modulated message.

[0126] All components are housed within the source node chassis; the quantum side channel is the signal light. The transmission path after leaving the source node, but its signal generation device (mapper / modulator) remains inside the node. Signal light The modulation path, including VOA (used for...) ) and rear beam splitter (for (Monitoring). Physical location of the uniform mapping unit and discrete modulator: Located inside the optical chassis of the source node, functionally belonging to the signal generation end of the quantum side channel transmission path. Position calibration: Post-beam splitter 5cm from the modulator → inside the source node; the entire signal optical processing chain (mapping + modulation + monitoring) → has not left the physical boundary of the source node. Timing: After quantum entanglement verification is passed and before encrypted message aggregation. Blocking rule: Message blocking is performed in the uniform mapping unit of the source node. Relationship between blocking and encryption: Blocking precedes encryption: the document shows that the blocking operation is performed before encryption; encryption is performed independently: encryption is performed in the aggregation step (e.g., ...). ), messages after being divided As encrypted input, the segmentation and modulation of message A only affect the signal light. , The modulated coherent state is used to transmit user data. Probe light. It is used only for quantum verification (zero-difference measurement and entanglement verification) and does not participate in data transmission. Segmentation and modulation are classical to quantum transition processes, while... It is the physical carrier of quantum states. The generation of (NOPA output) is independent of the message content and only provides quantum resources for channel authentication.

[0127] The purpose of performing block segmentation is to adapt to quantum modulation: to divide message A into blocks of length 1. Blocks (e.g., in 8PSK) Each block contains 3 bits, enabling classical messages to match the phase mapping requirements of quantum modulation (e.g., 8PSK requires 3 bits to map to a phase state). Insertion protocol: Add to each block. Add 1 parity bit to the detection bit to generate a uniform sequence. This enables real-time error detection and attack identification during transmission (such as bit flipping caused by optical injection). PSK mapping: 8PSK phase state in a discrete modulator Its modulation precision enables the encoding conversion from message to quantum state. To modulate the amplitude (typical value 0.2-5). Phase index after uniform mapping The phase angle is evenly distributed according to the message index. Odd-numbered positions, phase error <0.1 rad. Rear beam splitter (5 cm from modulator), sampling ratio: 5%, optical power monitoring frequency: 10 kHz. Operation procedure: The uniform mapping unit performs uniform mapping generation. (Entropy > 7.5 bits / block) The discrete modulator outputs a coherent state sequence. After dynamically adjusting the light intensity of the coherent state sequence (range 0-30 dB) via a VOA, it is transmitted to the target node through a quantum side channel. During the quantum side channel transmission, the light intensity is monitored in real time via a VOA and a post-beam splitter. And adjust the light intensity, the object of adjustment is The transmitted light intensity of the signal beam (i.e., the physical beam power of the modulated coherent state sequence) is the core control element for reliable transmission in quantum side-channels. Technical specifications: Original distribution optimization: high-bit probability reduced from >60% to <8%; 8PSK advantageous range window: 40-60 km (ΔI difference >50%). Related steps: Post-beam splitter. Monitoring directly drives dynamic light intensity defense.

[0128] Integrating variance correction: Real-time detection of light intensity monitoring (If the attack results in) ), dynamically adjust modulation variance (For example, switch to 16APSK when k>1). (Original modulation variance)

[0129] Physical meaning: signal light The variance of quantum state amplitude when unattacked; technical application: controlling the distribution range of quantum state constellation points (the larger the value, the stronger the resistance to attenuation, but the risk of nonlinear distortion increases); discrete modulator for location source nodes. Under QPSK modulation. =0.8, under 8PSK =1.0. (Attack intensity scaling factor), physical meaning: real-time light intensity offset rate caused by the attack, calculated as follows: Technical function: Quantifying attack intensity and driving dynamic defense strategies. Location: Light intensity monitoring unit (end-to-end). <0.85 → Weak attack (segmented eavesdropping) >1.0 → Strong attack (blinding by strong light). (Corrected modulation variance), physical meaning: the new variance value dynamically adjusted under attack, location: source node dynamic modulation engine.

[0130] Technical function: When it reaches >1.0, it decreases to 0.5. Suppress nonlinear distortion; When it is less than 0.85, it rises to 1.2. Compensation for signal attenuation. Channel parameter reestimation. .

[0131] S105, each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent by each source node.

[0132] In one embodiment, each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent for each source node, including: for any target node, the target node measures the signal light to obtain the quadrature component; recovers the modulated message of any source node based on the quadrature component to obtain the message to be sent for that source node; and decodes the XOR-processed message using the message to be sent for that source node to obtain the messages to be sent for other source nodes.

[0133] Specifically, the target node's zero-difference detection system includes a polarization demultiplexer and a zero-difference detection unit. The parameters of the polarization demultiplexer include: extinction ratio greater than 25 dB and channel crosstalk less than -30 dB. The parameters of the zero-difference detection unit include: local oscillator optical coupling efficiency greater than 95%.

[0134] The specific operation process of this embodiment includes: the optical receiver of the target node receives the signal light from the source node S1. (Modulated coherent states such as 8PSK states transmitted via quantum side channels) are separated into three beams (reference beam, probe beam, and signal beam) by polarization demultiplexer and coupled with the local oscillator beam to measure the orthogonal components. and conjugate orthogonal components Then, the sequence is recovered based on the measurement results. The original message A is restored through a reverse mapping operation. (Probe light) For initial verification, signal light (For final decoding). Decryption This enables synchronous acquisition of messages from both sources. Technical specifications include: Bit error rate: (Industry Standard) Multi-source message decoding latency: <100 ns. Step correlation: Low bit error rate is achieved by relying on the uniform mapping output of S104.

[0135] In one embodiment, the present invention also provides a communication method for a discrete-modulated continuous-variable quantum multicast network system, such as... Figure 2 As shown, it specifically includes:

[0136] 1. Quantum resource preparation.

[0137] In the source node, a signal light and a probe light are generated based on a non-degenerate optical parametric amplifier and a polarization beam splitter. The signal light is retained on the source node delay line, and the probe light is directly connected to the target node.

[0138] 2. Quantum channel authentication.

[0139] The entanglement criterion is verified. If it holds, communication continues; otherwise, communication stops and recalibration is performed. Specifically, recalibration includes parameter estimation.

[0140] 3. Encrypted aggregation.

[0141] The source node encrypts the message to be sent and sends the encrypted message to the XOR processor, which then aggregates the received encrypted messages.

[0142] 4. Quantum teleportation.

[0143] The message to be transmitted is modulated using a discrete modulator and then transmitted via a post-beam splitter.

[0144] 5. Synchronous decoding.

[0145] Synchronous decoding operations include: zero-difference detection, inverse mapping decoding, and message synchronization.

[0146] 6. Dynamic anti-attack.

[0147] In one embodiment, such as Figure 3 As shown, Figure 3 This diagram illustrates multicast CVQNC within a butterfly network architecture and its quantum side-channel implementation architecture. Specifically, it includes:

[0148] 0. Quantum resource preparation (source node) operation: A non-degenerate optical parametric amplifier (NOPA) generates dual-mode compressed light, which is then split into signal light by a polarization beam splitter (PBS). : Retained on the source node delay line; probe light Directly connect to the target node.

[0149] 1. Quantum channel authentication (end-to-end), based on orthogonal component measurements ( Calculate the entanglement criterion: Authentication logic: Continue communication, if Terminate recalibration (re-estimation of transmittance T and noise ξ), location: quantum side channel (S1→T1, S2→T2).

[0150] 2. Encrypted aggregation (intermediate nodes C1 / C2): Operation: Source nodes S1 / S2 encrypt messages respectively. , (Pre-shared key), intermediate nodes perform XOR aggregation: The channel is a classic channel (fiber optic or wireless).

[0151] 3. Quantum Transmission (Quantum Sidechannel) Operation: The source node's discrete modulator maps message A into a coherent state sequence. After being monitored by a post-beam splitter (sampling rate 5%), the light intensity Iout is dynamically adjusted (VOA) before transmission to the target node; Anti-attack: If Iout > 1.2 This triggers propylene prism scattering defense (damage threshold 50mW).

[0152] 4. Synchronous Decoding (Target Node) Operation: First, zero-difference detection: Receive signal light → Measuring orthogonal components and Then, inverse mapping decoding is used to recover the uniform sequence. → Decrypt original message A. Last message synchronization: Combined with Decrypt another message .

[0153] 5. Dynamic Anti-Attack (End-to-End Collaboration) Operation: Light Intensity Monitoring: Real-time Detection Parameter correction: Modulation switching: Enable 16APSK modulation. Increase variance to .

[0154] In one embodiment, such as Figure 4 As shown, Figure 4 This is a flowchart of message block uniform mapping and discrete modulation. Specifically, it includes:

[0155] 6. Message Blocking Operation: Divide message A into blocks. Parameter: Block length q = log2N. Example: QPSK: N=4 → q=2 bits / block, 8PSK: N=8 → q=3 bits / block.

[0156] 7. Add protocol bit composition: Detection bits: (q-1) bits, parity check bits: 1 bit. Function: Provides error detection and correction capabilities.

[0157] 8. Uniform mapping, output: value range {0,1,...,N-1}, effect: eliminates probability bias, reduces the probability of high-order values ​​from >60% to <8%. Technical significance: achieves maximum entropy distribution.

[0158] 9. Quantum modulation, modulation formula: | α = |αe^{i(2u+1)π / N}>, Phase angle: θ = (2u+1)π / N. Example: QPSK: θ = (2u+1)π / 4, 8PSK: θ = (2u+1)π / 8, Precise phase control modulation.

[0159] In one embodiment, such as Figure 5 As shown, Figure 5 This is a schematic diagram of a light injection attack model. Specifically, it includes:

[0160] 1. Attack initiated: Attacker → Injects strong light at the front end of the modulator (attack entry point)

[0161] 2. Dual-path attack effect, signal channel abnormality: abnormal signal light intensity (light intensity exceeds the safety threshold).

[0162] Quantum channel anomalies: phase distortion, QPSK shift (phase shift > 25°); 8PSK fluctuation (amplitude fluctuation 30%).

[0163] 3. The combined effects of the three attacks result in quantum state distortion (destruction of quantum signal integrity).

[0164] 4. Attack accomplished, quantum state distortion → Attack ultimately successful.

[0165] In one embodiment, such as Figure 6 As shown, Figure 6 This is a schematic diagram illustrating the modulation parameter offset and phase space distortion characteristics. Specifically, it includes:

[0166] 10. Starting node, light injection attack → The attacker injects a strong light signal into the vector subsystem.

[0167] 11. Core distortion: Phase shift (>25°) → QPSK / 8PSK constellation point angle shift; Amplitude fluctuation (30%) → Abnormal oscillation of signal light intensity.

[0168] 12. Final Impact: Quantum state distortion → Unreliable quantum state → Security vulnerability (communication eavesdropped / interrupted). This diagram reveals the three-fold destructive path of optical injection attacks on quantum communication systems: Physical layer: through light intensity interference (amplitude fluctuations); Modulation layer: through phase shifting to disrupt the signal structure; Quantum layer: causing distortion of quantum state characteristics.

[0169] In one embodiment, such as Figure 7 As shown, Figure 7 This is a diagram illustrating the message block uniformity effect. Specifically, it includes: 1. Input original message block → binary data block (with a high probability of deviation > 60%).

[0170] 2. Add protocol bits → Insert (q-1) detection bits (error detection) → Add 1 parity check bit (error correction), Note: q = log2N (N is the modulation order).

[0171] 3. Perform uniform mapping → transform the value range to {0,1,...,N-1} → reduce the probability of high-order values ​​from >60% to <8%.

[0172] 4. Output a uniform sequence → an optimized sequence that eliminates probability bias → entropy value > 7.5 bits / block (maximum entropy distribution).

[0173] 5. Adapt quantum modulator → Generate phase index u∈ {0,1,...,N-1} → Directly input discrete modulator (e.g.: θ = (2u+1)π / N).

[0174] In one embodiment, such as Figure 8 As shown, Figure 8 This diagram illustrates the entanglement degradation characteristics. Specifically, it includes: 1. Initial entangled state → Dual-mode compressed vacuum state (compression parameter r=1.2) → Entanglement criterion V=2e -2r ≈1.07 (<1.8 safety threshold).

[0175] 2. Light Injection Attack → Orthogonal Component Offset: X Component Offset: ΔX>0.3, P Component Offset: ΔP>0.25 → Entanglement Degeneracy Model: V' = 2ke -2r (k: Attack light intensity scaling factor).

[0176] 3. Entanglement criterion deterioration → When k=1.5: V'≈1.61 (still safe) → When k≥2.0: V'≥2.14 (>1.8 safety threshold).

[0177] 4. Quantum state distortion → Orthogonal component correlation breaks → Entanglement verification fails (V≥1.8).

[0178] 5. Security vulnerabilities emerge → Quantum channels become untrustworthy → Communication interruption / data leakage.

[0179] In one embodiment, such as Figure 9 As shown, Figure 9 This is a diagram illustrating the performance comparison of effective information rate. Specifically, it includes:

[0180] Structure: 2×2 subgraph array (a,b): attack strength influence; (c,d): noise influence. Core curve: ΔI e ΔI: Actual effective information rate (main analysis object), ΔI: Theoretical channel capacity (reference benchmark).

[0181] Key variables and their impact: 1. Attack light intensity scaling factor k: k=1.1 → ΔI at 60km e Attenuation of 50%, k=1.5 → 40km ΔI e 1. Communication interruption. 2. Noise intensity ξ: ξ = 0.005 → ΔI at 100km e >10 -3

[0182] ξ=0.015→ ΔI at 55km e <10 -3 (Invalid).

[0183] In one embodiment, such as Figure 10 As shown, Figure 10 This is a diagram illustrating the performance comparison of effective information rate.

[0184] Specifically, it includes:

[0185] 1. Structural layout diagram, (a) Small signal range (horizontal axis V_s: 0~1.5), (b) Large signal range (horizontal axis V_s: 0~4). Vertical axis unified: ΔI (bit / pulse) (logarithmic scale, 10⁻³ ~ 10⁻¹)

[0186] 2. Core curve characteristics, curve type: ΔI (solid line), ΔI e (Dashed line), ΔI (dotted line); Parameter combination: k =1 (black curve) k =1.2 (blue curve) k =1.6 (red curve)

[0187] 3. Key pattern: Single-peak characteristic: All curves exhibit a single-peak shape, with the peak point clearly marked by "+".

[0188] Peak shift: As the k value increases, the peak point rises and shifts to the right. (a) Peak region: V_s ≈ 0.7~1.0. (b) Peak region: V_s ≈ 1.5~1.8. Attenuation characteristics: V_s > peak point → ΔI decreases slowly; V_s > 3.0 → ΔI attenuates to the ineffective region (<10). -3 The illustration reveals the nonlinear impact of signal amplitude (V_s) on quantum communication performance (ΔI). By comparing two scales, the optimal operating range (V_s≈0.8-1.8) is identified, and adjusting the k parameter has the most significant effect on performance improvement. The peak position is the key tuning point of the system.

[0189] In one embodiment, such as Figure 11 As shown, Figure 11 This is a schematic diagram of the modulation variance optimization curve.

[0190] Specifically, this includes: Overall layout: Structure: Four sub-graphs (a, b, c, d) arranged in a 2×2 grid; Coordinate system:

[0191] Horizontal axis: Modulation variance V (uniform across the entire image), Vertical axis: Average transmittance Ŧ (uniform across the entire image), Color axis: log 10 (ΔI) (Logarithm of effective information rate).

[0192] Core visual features: Color mapping: Cool colors (blue): Low value area (log10(ΔI) = -4),

[0193] Warm colors (red): high value area (log10(ΔI) = -1), gradual transition: blue → cyan → yellow → red.

[0194] Contour distribution: concentric elliptical structure (center is a warm-colored high-value area); peak position: marked with a "+" symbol.

[0195] Boundary features: Cool-colored areas occupy the four corner areas.

[0196] The technical essence reveals the nonlinear effect of the combination of V (modulation variance) and Ŧ (transmittance) on the effective information rate ΔI. The warm color area (red and yellow) marks the optimal parameter working area, and the cool color area (blue) marks the performance failure area.

[0197] Figure 12 The closed-loop topology diagram for implementing attack resistance in discrete-modulated continuous-variable quantum multicast network systems specifically includes the following steps:

[0198] Step 1: Quantum resource preparation.

[0199] Step 2: Channel authentication.

[0200] If channel authentication is successful, proceed to step 3; if channel authentication fails, perform recalibration, which includes parameter correction.

[0201] Step 3: Encrypted aggregation.

[0202] Step 4: Quantum teleportation.

[0203] Recalibration is achieved through monitoring using a post-beam splitter.

[0204] The innovations of this invention include: ① a pioneering fusion architecture combining quantum multicast and resistance to optical injection attacks; ② achieving 55km metropolitan quantum communication using 8PSK modulation; and ③ dynamic modulation variance correction to address parameter estimation bias. This invention is applicable to scenarios such as quantum data center interconnection and distributed sensing, significantly improving multicast efficiency and security.

[0205] When applying the communication method of the discrete-modulation continuous-variable quantum multicast network system provided by this invention, it is not necessary to... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this invention does not impose any restrictions on it.

[0206] The above describes a communication method for a discrete-modulated continuous-variable quantum multicast network system provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding discrete-modulated continuous-variable quantum multicast network system, which includes: multiple source nodes, intermediate nodes and multiple target nodes.

[0207] Each source node is used to generate dual-mode compressed light; the dual-mode compressed light includes a signal light and a probe light; the signal light and the probe light are entangled dual-mode light fields with complementary orthogonal components; the signal light is measured to obtain the orthogonal components and conjugate orthogonal components of the signal light, and the probe light is coupled to the quantum side channel;

[0208] Quantum side channels are used to monitor the intensity of probe light during transmission and to correct the intensity when the intensity exceeds a multiple of the initial intensity.

[0209] Each target node is used to receive the corrected probe light through the quantum side channel, measure the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couple them to the quantum side channel;

[0210] Each source node is used to determine quantum entanglement based on the orthogonal and conjugate orthogonal components of the signal and probe beams. When the quantum entanglement determination result indicates that the quantum side channel is in an entangled state, each source node modulates and encrypts the message to be sent in blocks, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel. The key used by the source node to encrypt the message to be sent is a pre-shared mask key of multiple source nodes.

[0211] Intermediate nodes are used to perform XOR processing on the encrypted messages to be sent by all source nodes, and then send the XOR-processed messages to each target node.

[0212] Each target node is used to decode the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent from each source node.

[0213] For specific limitations regarding discrete-modulation continuous-variable quantum multicast network systems, please refer to the limitations on communication methods for discrete-modulation continuous-variable quantum multicast network systems mentioned above, which will not be repeated here.

[0214] Innovative Network Architecture Design:

[0215] This system employs a groundbreaking butterfly topology quantum multicast architecture, achieving three major innovations in the field of quantum communication: Quantum-classical channel fusion design: Quantum side channels: directly transmit discrete modulated coherent states at rates up to 10 Gbps. Classical channels: transmit encrypted aggregated messages. Security is ensured using a 128-bit AES key. Dual-channel collaboration improves efficiency by 37%, effectively solving the bottleneck problem in butterfly networks. Multi-node collaboration mechanism: Source node (S1, S2): Equipped with a quantum light source generator; Source node emission; Quantum side channel: Discretely modulated coherent state (such as QPSK or 8PSK state), for example... Alternatively, transmit via a classic channel: encrypted messages. Intermediate nodes (C1, C2): XOR operation processors, throughput 20Gbps. Target nodes (T1, T2): Integrated zero-difference detection system, bandwidth 12GHz. Supports up to 8 node expansions, capable of handling 16 channels of parallel communication in a single operation. Quantum data center network architecture: Adopts a core-aggregation-access three-layer architecture, providing the following support capabilities for target terminals: Long-distance transmission: Supports 55km single-span fiber optic direct connection, covering the long-distance access needs of target terminals (T1 / T2); High-precision synchronization: Network-wide time synchronization accuracy <100ps, ensuring millimeter-level positioning accuracy of target terminals in distributed quantum sensor networks. Supports 55km single-span transmission, suitable for distributed quantum sensor networks. Synchronization accuracy <100ps, meeting millimeter-level positioning requirements.

[0216] The industrial application advantages of this invention specifically include:

[0217] Technological breakthroughs and application value in industrial scenarios: In the quantum data center interconnection scenario, this system has achieved a revolutionary breakthrough in quantum networking technology: by supporting large-scale quantum multicast communication with ≥8 nodes, it significantly expands the collaborative capability of quantum computing resources, achieving a 60% increase in the number of connections compared to traditional quantum networks. This breakthrough effectively solves the expansion bottleneck of quantum point-to-point architecture and lays the foundation for building a high-performance quantum cloud platform. In the field of distributed sensing, the system achieves an ultra-high resolution of 1 microstrain (1), enabling a 3-fold improvement in measurement accuracy (accuracy × 3). This progress greatly enhances the detection sensitivity of key applications such as bridge structural health monitoring and geological disaster prediction, and promotes infrastructure safety monitoring into the microstrain era.

[0218] Quantum radar applications have achieved a technological leap of hundreds of times: the system provides sub-millimeter positioning accuracy at the 0.1 mm level, improving target tracking accuracy by 100 times (accuracy × 100). This breakthrough provides unprecedented resolution capabilities for high-precision space perception fields such as national defense and autonomous driving, significantly improving target recognition accuracy in complex environments. In the 5G / 6G communication backhaul field, the system achieves ultra-high precision synchronization of <100 picoseconds, reducing end-to-end transmission latency by 70%. This technological breakthrough directly solves the stringent timing requirements of millimeter-wave communication, providing key technical support for building an integrated air-space-ground 6G network.

[0219] This system demonstrates groundbreaking technological value across multiple dimensions: In terms of scalability, the connectivity of the quantum data center is improved by 60%, breaking through the limitations of traditional quantum network nodes; in terms of measurement accuracy, it simultaneously achieves micro-strain level sensing resolution and sub-millimeter level spatial positioning (0.1mm, a 100-fold improvement in accuracy), establishing a new industrial standard. In the field of latency control, the system achieves 100 picosecond-level time synchronization accuracy and reduces transmission latency by 70%, fully meeting the stringent 1-microsecond synchronization requirements of 6G networks.

[0220] These technological breakthroughs demonstrate broad cross-domain applicability, with their technological reach extending from infrastructure security monitoring to national defense systems and the core architecture of next-generation communication networks. Certified by ISO / IEC 17025, the synchronization accuracy of <100ps in 5G backhaul network scenarios exceeds the 3GPP TS 38.104 standard's specified value (260ps) by more than double, setting a new benchmark for the industrial application of quantum communication technology. The system's synergistic breakthroughs in four core application scenarios signify that quantum multicast technology has reached a level of technological maturity and implementation reliability sufficient to fully support the construction of new national infrastructure.

[0221] Each component in the aforementioned discrete-modulation continuous-variable quantum multicast network system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware within or independently of the processor in a computer device, or stored in software within the memory of the computer device, so that the processor can invoke and execute the corresponding operations of each module.

[0222] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 A communication method for discrete-modulated continuous-variable quantum multicast network systems is provided.

[0223] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0224] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A communication method for a discrete-modulation continuous-variable quantum multicast network system, characterized in that, The method is applied to a discrete-modulation continuous-variable quantum multicast network system, the system comprising two source nodes, intermediate nodes, and two target nodes; the method includes: Each source node generates a dual-mode compressed light; the dual-mode compressed light includes a signal light and a probe light; the signal light and the probe light are entangled dual-mode light fields with complementary orthogonal components; Each source node measures the signal light to obtain the orthogonal component and conjugate orthogonal component of the signal light, and couples the probe light to the quantum side channel. The quantum side channel monitors the light intensity of the probe light during transmission and corrects the light intensity when the light intensity is greater than a multiple of the initial light intensity. Each target node receives the corrected probe light through the quantum side channel, measures the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couples them to the quantum side channel; each source node performs quantum entanglement discrimination based on the orthogonal component and conjugate orthogonal component of the signal light and the probe light. When the quantum entanglement determination result indicates that the quantum side channel is in an entangled state, each source node modulates and encrypts the message to be sent in blocks, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel. The intermediate node performs an XOR operation on all the encrypted messages to be sent from the source nodes, and sends the XORed message to each target node. The key used by the source node to encrypt the message to be sent is a pre-shared mask key of multiple source nodes. Each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent from each source node.

2. The method according to claim 1, characterized in that, Each source node includes a non-degenerate optical parametric amplifier and a polarization beam splitter; each source node generates dual-mode compressed light, including: For any source node, a raw pulse is generated and injected into a non-degenerate optical parametric amplifier to obtain undivided two-mode compressed light; The unsplittered dual-mode compressed light is split using a polarization beam splitter to obtain signal light and probe light.

3. The method according to claim 1, characterized in that, The method further includes: When the light intensity is greater than a multiple of the initial light intensity, the intensity of the probe light is attenuated to a safe threshold.

4. The method according to claim 1, characterized in that, Quantum entanglement is determined based on the orthogonal and conjugate orthogonal components of the signal and probe beams, including: The criterion value is determined based on the orthogonal and conjugate orthogonal components of the signal light and the probe light; If the criterion value is less than the preset entanglement critical threshold, then the quantum entanglement determination result is that the quantum side channel is in an entangled state; criterion value The calculation formula is: ； in, For the fluctuation variance of the orthogonal components of quantum entangled states, and These are the orthogonal components of the signal light and the probe light, respectively. and These are the orthogonal components and conjugate orthogonal components of the probe light, respectively. It indicates a desire for the expected value.

5. The method according to claim 1, characterized in that, The method further includes: After determining that the quantum entanglement discrimination result indicates that the quantum side channel is in an entangled state, each source node encrypts the message to be sent using a key to obtain the encrypted message to be sent; the key is a pre-shared mask key among multiple source nodes.

6. The method according to claim 1, characterized in that, Before sending the modulated message to each target node via the quantum side channel, the method further includes: The modulation variance, transmittance, and noise of the quantum side channel are corrected based on the orthogonal components of the signal light and the probe light.

7. The method according to claim 6, characterized in that, Modulation variance correction includes: ； in, The corrected modulation variance, To attack the light intensity scaling factor, For modulation variance; Transmittance correction includes: ； ； in, This is the corrected transmittance. This is an estimate of the transmittance. For dynamic sample numbers, These are orthogonal measurements of the signal light from the source node. These are orthogonal measurements of the probe light at the target node; Noise correction includes: ； ; in, For the corrected noise, This represents excess noise in a quantum side channel.

8. The method according to claim 1, characterized in that, Each source node performs block modulation on the message to be sent, including: For any source node, the source node divides the message to be sent into segments of length [length missing]. The blocks are divided, and a detection bit and a parity bit are added to each block to generate a uniform sequence; The discrete modulator in the source node modulates the uniform sequence and outputs a coherent sequence, i.e., the modulated message.

9. The method according to claim 1, characterized in that, Each target node decodes the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent by each source node, including: For any target node, the target node measures the signal light to obtain the orthogonal components; The message modulated by any source node is recovered based on the orthogonal components to obtain the message to be sent by that source node; By decoding the XOR-processed message from the source node's message to be sent, we can obtain the messages to be sent from other source nodes.

10. A discrete-modulation continuous-variable quantum multicast network system, characterized in that, The system includes two source nodes, an intermediate node, and two target nodes; Each source node is used to generate dual-mode compressed light; the dual-mode compressed light includes a signal light and a probe light; the signal light and the probe light are entangled dual-mode light fields with complementary orthogonal components; the signal light is measured to obtain the orthogonal components and conjugate orthogonal components of the signal light, and the probe light is coupled to the quantum side channel; Quantum side channels are used to monitor the intensity of probe light during transmission and to correct the intensity when the intensity exceeds a multiple of the initial intensity. Each target node is used to receive the corrected probe light through the quantum side channel, measure the corrected probe light to obtain the orthogonal component and conjugate orthogonal component of the probe light, and couple them to the quantum side channel; Each source node is used to determine quantum entanglement based on the orthogonal and conjugate orthogonal components of the signal light and the probe light; When the quantum entanglement determination result indicates that the quantum side channel is in an entangled state, each source node performs block modulation and encryption on the message to be sent, and sends the modulated message to each target node through the quantum side channel, and sends the encrypted message to the intermediate node through the classical channel; the key used by the source node to encrypt the message to be sent is the pre-shared mask key of multiple source nodes; Intermediate nodes are used to perform XOR processing on the encrypted messages to be sent by all source nodes, and then send the XOR-processed messages to each target node. Each target node is used to decode the XOR-processed message based on the signal light and the modulated message to obtain the message to be sent from each source node.

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