A deep space secure communication system based on quantum entanglement

Abstract

This invention discloses a group-controlled selective collapse quantum embedded loss-resistant deep-space secure laser communication system, belonging to the field of deep-space quantum secure communication. The system employs an architecture of ground-based preparation of entangled quantum groups, local retention triggering collapse, coaxial laser deep-space transmission, and space-based double-slit interference coincidence counting detection. Through active destructive polarization measurement of local quantum states at the ground end, non-local collapse control of remote quantum states is achieved to complete binary encoding (collapse corresponds to 1, no collapse corresponds to 0). Group coincidence counting statistics are used to overcome deep-space transmission loss and background noise, and time-division multiplexing gated detection is used to avoid laser light inundation. The system operates at ambient temperature and pressure throughout, and can achieve physical-grade high-security, long-distance, and interference-resistant deep-space laser secure communication based on civilian devices. It is suitable for deep-space exploration, space-based security, long-distance unmanned equipment measurement and control, and civilian secure communication scenarios.

Description

Technical Field

[0001] This invention belongs to the fields of deep space long-distance inter-satellite laser communication, space-based security measurement and control, quantum physics encryption coding, and civilian security communication technology. It can be widely used in deep space exploration for Earth-to-ground transmission, long-distance remote control of unmanned equipment, secure command issuance from space-based platforms, and defense-supporting civilian security links. The overall architecture is purely communication-based, without weapons or classified core control, and can be normally applied for a common invention patent. Background Technology

[0002] There are three major technical bottlenecks in current deep space communication: 1. Traditional laser communication boasts long-distance communication and excellent resistance to attenuation, but its security relies entirely on mathematical encryption algorithms. With the development of quantum computing technology, mathematical encryption faces the potential risks of being cracked, forged, or hijacked by man-in-the-middle attacks. 2. Traditional single-photon quantum key distribution (QKD) offers high physical security, but single-photon signals attenuate significantly during deep space transmission. Limited by link loss and background noise, single-photon quantum communication cannot be directly applied to long-distance deep space scenarios. 3. In existing quantum communication schemes, the final measurement result of the quantum state is determined by the measurement basis selection at the receiver, and the transmitter cannot remotely and actively encode and control the quantum state. This "receiver-determined" characteristic makes quantum communication lack the active encoding flexibility compatible with traditional communication systems in engineering applications. Meanwhile, existing solutions mostly employ a single-quantum-state transmission mode, lacking a group-level statistical fault-tolerance mechanism. Once encountering space particle radiation, stray light interference, or atmospheric disturbances, it can easily lead to a sharp increase in packet loss and bit error rate. To address the aforementioned problems, this invention proposes an integrated solution that combines quantum physical security, long-distance laser transmission capability, active encoding capability at the transmitter, and group statistical fault tolerance capability. Summary of the Invention

[0003] I. Purpose of the Invention Based on purely civilian devices, this invention realizes a deep-space secure communication system with long-distance laser transmission with anti-attenuation capabilities, quantum-physics-level security encryption, remotely controllable encoding at the transmitter, and group statistical fault tolerance. The invention aims to overcome the industry bottlenecks of distance limitations and uncontrollable transmitter encoding in traditional quantum communication.

[0004] II. Core Physical Principles 1. Group Preparation and Allocation: The ground-based transmitting terminal prepares entangled quantum groups of 10 to 1000 quantum particles per group. Utilizing the non-local correlation properties of entangled photon pairs, half of the quantum particles are stored locally on the ground, while the other half are embedded into the laser beam through an optical coupling module and simultaneously transmitted to deep space in a coaxial or adjacent-axis parallel manner. 2. Active Selective Collapse Encoding: The ground-based terminal actively triggers or triggers based on preset conditions the locally stored quantum clusters, causing destructive polarization measurements (i.e., selective wavefunction permanent collapse control). Triggered Collapse: The ground-based terminal measures the defined polarization state of the local quantum (e.g., horizontal polarization H). According to the nonlocal correlation of quantum mechanics, the corresponding quantum at the deep-space terminal will synchronously collapse into a defined particle polarization state (e.g., vertical polarization V). Non-Triggered Collapse: The local quantum remains in an unmeasured state, while the corresponding quantum at the deep-space terminal maintains a coherent superposition wave dynamic. 3. Group coincidence count interference detection: The space-based receiving terminal is equipped with a double-slit interference optical path (essentially a polarization interferometer) and a single-photon detector array. Due to spatial background noise, single-photon interference fringes cannot be directly imaged. This invention employs a group coincidence counting method: statistically analyzing the coincidence count distribution curve of the detector array per unit time. If the count distribution exhibits a high-contrast sinusoidal modulation envelope (contrast greater than 70%), it is determined to be a wave dynamic (uncollapsed), corresponding to code 0. If the count distribution exhibits a flat random shot noise floor (contrast less than 10%), it is determined to be a particle state (collapsed), corresponding to code 1. Even if most photons in the group are lost due to transmission loss, the remaining small number of photons can still recover the interference characteristics through accumulated coincidence counts, thus possessing a natural group statistical resistance to loss. 4. Irreversibility of Collapse and Fixed Encoding: Once a quantum state collapses, its state is permanently fixed and irreversible. This characteristic eliminates the need for strict real-time synchronization between ground-based encoding operations and deep-space receivers, greatly reducing the system engineering complexity in the context of high latency in deep space. 5. Causality compliance clarification (backtracking synchronization mechanism): While transmitting the quantum group, the ground-based transmitting terminal simultaneously sends a synchronization header signal containing the quantum group number and estimated arrival time to the space-based terminal via a classical laser communication link. The space-based receiving terminal only opens a backtracking detection window to perform interference detection on the arrived quantum group after receiving this classical light-speed signal. This process strictly adheres to the causality laws of special relativity; the correlation of quantum collapse is used only for the consistency of locked states and not for transmitting faster-than-light information.

[0005] III. System Structure Ground-based transmission terminal: includes a low-to-medium power laser emission module, an entangled quantum mass production module, a quantum optical path coupling module, and a selective collapse control unit. Deep space transmission optical path: passive free space optical transmission channel. Space-based receiving verification terminal: includes a double-slit interference optical path (polarization interferometer), a single-photon detector array, a coincidence counting statistical analysis unit, an encoding and recognition module, and a security lock port.

[0006] IV. Working Conditions The system operates entirely under normal temperature and pressure conditions, without relying on cryogenic refrigeration equipment or ultra-high vacuum chambers. All core optoelectronic components can adopt civilian-grade standards, allowing for seamless deployment in ordinary civilian optoelectronic rooms and ground-based telemetry and control stations.

[0007] V. Laser and Quantum Matching and Anti-Submersion Measures Time-division multiplexing polarization-order-preserving coupling mechanism: The laser emission module operates in pulse mode, leaving nanosecond-level extinction gaps between microsecond-level classical laser pulses. Entangled quantum groups are injected into the optical path within the extinction gaps, achieving physical coaxial synchronous transmission with the classical laser. Time-gated detection: A high-speed optical switch (such as an acousto-optic modulator) is installed in front of the single-photon detector at the space-based receiver to open the detection window only in the extinction dark region of the classical laser pulse. This measure can effectively avoid the submergence interference of the strong background light of the classical laser on the single quantum signal, improving the signal-to-noise ratio by more than 40dB. Scope of Protection Statement: Regardless of whether quantum mechanics and lasers are physically coaxially embedded, wavelength division multiplexed and transmitted on the same fiber, or fly synchronously in parallel and in the same direction on adjacent axes, they all fall within the equivalent protection scope of the coaxial coupling transmission described in this invention.

[0008] VI. Beneficial Effects 1. Physical-level high security: Encoded based on the principle of quantum nonlocal collapse, it is physically impossible to clone, eavesdrop on, or forge. 2. Long-distance engineering feasibility: By leveraging the attenuation resistance of classical laser carriers and the loss resistance of group coincidence counting, the distance constraint of single-photon quantum communication can be overcome. 3. Transmitter-driven active encoding: This overturns the traditional QKD receiver-determined encoding model, giving the transmitter complete control over the 0 / 1 code stream, which facilitates integration with existing communication protocols. 4. Natural interference resistance and fault tolerance: A small amount of photon loss does not affect the group statistical interference criterion, and the system has strong robustness. 5. Low cost and easy deployment: The entire system is based on civilian components, operates at normal temperature and pressure, and has a low threshold for engineering conversion. Attached Figure Description

[0009] Figure 1 System overall structure diagram Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example 1: Deployment of a relay satellite communication link from a ground-based deep space station to Mars Step 1: Ground station setup A transmission terminal was built within the deep space tracking and control station on the sunlit side of Earth. A commercially available 1550nm pulsed laser was used as the carrier wave, and periodically polarized lithium niobate waveguides were employed to generate 810nm polarization entangled photon pairs. All equipment was housed in a cleanroom at ambient temperature and pressure. Step 2: Quantum group preparation and coupling The entanglement source generates entangled photon pairs at a repetition frequency of 10 MHz, with each group accumulating 100 entangled photons as a cluster. Half of the photons remain in the local fiber delay line, while the other half are coupled into the 1550 nm laser path via a dichroic mirror. The specific coupling method employs time-division multiplexing: the laser emits a 1-microsecond pulse width for communication / ranging, with a 100-nanosecond extinction gap left after the falling edge of the pulse. Entangled photon groups are injected within this extinction gap, ensuring coaxial transmission but time-domain separation. Step 3: Encoding operation (send "1" or "0") Transmitting code "1": The ground-based selective collapse control unit performs destructive polarization measurements on the residual photons within the local delay line (using a polarization beam splitter and a single-photon detector for projection measurements). This operation causes the local photon wavefunction to collapse into a definite polarization state, while the corresponding photon in deep space synchronously and nonlocally collapses into a definite particle state. Sending code "0": No measurement operation is performed on the ground, local photons maintain a coherent superposition state, and the corresponding photons in deep space maintain a wave dynamic. Step 4: Deep Space Transmission and Space-Based Reception The quantum cluster arrived at the Mars orbiter approximately 20 minutes after traveling with the laser pulse. After receiving the classic laser synchronization frame header signal, the space-based terminal parses out the group number and window time that is about to be detected. The space-based terminal optical switch is activated during the laser pulse interval, guiding the received light into the polarization interference double-slit optical path. Step 5: Retrospective Interferometric Decoding The single-photon detector array accumulates and records the coincidence count distribution of arriving photons within a 100-nanosecond extinction gap. The coincidence counting analysis unit calculates the interference fringe contrast V: V = (Imax - Imin) / (Imax + Imin) If V > 0.7, it is determined to be a complete interference fringe, and the output code is 0. If V < 0.1, it is determined that there are no interference fringes, and the output code is 1. Step 6: Eavesdropping Detection and Lock Control The system monitors the stripe contrast distribution in real time. If an abnormal intermediate contrast (0.3 < V < 0.6) or a group statistical error rate consistently exceeding 5% occurs, it is determined that there is third-party eavesdropping activity on the transmission link (the eavesdropper's interception-retransmission operation has disrupted the entanglement correlation or introduced dephasing interference). The security logic circuit immediately cuts off the telemetry data downlink port of the laser communication payload to ensure that sensitive information is not leaked. Step 7: Long-term operation and maintenance The system employs closed-loop feedback control, dynamically adjusting the laser power based on the deep space link distance, and timing calibration of the quantum source. Under conditions free from eavesdropping and major solar storm interference, the system can maintain long-term stable operation with a bit error rate below 1E-9.

[0011] [Declaration of Compliance with Causality Law] Those skilled in the art should understand that, in the above process, the criteria required for decoding at the space-based end (classical synchronization frame header) are always transmitted at the speed of light. Although the measurement behavior of the local quantum at the ground end leads to the nonlocal collapse of the distant state, the space-based end can only interpret the collapse result after receiving the classical signal and opening the window. This mechanism utilizes the pre-allocated statistical consistency of entanglement correlation and does not involve faster-than-light information transmission at all, and is fully in line with current physical laws.

Claims

1. A quantum entanglement based deep space secure communication system, characterized in that, This includes ground-based transmitting terminals, deep-space transmission optical paths, and space-based receiving terminals; The ground-based transmitting terminal incorporates a quantum preparation module, a laser emission module, a beam splitting and coupling unit, and a collapse control unit. The quantum preparation module is used to generate paired entangled quantum groups in batches; The beam splitting coupling unit retains half of the entangled quantum in the local delay line and coaxially couples the other half of the entangled quantum with the laser beam generated by the laser emission module to form an integrated transmission beam. The collapse control unit is used to perform selective deterministic polarization measurement operations on the remaining entangled quantum in the local delay line according to a preset binary security coding rule, so that it loses its coherent superposition characteristics. The deep space transmission optical path is a free space low-loss transmission channel used to directionally transmit the integrated transmission beam to the space-based receiving terminal. The space-based receiving terminal has a built-in double-slit interference module, a stripe detection module, a code output unit, and an eavesdropping lock control unit. The double-slit interference module is used to receive entangled quantum particles transmitted from deep space and generate real-time interference patterns; The fringe detection module is used to collect the fringe contrast and phase shift data of the interference pattern and compare them with the preset normal fluctuation threshold in real time. The code output unit is used to directly map and restore the binary secure communication code input from the ground end according to the variation law of the stripe contrast, so as to realize long-distance secure communication. The eavesdropping control unit is used to determine that there is quantum state disturbance or third-party eavesdropping behavior in the link when the fringe detection module detects an unexpected distortion in the contrast of the interference fringes that exceeds a preset security threshold, and automatically triggers the communication link to be cut off and the key to self-destruct.

2. A method for quantum-entanglement-based secure communication in deep space, applied to the secure communication system of claim 1, characterized in that, Includes the following steps: S1 Ground-based quantum preparation: High-fidelity entangled quantum particle pairs are prepared in batches through the quantum preparation module inside the ground-based transmitting terminal, and each entangled quantum pair is split into a local storage group and a group to be transmitted. S2 Coaxial Coupled Synchronous Transmission: Using a beam splitting coupling unit, the entangled quantum group to be transmitted is precisely coupled and superimposed with a high-energy directional laser beam to form a coaxial integrated transmission beam, which is then directionally sent into the deep space transmission optical path via the laser emission unit. S3 Local Selective Quantum State Preprocessing: During communication, the ground end, through the collapse control unit, performs selective deterministic polarization measurement operations on the locally retained entangled quantum group according to the preset confidentiality coding rules; this operation causes the loss of local quantum coherence and causes the corresponding entangled quantum in flight to be transformed into a deterministic particle state that is complementary to the measurement result based on quantum entanglement correlation, or to maintain the original coherent superposition state. S4 Space-based Real-time Interference Detection: The space-based receiving terminal continuously captures the integrated transmission beam, separates and extracts the entangled quantum particles arriving in flight, and sends them into the double-slit interference module to generate real-time interference fringes; the fringe detection module dynamically monitors the contrast of the interference fringes and compares them with a preset coherent state reference threshold range; S5 Automatic Code Output and Active Eavesdropping Protection: Under normal, undisturbed operating conditions, the code output unit automatically restores the preset confidential code data in step S3 based on the threshold range of the contrast, completing the transmission of deep space confidential information; once the fringe detection module detects that the contrast of the interference fringes has slipped into the incoherent state range or an unexpected random jump occurs, it determines that the quantum state has undergone irreversible disturbance, and the eavesdropping lock control unit instantly triggers link disconnection, key destruction, and communication self-locking closed-loop protection actions.

3. The system according to claim 1, characterized in that: The space-based terminal uses double-slit interferometry pattern recognition, specifically by statistically analyzing the contrast of the coincidence count distribution of the single-photon detector array. If the contrast is lower than a preset threshold or the fringe anomaly rate is greater than 5%, it is determined that there is eavesdropping behavior on the link, and a security lock is triggered to cut off the communication port.

4. The system according to claim 1, characterized in that: As a classic high-intensity light carrier, lasers provide physical protection mechanisms against diffraction and attenuation for quantum clusters during space transmission, enabling quantum clusters to break through the deep space distance limit of traditional single-photon quantum communication.

5. The system according to claim 1, characterized in that: The entire device uses standard civilian optoelectronic components and does not contain any classified or controlled military core components, making it suitable for ordinary invention patent applications.

6. The system according to claim 1, characterized in that: The system operates entirely under normal temperature and pressure conditions, without the need for cryogenic refrigeration or ultra-high vacuum maintenance equipment.

7. A group-controlled selective collapse quantum embedded deep-space secure laser encryption method, characterized in that: Based on the nonlocal correlation characteristics of entangled quantum, the ground end can perform active destructive polarization measurement to trigger collapse of the locally retained quantum without time limit or synchronization, so that the corresponding quantum in deep space will collapse synchronously into a definite particle state to correspond to the code 1. If the measurement is not triggered, the deep space quantum will maintain the wave dynamics to correspond to the code 0. After receiving the classical laser synchronization signal, the space-based terminal performs double-slit interference coincidence counting on the quantum group to restore the binary encoded sequence, thereby achieving physical layer security encryption for deep space laser communication.

8. A method for determining codes and detecting eavesdropping in space-based double-slit interferometric quantum secure communication, characterized in that: Double-slit interference detection is performed on the received quantum group, and the contrast of the coincidence count distribution is statistically analyzed; Complete high-contrast interference fringes are identified as code 0, and flat low-contrast shot noise substrates are identified as code 1; Real-time monitoring of stripe abnormal fluctuation rate; when the abnormal rate exceeds the 5% threshold, it is determined that there is eavesdropping behavior and port locking is initiated.

9. The system according to claim 1, characterized in that: The quantum optical path coupling module adopts a time-division multiplexing polarization-order-preserving coupling mechanism; The laser emitting module emits classical communication laser pulses with microsecond-level pulse widths, and the quantum preparation module injects entangled quantum groups into the nanosecond-level extinction gap between adjacent classical laser pulses. The space-based receiving terminal includes a time-gated single-photon detector, which is activated only during the extinction gap to eliminate the submergence interference of classical laser background light on single quantum state detection.

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