Inter-satellite key agreement method, satellite and related device

Abstract

The present disclosure provides an inter-satellite key agreement method, a satellite and related equipment, and relates to the technical field of communication. The method comprises: in response to entering a visibility window between a first satellite and a second satellite, sending a beacon optical signal to the second satellite, wherein the visibility window is a time period between the first satellite and the second satellite with a line-of-sight condition for establishing an optical link; receiving an acknowledgement optical signal fed back by the second satellite; extracting a key ciphertext from the acknowledgement optical signal; and unpacking the key ciphertext to obtain a shared key, wherein the shared key is generated by a post-quantum cryptographic algorithm. Through the above technical means, the problems of high delay and poor reliability of the post-quantum cryptographic algorithm key agreement in the inter-satellite optical link in the related art are solved.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to a method for inter-satellite key negotiation, a satellite, and related equipment. Background Technology

[0002] With the development of satellite internet, inter-satellite optical links have become the mainstream of broadband backbone networks, and their data encapsulation mostly adopts traditional asymmetric algorithms. However, traditional asymmetric algorithms are threatened by quantum computing, while directly introducing post-quantum cryptography algorithms, due to their large key size and numerous handshake interactions, can easily lead to high latency or even negotiation failure in high-dynamic scenarios such as high-speed satellite movement and frequent link connection and disconnection, seriously affecting network throughput and communication continuity.

[0003] Public content

[0004] This disclosure provides a satellite-to-satellite key negotiation method, a satellite, and related equipment, thereby reducing the key negotiation latency of post-quantum cryptography algorithms and improving the reliability of key negotiation in post-quantum cryptography algorithms.

[0005] According to one aspect of this disclosure, a satellite-to-satellite key negotiation method is provided, applied to a first satellite, comprising: in response to entering a visibility window between the first satellite and a second satellite, sending a beacon light signal to the second satellite, wherein the visibility window is a time period during which the first satellite and the second satellite have line-of-sight conditions sufficient to establish an optical link; receiving an acknowledgment light signal from the second satellite; extracting key ciphertext from the acknowledgment light signal; and decapsulating the key ciphertext to obtain a shared key, wherein the shared key is generated by a post-quantum cryptography algorithm.

[0006] In some exemplary embodiments, before sending a beacon light signal to the second satellite in response to entering a visibility window between the first and second satellites, the method further includes: acquiring orbital ephemeris information of the first and second satellites; and predicting the visibility window using an orbital prediction model based on the orbital ephemeris information of the first and second satellites.

[0007] In some exemplary embodiments, before sending a beacon light signal to the second satellite in response to entering a visibility window between the first and second satellites, the method further includes sending the public key of the first satellite to the second satellite before the visibility window.

[0008] In some exemplary embodiments, decapsulating the key ciphertext to obtain a shared key includes: decapsulating the key ciphertext using the private key of the first satellite to obtain the shared key.

[0009] In some exemplary embodiments, in response to entering a visibility window between the first and second satellites, sending a beacon light signal to the second satellite includes: acquiring orbital ephemeris information of the second satellite; predicting the position of the second satellite based on the orbital ephemeris information of the second satellite; and sending the beacon light signal within the maximum deviation range of the position.

[0010] In some exemplary embodiments, after receiving the confirmation light signal from the second satellite, the method further includes: performing fine tracking of the second satellite based on the confirmation light signal.

[0011] In some exemplary embodiments, after decapsulating the key ciphertext to obtain the shared key, the method further includes: determining that the optical link has been established when the optical link between the first satellite and the second satellite meets preset conditions; and sending a key negotiation success notification to the second satellite.

[0012] In some exemplary embodiments, after sending a key negotiation success notification to the second satellite and decapsulating the data, the method further includes: encapsulating the first service data using a shared key to obtain the first service ciphertext; and sending the first service ciphertext to the second satellite.

[0013] In some exemplary embodiments, after sending a key negotiation success notification to the second satellite for decapsulation, the method further includes: receiving the second service ciphertext sent by the second satellite; and decapsulating the second service ciphertext using a shared key to obtain the second service data.

[0014] According to another aspect of this disclosure, a satellite-to-satellite key negotiation method is provided, applied to a second satellite, comprising: receiving a beacon light signal sent by a first satellite when entering a visibility window between the first and second satellites, wherein the visibility window is a time period during which the first and second satellites have line-of-sight conditions sufficient to establish an optical link; generating a shared key using a post-quantum cryptography algorithm; encapsulating the shared key to obtain key ciphertext; and sending an acknowledgment light signal back to the first satellite, wherein the acknowledgment light signal carries the key ciphertext.

[0015] In some exemplary embodiments, before receiving a beacon light signal transmitted by the first satellite when it enters a visibility window between the first and second satellites, the method further includes receiving the public key of the first satellite transmitted by the first satellite before entering the visibility window.

[0016] In some exemplary embodiments, the shared key is encapsulated to obtain key ciphertext, including: encapsulating the shared key using the public key of the first satellite to obtain key ciphertext.

[0017] In some exemplary embodiments, receiving a beacon light signal transmitted by the first satellite as it enters a visibility window between the first and second satellites includes detecting the beacon light signal by covering the maximum deviation range of the first satellite's position with a large field-of-view detector.

[0018] In some exemplary embodiments, after receiving a beacon light signal sent by the first satellite when it enters a visibility window between the first and second satellites, the method further includes: coarsely tracking the first satellite based on the beacon light signal.

[0019] In some exemplary embodiments, after sending a confirmation optical signal back to the first satellite, the method further includes receiving a key negotiation success notification sent by the first satellite.

[0020] In some exemplary embodiments, after receiving a key negotiation success notification sent by the first satellite, the method further includes: receiving a first service ciphertext sent by the first satellite; and decapsulating the first service ciphertext using a shared key to obtain first service data.

[0021] In some exemplary embodiments, after receiving a key negotiation success notification sent by the first satellite, the method further includes: encapsulating the second service data using a shared key to obtain second service ciphertext; and sending the second service ciphertext to the first satellite.

[0022] According to another aspect of this disclosure, a first satellite is provided, comprising: a first transmitting unit configured to transmit a beacon light signal to a second satellite in response to entering a visibility window between the first satellite and a second satellite, wherein the visibility window is a time period during which the first satellite and the second satellite have line-of-sight conditions sufficient to establish an optical link; a first receiving unit configured to receive an acknowledgment light signal fed back by the second satellite; an extraction unit configured to extract key ciphertext from the acknowledgment light signal; and a decapsulation unit configured to decapsulate the key ciphertext to obtain a shared key.

[0023] According to another aspect of this disclosure, a second satellite is provided, comprising: a second receiving unit configured to receive a beacon light signal transmitted by a first satellite when it enters a visibility window between the first and second satellites, wherein the visibility window is a time period during which the first and second satellites have line-of-sight conditions sufficient to establish an optical link; a generating unit configured to generate a shared key; an encapsulation unit configured to encapsulate the shared key to obtain key ciphertext; and a second transmitting unit configured to send an acknowledgment light signal back to the first satellite, wherein the acknowledgment light signal carries the key ciphertext.

[0024] According to another aspect of this disclosure, an electronic device is provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform any of the methods described above by executing the executable instructions.

[0025] According to another aspect of this disclosure, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements any of the methods described above.

[0026] According to another aspect of this disclosure, a computer program product is provided, including computer instructions stored in a computer-readable storage medium, which, when executed by a processor, implement operation instructions for any of the methods described above.

[0027] In the embodiments of this disclosure, in response to entering the visibility window between the first and second satellites, a beacon light signal is sent to the second satellite, and an acknowledgment light signal is received from the second satellite. The ciphertext is extracted from the acknowledgment light signal, and the ciphertext is decapsulated to obtain the shared key generated by the post-quantum cryptography algorithm. This embodiment negotiates the ciphertext during the standard initialization process of beacon light scanning and acquisition, thereby solving the problems of high latency and poor reliability of key negotiation in inter-satellite optical links in related technologies, thus reducing key negotiation latency and improving key negotiation reliability.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0030] Figure 1 A schematic diagram of a satellite communication system according to an embodiment of the present disclosure is shown.

[0031] Figure 2 A flowchart of an inter-satellite key negotiation method is shown in an embodiment of this disclosure.

[0032] Figure 3 A flowchart illustrating a link visibility window prediction method according to an embodiment of this disclosure is shown.

[0033] Figure 4 A flowchart illustrating a service data transmission method according to an embodiment of this disclosure is shown.

[0034] Figure 5 A flowchart of another inter-satellite key negotiation method is shown in an embodiment of this disclosure.

[0035] Figure 6A flowchart of another inter-satellite key negotiation method is shown in this disclosure.

[0036] Figure 7 A schematic diagram of a first satellite according to an embodiment of this disclosure is shown.

[0037] Figure 8 A schematic diagram of a second satellite according to an embodiment of this disclosure is shown.

[0038] Figure 9 A schematic diagram of an electronic device provided in an embodiment of this disclosure is shown. Detailed Implementation

[0039] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0040] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0041] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.

[0042] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0043] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0044] It should be noted that, unless otherwise specified, the embodiments of this disclosure and the technical features thereof can be combined with each other.

[0045] To facilitate understanding, the following is an explanation of several terms used in this disclosure: PQC (Post-Quantum Cryptography) refers to a new generation of cryptographic algorithms that can resist attacks from quantum computers. Its security is based on mathematical problems (such as lattices, encoding, multivariables, etc.) rather than traditional large number factorization or discrete logarithm problems. It aims to replace classical public-key cryptography schemes such as RSA and ECC, which are no longer secure in the quantum era, and to ensure the long-term confidentiality and integrity of future information systems in a quantum computing environment.

[0046] ML-KEM (Module-Lattice-Based Key Encapsulation Mechanism): A post-quantum key encapsulation standard based on structured lattice problems, used to securely negotiate shared keys over insecure channels; its core operations include key generation, encapsulation (generating ciphertext and shared key), and decapsulation (recovering the shared key from the ciphertext). It features small key size and high computational efficiency, and is suitable for resource-constrained scenarios such as satellite communication.

[0047] LOS (Line-of-Sight): refers to the straight-line propagation condition where electromagnetic waves or light signals can directly reach the receiving end without obstruction in the propagation path. It is a basic prerequisite for establishing laser inter-satellite links. In satellite communication, orbit prediction and attitude control are required to ensure that two satellites meet strict line-of-sight alignment requirements within the visible window. Otherwise, the beam will be blocked by the Earth or other obstacles, resulting in link interruption.

[0048] Satellite fine tracking: After the satellite coarse tracking completes the approximate alignment, a high-bandwidth, high-precision feedback control system (such as a fast reflector or piezoelectric actuator) is used to perform real-time correction of the beam direction at the micrometer or even sub-micro-radian level to compensate for high-frequency errors such as platform vibration, thermal deformation and atmospheric disturbance, and ensure that the laser communication terminal maintains stable beam alignment and efficient coupling in dynamic environments.

[0049] Coarse satellite tracking: In the initial acquisition phase, a wide field-of-view sensor and a low-speed actuator are used to achieve a wide-range search and preliminary alignment of the beam, reducing the pointing error to the acquisition range of the fine tracking system. This process usually relies on ephemeris prediction, beacon scanning and closed-loop feedback. It has a slow response speed but a large coverage angle and is an indispensable pre-process for establishing a stable optical link.

[0050] AES (Advanced Encryption Standard): A symmetric block cipher algorithm that achieves efficient and secure plaintext encapsulation through multiple rounds of byte substitution, row shifting, column mixing, and round key addition. Due to its user-friendly hardware implementation and high throughput, it is widely used in satellite communications for real-time encapsulation and protection of service data, and is often used in conjunction with session keys negotiated by PQC.

[0051] FPGA (Field-Programmable Gate Array): A semiconductor device whose internal logic units and interconnect structures can be configured by software, combining hardware parallel processing capabilities with software flexibility. In satellite payloads, it is often used to implement high-speed acceleration of PQC algorithms, signal processing, and protocol stack offloading. Compared with ASIC, it has a shorter development cycle and is reconfigurable. Compared with CPU / GPU, it has lower power consumption and higher determinism, making it particularly suitable for cryptographic tasks in space environments with stringent requirements for performance and reliability.

[0052] The APT (Acquisition, Pointing and Tracking) subsystem is a comprehensive system integrating optical sensing, mechanical actuation and control algorithms. It is responsible for establishing and maintaining the laser communication link. Its workflow sequentially completes target acquisition (through beacon scanning), coarse pointing (wide-range alignment) and fine tracking (high-precision image stabilization). It is a key supporting technology for realizing high-speed inter-satellite laser communication and directly determines the link establishment time, stability and availability.

[0053] Figure 1 The diagram illustrates a satellite communication system according to an embodiment of the present disclosure. The satellite communication system includes a first satellite and a second satellite. Both the first satellite and the second satellite include an orbital ephemeris prediction module 101, a satellite computer 102, and a laser communication terminal 103. The satellite computer 102 includes an FPGA PQC acceleration module 1021, and the laser communication terminal 103 includes an APT subsystem 1031 and an optical transceiver module 1032.

[0054] The first and second satellites communicate via an inter-satellite optical link to achieve secure key negotiation and service communication. Both parties run their respective orbit ephemeris prediction modules 101 to predict the visibility window. The orbit ephemeris prediction module 101 has a built-in orbit prediction model.

[0055] Before the visibility window, the satellite computer 102 on the first satellite 11 distributes its PQC public key pk to the second satellite via the telemetry, tracking, and command link (low speed / routing).

[0056] Once the visibility window is entered, the first satellite's satellite computer 102 calls the APT subsystem 1031 of the laser communication terminal 103 to transmit a beacon light signal, and the second satellite's satellite computer 102 calls the APT subsystem 1031 of the laser communication terminal 103 to complete beacon acquisition and coarse tracking.

[0057] The satellite's onboard computer 102 calls the optical transceiver module 1032 in the laser communication terminal 103 to perform encrypted piggybacking and encapsulation service transmission, including the second satellite's feedback confirmation optical signal. After the first satellite locks in with precise tracking, it extracts the encrypted ct, and the onboard computer 102 calls the FPGA PQC acceleration module 1021 to perform decapsulation and restore the shared key K. After successful key negotiation, both parties use K to encapsulate the service data with AES and carry out high-speed, quantum-resistant encrypted service transmission through the optical transceiver module 1032. The entire process relies on the APT subsystem to ensure accurate beam alignment and stable link.

[0058] Figure 2 This diagram illustrates a flowchart of an inter-satellite key negotiation method according to an embodiment of the present disclosure. The method is applied to a first satellite, and the method is as follows: Figure 2 As shown, it includes the following steps: S201, in response to entering the visibility window between the first satellite and the second satellite, a beacon light signal is sent to the second satellite, wherein the visibility window is the time period during which the line-of-sight conditions for establishing an optical link between the first satellite and the second satellite are met.

[0059] As an example, the beacon light signal is an optical guidance signal sent by the first satellite to the second satellite to trigger a response from the other satellite and to assist in optical link acquisition and tracking.

[0060] The exemplary condition that the first and second satellites have the line-of-sight (LOS) condition for establishing an optical link refers to the fact that, under the constraints of space orbital dynamics, the two satellites have a line-of-sight (LOS) distance with no physical obstruction in their spatial geometric positions.

[0061] S202 receives the confirmation optical signal from the second satellite.

[0062] As an example, the confirmation optical signal is an optical response signal fed back by the second satellite after receiving the beacon optical signal, which carries the encapsulated key ciphertext.

[0063] S203, Extract the key ciphertext from the confirmation optical signal; As an example, the key ciphertext is a shared key encapsulated by a post-quantum cryptography algorithm and encapsulated in the physical layer frame header of the acknowledgment optical signal.

[0064] S204, decapsulate the key ciphertext to obtain the shared key, which is generated by a post-quantum cryptography algorithm.

[0065] An exemplary post-quantum cryptographic algorithm is the ML-KEM algorithm.

[0066] In this embodiment, the first satellite actively sends a beacon light signal when entering the visibility window between itself and the second satellite. Upon detecting the beacon light signal, the second satellite sends back an acknowledgment light signal carrying the key ciphertext. The first satellite extracts the key ciphertext from the acknowledgment light signal and decapsulates it to obtain the shared key generated by the post-quantum cryptography algorithm. This embodiment embeds the key negotiation process into the physical layer interaction of the optical link establishment, utilizing the inherent transmission timing of the beacon light signal and the acknowledgment light signal to complete the shared key transfer, avoiding additional network layer handshake overhead. Since the key ciphertext is directly modulated onto the acknowledgment light signal, no independent data channel or multiple round trips are required, thereby reducing communication latency under highly dynamic topologies. Simultaneously, the use of a post-quantum cryptography algorithm to generate the shared key enables key negotiation and subsequent business data transmission to possess quantum computing resistance, thus ensuring the long-term security of inter-satellite optical communication. This solves the problems of high latency and poor reliability of key negotiation using post-quantum cryptography algorithms in inter-satellite optical links in related technologies, thereby reducing key negotiation latency and improving key negotiation reliability.

[0067] Figure 3 This invention discloses a flowchart of a link visibility window prediction method according to an embodiment of the present disclosure. The method is as follows: Figure 3 As shown, it includes the following steps: S301, Obtain orbital ephemeris information of the first and second satellites; S302 uses an orbit prediction model to predict visibility windows based on the orbital ephemeris information of the first and second satellites.

[0068] As an example, orbital ephemeris information is data that describes the trajectory of a satellite in space, including parameters such as position, velocity, and orbital elements.

[0069] As an example, the orbit prediction model is a computational framework based on celestial mechanics or numerical integration methods, used to extrapolate a satellite's trajectory over a future period based on input orbital ephemeris information. This orbit prediction model is an existing model and will not be elaborated upon further here.

[0070] In this embodiment, the first satellite acquires its own orbital ephemeris information and that of the second satellite, and uses an orbital prediction model to calculate their future relative positions, thereby pre-determining the start and end times of the visibility window. Through this technical means, the determination of the visibility window is transformed from real-time detection to pre-prediction, enabling the first satellite to complete beam pointing preparation before the window opens, avoiding the time wasted searching for targets temporarily within the window.

[0071] In an optional embodiment, before sending a beacon light signal to the second satellite in response to entering a visibility window between the first and second satellites, the method further includes: receiving visibility window forecast data uploaded by a ground station, wherein the visibility window forecast data is generated by a ground control center based on the orbital ephemeris information of the first and second satellites; parsing the visibility window forecast data to extract the start time and duration of the next visibility window between the first and second satellites. Through the above technical means, the consumption of onboard computing resources is reduced.

[0072] In some exemplary embodiments, before sending a beacon light signal to the second satellite in response to entering a visibility window between the first and second satellites, the method further includes sending the public key of the first satellite to the second satellite before the visibility window.

[0073] As an example, the public key can be a PQC public key, which is used to encapsulate or key encapsulate public parameters that can be securely obtained by the communication peer and used to generate ciphertext that can only be decapsulated by the party holding the corresponding private key.

[0074] In this embodiment, the first satellite sends its public key to the second satellite before the visibility window opens. This allows the second satellite to possess the first satellite's public key before the visibility window arrives, enabling it to immediately encapsulate the shared key with the public key and modulate it into the acknowledgment light signal upon receiving the beacon light signal. Since public key transmission does not rely on high-precision optical alignment, it can be completed under relatively relaxed communication conditions, thus avoiding the occupation of valuable optical link resources for public key exchange within the short visibility window and improving the payload efficiency of key negotiation during the window period.

[0075] In some exemplary embodiments, decapsulating the key ciphertext to obtain a shared key includes: decapsulating the key ciphertext using the private key of the first satellite to obtain the shared key.

[0076] As an example, the private key is a confidential parameter paired with the public key, held only by the first satellite, and used to decrypt the key ciphertext encapsulated using the public key.

[0077] In this embodiment, the first satellite uses its own private key to decrypt the ciphertext of the key extracted from the confirmation optical signal, thereby recovering the shared key. This embodiment limits the decryption operation to be completed locally on the first satellite, ensuring that the shared key is never transmitted in plaintext on the inter-satellite link; since the private key is always stored in the secure storage area of ​​the first satellite and does not participate in any external interaction, even if the confirmation optical signal is intercepted by a third party, the attacker will not be able to recover the shared key due to the lack of the private key.

[0078] In one optional embodiment, decapsulating the key ciphertext to obtain a shared key includes: decapsulating the key ciphertext using the private key of the first satellite to obtain the original key material; and applying a key derivation function to the original key material to generate a shared key, wherein the key derivation function is a function that conforms to the post-quantum security standard.

[0079] In some exemplary embodiments, in response to entering a visibility window between the first and second satellites, sending a beacon light signal to the second satellite includes: acquiring orbital ephemeris information of the second satellite; predicting the position of the second satellite based on the orbital ephemeris information of the second satellite; and sending the beacon light signal within the maximum deviation range of the position.

[0080] As an example, the maximum deviation range is a spatial region determined by combining orbit prediction uncertainty and beam divergence angle, used to cover possible deviations between the actual position of the second satellite and its predicted position, ensuring that the beacon light signal can be effectively received by the other party.

[0081] In this embodiment, before transmitting the beacon light signal, the first satellite first acquires the orbital ephemeris information of the second satellite and predicts its current position accordingly. Then, it transmits the beacon light signal within the maximum deviation range of the predicted position. This embodiment extends the beam pointing from a single precise point to a tolerance area to address positioning deviations caused by factors such as orbit prediction errors, platform attitude jitter, and atmospheric refraction. Because the beacon light signal covers the possible spatial range of the second satellite, even if there is a certain error in the prediction, the second satellite remains within the beam's illumination area, thereby avoiding link acquisition failure due to pointing inaccuracies and improving the robustness of optical link establishment.

[0082] In some exemplary embodiments, after receiving the confirmation light signal from the second satellite, the method further includes: performing fine tracking of the second satellite based on the confirmation light signal.

[0083] In this embodiment, after receiving the acknowledgment light signal from the second satellite, the first satellite uses the acknowledgment light signal as a reference to initiate a fine tracking mechanism. This embodiment simultaneously utilizes the acknowledgment light signal as both a key negotiation carrier and an optical beacon, enabling the first satellite to directly extract angular error information from the demodulated signal and drive a fast-reflecting mirror or precision pointing structure for real-time correction.

[0084] In some exemplary embodiments, after decapsulating the key ciphertext to obtain the shared key, the method further includes: determining that the optical link has been established when the optical link between the first satellite and the second satellite meets preset conditions; and sending a key negotiation success notification to the second satellite.

[0085] The exemplary conditions include receiving optical power greater than a preset power and bit error rate less than a preset bit error rate.

[0086] In this embodiment, when the optical link meets preset conditions, a key negotiation success notification is sent to the second satellite to inform the second satellite that service data can be exchanged. Through the above technical means, the actual quality of the optical link is verified, ensuring the reliability of secure communication. Figure 4 This diagram illustrates a flowchart of a service data transmission method according to an embodiment of the present disclosure. The method is as follows: Figure 4 As shown, it includes the following steps: S401, use the shared key to encapsulate the first service data to obtain the first service ciphertext; S402, send the first business ciphertext to the second satellite.

[0087] In this embodiment, the first service data is encapsulated using the AES algorithm based on a shared key to obtain the first service ciphertext. This ciphertext is then transmitted to the second satellite. Through these technical means, the service data transmission acquires quantum computing resistance, thereby ensuring the long-term security of inter-satellite optical communication.

[0088] In some exemplary embodiments, after sending a key negotiation success notification to the second satellite for decapsulation, the method further includes: receiving the second service ciphertext sent by the second satellite; and decapsulating the second service ciphertext using a shared key to obtain the second service data.

[0089] In this embodiment, the first satellite receives the second service ciphertext sent by the second satellite, and decapsulates the second service ciphertext using the AES algorithm based on the shared key to obtain the second service data. Through these technical means, the service data transmission acquires quantum computing resistance, thereby ensuring the long-term security of inter-satellite optical communication.

[0090] Figure 5 This invention discloses a flowchart of another inter-satellite key negotiation method in an embodiment of the present disclosure, which is as follows: Figure 5 As shown, it includes the following steps: S501, Receive the beacon light signal sent by the first satellite when it enters the visibility window between the first satellite and the second satellite, wherein the visibility window is the time period during which the line-of-sight conditions for establishing an optical link between the first satellite and the second satellite are met; S502 uses a post-quantum cryptography algorithm to generate a shared key; S503 encapsulates the shared key to obtain the key ciphertext; S504 sends a confirmation optical signal back to the first satellite, which carries the key ciphertext.

[0091] In this embodiment, the second satellite, acting as both the responder in the key negotiation and the generator of the shared key, receives the beacon light signal actively transmitted by the first satellite when the visibility window is open. It then uses the ML-KEM algorithm to generate the shared key, encapsulates the shared key to form ciphertext, and finally modulates the ciphertext into an acknowledgment light signal and feeds it back to the first satellite. It should be noted that the generation of the shared key using the ML-KEM algorithm and the encapsulation of the shared key to form the ciphertext are completed simultaneously.

[0092] This embodiment embeds the key negotiation process into the physical layer interaction of the optical link establishment, utilizing the inherent transmission timing of the beacon optical signal and the acknowledgment optical signal to complete the shared key transfer, avoiding additional network layer handshake overhead. Since the key ciphertext is directly modulated onto the acknowledgment optical signal, no independent data channel or multiple round trips are required, thereby reducing communication latency under highly dynamic topologies. Simultaneously, a post-quantum cryptography algorithm is used to generate the shared key, enabling key negotiation and subsequent service data transmission to have quantum computing resistance, thus ensuring the long-term security of inter-satellite optical communication. This addresses the problems of high latency and poor reliability in key negotiation using post-quantum cryptography algorithms in inter-satellite optical links in related technologies, thereby reducing key negotiation latency and improving key negotiation reliability.

[0093] In some exemplary embodiments, before receiving a beacon light signal transmitted by the first satellite when it enters a visibility window between the first and second satellites, the method further includes receiving the public key of the first satellite transmitted by the first satellite before entering the visibility window.

[0094] In this embodiment, the second satellite acquires the first satellite's public key before the visibility window opens. Since public key transmission has lower requirements for link precision, it can be completed under non-precise alignment conditions, thus avoiding the occupation of valuable high-precision optical link resources for public key exchange within the short visibility window. When the beacon light signal arrives, the second satellite can immediately use the pre-stored public key to encapsulate the newly generated shared key, significantly shortening the processing latency within the window and improving the payload efficiency of key negotiation.

[0095] In some exemplary embodiments, the shared key is encapsulated to obtain key ciphertext, including: encapsulating the shared key using the public key of the first satellite to obtain key ciphertext.

[0096] In this embodiment, based on the public key of the first satellite, the shared key is encapsulated using the ML-KEM algorithm to generate a key ciphertext that can only be decapsulated by the first satellite using its private key. This ensures that the shared key is not exposed on the inter-satellite link.

[0097] In some exemplary embodiments, receiving a beacon light signal transmitted by the first satellite as it enters a visibility window between the first and second satellites includes detecting the beacon light signal by covering the maximum deviation range of the first satellite's position with a large field-of-view detector.

[0098] An exemplary large field-of-view detector is one whose detection range is greater than its maximum deviation range.

[0099] In this embodiment, the second satellite does not passively wait for a precisely pointed beam, but instead uses a wide field-of-view detector to stare at the maximum deviation range of the first satellite's predicted position. Since the first satellite scans and transmits beacon light signals within this range, the second satellite's wide field-of-view staring can effectively capture the scanning beam, thereby addressing positioning deviations caused by factors such as orbit prediction errors and improving the capture probability.

[0100] In some exemplary embodiments, after receiving a beacon light signal sent by the first satellite when it enters a visibility window between the first and second satellites, the method further includes: coarsely tracking the first satellite based on the beacon light signal.

[0101] In this embodiment, after successfully acquiring the beacon light signal, the second satellite uses the beacon light signal as a reference to initiate coarse tracking. Coarse tracking lays the foundation for subsequent confirmation of the accurate transmission of the light signal, ensuring that the feedback beam is accurately pointed to the receiving aperture of the first satellite, and avoiding the loss of key ciphertext due to pointing deviation.

[0102] In some exemplary embodiments, after sending a confirmation optical signal back to the first satellite, the method further includes receiving a key negotiation success notification sent by the first satellite.

[0103] In this embodiment, after receiving a key negotiation success notification from the first satellite, it is confirmed that service data can be exchanged with the first satellite. This means that the second ciphertext can be sent to the first satellite, or preparations can be made to receive the first ciphertext sent by the first satellite. Through the above technical means, the actual quality of the optical link is verified, ensuring the reliability of secure communication.

[0104] In some exemplary embodiments, after receiving a key negotiation success notification sent by the first satellite, the method further includes: receiving a first service ciphertext sent by the first satellite; and decapsulating the first service ciphertext using a shared key to obtain first service data.

[0105] In this embodiment, the second satellite receives the first service ciphertext sent by the first satellite, and decapsulates the first service ciphertext using the AES algorithm based on a shared key to obtain the first service data. Through these technical means, the service data transmission acquires quantum computing resistance, thereby ensuring the long-term security of inter-satellite optical communication.

[0106] In some exemplary embodiments, after receiving a key negotiation success notification sent by the first satellite, the method further includes: encapsulating the second service data using a shared key to obtain second service ciphertext; and sending the second service ciphertext to the first satellite.

[0107] In this embodiment, the second service data is encapsulated using the AES algorithm based on a shared key to obtain the second service ciphertext. This ciphertext is then sent to the first satellite. Through these technical means, the service data transmission acquires quantum computing resistance, thereby ensuring the long-term security of inter-satellite optical communication.

[0108] Figure 6 This invention discloses a flowchart of another inter-satellite key negotiation method in an embodiment of the present disclosure, the method being as follows: Figure 6 As shown, it includes the following steps: S601, the first satellite runs the ML-KEM key generation algorithm to generate a public key pk and a private key sk.

[0109] S602, the first satellite predicts visibility window, and sends the public key pk to the second satellite via a low-speed / routing link.

[0110] S603, the second satellite stores the received public key pk and waits for the visibility window to open.

[0111] S604, entering the visibility window, the first satellite transmits a beacon light signal to the second satellite and scans within the maximum deviation range.

[0112] S605, the second satellite detected the beacon light signal and performed coarse tracking and locking.

[0113] S606, the second satellite runs the ML-KEM encapsulation algorithm (using the first satellite's public key pk) to generate a shared key K and ciphertext ct.

[0114] S607, the second satellite sends an acknowledgment optical signal to the first satellite, in which the physical layer frame header is modulated and carries the ciphertext ct.

[0115] S608, the first satellite detected the confirmation light signal and entered the fine tracking closed-loop locking period.

[0116] S609, the first satellite extracts the ciphertext ct from the physical layer frame header of the confirmed optical signal.

[0117] S610, the first satellite runs the ML-KEM decapsulation algorithm on the onboard FPGA (input ct and private key sk) to recover the shared key K.

[0118] S611, the first satellite confirms that the optical link has been established and sends a key negotiation success notification to the second satellite.

[0119] S612, the first satellite uses the shared key K to encapsulate the first service data with AES and sends the first service ciphertext to the second satellite.

[0120] S613, the second satellite uses the shared key K to encapsulate the second service data with AES and sends the second service ciphertext to the first satellite.

[0121] Based on the same disclosed concept, this disclosure also provides a first satellite and a second satellite, as shown in the following embodiments. Since the principles by which the first and second satellites solve the problem are similar to those in the above method embodiments, the implementation of the first and second satellites can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0122] Figure 7 This diagram illustrates a first satellite according to an embodiment of the present disclosure, such as... Figure 7 As shown, the first satellite may include: The first transmitting unit 701 is configured to transmit a beacon light signal to the second satellite in response to entering a visibility window between the first satellite and the second satellite, wherein the visibility window is the time period during which the line-of-sight conditions for establishing an optical link are met between the first satellite and the second satellite. The first receiving unit 702 is configured to receive the confirmation optical signal fed back by the second satellite; Extraction unit 703 is configured to extract key ciphertext from the confirmation optical signal; The decapsulation unit 704 is configured to decapsulate the key ciphertext to obtain the shared key.

[0123] In some exemplary embodiments, the first transmitting unit 701 is further configured to acquire orbital ephemeris information of the first satellite and the second satellite; and to predict a visibility window using an orbital prediction model based on the orbital ephemeris information of the first satellite and the second satellite.

[0124] In some exemplary embodiments, the first transmitting unit 701 is also configured to transmit the public key of the first satellite to the second satellite before the visibility window.

[0125] In some exemplary embodiments, the decapsulation unit 704 is also configured to decapsulate the key ciphertext using the private key of the first satellite to obtain the shared key.

[0126] In some exemplary embodiments, the first transmitting unit 701 is further configured to acquire orbital ephemeris information of the second satellite; predict the position of the second satellite based on the orbital ephemeris information of the second satellite; and transmit a beacon light signal within the maximum deviation range of the position.

[0127] In some exemplary embodiments, the first receiving unit 702 is also configured to perform fine tracking of the second satellite based on the confirmation optical signal.

[0128] In some exemplary embodiments, the first transmitting unit 701 is further configured to determine that the optical link has been established when the optical link between the first satellite and the second satellite meets preset conditions, and to send a key negotiation success notification to the second satellite.

[0129] In some exemplary embodiments, the first transmitting unit 701 is further configured to encapsulate the first service data using a shared key to obtain the first service ciphertext; and to transmit the first service ciphertext to the second satellite.

[0130] In some exemplary embodiments, the first receiving unit 702 is also configured to receive second service ciphertext transmitted by the second satellite; and to decapsulate the second service ciphertext using a shared key to obtain second service data.

[0131] Figure 8 This diagram illustrates a second satellite according to an embodiment of the present disclosure, such as... Figure 8 As shown, the second satellite may include: The second receiving unit 801 is configured to receive a beacon light signal sent by the first satellite when it enters the visibility window between the first satellite and the second satellite, wherein the visibility window is the time period during which the line-of-sight conditions for establishing an optical link are met between the first satellite and the second satellite. Generation unit 802 is configured to generate a shared key; Encapsulation unit 803 is configured to encapsulate the shared key to obtain key ciphertext; The second transmitting unit 804 is configured to send a confirmation optical signal back to the first satellite, wherein the confirmation optical signal carries a key ciphertext.

[0132] It should be noted that the generation unit 802 uses the ML-KEM algorithm to generate the shared key, and the encapsulation unit 803 uses the ML-KEM algorithm to encapsulate the shared key to form the key ciphertext, which is completed synchronously.

[0133] In some exemplary embodiments, the second transmitting unit 804 is also configured to receive the public key of the first satellite transmitted by the first satellite before entering the visibility window.

[0134] In some exemplary embodiments, the encapsulation unit 803 is also configured to encapsulate the shared key using the public key of the first satellite to obtain key ciphertext.

[0135] In some exemplary embodiments, the second receiving unit 801 is also configured to detect beacon light signals by covering the maximum deviation range of the first satellite's position with a wide field-of-view detector.

[0136] In some exemplary embodiments, the second receiving unit 801 is also configured to perform coarse tracking of the first satellite based on beacon light signals.

[0137] In some exemplary embodiments, the second receiving unit 801 is also configured to receive a key negotiation success notification sent by the first satellite.

[0138] In some exemplary embodiments, the second receiving unit 801 is further configured to receive the first service ciphertext transmitted by the first satellite; and to decapsulate the first service ciphertext using a shared key to obtain the first service data.

[0139] In some exemplary embodiments, the second transmitting unit 804 is further configured to encapsulate the second service data using a shared key to obtain the second service ciphertext; and to transmit the second service ciphertext to the first satellite.

[0140] Those skilled in the art will understand that various aspects of this disclosure can be implemented as a system, method, or program product. Therefore, various aspects of this disclosure can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, collectively referred to herein as a "circuit," "module," or "system."

[0141] The following reference Figure 9 To describe an electronic device 900 according to such an embodiment of the present disclosure. Figure 9 The electronic device 900 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0142] like Figure 9 As shown, the electronic device 900 is presented in the form of a general-purpose computing device. The components of the electronic device 900 may include, but are not limited to: at least one processor 910, at least one memory 920, and a bus 930 connecting different system components (including memory 920 and processor 910).

[0143] The memory stores program code that can be executed by the processor 910, causing the processor 910 to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this disclosure. For example, the processor 910 can perform the following steps of the above method embodiments: in response to entering a visibility window between the first satellite and the second satellite, sending a beacon light signal to the second satellite, wherein the visibility window is a time period during which the line-of-sight conditions for establishing an optical link between the first satellite and the second satellite are met; receiving an acknowledgment light signal from the second satellite; extracting key ciphertext from the acknowledgment light signal; and decapsulating the key ciphertext to obtain a shared key, wherein the shared key is generated by a post-quantum cryptography algorithm.

[0144] The memory 920 may include a readable medium in the form of volatile memory, such as random access memory (RAM) 9201 and / or cache memory 9202, and may further include read-only memory (ROM) 9203.

[0145] The memory 920 may also include a program / utility 9204 having a set (at least one) of program modules 9205, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0146] Bus 930 can represent one or more of several types of bus structures, including a memory bus or memory controller, peripheral bus, graphics acceleration port, processor, or a local bus using any of the various bus structures.

[0147] Electronic device 900 can also negotiate inter-satellite keys with one or more external devices 940 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), and with one or more networks that enable users to interact with electronic device 900, and / or with any device that enables electronic device 900 to negotiate inter-satellite keys with one or more other computing devices (e.g., routers, modems, etc.). This inter-satellite key negotiation can be performed via input / output (I / O) interface 950. Furthermore, electronic device 900 can also negotiate inter-satellite keys with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via network adapter 960. As shown in the figure, network adapter 960 negotiates inter-satellite keys with other modules of electronic device 900 via bus 930. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with electronic device 900, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0148] In the disclosed exemplary embodiments, a computer-readable storage medium is also provided, which may be a readable signal medium or a readable storage medium.

[0149] In some possible implementations, various aspects of this disclosure may also be implemented as a program product comprising program code that, when run on a terminal device, causes the terminal device to perform the steps described in the foregoing “Detailed Description” section of this specification according to various exemplary embodiments of this disclosure.

[0150] More specific examples of computer-readable storage media in this disclosure may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0151] In this disclosure, a computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of transmitting, propagating, or transmitting a program for use by or in connection with an instruction execution system, apparatus, or device.

[0152] Optionally, the program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0153] In practical implementation, program code for performing the operations of this disclosure can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on a terminal device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0154] This disclosure provides a computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform an inter-satellite key negotiation method provided in various alternative embodiments of this disclosure.

[0155] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0156] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0157] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0158] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this disclosure is indicated by the appended claims.

Claims

1. A method for inter-satellite key negotiation, characterized in that, Applied to the first satellite, including: In response to entering the visibility window between the first satellite and the second satellite, a beacon light signal is sent to the second satellite, wherein the visibility window is the time period during which the line-of-sight conditions for establishing an optical link between the first satellite and the second satellite are met; Receive the confirmation optical signal fed back by the second satellite; Extract the key ciphertext from the confirmation optical signal; The key ciphertext is decapsulated to obtain a shared key, which is generated by a post-quantum cryptography algorithm.

2. The method according to claim 1, characterized in that, Before sending a beacon light signal to the second satellite in response to entering the visibility window between the first and second satellites, the method further includes: Obtain the orbital ephemeris information of the first satellite and the second satellite; Based on the orbital ephemeris information of the first satellite and the second satellite, the visibility window is predicted using an orbital prediction model.

3. The method according to claim 1, characterized in that, Before sending a beacon light signal to the second satellite in response to entering the visibility window between the first and second satellites, the method further includes: Send the public key of the first satellite to the second satellite in front of the visibility window.

4. The method according to claim 1, characterized in that, The step of decapsulating the key ciphertext to obtain the shared key includes: The shared key is obtained by decapsulating the ciphertext of the key using the private key of the first satellite.

5. The method according to claim 1, characterized in that, The step of sending a beacon light signal to the second satellite in response to entering the visibility window between the first and second satellites includes: Obtain the orbital ephemeris information of the second satellite; Based on the orbital ephemeris information of the second satellite, predict the position of the second satellite; The beacon light signal is transmitted within the maximum deviation range of the stated location.

6. The method according to claim 1, characterized in that, After receiving the confirmation optical signal from the second satellite, the method further includes: The second satellite is precisely tracked based on the confirmed optical signal.

7. The method according to claim 1, characterized in that, After decapsulating the key ciphertext to obtain the shared key, the method further includes: When the optical link between the first satellite and the second satellite meets the preset conditions, it is determined that the optical link has been established. A key negotiation success notification is sent to the second satellite.

8. The method according to claim 7, characterized in that, After sending the key negotiation success notification to the second satellite and decapsulating it, the method further includes: The first service data is encapsulated using the shared key to obtain the first service ciphertext; The first service ciphertext is sent to the second satellite.

9. The method according to claim 7, characterized in that, After sending the key negotiation success notification to the second satellite and decapsulating it, the method further includes: Receive the second service ciphertext sent by the second satellite; The second service ciphertext is decapsulated using the shared key to obtain the second service data.

10. A method for inter-satellite key negotiation, characterized in that, Applied to the second satellite, including: Receive a beacon light signal sent by a first satellite when it enters the visibility window between the first satellite and the second satellite, wherein the visibility window is the time period during which the first satellite and the second satellite have line-of-sight conditions to establish an optical link; Generate a shared key using post-quantum cryptography algorithms; The shared key is encapsulated to obtain the key ciphertext; A confirmation optical signal is sent back to the first satellite, wherein the confirmation optical signal carries the key ciphertext.

11. The method according to claim 10, characterized in that, Before receiving the beacon light signal transmitted by the first satellite when it enters the visibility window between the first satellite and the second satellite, the method further includes: Receive the public key of the first satellite sent by the first satellite before entering the visibility window.

12. The method according to claim 10, characterized in that, The process of encapsulating the shared key to obtain ciphertext includes: The shared key is encapsulated using the public key of the first satellite to obtain the key ciphertext.

13. The method according to claim 10, characterized in that, Receiving the beacon light signal sent by the first satellite when it enters the visibility window between the first and second satellites includes: The beacon light signal is detected by covering the maximum deviation range of the first satellite's position using a wide field-of-view detector.

14. The method according to claim 10, characterized in that, After receiving the beacon light signal sent by the first satellite when it enters the visibility window between the first satellite and the second satellite, the method further includes: The first satellite is coarsely tracked based on the beacon light signal.

15. The method according to claim 10, characterized in that, After sending a confirmation optical signal back to the first satellite, the method further includes: Receive the key negotiation success notification sent by the first satellite.

16. The method according to claim 15, characterized in that, After receiving the key negotiation success notification sent by the first satellite, the method further includes: Receive the first service ciphertext sent by the first satellite; The first service ciphertext is decapsulated using the shared key to obtain the first service data.

17. The method according to claim 15, characterized in that, After receiving the key negotiation success notification sent by the first satellite, the method further includes: The second service data is encapsulated using the shared key to obtain the second service ciphertext; Send the second service ciphertext to the first satellite.

18. A first satellite, characterized in that, include: The first transmitting unit is configured to transmit a beacon light signal to the second satellite in response to entering a visibility window between the first satellite and the second satellite, wherein the visibility window is a time period during which the line-of-sight conditions for establishing an optical link are met between the first satellite and the second satellite; The first receiving unit is configured to receive the confirmation light signal fed back by the second satellite; The extraction unit is configured to extract the key ciphertext from the confirmation optical signal; The decapsulation unit is configured to decapsulate the key ciphertext to obtain the shared key.

19. A second satellite, characterized in that, include: The second receiving unit is configured to receive a beacon light signal sent by the first satellite when it enters the visibility window between the first satellite and the second satellite, wherein the visibility window is the time period during which the first satellite and the second satellite have line-of-sight conditions to establish an optical link. The generation unit is configured to generate a shared key; The encapsulation unit is configured to encapsulate the shared key to obtain key ciphertext; The second transmitting unit is configured to send a confirmation optical signal back to the first satellite, wherein the confirmation optical signal carries the key ciphertext.

20. An electronic device, characterized in that, include: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the method of any one of claims 1-9 or 10-17 by executing the executable instructions.

21. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1-9 or 10-17.

22. A computer program product comprising computer instructions stored in a computer-readable storage medium, wherein the computer instructions, when executed by a processor, implement the operation instructions of the method according to any one of claims 1-9 or 10-17.

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