A secure communication method, apparatus, medium and electronic device

Abstract

The present specification provides a secure communication method, device, medium and electronic equipment. In the method, first, initial key negotiation based on a post-quantum cryptographic algorithm is performed to generate an initial shared key, a quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, and the quantum random number seed is stored in a quantum seed cache area. Then, according to a communication session establishment request, a target quantum random number seed is extracted from the quantum seed cache area, a current session key is generated based on the initial shared key or the last round session key and the target quantum random number seed through a key derivation function, and finally, data transmission is performed based on the current session key.

Description

Technical Field

[0001] This specification relates to one or more embodiments in the field of network security technology, and in particular to a secure communication method, apparatus, medium and electronic device. Background Technology

[0002] Currently, with the rapid development of quantum computing technology, traditional public-key cryptography algorithms (such as RSA and ECC) face the risk of being efficiently cracked by Shor's algorithm. To address this threat, post-quantum cryptography (PQC) algorithms have been widely adopted. Specifically, PQC algorithms are mainly constructed based on several types of mathematically difficult problems, the most representative of which is lattice-based cryptography. Its security relies on lattice-based difficult problems (such as the shortest vector problem (SVP) and the learning with error problem (LWE). These assumptions are collectively referred to as "lattice assumptions".

[0003] However, the security of the PQC algorithm relies on the algebraic structure assumption, the "lattice hypothesis." This means that once the "lattice hypothesis" is broken, new mathematical methods or quantum algorithms can overcome it, and lattice-based post-quantum cryptography algorithms will lose their mathematical foundation, thus facing the risk of overall security collapse. Summary of the Invention

[0004] In view of the above, one or more embodiments of this specification provide the following technical solutions: According to a first aspect of one or more embodiments of this specification, a secure communication method is provided, comprising: Perform initial key negotiation based on post-quantum cryptography algorithm to generate initial shared key; The quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, and the quantum random number seed is stored in a quantum seed cache. Based on the communication session establishment request, the target quantum random number seed is extracted from the quantum seed cache. The current session key is generated using a key derivation function based on the initial shared key or the previous session key, and the target quantum random number seed; Data transmission is performed based on the current session key.

[0005] According to a second aspect of one or more embodiments of this specification, a secure communication device is provided, comprising: The first-round negotiation module is used to perform initial key negotiation based on post-quantum cryptography algorithms and generate an initial shared key; The random seed generation module is used to perform a quantum key distribution process through a quantum channel, obtain a quantum random number seed, and store the quantum random number seed in a quantum seed cache. The extraction module is used to extract the target quantum random number seed from the quantum seed cache according to the communication session establishment request; The generation module is used to generate the current session key based on the initial shared key or the previous round session key and the target quantum random number seed using a key derivation function; The data transmission module is used to transmit data based on the current session key.

[0006] According to a third aspect of one or more embodiments of this specification, an electronic device is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor implements the steps of the secure communication method described above by executing the executable instructions.

[0007] According to a fourth aspect of one or more embodiments of this specification, a computer-readable storage medium is provided that stores computer instructions thereon, which, when executed by a processor, implement the steps of the secure communication method described above.

[0008] According to a fifth aspect of one or more embodiments of this specification, a computer program product is provided, comprising a computer program / instructions that, when executed by a processor, implement the steps of the above-described secure communication method.

[0009] In this method, an initial key negotiation based on a post-quantum cryptography algorithm is first performed to generate an initial shared key. Then, a quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, which is stored in a quantum seed buffer. Next, based on the communication session establishment request, a target quantum random number seed is extracted from the quantum seed buffer. The current session key is generated using a key derivation function based on the initial shared key or the previous session key and the target quantum random number seed. Finally, data transmission is performed based on the current session key.

[0010] As can be seen from the above method, an initial shared key can be generated by performing initial key negotiation based on a post-quantum cryptography algorithm. Furthermore, the quantum random number seed obtained through the quantum key distribution process is stored in a quantum seed cache. On the one hand, when a subsequent communication session is established, the target quantum random number seed can be extracted from the quantum seed cache and combined with the initial shared key or the previous session key to generate the current session key via a key derivation function. This combines the initial computational security provided by the post-quantum cryptography algorithm with the random enhancement provided by quantum randomness, thereby improving the security of the session key generation process. On the other hand, since subsequent sessions can generate the current session key based on the generated initial shared key or the previous session key combined with the cached target quantum random number seed, there is no need to repeatedly perform the high-overhead initial key negotiation each time a communication session is established. Therefore, the computational overhead and communication latency caused by repeated negotiation can be reduced. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the architecture of a secure communication system provided in an exemplary embodiment.

[0012] Figure 2 This is a flowchart illustrating a secure communication method provided in an exemplary embodiment.

[0013] Figure 3 This is a schematic diagram illustrating the process of generating a candidate shared key in an exemplary practical example.

[0014] Figure 4 This is a schematic diagram of an identity authentication process provided in an exemplary embodiment.

[0015] Figure 5 This is a schematic diagram of a quantum key distribution process provided in an exemplary embodiment.

[0016] Figure 6 This is a schematic diagram of the current session key generation process provided in an exemplary embodiment.

[0017] Figure 7 This is a schematic structural diagram of a device provided in an exemplary embodiment.

[0018] Figure 8 This is a block diagram of a secure communication device provided in an exemplary embodiment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0020] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this manual are all information and data authorized by the user or fully authorized by all parties. The collection, use and processing of related data shall comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation portals shall be provided for users to choose to authorize or refuse.

[0021] In the field of network security communications, with the rapid development of quantum computing technology, traditional public-key cryptography algorithms face the risk of being efficiently cracked by Shor's algorithm. To address this issue, post-quantum cryptography algorithms have gradually gained attention. Typically, post-quantum cryptography algorithms are constructed based on several mathematically difficult problems, among which lattice-based cryptography is a commonly used problem. However, the security of post-quantum cryptography algorithms based on lattice-based keys depends on the algebraic structure assumptions corresponding to the lattice-based difficult problems.

[0022] In other words, the security of post-quantum cryptography algorithms is still essentially based on the validity of relevant mathematical assumptions. Once these assumptions are broken by new mathematical methods or stronger quantum algorithms, the post-quantum cryptography algorithms built on these assumptions will lose their security foundation, thereby exposing communication systems to risks such as key leakage, cracking of ciphertext, and failure of identity authentication.

[0023] This can be understood as follows: lattice-based post-quantum cryptography algorithms typically rely on the premise that lattice-hard problems such as the error-laden learning problem and the shortest vector problem are currently difficult to solve efficiently, thus providing security support for key negotiation, encryption, and digital signatures. However, this security is not absolute security independent of conditions, but rather depends on assumptions about specific algebraic structures. Once these assumptions fail, attackers may recover the private key based on public information, recover the plaintext from the ciphertext, or forge legitimate signatures, thereby making communication links built based on the corresponding post-quantum cryptography algorithms vulnerable to real-time or post-incident attacks. This makes it difficult to meet the requirements of long-term confidentiality and continuous security in high-security communication scenarios.

[0024] Building upon this, this specification provides a secure communication method that incorporates a quantum random number seed into the session key generation process. By pre-storing and managing the quantum random number seed in a quantum seed cache, the method allows for the generation of the current session key even when the quantum link is temporarily unavailable. This reduces reliance on the real-time availability of the quantum link and ensures the continuity of communication. Furthermore, subsequent communication sessions can generate new current session keys based on the previous session key and the newly extracted target quantum random number seed, eliminating the need to re-execute the initial key negotiation based on post-quantum cryptography algorithms each time a communication session is established. This not only reduces the computational overhead and latency caused by repeated negotiation but also minimizes the exposure of new post-quantum asymmetric interaction information, thereby enhancing the overall security of the communication process.

[0025] To clearly describe the secure communication methods provided in this specification, some concepts involved in this specification will be explained below.

[0026] Post-quantum cryptography (PQC) refers to cryptographic algorithms designed to resist quantum computing attacks. In this specification, PQC is primarily used by both communicating parties to complete initial key negotiation and generate an initial shared key when establishing a trust relationship for the first time. This PQC algorithm can employ a lattice-based key encapsulation mechanism or other algorithms suitable for establishing shared secrets in a post-quantum environment. In this specification, the algorithm serves as an initial bootstrapping mechanism, rather than requiring repeated execution in every session.

[0027] Quantum Key Distribution (QKD) refers to the process by which two communicating parties generate shared quantum random material using a quantum channel and a corresponding classical post-processing procedure. In this specification, the result generated by the quantum key distribution process is used as a quantum random number seed, rather than being used directly as a large-scale encryption keystream for business data.

[0028] A quantum random number seed (QRNS) is a random number obtained through the quantum key distribution process and used as input material for key derivation. This QRNS can be a fixed-length random bit string or a random bit string of a target length extracted from a longer quantum random sequence. The QRNS is used, along with the initial shared key or the previous round's session key, as input to the key derivation function to generate the current session key.

[0029] A quantum seed buffer is a storage area used to store quantum random number seeds generated through the quantum key distribution process but not yet used in the generation of the current session key. This quantum seed buffer can be deployed at the communication transmitter, communication receiver, or within the corresponding security module to achieve the accumulation, screening, extraction, expiration, and subsequent reuse of quantum random materials, thereby reducing reliance on the real-time availability of the quantum link.

[0030] A key derivation function (KDF) is a function used to combine multiple key materials and derive a target session key. In this specification, the key derivation function is used to mix the initial shared key or the previous round's session key with the target quantum random number seed to output the current session key. This key derivation function can be a hash-based key derivation function or other functions that can achieve key extraction and expansion.

[0031] The previous session key refers to the session key actually used for data transmission in the previous communication session. In this specification, the previous session key is not only used for data protection in the previous round, but can also be used as part of the input for deriving subsequent session keys, so that subsequent session keys are associated with the state of the previous round of sessions, forming a continuous key evolution relationship.

[0032] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the architecture of a secure communication system provided in an exemplary embodiment.

[0034] Combination Figure 1 As can be seen, a secure communication system may include: a communication transmitter 101, a communication receiver 102, a quantum channel 103, and a classical channel 104.

[0035] Both the communication transmitter 101 and the communication receiver 102 can be electronic devices with data processing and communication capabilities, such as servers, personal computers, mobile terminals, or dedicated communication gateways. In practical applications, the communication transmitter 101 and the communication receiver 102 can be deployed in different locations to establish secure communication links across regions.

[0036] Quantum channel 103 provides quantum key distribution capability for communication transmitter 101 and communication receiver 102 to generate quantum random number seeds that can be used for key derivation in subsequent sessions. Quantum channel 103 can be implemented in various ways, such as fiber optic quantum links, free-space optical communication links, or satellite-based quantum relay links. Figure 1As shown, quantum channel 103 can access a quantum key distribution network, which includes quantum satellite 1031. Quantum satellite 1031 can establish quantum links with communication transmitter 101 and communication receiver 102 at different time windows, thereby supporting the remote and time-series quantum key distribution process.

[0037] Classical channel 104 is used to transmit service data and control signaling between communication transmitter 101 and communication receiver 102. Classical channel 104 can be any communication network capable of supporting conventional data transmission, such as the Internet, local area network, or dedicated wide area network. In this specification, communication transmitter 101 and communication receiver 102 can perform initial key negotiation based on post-quantum cryptography algorithm through classical channel 104, and complete encrypted data transmission based on the generated session key in subsequent sessions.

[0038] It should be noted that, Figure 1 The system architecture shown is merely an illustrative example and does not constitute a limitation on the system deployment. For example, the quantum channel 103 can consist solely of a ground-based fiber optic quantum link, or it can consist of multiple quantum satellites, multiple ground-based quantum nodes, or a combination of both, to achieve a more flexible quantum key distribution path. Furthermore, the communication transmitter 101 and the communication receiver 102 can each be internally deployed with functional modules for executing secure communication processes, such as a quantum seed buffer, a key derivation module, and a session management module, to collaboratively complete processes such as initial key negotiation, quantum random number seed management, session key generation, and encrypted data transmission.

[0039] In secure communication scenarios, when two parties need to establish or resume a high-security business session, the server can perform the following steps. For ease of description, the following uses the server corresponding to the communication sending end as the execution subject to explain the secure communication method provided in this manual in detail. The communication receiving end can execute the corresponding collaborative processing flow.

[0040] Figure 2 This is a flowchart illustrating a secure communication method provided in an exemplary embodiment, including the following steps: S200: Perform initial key negotiation based on post-quantum cryptography algorithm to generate initial shared key.

[0041] In this specification, when the communication sender and receiver establish a secure communication link for the first time, or when there is no valid session state that can be reused (e.g., the original session key has expired or become invalid, or the secure communication link has been re-established after a long interruption), the communication sender can perform initial key negotiation based on post-quantum cryptography algorithms to generate an initial shared key. This initial shared key is used to provide initial secret material for the generation of subsequent session keys and serves as the starting input for the entire key evolution chain.

[0042] For example, in cross-regional leased line communication scenarios, two servers located in different locations (such as a server used by an overseas branch and a server used by the home headquarters) need to establish a long-term, stable, and secure communication connection after initial deployment. In this case, the initial key negotiation process can be triggered when both servers initialize or connect to the network for the first time to complete identity verification and generate an initial shared key.

[0043] For example, in a high-security data synchronization scenario, the business master node and backup node (such as the financial transaction center server and the off-site disaster recovery center server) need to re-establish a synchronization link. At this time, if the local quantum seed cache is empty or the previously saved historical session state has been cleared, the initial key negotiation process can be restarted so that a preliminary secure connection can still be established based on the post-quantum cryptography algorithm when the quantum channel is not yet available.

[0044] Specifically, when the communication sender and receiver establish a connection for the first time, the communication sender can perform a complete initial key negotiation process. This initial key negotiation process can include two sub-processes: generating a candidate shared key and performing authentication. These two sub-processes are described in detail below. Figure 3 , Figure 4 As shown.

[0045] Figure 3 This is a schematic diagram illustrating the process of generating a candidate shared key in an exemplary practical example.

[0046] Combination Figure 3 As can be seen, in the sub-process of generating the candidate shared key, the communication sender can perform initial key negotiation based on the post-quantum cryptography algorithm to generate the candidate shared key. This candidate shared key employs a lattice-based key encapsulation mechanism. In other words, the communication sender and receiver can first establish a shared secret through this lattice-based key encapsulation mechanism.

[0047] For example, the sending end can generate its temporary public key K1 and private key K2 using the lattice-based key encapsulation mechanism described above. It can then send the public key K1 to the receiving end, allowing the receiving end to encapsulate a random value N using this public key, resulting in ciphertext M, which it then sends back to the sending end. Upon receiving the ciphertext M, the sending end can decrypt it using its private key K2 to obtain the random value N. At this point, both the sending and receiving ends possess the random value N. Based on this, they can generate an initial shared key using the same key derivation logic.

[0048] The key derivation logic described above can take many forms. For example, the random value N can be directly used as the initial shared key; or the random value N can be input into a key derivation function (such as a hash function like HKDF or SHA-256) to generate the initial shared key.

[0049] It should be noted that since the private key K2 is held only by the sending end of the communication, even if the ciphertext M is intercepted by a man in the middle during the key negotiation process, it cannot be cracked to obtain the random value N.

[0050] However, the true identity of the other party cannot be verified in the above process, making it vulnerable to man-in-the-middle attack (MITM).

[0051] Specifically, in the absence of an effective authentication mechanism, an attacker can intercept the public key K1 sent by the communication sender and replace it with their own generated public key K1' before sending it to the communication receiver. Simultaneously, the attacker intercepts the ciphertext M sent by the communication receiver, uses their private key to decrypt it into a random value N, and then re-encapsulates it using the communication sender's public key K1 to generate a new ciphertext M' before sending it to the communication sender. In this way, the attacker establishes independent shared keys with both the communication sender and the communication receiver, enabling them to eavesdrop on, tamper with, or even forge all communication content between the two parties without their knowledge.

[0052] Therefore, to avoid the risks of identity impersonation and data leakage caused by man-in-the-middle attacks, an identity authentication sub-process needs to be performed during the initial key negotiation process. The following combines... Figure 4 Please provide a detailed explanation.

[0053] Figure 4 This is a schematic diagram of an identity authentication process provided in an exemplary embodiment.

[0054] Combination Figure 4It can be seen that in the sub-process of identity authentication, the communication sender and receiver need to digitally sign the key messages in the key exchange process to prove that the messages do indeed come from the real communication party and have not been tampered with.

[0055] Specifically, after generating a temporary public key K1, the sending end not only sends K1 to the receiving end but also uses its long-term held signing private key to digitally sign the key exchange message transcription, including the public key K3, generating a signature SigA, which is then sent to the receiving end. Upon receiving the public key K1 and the signature SigA, the receiving end verifies the signature SigA using the sending end's signing public key, which it has either obtained beforehand or downloaded from a trusted certificate authority (CA). If the verification passes, it confirms that the public key K1 was indeed sent by the sending end and has not been tampered with by a man-in-the-middle attack.

[0056] Similarly, after generating ciphertext M by encapsulating a random value N with public key K1, the receiving end also uses its long-held signing private key to digitally sign the transcribed message containing ciphertext M, generating a signature SigB. It then sends both ciphertext M and signature SigB to the sending end. Upon receiving this, the sending end verifies the signature SigB using the receiving end's signing public key. If the verification passes, it confirms that ciphertext M was indeed sent by the receiving end.

[0057] In this way, both parties can confirm that the critical information sent by the other party does indeed originate from a real entity, and is not information that has been replaced, forged, or tampered with by an intermediary. If either party discovers a signature verification failure, a message context mismatch, or an abnormal identity status, it can terminate the current round of initial key negotiation and refuse to confirm the candidate shared key as the initial shared key.

[0058] It should be noted that the aforementioned signing private key and signing public key, which are held by the communication sender or receiver for a long period of time, can be static key pairs distributed in advance through secure channels, or key pairs in digital certificates issued based on the Public Key Infrastructure (PKI) system.

[0059] In practical applications, in order to balance signature verification efficiency, signature size, and resistance to future quantum computing attacks, the aforementioned signature algorithms can be ML-DSA signatures, SLH-DSA signatures, etc.

[0060] Among them, ML-DSA signature is a digital signature algorithm based on the module-lattice structure. Its advantages are that the signature size is small (usually within a few KB) and the generation and verification speed is fast, making it suitable for bandwidth-limited or latency-sensitive scenarios. However, its security also depends on the "lattice assumption". If the lattice assumption is broken, the signature mechanism will also fail.

[0061] SLH-DSA signatures are stateless digital signature algorithms based on hash functions (such as SPHINCS+). Their security relies solely on the one-wayness of the hash function, without depending on any algebraic structure assumptions. Therefore, even if future quantum computers break the lattice assumption, SLH-DSA signatures remain secure, and attackers cannot forge them. This ensures that communication systems using SLH-DSA signatures, even when the lattice assumption fails, can maintain the standard threat model required for QKD security proofs, although the classical channel may be eavesdropped on. Furthermore, although its signature size is relatively large and computationally expensive, its impact on overall communication performance is manageable because it is only executed once during the initial handshake.

[0062] Therefore, in practical applications, if the communication scenario has strict limitations on signature size and verification latency, the ML-DSA signature algorithm can be selected to leverage its lightweight characteristics to improve handshake efficiency and reduce bandwidth consumption. Conversely, if the communication data has extremely high sensitivity and a long lifespan (such as diplomatic secrets or core financial data), and the deployer wants to completely eliminate the dependence on the algebraic structure assumption to achieve the highest level of quantum security, the SLH-DSA signature algorithm can be selected. By sacrificing a small amount of initial handshake performance, it can obtain deterministic quantum immunity that can still resist man-in-the-middle attacks even if the lattice assumption is broken.

[0063] S202: Perform a quantum key distribution process through a quantum channel to obtain a quantum random number seed, and store the quantum random number seed in a quantum seed cache.

[0064] Furthermore, after obtaining the initial shared key, in order to avoid the lattice assumption being broken by new mathematical methods or more powerful quantum algorithms, thus posing a security risk to communication, the communication sender can perform the quantum key distribution process through a quantum channel.

[0065] Specifically, QKD requires two channels: a quantum channel for transmitting quantum states and a classical channel for post-processing operations such as basis vector alignment, bit error rate estimation, error correction, and privacy amplification to obtain the quantum random number seed. Figure 5 As shown.

[0066] Figure 5 This is a schematic diagram of a quantum key distribution process provided in an exemplary embodiment.

[0067] Combination Figure 5It can be seen that the quantum key distribution process can be divided into a quantum transmission stage and a post-processing stage. In the quantum transmission stage, the transmitting end can prepare a series of photons in specific polarization or phase states and send them to the receiving end through a quantum channel. This allows the receiving end to randomly select a measurement basis to measure the received photons and record the measurement results. Due to the no-cloning principle of quantum mechanics, any attempt by a third party to eavesdrop on the quantum channel will inevitably introduce disturbances, leading to an increase in the bit error rate between the communicating parties.

[0068] Specifically, the transmitting end can send a series of photons to the receiving end, such as randomly selecting photon sequences with horizontal, vertical, 45-degree, or 135-degree polarization states. In this case, the measurement base mentioned above is a polarizer with a specific transmission axis direction. When the vibration direction of the photon is parallel to the transmission axis direction of the polarizer, the photon can pass through the polarizer smoothly and be received by the detector (recorded as the corresponding bit value). When the vibration direction of the photon is perpendicular to the transmission axis direction of the polarizer, the photon is blocked and cannot pass through. If the vibration direction of the photon is at a certain angle to the transmission axis (such as 45 degrees), the photon passes through or does not pass through in a probabilistic manner, and after passing through, its vibration direction will collapse to the transmission axis direction of the polarizer.

[0069] Therefore, when a third party attempts to eavesdrop on a quantum channel, since they cannot know the exact polarization state of each photon in advance, they can only randomly select a polarizer for measurement. This random measurement not only leads to a large number of errors in the information obtained by the eavesdropper, but also irreversibly changes the original polarization state of the photons. Consequently, when these disturbed photons reach the communication receiver, even if the receiver selects the correct measurement basis, it may still obtain incorrect measurement results because the photon state has been altered by the eavesdropper. This results in a significant increase in the bit error rate when the two communicating parties compare their data, thus exposing the eavesdropping behavior.

[0070] Furthermore, after the measurement is completed at the receiving end, the sending and receiving ends can exchange information through a classical channel to coordinate key generation. First, the sending and receiving ends publicly disclose their respective measurement bases through the classical channel, retaining bits with the same measurement base to form an initial key string (Sifted Key). Next, both parties randomly select bits from the initial key string for public comparison to estimate the quantum bit error rate (QBER). If the QBER is lower than a preset security threshold, the channel is secure, and subsequent steps can continue; otherwise, the QKD process is terminated.

[0071] Subsequently, both parties use error correction protocols (such as LDPC codes or Cascade protocols) to eliminate inconsistent bits in the original key string, obtaining a consistent error-corrected key. Finally, to eliminate any information that an attacker might obtain, both parties perform privacy amplification, compressing the error-corrected key into a shorter final key, i.e., a quantum random number seed, using a hash function.

[0072] For example, suppose the transmitting and receiving ends obtain an original key string of 10,000 bits after basis vector alignment. They randomly select 1,000 bits for public comparison and find 5 inconsistent bits, calculating the quantum bit error rate (QBER) to be 0.5%. If the preset security threshold is 2%, since 0.5% is below 2%, both parties determine the channel is secure.

[0073] Subsequently, the sending and receiving ends can correct the remaining 9,000 bits to ensure that the keys held by both ends are completely consistent. Finally, to eliminate the influence of any small amount of information that an eavesdropper might obtain by intercepting some photons or listening to classical channels, the communicating parties can agree to use a specific hash function (such as SHA-256 or a general hash family based on the Toeplitz matrix) to compress the 9,000-bit error-corrected key into a final 256-bit key. This 256-bit key is the final quantum random number seed.

[0074] It is important to emphasize that the quantum random number seed generated in this specification is not used directly for data encryption, but rather as a high-entropy random input in the key derivation process, i.e., the quantum random number seed, to generate the session key. This is because in quantum key distribution technology, there is a strict constraint relationship between the statistical security parameter (ε) of key generation and the output key length (ℓ) (i.e., the ε-ℓ seesaw effect).

[0075] This can be understood as follows: if extremely high statistical security (i.e., extremely small ε) is desired, the length of the output key must be drastically compressed; conversely, if one attempts to directly generate a long keystream for encrypting large amounts of data using QKD, statistical security will significantly decrease, failing to meet classical cryptographic standards. Therefore, if QKD-generated keys are used directly for data encryption (such as in one-time keybook mode), either the key length is insufficient to cover a large amount of data, or the security is reduced to an unacceptable level due to forcibly increasing the length. Furthermore, the real-time yield requirements of the quantum channel are extremely high, making it difficult to continuously supply in constrained scenarios such as satellite overpasses. Therefore, in this specification, it is used as a fixed-length (e.g., 256-bit) random entropy source.

[0076] Furthermore, while the classical channel can be a public channel during quantum key distribution (QKD security primarily relies on the physical properties of quantum states and subsequent privacy amplification processes to eliminate eavesdropping), to further reduce the risk of side-channel leakage, prevent attackers from inferring the quantum channel state by analyzing the classical channel's communication patterns (such as message length and time intervals), and enhance the protection of sensitive post-processing data such as error correction checkers, the communication sender can also use an initial shared key to encrypt and authenticate the interactive data on the classical channel (such as basis vector alignment information, bit error rate estimation data, error correction checkers, etc.). This constructs an encrypted authentication channel, ensuring that even if an attacker intercepts the classical channel data, they cannot obtain any auxiliary information that could help crack the quantum key.

[0077] Furthermore, since symmetric encryption algorithms are more resistant to quantum computing than asymmetric encryption algorithms, they can ensure that the confidentiality of historical communication data can still be guaranteed even when quantum computers mature in the future.

[0078] Based on this, after generating an initial shared key, the transmitting and receiving ends can also use this initial shared key to protect the interactive data on the classical channel, thereby constructing an encrypted authentication channel for post-processing of quantum key distribution. Specifically, the transmitting and receiving ends can derive the channel key based on the initial shared key using a preset key derivation function. This key derivation function can be an HMAC-based Key Derivation Function (HKDF), or other derivation functions capable of key extraction and expansion; this specification does not impose any restrictions on this.

[0079] In one embodiment, the derived channel key can be a 256-bit symmetric key. The transmitting and receiving ends can use this channel key to encrypt and authenticate the service data and control signaling subsequently transmitted over the classical channel in AES-256-GCM mode. This control signaling may include basis vector alignment information, bit error rate estimation data, error correction checksums, privacy amplification parameters, and other interactive data related to quantum key distribution post-processing.

[0080] By employing the above methods, even if an attacker intercepts the transmission content on a classical channel, it will be difficult to directly obtain auxiliary information related to the quantum key distribution state. This helps reduce the risk of side-channel analysis and enhances the protection of post-processing interaction data. Furthermore, because this protection method uses a symmetric key system, it is more resistant to quantum attacks than asymmetric encryption methods. Therefore, even if quantum computing capabilities further improve in the future, the confidentiality and integrity of historical interaction data in the classical channel can still be guaranteed.

[0081] It should be noted that the physical implementation of quantum channels is not limited to a single medium. In this specification, quantum channels can be implemented in various ways, such as: ground point-to-point links based on optical fibers, ground wireless links based on free-space optical communication, and satellite-to-ground or inter-satellite links based on satellite relay, etc.

[0082] For fiber-optic ground point-to-point links, the transmitting and receiving ends can directly establish a quantum signal transmission channel via dedicated optical fibers. This method is suitable for quantum key distribution between relatively fixed communication nodes, especially for short to medium distance scenarios. However, due to fiber optic transmission loss and relay capacity limitations, this method has high deployment costs for longer transmission distances, limiting its applicability.

[0083] For terrestrial wireless links based on free-space optical communication, the communicating parties can directly transmit quantum signals through beams of light in the atmosphere. This method eliminates the need for laying dedicated optical fibers, offering high deployment flexibility and making it suitable for temporary, mobile, or line-of-sight communication scenarios. However, this method is susceptible to weather conditions, environmental turbulence, and line-of-sight limitations, thus restricting its stability.

[0084] For satellite-to-ground or inter-satellite links based on satellite relay, a quantum satellite can act as a relay node or associated auxiliary node in the quantum key distribution process. It establishes a quantum link with the transmitting end when passing over it, and with the receiving end when passing over it. Due to the temporal nature of satellite orbits, this method typically involves a geographically and temporally separate quantum key distribution process. This means that the transmitting and receiving ends do not need to be simultaneously within the satellite's field of view or directly visible to each other. After completing quantum key distribution with both ends, the satellite can also send synchronization information or association identifiers via classical channels to assist both parties in determining the corresponding target quantum random number seed from their respective cached quantum random number seeds.

[0085] It should be noted that in practical applications, due to the limitations of transmission loss and relay technology, terrestrial fiber optic links are usually only suitable for short-distance fixed-node communication, which is difficult to meet the needs of long-distance secure communication across regions, countries, or even the globe; while free-space optical communication is easily affected by weather and line-of-sight limitations. Therefore, satellite-based ground or inter-satellite links have become the main choice for realizing wide-area quantum secure communication.

[0086] However, satellite links typically have a clear time window limitation, meaning that the satellite can only establish a valid quantum link with the ground node during a specific transit period. In this case, if the system requires new quantum random materials to be acquired in real time each time a communication session is established, it may result in the inability to obtain new quantum random number seeds in a timely manner during the satellite's non-transit period, thus affecting the continuity of communication.

[0087] Based on this, after performing the quantum key distribution process and obtaining the quantum random number seed through the quantum channel, the communication sender and receiver can also allocate and cache the generation results according to the relationship between the total number of quantum random number seeds generated in a single quantum key distribution process and the preset seed requirement threshold.

[0088] Specifically, if the total number of quantum random number seeds generated in a single quantum key distribution process is greater than the preset seed requirement threshold, then the quantum random number seeds that meet the seed requirement threshold can be used as the target quantum random number seeds, and the remaining quantum random numbers can be stored in the quantum seed cache as backup seeds; if the total number of quantum random number seeds generated in a single quantum key distribution process is not greater than the preset seed requirement threshold, then all the generated quantum random numbers can be used as the target quantum random number seeds and stored in the quantum seed cache for use in subsequent sessions.

[0089] For example, in a satellite quantum key distribution process, after error estimation, error correction, and privacy amplification, the total amount of quantum random number seeds generated in a single operation may be greater than the length of random numbers required for a single round of session key generation. For example, the quantum random number seeds generated in a single operation may reach 1100 bits or even more, while a single round of session key generation only requires a portion of these quantum random number seeds. For example, the quantum random number seeds required to generate a round of AES-256 session key meet the key length requirement of symmetric encryption algorithms, which is 256 bits.

[0090] Therefore, the transmitting and receiving ends extract these 256 bits for generating the current or next round of session keys, while the remaining 844 bits are securely stored as a backup seed in the quantum seed buffer. These backup seeds can be used in rotation for multiple communication sessions during subsequent hours or even days when the satellite is not passing overhead. This ensures that even without real-time quantum link support, a forward security level based on quantum randomness can still be maintained, avoiding the risk of being forced to revert to PQC mode or stop communication due to a temporary interruption of the QKD link.

[0091] It should be noted that the aforementioned satellite transit window limitation refers to the typically short visible time of low-orbit quantum satellites relative to fixed ground stations, with a single effective communication session generally lasting only a few minutes to a dozen minutes. Furthermore, since the transmitting and receiving ends are usually located at different positions, the quantum satellite's transit times over the two ends are not consistent, resulting in a significant time difference between their corresponding available time windows, which can sometimes be quite long. Under these conditions, if the quantum key distribution process relies on both communicating parties being simultaneously online and completing real-time synchronous interaction, it is often difficult to implement directly in a satellite scenario. Moreover, during the satellite's non-transit period, the communicating parties cannot acquire new quantum random materials in real time, which may lead to subsequent session keys not receiving new quantum random number seeds in a timely manner, thus affecting communication continuity and forward security capabilities.

[0092] Therefore, in order to overcome the above problems, in addition to managing the quantum random number seed generated in a single quantum key distribution process through the quantum seed cache area mentioned above, so as to continuously provide quantum random material for session key generation during satellite non-overpass periods, a remote and time-separated processing method can also be used to complete the acquisition of quantum random number seeds.

[0093] Specifically, the communication transmitter and receiver can establish quantum links with the same quantum satellite at different times. When the first quantum satellite passes over the communication transmitter during a first time period, the transmitter can perform a quantum key distribution process with the first quantum satellite based on the quantum channel to generate a first quantum random number seed, which is then stored in the transmitter's quantum seed buffer. Subsequently, when the first quantum satellite passes over the receiver during a second time period, the receiver can perform a quantum key distribution process with the first quantum satellite based on the quantum channel to generate a second quantum random number seed, which is also stored in the receiver's quantum seed buffer. The first and second time periods are different.

[0094] Based on this, the communication transmitter and receiver can control the first quantum satellite to relay synchronization information to the communication transmitter and receiver through a classical channel, so that the communication transmitter and receiver can generate a consistent target quantum random number seed based on their respective cached quantum random number seeds.

[0095] The synchronization information can be understood as information used to indicate the correspondence between the quantum random number seeds on the transmitting end and the quantum random number seeds on the receiving end. In one embodiment, the synchronization information may include an association identifier, or may be composed of association identifiers. That is, the association identifier is a specific content in the synchronization information, used to uniquely identify a set of corresponding quantum random number seeds.

[0096] Specifically, after the first quantum satellite completes quantum key distribution and generates a first quantum random number seed with the communication transmitter in the first time period, and after completing quantum key distribution and generating a second quantum random number seed with the communication receiver in the second time period, the first quantum satellite can establish a correspondence between the first and second quantum random number seeds and assign a unique association identifier to this correspondence. This association identifier can be a number, label, index value, timestamp, or a combination thereof, as long as it can characterize that the first and second quantum random number seeds belong to the same set of correspondences. In other words, the same association identifier corresponds to a pairing relationship between a set of quantum random number seeds on the communication transmitter side and a set of quantum random number seeds on the communication receiver side.

[0097] Based on this, the communication transmitter can obtain the synchronization information transmitted by the first quantum satellite through a classical channel and parse the corresponding association identifier from the synchronization information. Subsequently, the communication transmitter can retrieve the first quantum random number seed corresponding to the association identifier from its quantum seed buffer based on the association identifier, and determine the first quantum random number seed as the target quantum random number seed.

[0098] Simultaneously, the first quantum satellite can also send the same synchronization information to the communication receiver via a classical channel, or send synchronization information containing the same association identifier. Upon receiving this synchronization information, the communication receiver can parse out the same association identifier and, based on this identifier, retrieve the second quantum random number seed corresponding to that identifier from the communication receiver's quantum seed buffer, thus identifying this second quantum random number seed as the corresponding target quantum random number seed.

[0099] In this way, although the transmitting and receiving ends complete quantum key distribution with the first quantum satellite at different time periods, and their respective quantum seed buffers may contain multiple sets of quantum random number seeds, they can still accurately locate the same set of corresponding quantum random number seeds in their respective buffers using the synchronization information sent by the first quantum satellite through a classical channel. Therefore, there is a pre-established correspondence between the target quantum random number seed determined by the transmitting end and the corresponding target quantum random number seed determined by the receiving end, thus supporting the consistent generation of subsequent session keys.

[0100] For example, the first quantum satellite can assign a transmitter-side local identifier to a first quantum random number seed obtained from a quantum key distribution with a communication transmitter, and assign a receiver-side local identifier to a second quantum random number seed obtained from a quantum key distribution with a communication receiver. Furthermore, a unified association identifier is established between these two local identifiers. Subsequently, the first quantum satellite can send synchronization information containing this association identifier to both the communication transmitter and the communication receiver. The communication transmitter and the communication receiver can then retrieve their respective quantum random number seeds from their local quantum seed buffers based on this association identifier.

[0101] As can be seen from the above, by introducing the first quantum satellite as a trusted relay or synchronization node, not only is the problem of spatiotemporal asynchrony solved, but the physical isolation characteristics of the satellite-to-ground link also make it difficult for attackers to simultaneously eavesdrop on both the first quantum satellite and the communication transmitter, and the two independent quantum links of the first quantum satellite and the communication receiver. This significantly improves the anti-attack capability of the quantum key distribution system. Even if a segment of the ground fiber optic or free-space link is subject to local interference or eavesdropping, as long as the other link remains secure, a secure shared key can still be generated through subsequent privacy amplification processing.

[0102] In addition, to reduce reliance on a single quantum satellite, the communication transmitter and receiver can perform the quantum key distribution process through different quantum satellites in multiple different time windows to obtain multiple sets of quantum random number seeds generated by different quantum satellites, and store these quantum random number seeds in the quantum seed cache.

[0103] When establishing a communication session, the sending and receiving ends can select the target quantum random number seed corresponding to the current session from the quantum seed cache according to a preset extraction strategy.

[0104] The extraction strategy described above can be implemented in various ways. For example, it can be extracted according to the generation time order of the quantum random number seeds, or it can be extracted in rotation according to the satellite identifiers corresponding to different quantum satellites. Alternatively, it can be randomly selected or a group of quantum random number seeds from multiple quantum random number seeds that meet the validity conditions as the target quantum random number seed. This specification does not limit the specific extraction strategy, as long as the communication transmitter and the communication receiver can determine their corresponding quantum random number seeds based on consistent rules.

[0105] In other words, the sending and receiving ends of the communication can use the same extraction strategy to select the target quantum random number seed and its corresponding counterpart from their respective quantum seed buffers for the current session, in order to generate the current session key. Thus, even if the quantum seed buffers simultaneously store multiple sets of quantum random number seeds from multiple quantum satellites, the two communicating parties can still complete the seed selection and mapping according to a unified rule.

[0106] In this way, the quantum seed cache can simultaneously store quantum random number seeds from multiple quantum satellites, thus ensuring that the source of the target quantum random number seed is no longer fixed to a single satellite node. This means that even if a quantum satellite malfunctions, is attacked, or its corresponding link becomes temporarily unavailable, the system can still utilize quantum random number seeds generated and cached by other quantum satellites to participate in subsequent session key generation. Furthermore, even if a specific satellite is controlled by an attacker or its generated key sequence has potential flaws, the attacker cannot predict which satellite's seed the communicating parties will ultimately choose, thus preventing targeted attacks.

[0107] S204: Based on the communication session establishment request, extract the target quantum random number seed from the quantum seed buffer.

[0108] After generating and caching the quantum random number seed, the communication sender and receiver can extract the target quantum random number seed required for the current session from their respective quantum seed caches when they receive a communication session establishment request, for use in the subsequent generation of the current session key.

[0109] In one embodiment, the communication transmitter and receiver can timestamp each quantum random number seed stored in the quantum seed buffer. Correspondingly, upon receiving a communication session establishment request, the communication transmitter and receiver can select quantum random number seeds within a preset threshold range from the quantum seed buffer based on the difference between the current timestamp and the timestamp corresponding to each quantum random number seed, and use the selected quantum random number seeds as target quantum random number seeds.

[0110] In addition, at specified time intervals, the communication transmitter and receiver can also filter out quantum random number seeds in the quantum seed cache that have been stored for longer than a preset time limit.

[0111] Furthermore, in practical applications, the extraction process in step S204 can be flexibly handled in conjunction with the security requirements of different communication sessions. That is, the communication sender and receiver can establish requests for different communication sessions and adopt different extraction strategies or security level strategies to achieve dynamic matching between communication security levels and quantum resource usage.

[0112] For example, for communication sessions with high security requirements, the sending and receiving ends can, upon receiving a communication session establishment request, prioritize retrieving a target quantum random number seed that meets the timeliness requirements from the quantum seed buffer. This target quantum random number seed, along with the initial shared key or the previous session key, can then be input into the key derivation function during the subsequent generation of the current session key, injecting new quantum randomness into the current session key. For communication sessions with relatively low security requirements, the sending and receiving ends can also reduce the consumption of quantum random number seeds according to system policies, or, when system configuration conditions are met, not retrieve a new quantum random number seed from the quantum seed buffer, but instead use existing shared key materials to generate the current session key. This approach improves the utilization efficiency of quantum random materials while ensuring the security of critical communications.

[0113] Based on this, when the quantum seed buffer is empty, the communication transmitter and receiver can enter a processing mode independent of the current quantum random number seed. Specifically, the transmitter and receiver can directly input the initial shared key into the key derivation function to generate the current session key, or re-execute the initial key negotiation based on the post-quantum cryptography algorithm to generate a new shared key, and then input that shared key into the key derivation function to generate the current session key. In this way, even if the quantum random number seed in the quantum seed buffer is exhausted, the system can still continue to establish a communication session without directly interrupting communication due to a temporary lack of quantum random material.

[0114] Therefore, by combining timestamp management, expiration filtering, and session-level extraction strategies in step S204, the management efficiency of the quantum seed cache can be improved, and the extraction of the target quantum random number seed can be flexibly determined according to the security requirements of different communication sessions, thereby providing more stable and adjustable support for the generation of the current session key.

[0115] S206: Generate the current session key using the key derivation function based on the initial shared key or the previous session key, and the target quantum random number seed.

[0116] Furthermore, if the current session is the first round of communication between the sending end and the receiving end, the initial shared key and the target quantum random number seed can be input into the key derivation function to obtain the current session key.

[0117] If the current session is not the first session, the sending and receiving ends can input the previous session key and the target quantum random number seed into the key derivation function to obtain the current session key, as follows: Figure 6 As shown.

[0118] Figure 6 This is a schematic diagram of the current session key generation process provided in an exemplary embodiment.

[0119] Combination Figure 6 As can be seen, for the first round of the session, the sending and receiving ends of the communication take the initial shared key KPQC generated in step S200 and the target quantum random number seed Squantum extracted from the quantum seed buffer as input parameters and input them into the key derivation function (such as HKDF). After hash operation, the output is the first round session key Ksession1. For the Nth round of the session, the sending and receiving ends of the communication take the session key KsessionN-1 generated at the end of the previous round (i.e., the N-1th round) and the newly extracted target quantum random number seed Squantum as input parameters and input them into the same key derivation function. After hash operation, the output is the current Nth round session key KsessionN.

[0120] Therefore, because the previous session key can be used as one of the input factors for key derivation, the generation of the current session key not only depends on the secret or quantum randomness of the initial negotiation but is also tightly bound to the security state of the previous communication. This means that even if an attacker cracks the initial shared key or obtains the quantum random number seed of a certain round at some point in the future, due to the one-way nature of the hash function, the attacker cannot reverse-engineer the session key of any previous round. Each session key is independent and irreversible; the leakage of an old key will not jeopardize the security of historical communication data.

[0121] Furthermore, in order to achieve rapid reconnection after a brief interruption or jitter in the communication link, and to avoid the additional delay and computational overhead introduced by re-executing the time-consuming PQC initial handshake protocol (such as key encapsulation and decapsulation), when the communication link is detected to be interrupted and reconnected, the session key used in the previous round of the session can be reused as the current shared key. Then, the quantum key distribution process can be performed to obtain a new target quantum random number seed, and a new session key can be generated based on the current shared key and the new target quantum random number seed.

[0122] S208: Data transmission is performed based on the current session key.

[0123] After generating the current session key, the sending and receiving ends can transmit data based on it. Specifically, the sending end can use the current session key to perform encryption and integrity protection on the service data to be sent, generating corresponding ciphertext data, which is then sent to the receiving end via a classic channel. Upon receiving the ciphertext data, the receiving end can verify and decrypt it based on the same current session key, thereby recovering the service data sent by the sending end.

[0124] In one embodiment, the current session key can be directly used as the key for the symmetric encryption process. Furthermore, in other embodiments, different subkeys for data encryption and integrity authentication can be derived from the current session key to perform encryption and authentication processes respectively. This specification does not limit this, as long as the sending and receiving ends can complete data protection and data recovery based on consistent key usage rules.

[0125] In actual data transmission, the current session key can be applied to various types of data interaction. For example, it can be used to protect business messages, control signaling, state synchronization data, or session management data. This not only ensures the confidentiality of business data during transmission but also improves the integrity and tamper resistance of related communication content.

[0126] Furthermore, after a communication session ends, or when the preset key update conditions are met during communication, the communication sender and receiver can re-execute steps S204 to S206 to extract a new target quantum random number seed from the quantum seed buffer and generate a new current session key based on the new target quantum random number seed and the initial shared key or the previous session key.

[0127] The preset key update conditions mentioned above may include reaching a preset data transmission volume threshold, reaching a preset session duration threshold, detecting a link reconnection event, or system policy requiring a session key refresh.

[0128] The above method enables dynamic rolling of session keys, allowing different current session keys to correspond to different time periods or different data transmission stages. In this way, even if the current session key is leaked at a certain moment, its impact can usually be limited to the corresponding session or transmission interval, thereby reducing the impact of a single key leak on overall communication security.

[0129] Figure 7 This is a schematic structural diagram of a device provided in an exemplary embodiment. For example... Figure 7As shown, device 700 mainly consists of a communication interface 702, a user interface 704, a processor 706, and a data storage 708. These components are interconnected and communicate with each other via a system bus, network, or other connection mechanism 710. Communication interface 702 enables device 700 to communicate with other devices, access networks, and transmission networks via analog or digital modulation. For example, communication interface 702 may include a chipset and antenna for wireless communication with a radio access network or access point. Furthermore, communication interface 702 can be a wired interface such as Ethernet, Token Ring, or a USB port, or a wireless interface such as Wi-Fi, Bluetooth, Global Positioning System (GPS), or a wide-area wireless interface (e.g., WiMAX or LTE). Of course, communication interface 702 can also support other forms of physical layer interfaces and standard or proprietary communication protocols. Communication interface 702 may also include multiple physical communication interfaces, such as Wi-Fi, Bluetooth, and wide-area wireless interfaces.

[0130] User interface 704 includes receiving user input and providing output to the user. Therefore, user interface 704 may include input components such as a keypad, keyboard, touch-sensitive or presence-sensitive panel, computer mouse, trackball, joystick, microphone, still camera, and video camera, and output components such as a display screen (which may be combined with a touch-sensitive panel), CRT, LCD, LED, display using DLP technology, printer, and other similar devices known or developed in the future. User interface 704 may also generate auditory output via speakers, speaker jacks, audio output ports, audio output devices, headphones, and other similar devices known or developed in the future. In some embodiments, user interface 704 may include software, circuitry, or other forms of logic capable of transmitting and receiving data from external user input / output devices. Additionally or alternatively, device 700 may support remote access from other devices via communication interface 702 or another physical interface (not shown). User interface 704 may be configured to receive user input, the position and movement of which may be indicated by indicators or cursors described herein. User interface 704 may also be configured as a display device for rendering or displaying text fragments.

[0131] Processor 706 may contain one or more general-purpose processors and / or special-purpose processors.

[0132] Data storage 708 may include one or more volatile and / or non-volatile storage components and may be integrated wholly or partially with processor 706. Data storage 708 may include removable and non-removable components.

[0133] Processor 706 is capable of executing program instructions 718 (e.g., compiled or uncompiled program logic and / or machine code) stored in data storage 708 to perform the various functions described herein. Data storage 708 may contain a non-transitory computer-readable medium on which program instructions are stored, which, when executed by device 700, enable device 700 to perform any methods, processes, or functions disclosed in this specification and / or the accompanying drawings. Processor 706 executing program instructions 718 may result in processor 706 using data 712.

[0134] For example, program instructions 718 may include an operating system 722 (e.g., an operating system kernel, device drivers, and / or other modules) installed on device 700 and one or more applications 720 (e.g., a browser, social application, or game application). Similarly, data 712 may include operating system data 716 and application data 714. Operating system data 716 is primarily accessible to the operating system 722, while application data 714 is primarily accessible to one or more applications 720. Application data 714 may reside in a file system visible or hidden from the user of device 700.

[0135] Application 720 can communicate with operating system 722 through one or more application programming interfaces (APIs). These APIs help application 720 read and / or write application data 714, transmit or receive information via communication interface 702, receive or display information on user interface 704, etc.

[0136] In some terminology, application 720 may be simply referred to as "app". Furthermore, application 720 can be downloaded to device 700 through one or more online app stores or app markets. However, applications can also be installed on device 700 in other ways, such as through a web browser or a physical interface on device 700 (e.g., a USB port).

[0137] Please refer to Figure 8 Secure communication devices can be applied to, for example Figure 7 The device shown implements the technical solution described in this specification. The secure communication device may include: The first-round negotiation module 801 is used to perform initial key negotiation based on post-quantum cryptography algorithm and generate initial shared key; The random seed generation module 802 is used to perform a quantum key distribution process through a quantum channel, obtain a quantum random number seed, and store the quantum random number seed in a quantum seed cache. Extraction module 803 is used to extract a target quantum random number seed from the quantum seed cache according to a communication session establishment request; The generation module 804 is used to generate the current session key based on the initial shared key or the previous round session key and the target quantum random number seed through the key derivation function; The data transmission module 805 is used to transmit data based on the current session key.

[0138] Optionally, the random seed generation module 802 is further configured to determine whether the total number of quantum random number seeds generated in a single quantum key distribution process is greater than a preset seed requirement threshold; if so, the quantum random number seeds that meet the seed requirement threshold are used as the target quantum random number seeds, and the remaining quantum random numbers are used as backup seeds.

[0139] Optionally, the random seed generation module 802 is further configured to timestamp each quantum random number seed stored in the quantum seed cache; The extraction module 803 is specifically used to extract a quantum random number seed from the quantum seed cache whose difference between the corresponding marked timestamp and the current timestamp is within a preset threshold, and use it as the target quantum random number seed.

[0140] Optionally, the random seed generation module 802 is further configured to filter out quantum random number seeds in the quantum seed cache that have been stored for a longer time than a preset timeout threshold at specified time intervals.

[0141] Optionally, the generation module 804 is specifically used to generate a first-round session key in the first communication session based on the initial shared key or the previous round session key and the target quantum random number seed through a key derivation function; and to generate a current session key in subsequent communication sessions based on the session key used in the previous round of communication sessions and the currently extracted target quantum random number seed through a key derivation function.

[0142] Optionally, the data transmission module 805 is further configured to, when a communication link is reconnected after an interruption is detected, reuse the session key used in the previous session as the current shared key; perform a quantum key distribution process to obtain a new target quantum random number seed; and generate a new session key based on the current shared key and the new target quantum random number seed.

[0143] Optionally, the random seed generation module 802 is specifically configured to: During a first time period over the first quantum satellite's overpass communication transmitter, perform quantum key distribution with the first quantum satellite based on a quantum channel to generate a first quantum random number seed and store it in the quantum seed buffer of the communication transmitter; During a second time period over the first quantum satellite's overpass communication receiver, perform quantum key distribution with the communication receiver based on a quantum channel through the first quantum satellite to generate a second quantum random number seed and store it in the quantum seed buffer of the communication receiver; The first time period and the second time period do not overlap; Obtain synchronization information relayed by the first quantum satellite based on a classical channel, and based on the synchronization information, determine a target quantum random number seed from multiple quantum random number seeds cached in the quantum seed buffer of the communication transmitter, and enable the communication receiver to determine the corresponding target quantum random number seed based on the synchronization information.

[0144] Optionally, the first quantum satellite stores the association identifier between the first quantum random number seed and the second quantum random number seed; The random seed generation module 802 is specifically used to: obtain the association identifier transmitted by the first quantum satellite based on a classical channel; retrieve the first quantum random number seed corresponding to the association identifier from the quantum seed buffer of the communication transmitter based on the association identifier, and determine it as the target quantum random number seed; and transmit the association identifier to the communication receiver through the first quantum satellite based on a classical channel, so that the communication receiver retrieves the second quantum random number seed corresponding to the association identifier from the quantum seed buffer of the communication receiver based on the received association identifier, and determines it as the corresponding target quantum random number seed.

[0145] Optionally, the random seed generation module 802 is specifically used to perform a quantum key distribution process with the communication receiver through different quantum satellites in multiple different time windows to obtain multiple sets of quantum random number seeds generated by relays from different quantum satellites; and to store the multiple sets of quantum random number seeds and their corresponding satellite identifiers and / or time identifiers in the quantum seed buffer of the communication transmitter.

[0146] Optionally, the extraction module 803 is further configured to, when the quantum seed buffer is empty, input the initial shared key or the shared key regenerated by the post-quantum cryptography algorithm into the key derivation function to generate the current session key.

[0147] Optionally, the first-round negotiation module 801 is specifically used to: perform initial key negotiation based on post-quantum cryptography algorithm to generate candidate shared keys; the candidate shared keys adopt a lattice-based key encapsulation mechanism; perform a hash-based digital signature algorithm to authenticate the communication sender and the communication receiver during the initial key negotiation process; if the authentication determines that the communication sender and the communication receiver are not abnormal, then the candidate shared key is used as the initial shared key.

[0148] For ease of description, the above devices are described by dividing them into various modules or units based on their functions. Of course, when implementing one or more of these specifications, the functions of each module or unit can be implemented in the same or different software and / or hardware, or a module that performs the same function can be implemented by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0149] Based on the same concept as the methods described above, this specification also provides an electronic device, including: a processor; a memory for storing processor-executable instructions; wherein the processor performs the steps of the method as described in any of the above embodiments by executing the executable instructions.

[0150] Based on the same concept as the methods described above, this specification also provides a computer-readable storage medium having computer instructions stored thereon that, when executed by a processor, implement the steps of the methods as described in any of the above embodiments.

[0151] Based on the same concept as the methods described above, this specification also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the methods as described in any of the above embodiments.

[0152] What those skilled in the art will understand is: In this specification, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitation, the presence of additional identical or equivalent elements in a process, method, product, or apparatus that includes said elements is not excluded.

[0153] In this specification, “a,” “an,” and “the” do not specifically refer to the singular, but may also include the plural.

[0154] In this specification, ordinal numbers such as "first," "second," etc., do not necessarily indicate order; they are often used to distinguish between objects. For example, "first server" and "second server" usually refer to two servers. To differentiate between these two servers, they are described as "first server" and "second server." Of course, sometimes these two servers may be the same server.

[0155] In this specification, unless explicitly stated otherwise, "receiving and sending data" does not necessarily mean direct receiving and sending; it can also mean indirect receiving and sending. For example, A receiving data sent by B can be understood as A directly receiving the data sent by B, or it can be understood as A indirectly receiving the data sent by B through other entities such as C. Similarly, B sending data to A can be understood as B sending the data directly to A, or it can be understood as B indirectly sending the data to A through other entities such as C. Here, C can be one entity, or it can be two or more entities.

[0156] In this specification, unless explicitly stated otherwise, the relationships between structures can be direct or indirect. For example, when describing "A is connected to B," unless it is explicitly stated that A and B are directly connected, it should be understood that A can be directly connected to B or indirectly connected to B. Similarly, when describing "A is on top of B," unless it is explicitly stated that A is directly above B (AB is adjacent and A is above B), it should be understood that A can be directly above B or indirectly above B (AB is separated by other elements, and A is above B). And so on.

[0157] This specification uses specific terms to describe embodiments thereof. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples, without contradiction.

[0158] Although one or more embodiments of this specification provide method steps as described in the embodiments or flowcharts, it is understood that the order of steps listed in the embodiments or flowcharts is only one of many possible execution orders and does not represent the only execution order. Therefore, when the claims involve method steps, any changes or adjustments to the order of such steps, or the parallelism between steps, are also within the scope of protection of the claims.

Claims

1. A secure communication method, comprising: Perform initial key negotiation based on post-quantum cryptography algorithm to generate initial shared key; The quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, and the quantum random number seed is stored in a quantum seed cache. Based on the communication session establishment request, the target quantum random number seed is extracted from the quantum seed cache. The current session key is generated using a key derivation function based on the initial shared key or the previous session key, and the target quantum random number seed; Data transmission is performed based on the current session key.

2. The method of claim 1, further comprising: Determine whether the total number of quantum random number seeds generated in a single quantum key distribution process exceeds a preset seed requirement threshold; If so, the quantum random number seed that meets the seed requirement threshold is used as the target quantum random number seed, and the remaining quantum random numbers are used as backup seeds.

3. The method of claim 1, further comprising: Each quantum random number seed stored in the quantum seed cache is timestamped; Extracting the target quantum random number seed from the quantum seed cache specifically includes: The quantum random number seed whose difference between the corresponding marked timestamp and the current timestamp is within a preset threshold is extracted from the quantum seed cache and used as the target quantum random number seed.

4. The method of claim 3, further comprising: At specified time intervals, quantum random number seeds that have been stored in the quantum seed cache for longer than a preset timeout threshold are filtered out.

5. The method as described in claim 1, wherein the current session key is generated by a key derivation function based on the initial shared key or the previous round session key, and the target quantum random number seed, specifically includes: In the initial communication session, the first-round session key is generated using a key derivation function based on the initial shared key or the previous session key, and the target quantum random number seed; In subsequent communication sessions, the current session key is generated using the key derivation function based on the session key used in the previous communication session and the currently extracted target quantum random number seed.

6. The method of claim 5, further comprising: When a communication link is detected to be interrupted and reconnected, the session key used in the previous session is reused as the current shared key. Perform a quantum key distribution process to obtain a new target quantum random number seed; A new session key is generated based on the current shared key and the new target quantum random number seed.

7. The method of claim 1, wherein the quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, comprising: During a first time period over the first quantum satellite's overpass communication transmitter, quantum key distribution is performed with the first quantum satellite based on the quantum channel to generate a first quantum random number seed and store it in the quantum seed buffer of the communication transmitter. During a second time period over the first quantum satellite's overpass communication receiver, the first quantum satellite performs quantum key distribution with the communication receiver based on a quantum channel, generates a second quantum random number seed, and stores it in the quantum seed buffer of the communication receiver; the first time period and the second time period do not overlap; The synchronization information of the first quantum satellite based on classical channel relay is obtained, and based on the synchronization information, a target quantum random number seed is determined from multiple quantum random number seeds cached in the quantum seed buffer of the communication transmitter, and the communication receiver determines the corresponding target quantum random number seed based on the synchronization information.

8. The method of claim 7, wherein the first quantum satellite stores the association identifier of the first quantum random number seed and the second quantum random number seed; Acquiring synchronization information of the first quantum satellite based on classical channel relay, and determining a target quantum random number seed from multiple quantum random number seeds cached in the quantum seed buffer of the communication transmitter based on the synchronization information, and enabling the communication receiver to determine the corresponding target quantum random number seed based on the synchronization information, specifically includes: Obtain the association identifier transmitted by the first quantum satellite via a classical channel; Based on the association identifier, the first quantum random number seed corresponding to the association identifier is retrieved from the quantum seed buffer of the communication transmitter and determined as the target quantum random number seed; The first quantum satellite sends the association identifier to the communication receiver via a classical channel, so that the communication receiver can retrieve the second quantum random number seed corresponding to the association identifier from its quantum seed buffer based on the received association identifier, and determine it as the corresponding target quantum random number seed.

9. The method as described in claim 1, wherein a quantum key distribution process is performed through a quantum channel to obtain a quantum random number seed, and the quantum random number seed is stored in a quantum seed cache, specifically comprising: In multiple different time windows, quantum key distribution processes are performed with the communication receivers via different quantum satellites to obtain multiple sets of quantum random number seeds generated by relays from different quantum satellites. The multiple sets of quantum random number seeds and their corresponding satellite identifiers and / or time identifiers are stored in the quantum seed buffer of the communication transmitter.

10. The method of claim 1, further comprising: When the quantum seed buffer is empty, the initial shared key or the shared key regenerated by the post-quantum cryptography algorithm is input into the key derivation function to generate the current session key.

11. The method as described in claim 1, performing initial key negotiation based on a post-quantum cryptography algorithm to generate an initial shared key, specifically includes: Perform initial key negotiation based on post-quantum cryptography algorithm to generate candidate shared keys; The candidate shared key adopts a lattice-based key encapsulation mechanism; A hash-based digital signature algorithm is executed to authenticate the communication sender and receiver during the initial key negotiation process; If the identity authentication confirms that there are no abnormalities in the communication sender and the communication receiver, then the candidate shared key will be used as the initial shared key.

12. A secure communication device, comprising: The first-round negotiation module is used to perform initial key negotiation based on post-quantum cryptography algorithms and generate an initial shared key; The random seed generation module is used to perform a quantum key distribution process through a quantum channel, obtain a quantum random number seed, and store the quantum random number seed in a quantum seed cache. The extraction module is used to extract the target quantum random number seed from the quantum seed cache according to the communication session establishment request; The generation module is used to generate the current session key based on the initial shared key or the previous round session key and the target quantum random number seed using a key derivation function; The data transmission module is used to transmit data based on the current session key.

13. An electronic device, comprising: processor; A memory for storing processor-executable instructions; wherein the processor implements the steps of the method as described in any one of claims 1-11 by executing the executable instructions.

14. A computer-readable storage medium having stored thereon computer instructions that, when executed by a processor, implement the steps of the method as claimed in any one of claims 1-11.

15. A computer program product comprising a computer program / instructions that, when executed by a processor, implement the steps of the method as claimed in any one of claims 1-11.

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