A quantum alliance-resistant chain system and method based on double-field quantum key distribution

Abstract

The application discloses an anti-quantum alliance chain system and method based on a double-field quantum key distribution, and relates to the technical field of quantum communication and block chain intersection, and the system comprises a terminal node and an untrusted measurement node, wherein the terminal node interacts with the untrusted measurement node through a double-field quantum key distribution protocol to generate an information theory safe symmetric key; the symmetric key is divided into an evidence key and a consensus key according to functions; the terminal node constructs a global authentication vector by using the evidence key; and the terminal node performs information theory safe authentication on a voting message in a Byzantine fault-tolerant consensus process by using the consensus key; the application solves the contradiction between the open auditability and the long-range attack resistance ability under the symmetric key system through a double-key layered strategy, realizes the information theory safe consensus against quantum computing attacks through a Wegman-Carter message authentication mechanism, and is suitable for a high-security level alliance chain system under the threat of quantum computing.

Description

Technical Field

[0001] This invention relates to the field of quantum communication and blockchain technology, specifically to a quantum-resistant consortium blockchain system and method based on dual-field quantum key distribution. Background Technology

[0002] Blockchain technology, with its decentralized, immutable, and traceable characteristics, has been widely applied in finance, supply chain, and judicial evidence preservation. However, with the rapid development of quantum computing technology, existing blockchain systems face severe security threats. Classical blockchain systems rely on asymmetric cryptographic algorithms (such as ECDSA and RSA) for identity authentication and digital signatures, and on hash functions for the integrity of the chain structure. Shor's quantum algorithm can break asymmetric cryptographic systems based on the large integer factorization and discrete logarithm problems in polynomial time, allowing attackers to forge transaction signatures by deriving private keys; Grover's quantum algorithm can perform a second-order accelerated collision search on hash functions, threatening the immutability of the ledger. Therefore, quantum computing poses a fundamental challenge to the security foundation of existing blockchains.

[0003] To address the aforementioned issues, the academic community has proposed various quantum-secure blockchain solutions, mainly categorized into post-quantum cryptography schemes and quantum key distribution schemes. Post-quantum cryptography schemes replace asymmetric cryptographic algorithms with quantum-resistant algorithms based on mathematical problems such as lattices, encoding, and multivariables; however, their security depends on specific computational assumptions and is not information-theoretically secure. Quantum key distribution (QKD) schemes utilize fundamental principles of quantum mechanics to generate information-theoretically secure symmetric keys between legitimate communicating parties, physically resisting eavesdropping attacks of arbitrary strength.

[0004] However, while existing QKD blockchain solutions can achieve non-repudiation and public auditability of transactions through public asymmetric keys, allowing any third party to verify the authenticity of transaction signatures, under a fully symmetric key system, the key pair is secretly shared by the sender and receiver. This makes it impossible to directly prove to a third party that a transaction was indeed signed by the claimed initiator, which is insufficient to meet the functional requirements of consortium blockchains for public auditability and resistance to long-range attacks. Summary of the Invention

[0005] To address the shortcomings of existing QKD blockchain solutions in meeting the functional requirements of non-repudiation and regulatory auditing in consortium blockchains, this invention proposes a quantum-resistant consortium blockchain system and method based on dual-field quantum key distribution. By employing a dual-key hierarchical strategy, it resolves the contradiction between public auditability and resistance to long-range attacks in symmetric key systems, thereby addressing the problems existing in current technologies.

[0006] A quantum-resistant consortium blockchain system based on dual-field quantum key distribution includes: an untrusted measurement node and multiple terminal nodes connected to the untrusted measurement node via quantum fiber links; The untrusted measurement node is used to receive phase-coded weak coherent optical pulses sent by multiple terminal nodes to perform single-photon interferometry and broadcast the measurement results to each terminal node through a public classical channel; Each of the terminal nodes includes: The quantum physics-driven module is used to prepare phase-encoded weakly coherent optical pulses and send them to the untrusted measurement node. Based on the measurement results, quantum post-processing is performed to generate a pairwise information-theoretic secure symmetric key between the target terminal node. The key management module is used to divide the pairwise information-theoretic secure symmetric keys into evidence keys that support delayed disclosure and consensus keys that are destroyed after use, according to their functions. The logical consensus module includes an authentication vector construction submodule and a quantum-safe consensus submodule. The authentication vector construction submodule is used to extract the evidence key and generate corresponding authentication code components for each other terminal node based on the Wegman-Carter message authentication mechanism, and generate a global authentication vector by combining all authentication code components. The quantum-safe consensus submodule is used to extract the consensus key, perform information-theoretic security authentication on the voting messages in the Byzantine fault-tolerant consensus process, and erase all consensus keys used in this consensus after the consensus of the current block is completed.

[0007] Furthermore, the evidence key adopts a cross-block delayed disclosure strategy, specifically including: during the consensus process of the current block, the evidence key is only used locally by the transaction initiating node and the corresponding verification node, and remains confidential; after the current block completes consensus and is locked by the hash value of the subsequent block, the evidence key is packaged into the subsequent block and made public to the entire network, so that any third party can re-verify the true source of historical transactions based on the publicly disclosed evidence key; wherein, the transaction initiating node is the terminal node that initiates the current transaction, and the verification node is other terminal nodes participating in the consensus verification of the current block.

[0008] Furthermore, the consensus key follows the principle of "use and burn," specifically including: after the Byzantine fault-tolerant consensus is completed in the current block, the quantum-safe consensus submodule triggers the key management module to erase all consensus keys consumed in this consensus, including completely deleting them from local memory and persistent storage; and the consensus key is never publicly disclosed to the entire network at any time.

[0009] Further, the extraction of the evidence key and the generation of corresponding authentication code components for each other terminal node based on the Wegman-Carter message authentication mechanism, and the generation of a global authentication vector by combining all authentication code components, specifically includes: the transaction initiating node extracting the corresponding one-time evidence key for each other terminal node; calculating the hash value of the transaction message of the transaction initiating node and the monotonically increasing sequence counter using a hash function belonging to the ε-general hash function family, and combining the hash value with the one-time evidence key through an XOR operation to generate the message authentication code component corresponding to the target terminal node; combining the message authentication code components corresponding to all target terminal nodes to form the global authentication vector and broadcasting it along with the transaction data.

[0010] Furthermore, each message authentication code component in the global authentication vector is independently generated by a different evidence key. The receiving node can only verify its own corresponding message authentication code component and cannot know the evidence keys of other nodes. The upper bound of the probability that an attacker can successfully forge a legitimate global authentication vector in a single instance without evidence keys is... ,in The length of the evidence key used each time.

[0011] Furthermore, the Byzantine fault-tolerant consensus process executed in the logical consensus module satisfies The fault tolerance boundary constraint is defined, where n is the total number of terminal nodes and f is the maximum number of malicious nodes that the system can tolerate. The security of the Byzantine fault-tolerant consensus protocol is based on the quorum intersection principle. It is proved through the pigeonhole principle that when the number of malicious nodes does not exceed f, there is no possibility that honest verification nodes will vote on conflicting blocks at the same time.

[0012] Furthermore, the measurement results of the untrusted measurement node only reflect the relative phase difference between the optical pulses sent by any two terminal nodes, without revealing the absolute phase information of any single terminal node.

[0013] This invention also includes a quantum-resistant consortium blockchain method based on dual-field quantum key distribution, applied to the aforementioned quantum-resistant consortium blockchain system based on dual-field quantum key distribution, comprising the following steps: Each terminal node interacts with the untrusted measurement node through a dual-field quantum key distribution protocol to generate pairs of information-theoretic secure symmetric keys, and divides the pairs of information-theoretic secure symmetric keys into evidence keys and consensus keys, which are stored in independent key buffer pools respectively. The transaction initiating node generates transaction data based on local business requests, extracts evidence keys from the key buffer pool, generates corresponding Wegman-Carter message authentication code components for each other terminal node, and generates a global authentication vector by combining all authentication code components; the transaction data and the global authentication vector are encapsulated and broadcast to the consensus network; wherein, the transaction initiating node is the terminal node that initiates the current transaction; In a consensus network, the consensus master node packages the transactions to be processed into candidate blocks and broadcasts them to the entire network. Each verification node uses its local consensus key to verify the legality of the candidate blocks and generates voting messages. After collecting valid votes that meet the quorum, the block is confirmed to have reached a consensus across the entire network. The verification nodes are other terminal nodes that participate in the consensus verification of the current block. After reaching a consensus on the blocks, each terminal node appends the current block to the end of its local ledger and packages the evidence keys corresponding to all transactions in the previous block into the reserved field of the current block body and broadcasts them with the current block, thereby making historical transactions publicly auditable.

[0014] Furthermore, each verification node verifies the legality of the candidate block using its local consensus key, specifically including: verifying the global authentication vector of the candidate block using the consensus key shared with the consensus master node to confirm the authenticity and integrity of the block; and performing secondary verification on the local message authentication code component of each transaction within the block to confirm that all transactions within the block are legal and valid.

[0015] Furthermore, the evidence keys corresponding to all transactions in the previous block are packaged into the reserved field of the current block body and broadcast to form publicly available evidence keys. The publicly available evidence keys are used by regulatory nodes or auditing third parties to recalculate the global authentication vector of each transaction in the historical blocks and compare it with the global authentication vector of the original record component by component to verify the integrity and authenticity of the historical transactions.

[0016] This invention provides a quantum-resistant consortium blockchain system based on dual-field quantum key distribution, which has the following advantages: This invention divides symmetric keys into evidence keys and consensus keys through a key management module and stores them independently. It utilizes the evidence keys to construct a Wegman-Carter global authentication vector to replace classical digital signatures, achieving non-repudiation and public auditability of transactions without relying on asymmetric cryptography. The consensus key is immediately erased after the Byzantine fault-tolerant consensus is completed, achieving "use and destroy," fundamentally eliminating the possibility of attackers forging historical consensus votes afterward, and endowing the system with forward security against long-range attacks. This invention resolves the contradiction between public auditability and resistance to long-range attacks in symmetric key systems through a dual-key layered strategy, providing a complete quantum-resistant solution for high-security consortium blockchains. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall architecture and network topology of the quantum-resistant consortium blockchain system based on dual-field quantum key distribution in an embodiment of the present invention; Figure 2 This is a schematic diagram of the dual-key management strategy and system operation process in an embodiment of the present invention; Figure 3 This is a diagram illustrating the feasible domain of system performance and engineering feasibility in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] With the rapid development of quantum computing technology, existing blockchain systems face severe security threats. To address this issue, the academic community has proposed a variety of quantum-safe blockchain solutions, mainly divided into two categories: post-quantum cryptography and quantum key distribution. Post-quantum cryptography replaces asymmetric cryptographic algorithms with anti-quantum algorithms based on mathematical problems such as lattices, encoding, and multivariables. However, its security depends on specific computational assumptions and is not information-theoretic secure. Quantum key distribution (QKD) schemes utilize the basic principles of quantum mechanics to generate information-theoretic secure symmetric keys between legitimate communicating parties, resisting eavesdropping attacks of arbitrary strength from a physical perspective. However, existing QKD blockchain schemes generally have the following defects: (1) High quantum link complexity in network topology. Existing schemes mostly adopt end-to-end direct connection BB84-type QKD protocols. Each node pair requires an independent quantum link. N nodes require O(N²) quantum links, which makes the system construction and maintenance costs increase quadratically with the number of nodes, severely restricting the scalability of consortium blockchains. (2) Lack of public auditability under symmetric key systems. Classical blockchains achieve non-repudiation and public auditability of transactions through public asymmetric keys, allowing any third party to verify the authenticity of transaction signatures using the public key. However, in a fully symmetric key system, the key pair is secretly shared by the sender and receiver, making it impossible to directly prove to a third party that a transaction was indeed signed by the claimed initiator, which is difficult to meet the functional requirements of non-repudiation and regulatory auditing for consortium blockchains. (3) Risk of long-range attacks on historical transactions. In QKD blockchains, if static keys or long-term unchanging keys are used to authenticate blocks, attackers can accumulate all the ciphertext even if they cannot crack it at present, and launch a backtracking attack when quantum computing capabilities mature in the future, which poses a risk that the entire historical ledger may be tampered with or forked and replaced. (4) Overly strong security assumptions about the side-channel of quantum devices. Some schemes assume that the QKD sending and receiving devices are completely trustworthy, and do not fully consider the security threats to the quantum physical layer from side-channel attacks such as Trojan attacks and detector blinding, resulting in security blind spots in actual complex engineering environments.

[0020] Based on this, and to address the shortcomings of existing technologies, this invention proposes a quantum-resistant consortium blockchain system and method based on global authentication vectors and key layering. The following describes the proposed method in detail, using a dual-field quantum key distribution system based on untrusted measurement nodes and a phase-encoded weak coherence state protocol as its foundation. This invention can be integrated into dual-field QKD networks of arbitrary structures, does not require direct quantum links between terminal nodes, and achieves measurement device-independent security using untrusted measurement nodes.

[0021] This invention provides a quantum-resistant consortium blockchain system based on dual-field quantum key distribution, comprising: (1) Untrusted measurement node, used to receive phase-coded weak coherent optical pulses sent by multiple terminal nodes, perform single-photon interferometry, and broadcast the measurement results to each terminal node through a public classical channel.

[0022] (2) Multiple terminal nodes are connected to the untrusted measurement node through a dedicated quantum fiber link to form a star quantum network topology; each terminal node includes a quantum physics driving module, a key management module and a logical consensus module.

[0023] ① A quantum physics-driven module is used to prepare phase-encoded weakly coherent optical pulses and send them to the untrusted measurement node, as well as to receive the measurement results and perform basis vector comparison, error correction, and privacy amplification to generate a pairwise information-theoretic secure symmetric key with the target terminal node. The untrusted measurement node does not have key storage or logical computation capabilities; its measurement results only reflect the relative phase difference between the optical pulses sent by the two terminal nodes, without revealing the absolute phase information of any single terminal node. This achieves physical layer security at the measurement device independence level, and in principle, is immune to all known side-channel attacks targeting the measurement device.

[0024] ② The key management module divides the symmetric key into evidence keys and consensus keys and stores them separately. The evidence key is used for the authentication of transaction content and delayed disclosure across blocks. It is kept strictly confidential until the block reaches consensus and completes chain confirmation, and is only made public to the entire network after subsequent block confirmation. The consensus key is used for the authentication of consensus voting messages and adopts a lifecycle management of "use and destroy". It is completely erased from the node's memory and persistent storage immediately after each consensus is completed.

[0025] The evidence key adopts a cross-block delayed disclosure strategy: during the consensus process of the current block, the evidence key is only used locally by the transaction initiating node and the corresponding verification node, and remains confidential; after the current block completes consensus and is locked by the hash value of the subsequent block, the evidence key is packaged into the subsequent block and made public to the entire network, so that any third party can re-verify the true source of historical transactions based on the publicly disclosed evidence key, realizing non-repudiation and public auditability under the symmetric key system.

[0026] The consensus key follows the principle of "use and burn": after the Byzantine fault-tolerant consensus process of the current block is completed, all participating nodes immediately erase all consensus keys consumed in this consensus from their local memory and persistent storage; the consensus key is never disclosed to the entire network at any time, so that even if an attacker obtains all the publicly disclosed evidence keys, they cannot forge historical consensus votes to build an alternative blockchain, thus achieving forward security that resists long-range attacks.

[0027] ③ The logical consensus module includes an authentication vector construction submodule and a quantum-safe consensus submodule. The authentication vector construction submodule uses the evidence key to generate a message authentication code based on the Wegman-Carter universal hash for each transaction, and combines the authentication code components for each verification node into a global authentication vector to replace classical digital signatures, achieving non-repudiation of transactions at the information-theory security level. The quantum-safe consensus submodule uses the consensus key to perform information-theory security authentication on each voting message in the Byzantine fault-tolerant consensus protocol, ensuring that the consensus process can still achieve legitimacy and consistency under attacks from quantum adversaries.

[0028] The global authentication vector is constructed as follows: For each other terminal node in the network, the transaction initiating node extracts the corresponding one-time evidence key, calculates the hash value of the transaction message and the sequence counter using a general hash function, and generates the corresponding message authentication code component through XOR operation; the message authentication code components corresponding to all target terminal nodes are combined to form a global authentication vector and broadcast along with the transaction data.

[0029] Each message authentication code component in the global authentication vector is generated independently by a different evidence key. The receiving node can only verify its own corresponding message authentication code component and cannot know the evidence keys of other nodes. The upper bound of the probability that an attacker can successfully forge a legitimate global authentication vector in a single instance without a masking key is... in The length of the evidence key used each time (i.e., the bit length of the masking key) is specified, thus guaranteeing the authentication vector's resistance to quantum forgery at the information theory level.

[0030] The Byzantine Fault-Tolerant Consensus Protocol executed by the logical consensus module satisfies The fault tolerance boundary constraint is defined, where n is the total number of terminal nodes and f is the maximum number of malicious nodes that the system (the consortium blockchain consensus network composed of n terminal nodes) can tolerate. The security of the consensus protocol is based on the quorum principle. The pigeonhole principle is used to prove that when the number of malicious nodes does not exceed f, there is no possibility that honest verification nodes will vote on conflicting blocks at the same time, thus ensuring the global consistency of the ledger.

[0031] ④ The middleware adaptation layer is set between the quantum link layer and the blockchain business layer. It receives and stores the symmetric keys generated by the quantum physics driving module through an asynchronous key buffer pool, and provides a standardized key extraction interface to the logical consensus module. This decouples the execution of the upper-layer consensus protocol from the underlying quantum key generation rate. Even if an untrusted measurement node experiences a service interruption, the system can still maintain normal consensus service within the validity period of the local key buffer pool.

[0032] Based on the above inventive concept, this invention provides a quantum-resistant consortium chain method based on dual-field quantum key distribution, applied to the above system, comprising the following steps: S1. Key Negotiation and Key Layering: Each terminal node interacts with the untrusted measurement node through a dual-field quantum key distribution protocol to generate a pair of information-theoretic secure symmetric keys. These keys are then divided into evidence keys and consensus keys by the key management module according to an agreed ratio and stored in separate key buffer pools.

[0033] S2, Transaction Construction and Authentication Vector Generation: The transaction initiating node extracts the one-time key fragment corresponding to each verification node from the evidence key pool, calculates the hash value of the transaction message and the sequence counter using a general hash function, and generates a message authentication code component for that verification node through an XOR operation; combines the components corresponding to all target verification nodes into a global authentication vector, and broadcasts it to the consensus network along with the transaction data (the consensus network refers to the logical network composed of all terminal nodes participating in the Byzantine fault-tolerant consensus process in the system).

[0034] S3, Quantum-Safe Byzantine Fault-Tolerant Consensus: The consensus master node packages the transactions to be processed into candidate blocks and broadcasts them to the entire network. Each validator node uses the consensus key shared with the master node to verify the validity of the global authentication vector in the candidate block and performs local verification on the message authentication code component of each transaction within the block. After the verification passes, a voting message is generated based on the consensus key and broadcast. Once the consensus is satisfied with the verification, the validator node continues to verify the validity of the global authentication vector in the candidate block. After a valid vote requiring a quorum, the block is confirmed to have reached a network-wide consensus. The consensus master node is automatically determined by a built-in Byzantine fault-tolerant master node rotation mechanism combined with quantum random numbers. The master node index is calculated as (current view number mod n) + 1, based on the current view number and the total number of terminal nodes n. Verification nodes are all terminal nodes in the consensus network, referring to all terminal nodes that receive the candidate block broadcast.

[0035] In the quantum-safe Byzantine fault-tolerant consensus process, the verification of the legality of candidate blocks by each verification node includes: verifying the global authentication vector of the candidate block using the consensus key shared with the master node to confirm the authenticity and integrity of the block; performing secondary verification on the local message authentication code component of each transaction within the block to confirm that all transactions within the block are legal and valid; and generating a voting message based on the consensus key and broadcasting it to the entire network after the verification is passed.

[0036] S4. Block Confirmation and Delayed Disclosure of Evidence Keys: Each node appends the consensus block to the end of its local ledger; when constructing the next block, it packages the evidence keys corresponding to all transactions in the previous block into the reserved field of the current block body and broadcasts it with the current block, so that the verification nodes and regulatory third parties in the network can re-verify the true source of historical transactions based on the publicly available evidence keys, and realize the public auditability of historical transactions.

[0037] Based on the above inventive concept, the present invention proposes the following embodiments, which specifically include the following steps: S1. System initialization and dual-field QKD key negotiation.

[0038] Reference Figure 1 , Figure 1 The overall architecture and network topology of the system of this invention are demonstrated. The system consists of one untrusted measurement node and n terminal nodes, and adopts a quantum link-blockchain service layered design, which is divided into a blockchain service layer, a middleware adaptation layer, and a quantum link layer from top to bottom. In the quantum link layer, the n terminal nodes are connected to the same untrusted measurement node through dedicated quantum fiber links, forming a star topology.

[0039] Reference Figure 2 , Figure 2 The demonstration showcased the internal functional modules of the terminal node and the dual-key hierarchical management process. Each terminal node includes a quantum physics-driven module, a key management module, and a logical consensus module. A middleware adaptation layer is provided between the key management module and the quantum physics-driven module, using an asynchronous key buffer pool to decouple the upper and lower layers. The quantum keys generated by the underlying TF-QKD are divided into evidence keys and consensus keys according to an agreed ratio and stored in independent buffer pools for upper-layer services to retrieve as needed.

[0040] The key negotiation process is illustrated using terminal node A and terminal node B as an example. Node A randomly selects a phase. and randomized phase Preparation of weakly coherent optical pulses Node B is prepared similarly. Both pulses are simultaneously transmitted to an untrusted measurement node via equal-length optical fibers. The measurement node performs Bell state single-photon interferometry on the two pulses and outputs the results to the detector. and The response result. If Response, corresponding to relative phase difference ;like Response, corresponding to relative phase difference The measurement nodes broadcast the detector's response via a public classical channel.

[0041] Node A and Node B each publish their randomized phases. , And basis selection, retaining bits under phase-matched basis. The qubit error rate (QBER) is estimated using the publicly available partial original key, information coordination and privacy amplification are performed, and finally, a qubit of length is obtained. Pairwise information-theoretic secure symmetric keys The security of this process is based on the measurement device independence of dual-field QKD: untrusted measurement nodes can only obtain the relative phase information of the two light pulses, and cannot know the absolute phase of any single terminal. This means that the role of the measurement node in the system is strictly limited to "a pure functional component providing physical interferometry," rather than a third-party intermediary that requires the trust of all parties in a traditional blockchain network. Even under the most extreme security assumptions—that the measurement node is completely controlled by an attacker and all its internal states are stolen—the attacker still cannot obtain any generated key information from the node, let alone access the blockchain consensus network to tamper with data. This "zero-trust" architecture eliminates the possibility of the measurement node becoming a system security bottleneck at the physical level, and effectively reduces the hardware threshold and deployment cost of each terminal node by reusing this core measurement device across the entire network. Therefore, all side-channel attacks targeting the measurement device are immune at the physical layer.

[0042] Key Input is sent to the key management module, according to the agreed ratio. Divided into evidence keys and consensus key The evidence key is used for transaction authentication, employing a delayed disclosure lifecycle strategy to support the public auditability of transactions; the consensus key is used for consensus voting authentication, strictly adhering to the principle of one-time use and self-destruction. The lifecycles of the two keys are strictly separated. The overall process of this dual-key hierarchical mechanism is as follows: Figure 2 As shown.

[0043] S2. Construction of Global Authentication Vector and Derivation of Information Theory Security When terminal node A initiates a transaction At that time, node A retrieves the evidence key pool containing the information of each verification node. Corresponding currently unused evidence key fragment For each target node The local authentication code components constructed by node A are as follows.

[0044] First, node A maintains a monotonically increasing sequence counter. Concatenate it with the transaction message $M$ to form , utilizing subordinate Family of general hash functions hash function ,calculate General family of hash functions Satisfy: For any two distinct messages ,from Randomly selected from

[0045] satisfy In this embodiment, a polynomial-based construction is used, and the label length is... Bit, .

[0046] The core idea of ​​this construction is to combine a "general, reusable compression function" with a "one-time, absolutely random masking key." General hash function It is responsible for compressing transaction messages of arbitrary length into fixed-length digests, but it is a public algorithm and cannot be used alone for authentication; information-theoretic secure evidence key fragments. This serves as a one-time password book, where the hash value is XORed to mask it. Since the masking key is only known to the transaction initiating node A and the target verification node... The shared true random number is marked as used after each use, and no third party (including other verification nodes) can forge a legitimate message authentication code component without this masking key.

[0047] Then, the hash value and the evidence key fragment are XORed bitwise to obtain the node-oriented result. Message authentication code components: (1) Node A combines the MAC components of all target verification nodes to form a global authentication vector. With transaction data and counter They broadcast it together.

[0048] The information-theoretic security derivation of this construct is as follows. For a single verification node... The attacker attempted to transact Replace with fake transactions And it does not trigger a verification failure. Because For only A and A shared, truly random key, unknown to the attacker, means the probability of successfully forging it is equal to guessing. To eliminate the probability of XOR masking:

[0049] (2) in This refers to the length of the evidence key used each time. In this embodiment... Bits, therefore the probability of forgery at a single node is This is negligible. Since each component in the global authentication vector is generated by an independent key, if an attacker attempts to deceive all verification nodes simultaneously, their success probability is the product of the forgery probabilities of each component. Security is guaranteed by the weakest link. Therefore, this authentication vector achieves information-theoretic security and non-repudiation under a fully symmetric key system: as long as the evidence key is not published, no node can forge a legitimate authentication code; and once the evidence key is delayed in being published in a subsequent block, any third party can recalculate it. and with the original The comparison confirmed that the transaction was indeed initiated by Company A.

[0050] S3, Quantum-Safe Byzantine Fault-Tolerant Consensus Process and Derivation The consensus master node packages multiple transactions encapsulated by globally certified vectors into candidate blocks. And broadcast. Verify node receive Then, the following algorithm flow is executed: a quantum-safe Byzantine consensus algorithm based on MAC vector authentication, with the input being the verification node. Consensus key held (with the master node) Shared evidence key (Shared with all transaction initiating nodes), candidate blocks Output is a block The consensus result (Commit or Abort) specifically includes the following steps.

[0051] Step 1 Block Integrity Verification: Using For candidate blocks The block header is used to calculate the message authentication code. If the code does not match, an Abort is broadcast and the process terminates; otherwise, proceed to step 2.

[0052] Step 2 Transaction authentication vector verification: For Each transaction Extracting the global authentication vector from the following: Components for the target Using the evidence keys they possess and counter Calculate the expected value Compare the two. If they are equal, the mark is valid; otherwise, the mark is invalid.

[0053] Step 3 Business Logic Validation: Check valid transaction execution permissions, double-spending, etc., and form a local set of valid transactions. .

[0054] Step 4: Prepare message generation: using Generate a block hash containing node identifiers and block hashes. , Merkelgen The Prepare message is broadcast after being authenticated with the consensus key.

[0055] Step 5: Message Collection and Quorum Verification: Collect Prepare messages from other nodes and verify their integrity using the corresponding consensus key. Consistency. When at least [amount] is collected. When a valid Prepare message (including itself) is received, the quorum requirement is met, and the process proceeds to step 6.

[0056] Step 6: Commit Message and Local Commit: Broadcast the Commit message and commit the block. Append to the ledger and output Commit.

[0057] Step 7 Timeout Handling: If not enough Prepare messages are collected within the timeout period, a view change is initiated.

[0058] The working principle of the above process to resist Byzantine fault nodes is derived as follows. Let the total number of nodes be... The maximum number of malicious nodes that can be tolerated is ,satisfy In step 5, the quorum requirement is at least... Prepare messages from each node. Since the number of honest nodes is at least [number missing]. The honest node group itself constitutes a quorum, thus ensuring liveness. Regarding security, assume there are two contradictory blocks. and If both quorum members are obtained, then there exist two quorum sets. and , According to the pigeonhole principle, Therefore, the intersection contains at least the following: There are a maximum of [number] nodes. Since there are at most [number] nodes... There are at least one honest node within the intersection of all malicious nodes. If this honest node sends Prepare messages to both contradictory blocks, it violates the protocol rule (based on the same key and transaction content, only one consistent result can be obtained). Therefore, it is impossible for two contradictory blocks to simultaneously obtain a quorum, thus proving the uniqueness of the consensus.

[0059] Throughout the consensus process, all voting messages use a one-time consensus key. Information-theoretic security authentication is performed, and the key is immediately erased from memory and persistent storage after consensus is achieved (use-and-destroy). This ensures that even if attackers gain unlimited quantum computing power in the future, they cannot obtain the destroyed consensus key to forge historical votes, thus guaranteeing the consensus process's resistance to long-range quantum attacks from the ground up.

[0060] S4. Delayed Disclosure of Evidence Keys and Mechanisms Against Long-Range Attacks After consensus is reached, the block It is appended to the local ledger by each node. The evidence key remains confidential at this point. (See reference...) Figure 3 , Figure 3 This demonstrates the complete lifecycle management strategy for evidence keys and consensus keys, including the generation phase, usage phase, delayed disclosure phase, and destruction phase. (The next block...) After reaching consensus and locking its hash, the node builds the block. When the block body is in the block, the block will be Evidence keys used in all transactions The data is packaged into the reserved "previous period evidence key" field and included with the block. The information was broadcast publicly. At this point, the evidence key entered a delayed disclosure phase.

[0061] Regulatory nodes or auditing third parties upon receiving blocks Afterwards, the publicly available evidence key can be extracted to re-examine the block. For each transaction in the process, a global authentication vector is calculated and linked to... The authentication vector of the original record is compared component by component. If all components match, it can be believed that the transaction was indeed generated by the node that declared it to have been tampered with. After the evidence key is made public, the corresponding consensus key immediately enters the destruction phase and is completely removed from the local cache to ensure that the key material is not reused.

[0062] The derivation of this mechanism against long-range attacks is as follows. Assume an attacker attempts to use a publicly available evidence key to forge an alternative transaction to replace the block in the future. The old transaction in the block is used to regenerate a longer chain. Since the evidence key is only revealed in subsequent blocks, this block... It has been blocked by at least one subsequent block. Hash locking of blocks. hash value Depends on blocks The complete content and hash. If an attacker tampers with... Transactions in the middle, The hash change, thus making The hashes are incompatible. For an attacker to succeed, they must recalculate the hashes simultaneously. , This includes all subsequent blocks, and the alternative chain's length exceeds that of the current main chain. However, with honest nodes continuously participating in consensus, the main chain length grows with honest computing power; an attacker cannot generate legitimate consensus votes for subsequent blocks without possessing all the consensus keys. In particular, the self-destructing consensus keys are permanently lost, preventing attackers from generating quorum-verified Prepare or Commit messages for any new block in the alternative chain. Therefore, the alternative chain cannot be accepted by honest nodes. Thus, delayed publication of evidence keys combined with self-destructing consensus keys constructs a comprehensive defense against long-range attacks from both transaction content and consensus process dimensions.

[0063] S5, System Performance Analysis and Security Improvement Effects The key layering architecture and delayed disclosure strategy of this invention enable the public auditability and non-repudiation properties, originally only available in public key systems, to be achieved under a symmetric key system. For example... Figure 1 As shown, the star topology based on dual-field QKD increases the number of quantum links from... Down to This significantly reduces the construction and maintenance costs of consortium blockchains. For example, when a consortium blockchain contains 20 nodes, a traditional end-to-end QKD blockchain requires 190 quantum links, while this invention only requires 20, reducing the number of links by 89.5%.

[0064] Regarding consensus efficiency, such as Figure 3 As shown, the global authentication vector integrates the multi-party authentication of each transaction into a single broadcast. The authentication code calculation only involves general hashing and XOR operations, achieving microsecond-level latency on a conventional CPU. Figure 2 As shown in the middleware adaptation layer, the incremental asynchronous key buffer pool realizes the rate decoupling of quantum key generation and upper-layer consensus. Even if the untrusted measurement node is interrupted for a short period of time, the system can still maintain consensus service for several minutes with the help of the pre-set key in the buffer pool. The measured availability exceeds 99.9%.

[0065] In terms of security enhancement, defense-in-depth is achieved through the following layers (each layer corresponds to...). Figure 1 (layered architecture) (1) Physical layer: Dual-field QKD’s measurement device-independent property is immune to all known measurement side-channel attacks.

[0066] (2) Key management layer ( Figure 2 The consensus key is destroyed after use, eliminating any possibility of historical vote forgery, and the delayed disclosure of the evidence key gives the symmetric key system public auditability.

[0067] (3) Data layer: Delayed disclosure of evidence keys and hash chain locking jointly defend against long-range tampering of transaction content.

[0068] (4) Consensus Layer Figure 3 Byzantine fault tolerance protocols maintain legitimacy and consistency under the information-theoretic security principle of line-by-line authentication.

[0069] Experiments have verified that on a dual-field QKD network with a 100 km fiber optic link, this system can still achieve second-level block generation, a 100% transaction non-repudiation verification success rate, and maintain zero successful tampering records under simulated quantum attacks. Compared to existing consortium blockchain schemes based on post-quantum cryptography, this invention does not rely on any mathematically difficult assumptions, provides unconditional security, and does not add any additional hardware monitoring or optical power detection modules. It is purely software-deployed and easily integrated into existing QKD networks.

[0070] Compared with the prior art, the present invention has the following beneficial effects: (1) The complexity of quantum links is reduced by orders of magnitude. This invention adopts a star topology based on untrusted measurement nodes and a dual-field QKD protocol. N terminal nodes only need N quantum fiber links to realize the generation of information-theoretic secure keys between any pair of nodes, reducing the link complexity from O(N²) of the existing scheme to O(N), which significantly reduces the construction and operation and maintenance costs of the consortium blockchain system.

[0071] (2) Public auditability and non-repudiation under symmetric key systems. This invention separates transaction authentication and ledger public verification in the time dimension through a cross-block delayed disclosure mechanism for evidence keys: the evidence keys are kept confidential during the consensus phase to ensure security, and are made public after subsequent block confirmation to achieve post-audit. Any third party can use the publicly disclosed evidence keys to recalculate the global authentication vector and verify the integrity and authenticity of historical transactions, thereby solving the non-repudiation problem of fully symmetric key systems without introducing asymmetric cryptography.

[0072] (3) Systematic resistance to long-range attacks. This invention strictly separates the lifecycles of consensus keys and evidence keys: consensus keys are destroyed after use and are not publicly disclosed in any form, so attackers cannot obtain authentication credentials for the historical consensus process, and even if they collect all historical ciphertext, they cannot forge an alternative blockchain afterward; although evidence keys are eventually made public, their public release time is later than the chain confirmation of the relevant blocks, and the hash links of historical blocks have formed an irreversible time-series lock. Any attempt by attackers to retroactively forge early transactions using the subsequently published evidence keys will be detected and rejected immediately by honest nodes based on the chain hash integrity verification. This constructs a complete defense against long-range attacks from historical consensus messages to historical transaction content.

[0073] (4) Physical layer security immunity at the measurement device-independent level. This invention adopts the dual-field QKD protocol to converge the trust boundary of quantum security to the light source and single-photon detector of the terminal node, achieving zero trust for intermediate untrusted measurement nodes; all operations of untrusted measurement nodes can be verified by the terminal node through basis vector comparison and privacy amplification. From the architectural design, it systematically immunizes against all known side-channel attacks against measurement devices (including detector blinding, wavelength attacks, Trojan horse attacks, etc.), providing a solid information theory security foundation for the upper-layer consensus system.

[0074] (5) Asynchronous decoupling of quantum security and underlying key generation. This invention introduces a middleware adaptation layer and a key buffer pool mechanism to decouple the upper-layer consensus logic from the underlying quantum key generation rate. Even if the service capability of an untrusted measurement node is temporarily reduced due to physical failure or network interruption, the system can still continue to run within the validity period of the buffer pool, which significantly improves the availability and robustness of the system in complex engineering environments.

[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution, characterized in that, include: An untrusted measurement node and multiple terminal nodes connected to the untrusted measurement node via quantum fiber links; The untrusted measurement node is used to receive phase-coded weak coherent optical pulses sent by multiple terminal nodes to perform single-photon interferometry and broadcast the measurement results to each terminal node through a public classical channel; Each of the terminal nodes includes: The quantum physics-driven module is used to prepare phase-encoded weakly coherent optical pulses and send them to the untrusted measurement node. Based on the measurement results, quantum post-processing is performed to generate a pairwise information-theoretic secure symmetric key between the target terminal node. The key management module is used to divide the pairwise information-theoretic secure symmetric keys into evidence keys that support delayed disclosure and consensus keys that are destroyed after use, according to their functions. The logical consensus module includes an authentication vector construction submodule and a quantum-safe consensus submodule. The authentication vector construction submodule is used to extract the evidence key and generate corresponding authentication code components for each other terminal node based on the Wegman-Carter message authentication mechanism, and generate a global authentication vector by combining all authentication code components. The quantum-safe consensus submodule is used to extract the consensus key, perform information-theoretic security authentication on the voting messages in the Byzantine fault-tolerant consensus process, and erase all consensus keys used in this consensus after the consensus of the current block is completed.

2. The quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 1, characterized in that, The evidence key employs a cross-block delayed disclosure strategy, specifically including: during the consensus process of the current block, the evidence key is used locally only by the transaction initiating node and the corresponding verification node, remaining confidential; after the current block completes consensus and is locked by the hash value of subsequent blocks, the evidence key is packaged into the subsequent block and made public to the entire network, enabling any third party to re-verify the true source of historical transactions based on the publicly disclosed evidence key; wherein, the transaction initiating node is the terminal node that initiates the current transaction, and the verification node is other terminal nodes participating in the consensus verification of the current block.

3. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 1, characterized in that, The consensus key follows the principle of "use and burn," specifically including: after the Byzantine fault-tolerant consensus is completed in the current block, the quantum-safe consensus submodule triggers the key management module to erase all consensus keys consumed in this consensus, including completely deleting them from local memory and persistent storage; and the consensus key is never publicly disclosed to the entire network at any time.

4. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 2, characterized in that, The process of extracting the evidence key and generating corresponding authentication code components for each other terminal node based on the Wegman-Carter message authentication mechanism, and generating a global authentication vector by combining all authentication code components, specifically includes: the transaction initiating node extracting the corresponding one-time evidence key for each other terminal node; calculating the hash value of the transaction message of the transaction initiating node and the monotonically increasing sequence counter using a hash function belonging to the ε-general hash function family, and combining the hash value with the one-time evidence key through an XOR operation to generate the message authentication code component corresponding to the target terminal node; combining the message authentication code components corresponding to all target terminal nodes to form the global authentication vector and broadcasting it along with the transaction data.

5. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 4, characterized in that, Each message authentication code component in the global authentication vector is independently generated by a different evidence key. The receiving node can only verify its own corresponding message authentication code component and cannot know the evidence keys of other nodes. The upper bound of the probability that an attacker can successfully forge a legitimate global authentication vector in a single instance without evidence keys is... ,in The length of the evidence key used each time.

6. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 1, characterized in that, The Byzantine fault-tolerant consensus process executed in the logical consensus module satisfies The fault tolerance boundary constraint is defined, where n is the total number of terminal nodes and f is the maximum number of malicious nodes that the system can tolerate. The security of the Byzantine fault-tolerant consensus protocol is based on the quorum intersection principle. It is proved through the pigeonhole principle that when the number of malicious nodes does not exceed f, there is no possibility that honest verification nodes will vote on conflicting blocks at the same time.

7. A quantum-resistant consortium blockchain system based on dual-field quantum key distribution according to claim 1, characterized in that, The measurement results of the untrusted measurement node only reflect the relative phase difference between the optical pulses sent by any two terminal nodes, without revealing the absolute phase information of any single terminal node.

8. A quantum-resistant consortium chain method based on dual-field quantum key distribution, characterized in that, The method applied to the quantum-resistant consortium blockchain system based on dual-field quantum key distribution as described in claim 1 includes the following steps: Each terminal node interacts with the untrusted measurement node through a dual-field quantum key distribution protocol to generate pairs of information-theoretic secure symmetric keys, and divides the pairs of information-theoretic secure symmetric keys into evidence keys and consensus keys, which are stored in independent key buffer pools respectively. The transaction initiating node generates transaction data based on local business requests, extracts evidence keys from the key buffer pool, generates corresponding Wegman-Carter message authentication code components for each other terminal node, and generates a global authentication vector by combining all authentication code components; the transaction data and the global authentication vector are encapsulated and broadcast to the consensus network; wherein, the transaction initiating node is the terminal node that initiates the current transaction; In a consensus network, the consensus master node packages the transactions to be processed into candidate blocks and broadcasts them to the entire network. Each verification node uses its local consensus key to verify the legality of the candidate blocks and generates voting messages. After collecting valid votes that meet the quorum, the block is confirmed to have reached a consensus across the entire network. The verification nodes are other terminal nodes that participate in the consensus verification of the current block. After reaching a consensus on the blocks, each terminal node appends the current block to the end of its local ledger and packages the evidence keys corresponding to all transactions in the previous block into the reserved field of the current block body and broadcasts them with the current block, thereby making historical transactions publicly auditable.

9. A quantum-resistant consortium chain method based on dual-field quantum key distribution according to claim 8, characterized in that, Each verification node verifies the legality of the candidate block using its local consensus key. Specifically, this includes: verifying the global authentication vector of the candidate block using the consensus key shared with the consensus master node to confirm the authenticity and integrity of the block; and performing secondary verification on the local message authentication code component of each transaction within the block to confirm that all transactions within the block are legal and valid.

10. A quantum-resistant consortium chain method based on dual-field quantum key distribution according to claim 8, characterized in that, The evidence keys corresponding to all transactions in the previous block are packaged into the reserved field of the current block body and broadcast to form publicly available evidence keys. The publicly available evidence keys are used by regulatory nodes or auditing third parties to recalculate the global authentication vector of each transaction in the historical blocks and compare it with the global authentication vector of the original record component by component to verify the integrity and authenticity of the historical transactions.

Images