A UTXO type blockchain group covert communication method based on orthogonal code words and revocable management and control, a computing device and a computer readable storage medium

Abstract

The application discloses a UTXO type blockchain group covert communication method based on orthogonal code words and revocable control, a computing device and a computer readable storage medium, wherein the method comprises the following steps: S1, group offline initialization and security parameter maintenance; S2, joint encoding and load construction; S3, transaction field embedding and chain loading; S4, on-chain monitoring screening and index recovery; S5, projection type local decoding; S6, group revocable control; the orthogonal code word joint encoding, UTXO transaction field bearing and address marking screening mechanism can realize multi-receiver shared load bearing and separable decoding without introducing additional protocol fields; and through the group dynamic control and revocation update mechanism, the dishonest members can be excluded and the seed / epoch can be updated, so that the concealment, bearing efficiency and continuous controllability can be considered in the dynamic member environment.

Description

Technical Field

[0001] This invention relates to the field of blockchain security and covert communication technology, and in particular to a covert communication method, computing device, and computer-readable storage medium for blockchain groups based on orthogonal codewords and revocable control of UTXO type. Background Technology

[0002] In recent years, blockchain networks, with their core technological characteristics of decentralization, immutability, and auditability, have been widely applied in many fields such as digital payments, supply chain traceability, and distributed collaboration. Meanwhile, information concealment and covert communication technologies, relying on the inherent attributes of blockchain transactions—network-wide broadcasting, immutability, and permanent retention—have gradually become a research hotspot in the fields of network security and privacy protection. Compared to traditional IP network covert channels, blockchain-based covert communication possesses natural cross-domain propagation capabilities and extremely strong resistance to interception and interference from intermediate nodes, significantly improving the stability and survivability of communication links. Among these, UTXO (Unspent Transaction Output) type blockchain systems provide natively usable carriers for embedding covert information through standardized protocol fields such as the number of transaction outputs, output amount, and output address. This allows communicating parties to complete the carrying and on-chain transmission of covert information without introducing additional protocol fields or violating the standard transaction format and on-chain verification rules.

[0003] To achieve covert communication on blockchain, existing technologies have proposed a variety of embedding schemes. The mainstream schemes include information embedding based on transaction amount perturbation, information carrying based on address encoding or script fields, and steganography design based on transaction structure features. All of the above schemes can complete the writing and reading of covert information in the on-chain transaction stream, and can better meet the covert communication needs in "one-to-one" peer-to-peer scenarios. However, in the context of covert group communication, the communication mode expands from the traditional "one-to-one" to "one-to-many" and even "many-to-many". The communication system needs to simultaneously meet core requirements such as the separable decoding of messages from multiple receivers, efficient screening and location of on-chain encrypted transactions, and flexible adaptation to dynamic changes in group members. Existing point-to-point solutions cannot be directly adapted to group scenarios and have many technical defects: On the one hand, existing solutions for group scenarios mostly adopt the implementation method of sending multiple encrypted transactions to different receivers, which directly leads to a significant increase in on-chain transaction load and a significant increase in the suspiciousness of communication behavior. At the same time, it is difficult to guarantee communication throughput and latency performance under limited transaction budgets. Although some solutions attempt to carry multiple covert messages in a single transaction, they lack a strict message separability structure design. The message components of different receivers are prone to mutual interference, which not only leads to increased decoding errors but also requires additional interaction and collaborative decoding between receivers. This cannot be adapted to the passive listening reception model that relies solely on public on-chain data.

[0004] In addition, during actual covert group communication, dynamic events such as member withdrawal, receiver default, and key leakage occur frequently, placing extremely high demands on the dynamic control and security isolation capabilities of the communication system. Existing blockchain covert communication solutions generally lack a full-process control mechanism to support the dynamic revocation of group members: First, even after revocation, a receiver can still use the acquired filtering rules to continuously locate subsequent encrypted transactions on the chain, causing continuous leakage of communication content; second, even with permission control through key updates and changing tagging rules, if the payload encoding structure is not linked to the revocation strategy, the revoked member can still decode some messages using historical codewords or structural features; third, most solutions require redistributing all communication parameters or even redesigning the information embedding structure after a member revocation event, resulting in high system overhead, high multi-node collaboration costs, and difficulty in achieving rapid permission switching and continuous controllability of the communication process while maintaining communication covertness.

[0005] In summary, existing technologies have not yet formed a unified technical framework for group covert communication on UTXO-type blockchains. They cannot achieve orthogonal separable encoding and transmission of multi-recipient messages in a single transaction or a small number of transactions, nor can they form a complete technical closed loop between on-chain screening and location, index recovery and local decoding. Furthermore, they cannot take into account the control requirements of dynamic revocation of group members and rolling updates of keys, and it is difficult to simultaneously guarantee the throughput efficiency, message separability, system controllability and communication covertness of covert communication in dynamic group environments. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for allocating multi-UAV collaborative reconnaissance tasks based on temporal state perception and hierarchical replanning, as well as a computer-readable storage medium and electronic device, to solve the aforementioned problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution.

[0008] A method for covert communication in a UTXO-type blockchain group based on orthogonal codewords and revocable control includes the following steps: S1. Group offline initialization and security parameter maintenance: Establish a group member set and a revocation set, generate and securely distribute the private orthogonal codewords for each legitimate recipient, generate and maintain a shared seed / key and version identifier epoch for transaction screening and decoding consistency, and update the shared seed / key and version identifier epoch when member changes or revocation is triggered. S2. Joint Orthogonal Coding and Payload Construction: The sender obtains a set of hidden messages to be sent to multiple trusted receivers, performs joint coding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to obtain a shared payload vector, and performs scaling, quantization and embeddability constraints on the shared payload vector to obtain a quantized payload vector. S3, Transaction Field Embedding and On-Chain Encryption: The quantized payload vector is embedded into the standard fields of the UTXO transaction output, and a hidden marker is generated based on the shared seed / key and version identifier epoch. The hidden marker is embedded into the bearable position of the transaction output address to construct the UTXO encrypted transaction and broadcast it on the chain. S4. On-chain monitoring, filtering, and index recovery: The receiver monitors the on-chain transaction stream, generates filtering rules based on the locally stored shared seed / key and version identifier epoch, filters candidate UTXO-based cryptographic transactions through hidden markers, and extracts standard fields from the candidate UTXO-based cryptographic transactions to perform output index recovery and sorting, reconstructing the quantized payload vector to be decoded. S5. Projection-based local decoding: The receiver reads its locally stored private orthogonal codewords and corresponding parameters, performs projection-based local decoding on the quantized payload vector to be decoded based on inner product projection, and only recovers the hidden message corresponding to the receiver without recovering the messages of other receivers. S6. Group Revocation Control: When a recipient is untrusted, leaves the group, exceeds the offline time limit, poses a risk of key leakage, or meets the preset revocation policy, the recipient is added to the revocation set. In subsequent joint encoding, the corresponding private orthogonal codeword is removed, and the shared seed / key and version identifier epoch are updated, so that the revoked receiver cannot continue to filter subsequent UTXO-carrying transactions and / or cannot complete the projection-type local decoding, thereby realizing the dynamic revocation and continuous controllability of group covert communication.

[0009] In one embodiment, step S1 specifically includes: S11. Parameter Initialization and Set Establishment: Let the total number of valid receivers in the group be... n Establish a group member set With cancellation set Maintaining a trusted set Initialize codeword dimensions sparse combination parameters Integer weight range It also generates a shared seed / key and version identifier epoch for subsequent permutation structure processing and hidden tag generation; S12, Orthogonal basis construction: Construction or selection of order is... orthogonal basis matrix ,satisfy , for An identity matrix of order 1 is used to ensure that the basis vectors are pairwise orthogonal and to accommodate integer domain operations. S13, Combination Codeword Generation: For the first... One receiver, from an orthogonal basis matrix Select from the row vectors Each index constitutes a subset of the indexes. From symmetric bounded intervals Medium uniform sampling integer weight Generate combined codewords Sparsity and weight randomness are used to improve the unpredictability and resistance to structure inference of private orthogonal codewords. S14. Structured permutation processing: Generating secret column permutations using a shared seed / key. With the corresponding permutation matrix By applying column permutations to the combined codewords, private orthogonal codewords are obtained. This reduces the risk of attackers inferring codeword structure through statistics or pattern matching; S15. Orthogonality Verification and Distribution Storage: Perform pairwise orthogonality verification on the private orthogonal codeword set, ensuring that any two receivers... satisfy When the orthogonality constraint is not satisfied, resampling is performed on the index subset and / or weights, or orthogonalization is performed on the private orthogonal codeword set until the orthogonality constraint is satisfied; after the verification passes, the private orthogonal codewords corresponding to each receiver are... The filtering and decoding parameters related to the shared seed / key and the version identifier epoch are distributed to the corresponding receiving end through a secure channel and stored locally. S16. Parameter Version Maintenance: Maintain the version correspondence between the shared seed / key and the version identifier epoch, record the effective range of each version identifier epoch, and ensure that the sender and the unrevoked trusted receiver use the same covert tag generation rules and parameter configuration within the same version identifier epoch to ensure parameter consistency throughout the communication process.

[0010] In one embodiment, step S2 specifically includes: S21. Message Alignment and Mapping: The sender obtains the target set of trusted data within the current version identifier epoch. T A collection of hidden messages from multiple receivers ( For a trustworthy set T (The current number of members), perform length alignment, symbol mapping or grouping encoding on each message to form a standardized message vector adapted to joint encoding; S22, Joint Orthogonal Coding: Reading a Trusted Set T Each receiver's private orthogonal codeword set Construct a shared load vector By utilizing the pairwise orthogonality of private orthogonal codewords, we can ensure that the message components of different receivers are completely decoupled in the shared payload space, thus providing a foundation for subsequent separable projection-based local decoding. S23. Scaling and Quantization: To adapt to the discrete value characteristics of UTXO trading fields, a scaling factor is introduced. For shared load vectors Perform quantization processing to obtain the quantized payload vector. , scaling factor The value range can be flexibly adjusted according to the granularity of available amount on the chain and the precision of the field; S24. Range Constraints and Rollback Strategies: For quantized load vectors Each component is subject to effective range constraints to meet the boundary requirements of the amount subsequently mapped to the UTXO transaction output; when a component goes out of bounds, at least one fallback strategy is executed: component truncation, adjustment of scaling factor. Remapping some message components or reselecting the payload fragment length until a quantized payload vector that meets the constraints is obtained; S25. Load fragmentation and cycle binding: Quantizing the load vector The organization is a payload sequence or a set of payload fragments, and is bound to the current version identifier epoch to ensure that the receiver can use the same round parameters to complete filtering and projection-based local decoding; when the payload length exceeds the capacity that a single UTXO-based encrypted transaction can carry, it is split into multiple UTXO-based encrypted transactions and sent in consecutive rounds.

[0011] In one embodiment, step S3 specifically includes: S31. Output Structure Configuration: Set the quantization load vector , construct containing The UTXO output carries the encrypted transaction, making the first output... Each transaction output corresponds to a payload component. At the same time, compliant change output and transaction fees are configured to ensure that transactions maintain standard validity under the rules of amount conservation and on-chain verification. S32. Amount Mapping and Constraints: Mapping Load Components A linear mapping is used to represent the amount output by the corresponding transaction. The preferred mapping rule is... ,in For the base amount, Both the amount step size and the amount step size control the granularity of the amount and the available range; at the same time, on-chain compliance constraints are applied. This includes blockchain native rules such as minimum output amount and dust prevention transactions; when the mapped amount does not meet the boundary constraints, the amount step size Δ is adjusted or the process is rolled back to step S2 to re-execute the quantization process. S33. Stealth Tag Generation and Length Control: Based on the shared seed / key and version identifier epoch, for each output index... Generate corresponding hidden markers ,in f( ) It is a combination of pseudo-random function or message authentication code and encoding truncation; and a fixed-length tag suffix is ​​obtained through encoding and truncation, so that the hidden tag satisfies low collision or no collision constraints within the same version identifier epoch, which facilitates fast matching and index recovery at the receiving end; S34. Address Bearing and Format Validity: Hidden Marks Embed the bearable location of the corresponding UTXO transaction output address to form a tagged output address. Embedding methods include embedding the hidden marker as an address suffix, or embedding the equivalent character position of the address without violating the address's legality and transaction verification rules; after embedding, it is necessary to ensure that the address still meets the encoding and verification rules of the corresponding blockchain to avoid causing protocol layer rejection or abnormal detection; S35, Constructing and Broadcasting Secret Transactions: As a transaction output pair, it completes the compliant construction of the UTXO-encrypted transaction and broadcasts it to the blockchain network, so that the transaction is represented as a standard UTXO transaction on the chain, which can be propagated and confirmed by the entire network as the block is completed.

[0012] In one embodiment, step S4 specifically includes: S41. On-chain monitoring and preprocessing: The receiver continuously monitors new blocks and transaction pool transactions on the blockchain network, extracting the output set of each transaction. It also performs pre-filtering on non-standard outputs and outputs that do not meet format constraints to reduce subsequent matching overhead; S42. Tag Matching and Filtering: Generate a corresponding set of hidden tags based on the locally stored shared seed / key and version identifier epoch, and apply this to the transaction output address. Perform suffix matching or equivalent matching to filter out transaction outputs carrying compliance hidden markers; S43. Candidate Decision and Fault Tolerance: When the number of outputs matching the hidden marker in the same transaction reaches a preset threshold... When the transaction is identified as a candidate UTXO-based encrypted transaction, and when there is output loss, reordering or noise on the chain, a fault tolerance range can be set on the threshold and matching rules to improve the noise robustness of the payload reconstruction; S44. Index Recovery: Based on the hidden markers and their generation rules, establish a mapping relationship between the hidden markers and the output indices, and recover the original index corresponding to each matching output. ; S45. Reordering and Reconstructing: Based on the restored original index. Sort the matching output in ascending / descending order to obtain an ordered sequence of amount fields, and remove duplicate or conflicting index entries; S46. Obtain the load by inverse mapping of amount: based on the preset base amount. With amount step size The sorted monetary sequence is inversely mapped to quantized payload components. This allows for the complete reconstruction of the quantized payload vector to be decoded. This serves as the input for subsequent projection-based local decoding.

[0013] In one embodiment, step S5 specifically includes: S51, Dequantization and Normalization: Based on the preset scaling factor The reconstructed quantized load vector y is dequantized to obtain the shared load vector. Simultaneously, normalization or offset removal processing can be performed on the shared payload vector to suppress decoding deviations caused by monetary mapping and rounding errors. S52, Projection Estimation: The receiver uses locally stored private orthogonal codewords. Calculate the projection estimate Based on the pairwise orthogonality of private orthogonal codewords, the message components of other receivers are completely suppressed in this projection calculation, and will not interfere with the recovery of the target message. S53, Decision and Inverse Mapping: On the projection estimate Perform threshold decision, rounding or symbol demapping to restore the real value to the original message symbol or message component; when the original message uses block coding or error correction coding, further perform the corresponding decoding operation to improve the error robustness of projection-based local decoding; S54. Locality and Covertness Constraints: The entire projection-based local decoding process relies solely on the private orthogonal codewords stored locally by the receiver. It shares the seed / key and version identifier epoch parameters, without requiring any interaction with the sender or other receivers. It is fully compatible with passive listening reception models, avoiding the exposure of communication traces and the decrease in concealment caused by additional interactions.

[0014] In one embodiment, step S6 specifically includes: S61. Revocation Trigger and Status Update: When a recipient exhibits untrustworthy behavior, actively leaves the group, goes offline for an extended period beyond the custom time limit, poses a risk of key leakage, or meets the preset revocation policy for breach of trust, they are added to the revocation set. Synchronously update the trusted set ; S62. Codeword Removal: In subsequent rounds of joint orthogonal coding, only the trusted set is used. The private orthogonal codeword set corresponding to the internal member is used to construct a shared payload vector. The private orthogonal codeword of the revoked receiver no longer participates in the construction of the payload space, thus blocking its ability to recover the message through projection-based local decoding at the encoding level. S63, Seed / Epoch Rolling Update: Synchronously update the shared seed / key seed and version identifier epoch to the new seed' and epoch', so that the generation of covert markers and index mapping rules in subsequent rounds completely depend on the new seed' and epoch, blocking the revoked recipient's ability to locate subsequent UTXO-carrying transactions from the screening level; S64. Update Distribution and Security Isolation: The updated seed' and epoch' are distributed only to recipients within the trusted set T via off-chain secure channels, on-chain ciphertext delivery, or threshold sharing splitting. The on-chain ciphertext delivery method embeds the ciphertext of seed' as part of the new round of shared payload vector into the UTXO ciphertext transaction, which can only be decrypted and obtained by trusted recipients. The threshold sharing method performs threshold sharing splitting on seed' before distributing it to trusted recipients, preventing revoked recipients from piecing together the complete seed' and ensuring secure isolation of parameter updates. S65. Revocation effect guarantee: After the revocation process is completed, the revoked recipient shall meet at least one of the following effects in subsequent communication rounds: unable to generate new hidden markers to complete candidate transaction screening, unable to recover the output index to reconstruct the payload, and unable to recover the valid message through projection-type local decoding, thereby realizing the dynamic revocation of permissions and continuous blocking of communication capabilities of the distrusted member.

[0015] This invention also provides a UTXO-type blockchain group covert communication system based on orthogonal codewords and revocable control, the system comprising: The group security parameter maintenance module is used to maintain the group member set and revocation set, and maintain the member validity status in real time; it generates and maintains a private orthogonal codeword dictionary, a shared seed / key and version identifier epoch, and performs parameter rotation updates after a preset parameter rotation cycle or revocation event is triggered, providing full-process parameter support for off-chain joint encoding and receiver filtering and decoding; The joint orthogonal coding and payload construction module is used to aggregate a set of covert messages to be sent to multiple receivers within a trusted set; perform joint orthogonal coding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to form a shared payload vector; and perform scaling quantization, range constraints and organization fragmentation on the shared payload vector to obtain an embeddable quantized payload vector, which serves as the payload input for subsequent transaction embedding. The transaction embedding and covert tag generation module is used to embed the quantized payload vector mapping into the standard fields of the UTXO transaction; it generates a covert tag associated with the output index based on the shared seed / key and version identifier epoch, and embeds the covert tag into the bearable position of the UTXO transaction output address; based on this, it constructs a compliant UTXO-based encrypted transaction and broadcasts it on the chain, so that the UTXO-based encrypted transaction always remains a valid standard UTXO transaction at the protocol layer; The transaction monitoring, filtering, and payload reconstruction module is used to continuously monitor on-chain transaction stream data; it generates covert marker matching rules based on the locally stored shared seed / key and version identifier epoch, and filters candidate UTXO-based cryptographic transactions according to the marker rules; it extracts the output address and amount fields from the candidate UTXO-based cryptographic transactions, performs output index recovery and sorting, and reconstructs the quantized payload vector to be decoded according to the amount inverse mapping rule, providing input for subsequent projection-based local decoding at the receiving end; The group dynamic management and revocation update module is used to monitor the status of group members and revocation trigger events. Based on the preset default judgment rules, it determines the defaulting objects that need to be removed and updates the set of trusted members. It triggers the rotation update of the shared seed / key and version identifier epoch and generates update parameters. At the same time, it drives the group security parameter maintenance module to complete the parameter synchronization of members in the trusted set. This enables subsequent joint encoding to remove the private orthogonal codewords corresponding to the revoked members and prevents the revoked members from continuing to generate covert markers to filter subsequent UTXO-carrying transactions and / or from completing projection-type local decoding. This achieves dynamic revocation and continuous control of group covert communication.

[0016] The present invention also provides a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method described above.

[0017] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves unified management and version control of group covert communication parameters by maintaining the group member set and withdrawal status offline / low-frequency, generating and maintaining a private orthogonal codeword dictionary and a shared seed / key and version identifier epoch. Even when members dynamically join, leave, or withdraw, the parameters of the sending end and the trusted receiving end remain consistent, providing a stable and reliable foundation for on-chain screening and projection-based local decoding, and effectively improving the continuity and controllability of group covert communication in dynamic environments.

[0019] 2. This invention introduces orthogonal codeword joint encoding and shared payload construction mechanism to linearly aggregate multiple covert messages for multiple receivers off-chain, so that messages from different receivers remain separable in the same payload space. This enables the carrying of information for multiple receivers in a single or a small number of UTXO transactions, avoiding the increase in on-chain load and suspicion caused by repeatedly sending multiple UTXO-based cryptographic transactions for each receiver. This significantly improves the carrying efficiency and throughput of group covert communication.

[0020] 3. This invention embeds the quantized payload vector mapping into standard fields such as the output amount of UTXO transactions, and embeds the hidden marker generated based on seed / epoch into the bearable position of the transaction output address, achieving covert writing without introducing additional protocol fields or changing transaction verification rules. The receiving end only needs to listen to the transaction stream on the public chain online to quickly filter candidate UTXO-carrying transactions according to the hidden marker rules, and obtain the payload to be decoded through index recovery and payload reconstruction, thereby reducing the full-chain scanning overhead and improving the efficiency of screening and positioning and the robustness against noise.

[0021] 4. This invention sets up a dynamic group management and revocation update mechanism. When events such as untrustworthy members, offline timeouts, or key leakage risks are detected, the trusted member set can be updated in a timely manner, and the private orthogonal codewords corresponding to the revoked members can be removed in subsequent joint encoding. At the same time, the seed / epoch rotation update is triggered and the parameters are synchronized, so that the revoked members cannot continue to generate covert markers to filter subsequent UTXO-carrying transactions and / or cannot complete projection-type local decoding. This achieves dynamic revocation and continuous blocking of covert group communication, taking into account real-time performance, security, and long-term controllability. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the UTXO-type blockchain group covert communication method based on orthogonal codewords and revocable control according to the present invention. Figure 2 This is a schematic diagram of the UTXO blockchain group covert communication embedding / extraction process of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 and Figure 2 As shown, this invention discloses a method for covert communication in a UTXO-type blockchain group based on orthogonal codewords and revocable control, comprising the following steps: S1. Group offline initialization and security parameter maintenance Establish a group member set and a revocation set; generate and securely distribute private orthogonal codewords to each legitimate recipient; generate and maintain a shared seed / key and version identifier epoch for transaction screening and decoding consistency; and update the shared seed / key and version identifier epoch when member changes or revocation is triggered. The specific steps are as follows: S11. Parameter Initialization and Set Establishment: Let the total number of valid receivers in the group be... n Establish a group member set With cancellation set Maintaining a trusted set Initialize codeword dimensions sparse combination parameters Integer weight range It also generates a shared seed / key and version identifier epoch for subsequent permutation structure processing and hidden tag generation; S12, Orthogonal basis construction: Construction or selection of order is... orthogonal basis matrix ,satisfy This ensures that the basis vectors are pairwise orthogonal and is compatible with integer field operations; S13, Combination Codeword Generation: For the first... One receiver, from an orthogonal basis matrix Select from the row vectors Each index constitutes a subset of the indexes. From symmetric bounded intervals Medium uniform sampling integer weight Generate combined codewords Sparsity and weight randomness are used to improve the unpredictability and resistance to structure inference of private orthogonal codewords. S14. Structured permutation processing: Generating secret column permutations using a shared seed / key. With the corresponding permutation matrix By applying column permutations to the combined codewords, private orthogonal codewords are obtained. This reduces the risk of attackers inferring codeword structure through statistics or pattern matching; S15. Orthogonality Verification and Distribution Storage: Perform pairwise orthogonality verification on the private orthogonal codeword set, ensuring that any two receivers... satisfy When the orthogonality constraint is not satisfied, resampling is performed on the index subset and / or weights, or orthogonalization is performed on the private orthogonal codeword set until the orthogonality constraint is satisfied; after the verification passes, the private orthogonal codewords corresponding to each receiver are... The filtering and decoding parameters related to the shared seed / key and the version identifier epoch are distributed to the corresponding receiving end through a secure channel and stored locally. S16. Parameter Version Maintenance: Maintain the version correspondence between the shared seed / key and the version identifier epoch, record the effective range of each version identifier epoch, and ensure that the sender and the unrevoked trusted receiver use the same covert tag generation rules and parameter configuration within the same version identifier epoch to ensure parameter consistency throughout the communication process.

[0025] S2, Joint Orthogonal Coding and Payload Construction The sender obtains a set of covert messages to be sent to multiple trusted receivers, performs joint encoding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to obtain a shared payload vector, and then performs scaling, quantization, and embeddability constraints on the shared payload vector to obtain a quantized payload vector; the specific steps are as follows: S21. Message Alignment and Mapping: The sender obtains the target set of trusted data within the current version identifier epoch. T A collection of hidden messages from multiple receivers ( For a trustworthy set T (The current number of members), perform length alignment, symbol mapping or grouping encoding on each message to form a standardized message vector adapted to joint encoding; S22, Joint Orthogonal Coding: Reading a Trusted Set T Each receiver's private orthogonal codeword set Construct a shared load vector By utilizing the pairwise orthogonality of private orthogonal codewords, we can ensure that the message components of different receivers are completely decoupled in the shared payload space, thus providing a foundation for subsequent separable projection-based local decoding. S23. Scaling and Quantization: To adapt to the discrete value characteristics of UTXO trading fields, a scaling factor is introduced. For shared load vectors Perform quantization processing to obtain the quantized payload vector. , scaling factor The value range can be flexibly adjusted according to the granularity of available amount on the chain and the precision of the field; S24. Range Constraints and Rollback Strategies: For quantized load vectors Each component is subject to effective range constraints to meet the boundary requirements of the amount subsequently mapped to the UTXO transaction output; when a component goes out of bounds, at least one fallback strategy is executed: component truncation, adjustment of scaling factor. Remapping some message components or reselecting the payload fragment length until a quantized payload vector that meets the constraints is obtained; S25. Load fragmentation and cycle binding: Quantizing the load vector The organization is a payload sequence or a set of payload fragments, and is bound to the current version identifier epoch to ensure that the receiver can use the same round parameters to complete filtering and projection-based local decoding; when the payload length exceeds the capacity that a single UTXO-based encrypted transaction can carry, it is split into multiple UTXO-based encrypted transactions and sent in consecutive rounds.

[0026] S3, Transaction Field Embedding and On-Chain Encryption The quantized payload vector is embedded into the standard fields of the UTXO transaction output, and a hidden token is generated based on the shared seed / key and version identifier epoch. The hidden token is then embedded into the bearable location of the transaction output address to construct the UTXO-based encrypted transaction and broadcast it on the blockchain. The specific steps are as follows: S31. Output Structure Configuration: Set the quantization load vector , construct containing The UTXO output carries the encrypted transaction, making the first output... Each transaction output corresponds to a payload component. At the same time, compliant change output and transaction fees are configured to ensure that transactions maintain standard validity under the rules of amount conservation and on-chain verification. S32. Amount Mapping and Constraints: Mapping Load Components A linear mapping is used to represent the amount output by the corresponding transaction. The preferred mapping rule is... ,in For the base amount, Both the amount step size and the amount step size control the granularity of the amount and the available range; at the same time, on-chain compliance constraints are applied. This includes blockchain native rules such as minimum output amount and dust prevention transactions; when the mapped amount does not meet the boundary constraints, the amount step size Δ is adjusted or the process is rolled back to step S2 to re-execute the quantization process. S33. Stealth Tag Generation and Length Control: Based on the shared seed / key and version identifier epoch, for each output index... Generate corresponding hidden markers ,in f( ) It is a combination of pseudo-random function or message authentication code and encoding truncation; and a fixed-length tag suffix is ​​obtained through encoding and truncation, so that the hidden tag satisfies low collision or no collision constraints within the same version identifier epoch, which facilitates fast matching and index recovery at the receiving end; S34. Address Bearing and Format Validity: Hidden Marks Embed the bearable location of the corresponding UTXO transaction output address to form a tagged output address. Embedding methods include embedding the hidden marker as an address suffix, or embedding the equivalent character position of the address without violating the address's legality and transaction verification rules; after embedding, it is necessary to ensure that the address still meets the encoding and verification rules of the corresponding blockchain to avoid causing protocol layer rejection or abnormal detection; S35, Constructing and Broadcasting Secret Transactions: As a transaction output pair, it completes the compliant construction of the UTXO-encrypted transaction and broadcasts it to the blockchain network, so that the transaction is represented as a standard UTXO transaction on the chain, which can be propagated and confirmed by the entire network as the block is completed.

[0027] S4, On-chain Listener Filtering and Index Recovery The receiver listens to the on-chain transaction stream, generates filtering rules based on the locally stored shared seed / key and version identifier epoch, filters candidate UTXO-carrying transactions through hidden tags, and extracts standard fields from the candidate UTXO-carrying transactions to perform output index recovery and sorting, reconstructing the quantized payload vector to be decoded; the specific steps are as follows: S41. On-chain monitoring and preprocessing: The receiver continuously monitors new blocks and transaction pool transactions on the blockchain network, extracting the output set of each transaction. It also performs pre-filtering on non-standard outputs and outputs that do not meet format constraints to reduce subsequent matching overhead; S42. Tag Matching and Filtering: Generate a corresponding set of hidden tags based on the locally stored shared seed / key and version identifier epoch, and apply this to the transaction output address. Perform suffix matching or equivalent matching to filter out transaction outputs carrying compliance hidden markers; S43. Candidate Decision and Fault Tolerance: When the number of outputs matching the hidden marker in the same transaction reaches a preset threshold... When the transaction is identified as a candidate UTXO-based encrypted transaction, and when there is output loss, reordering or noise on the chain, a fault tolerance range can be set on the threshold and matching rules to improve the noise robustness of the payload reconstruction; S44. Index Recovery: Based on the hidden markers and their generation rules, establish a mapping relationship between the hidden markers and the output indices, and recover the original index corresponding to each matching output. ; S45. Reordering and Reconstructing: Based on the restored original index. Sort the matching output in ascending / descending order to obtain an ordered sequence of amount fields, and remove duplicate or conflicting index entries; S46. Obtain the load by inverse mapping of amount: based on the preset base amount. With amount step size The sorted monetary sequence is inversely mapped to quantized payload components. This allows for the complete reconstruction of the quantized payload vector to be decoded. This serves as the input for subsequent projection-based local decoding.

[0028] S5, Projection-based partial decoding The receiver reads its locally stored private orthogonal codewords and corresponding parameters, and performs projection-based local decoding on the quantized payload vector to be decoded, recovering only the hidden message corresponding to that receiver and not the messages of other receivers; the specific steps are as follows: S51, Dequantization and Normalization: Based on the preset scaling factor The reconstructed quantized load vector y is dequantized to obtain the shared load vector. Simultaneously, normalization or offset removal processing can be performed on the shared payload vector to suppress decoding deviations caused by monetary mapping and rounding errors. S52, Projection Estimation: The receiver uses locally stored private orthogonal codewords. Calculate the projection estimate Based on the pairwise orthogonality of private orthogonal codewords, the message components of other receivers are completely suppressed in this projection calculation, and will not interfere with the recovery of the target message. S53, Decision and Inverse Mapping: On the projection estimate Perform threshold decision, rounding or symbol demapping to restore the real value to the original message symbol or message component; when the original message uses block coding or error correction coding, further perform the corresponding decoding operation to improve the error robustness of projection-based local decoding; S54. Locality and Covertness Constraints: The entire projection-based local decoding process relies solely on the private orthogonal codewords stored locally by the receiver. It shares the seed / key and version identifier epoch parameters, without requiring any interaction with the sender or other receivers. It is fully compatible with passive listening reception models, avoiding the exposure of communication traces and the decrease in concealment caused by additional interactions.

[0029] S6, Group control can be revoked Add the recipient to the revocation set when the recipient is untrusted, leaves the group, exceeds the offline time limit, poses a risk of key leakage, or meets the preset revocation policy. The corresponding private orthogonal codewords are removed during subsequent joint encoding, and the shared seed / key and version identifier epoch are updated simultaneously. This prevents the revoked receiver from continuing to filter subsequent UTXO-encrypted transactions and / or from completing projective partial decoding, thereby achieving dynamic revocation and continuous controllability of group covert communication. The specific steps are as follows: S61. Revocation Trigger and Status Update: When a recipient exhibits untrustworthy behavior, actively leaves the group, goes offline for an extended period beyond the custom time limit, poses a risk of key leakage, or meets the preset revocation policy for breach of trust, they are added to the revocation set. Synchronously update the trusted set ; S62. Codeword Removal: In subsequent rounds of joint orthogonal coding, only the trusted set is used. The private orthogonal codeword set corresponding to the internal member is used to construct a shared payload vector. The private orthogonal codeword of the revoked receiver no longer participates in the construction of the payload space, thus blocking its ability to recover the message through projection-based local decoding at the encoding level. S63, Seed / Epoch Rolling Update: Synchronously update the shared seed / key seed and version identifier epoch to the new seed' and epoch', so that the generation of covert markers and index mapping rules in subsequent rounds completely depend on the new seed' and epoch, blocking the revoked recipient's ability to locate subsequent UTXO-carrying transactions from the screening level; S64. Update Distribution and Security Isolation: The updated seed' and epoch' are distributed only to recipients within the trusted set T via off-chain secure channels, on-chain ciphertext delivery, or threshold sharing splitting. The on-chain ciphertext delivery method embeds the ciphertext of seed' as part of the new round of shared payload vector into the UTXO ciphertext transaction, which can only be decrypted and obtained by trusted recipients. The threshold sharing method performs threshold sharing splitting on seed' before distributing it to trusted recipients, preventing revoked recipients from piecing together the complete seed' and ensuring secure isolation of parameter updates. S65. Revocation effect guarantee: After the revocation process is completed, the revoked recipient shall meet at least one of the following effects in subsequent communication rounds: unable to generate new hidden markers to complete candidate transaction screening, unable to recover the output index to reconstruct the payload, and unable to recover the valid message through projection-type local decoding, thereby realizing the dynamic revocation of permissions and continuous blocking of communication capabilities of the distrusted member.

[0030] This invention also discloses a UTXO-type blockchain group covert communication system based on orthogonal codewords and revocable control, comprising: The group security parameter maintenance module is used to maintain the group member set and revocation set, and maintain the member validity status in real time; it generates and maintains a private orthogonal codeword dictionary, a shared seed / key and version identifier epoch, and performs parameter rotation updates after a preset parameter rotation cycle or revocation event is triggered, providing full-process parameter support for off-chain joint encoding and receiver filtering and decoding; The joint orthogonal coding and payload construction module is used to aggregate a set of covert messages to be sent to multiple receivers within a trusted set; perform joint orthogonal coding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to form a shared payload vector; and perform scaling quantization, range constraints and organization fragmentation on the shared payload vector to obtain an embeddable quantized payload vector, which serves as the payload input for subsequent transaction embedding. The transaction embedding and covert tag generation module is used to embed the quantized payload vector mapping into the standard fields of the UTXO transaction; it generates a covert tag associated with the output index based on the shared seed / key and version identifier epoch, and embeds the covert tag into the bearable position of the UTXO transaction output address; based on this, it constructs a compliant UTXO-based encrypted transaction and broadcasts it on the chain, so that the UTXO-based encrypted transaction always remains a valid standard UTXO transaction at the protocol layer; The transaction monitoring, filtering, and payload reconstruction module is used to continuously monitor on-chain transaction stream data; it generates covert marker matching rules based on the locally stored shared seed / key and version identifier epoch, and filters candidate UTXO-based cryptographic transactions according to the marker rules; it extracts the output address and amount fields from the candidate UTXO-based cryptographic transactions, performs output index recovery and sorting, and reconstructs the quantized payload vector to be decoded according to the amount inverse mapping rule, providing input for subsequent projection-based local decoding at the receiving end; The group dynamic management and revocation update module is used to monitor the status of group members and revocation trigger events. Based on the preset default judgment rules, it determines the defaulting objects that need to be removed and updates the set of trusted members. It triggers the rotation update of the shared seed / key and version identifier epoch and generates update parameters. At the same time, it drives the group security parameter maintenance module to complete the parameter synchronization of members in the trusted set. This enables subsequent joint encoding to remove the private orthogonal codewords corresponding to the revoked members and prevents the revoked members from continuing to generate covert markers to filter subsequent UTXO-carrying transactions and / or from completing projection-type local decoding. This achieves dynamic revocation and continuous control of group covert communication.

[0031] This invention also discloses a computing device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method disclosed in the above embodiments.

[0032] This invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method disclosed in the above embodiments.

[0033] Any aspects of this invention not described in detail are well-known to those skilled in the art.

[0034] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for covert communication in a UTXO-type blockchain group based on orthogonal codewords and revocable control, characterized in that, Includes the following steps: S1. Group offline initialization and security parameter maintenance: Establish a group member set and a revocation set, generate and securely distribute the private orthogonal codewords for each legitimate recipient, generate and maintain a shared seed / key and version identifier epoch for transaction screening and decoding consistency, and update the shared seed / key and version identifier epoch when member changes or revocation is triggered. S2. Joint Orthogonal Coding and Payload Construction: The sender obtains a set of hidden messages to be sent to multiple trusted receivers, performs joint coding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to obtain a shared payload vector, and performs scaling, quantization and embeddability constraints on the shared payload vector to obtain a quantized payload vector. S3, Transaction Field Embedding and On-Chain Encryption: The quantized payload vector is embedded into the standard fields of the UTXO transaction output, and a hidden marker is generated based on the shared seed / key and version identifier epoch. The hidden marker is embedded into the bearable position of the transaction output address to construct the UTXO encrypted transaction and broadcast it on the chain. S4. On-chain monitoring, filtering, and index recovery: The receiver monitors the on-chain transaction stream, generates filtering rules based on the locally stored shared seed / key and version identifier epoch, filters candidate UTXO-based cryptographic transactions through hidden markers, and extracts standard fields from the candidate UTXO-based cryptographic transactions to perform output index recovery and sorting, reconstructing the quantized payload vector to be decoded. S5. Projection-based local decoding: The receiver reads its locally stored private orthogonal codewords and corresponding parameters, performs projection-based local decoding on the quantized payload vector to be decoded based on inner product projection, and only recovers the hidden message corresponding to the receiver without recovering the messages of other receivers. S6. Group Revocation Control: When a recipient is untrusted, leaves the group, exceeds the offline time limit, poses a risk of key leakage, or meets the preset revocation policy, the recipient is added to the revocation set. In subsequent joint encoding, the corresponding private orthogonal codeword is removed, and the shared seed / key and version identifier epoch are updated, so that the revoked receiver cannot continue to filter subsequent UTXO-carrying transactions and / or cannot complete the projection-type local decoding, thereby realizing the dynamic revocation and continuous controllability of group covert communication.

2. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S1 specifically includes: S11. Parameter Initialization and Set Establishment: Assume the total number of valid receivers in the group is n, and establish the group member set. With cancellation set Maintaining a trusted set Initialize codeword dimensions sparse combination parameters Integer weight range And generate a shared seed / key and version identifier epoch; S12, Orthogonal basis construction: constructing or selecting a basis of order of... orthogonal basis matrix ,satisfy , for An identity matrix of order 1; S13, Combination Codeword Generation: For the first... One receiver, from an orthogonal basis matrix Select from the row vectors Each index constitutes a subset of the indexes. From symmetric bounded intervals Medium uniform sampling integer weight Generate combined codewords ; S14. Structured permutation processing: Generating secret column permutations using a shared seed / key. With the corresponding permutation matrix By applying column permutations to the combined codewords, private orthogonal codewords are obtained. ; S15. Orthogonality Check and Distribution Storage: Perform pairwise orthogonality checks on the private orthogonal codeword set to ensure that any... satisfy When the orthogonality constraint is not satisfied, resampling is performed on the index subset and / or weights, or orthogonalization is performed on the private orthogonal codeword set until the orthogonality constraint is satisfied; after the verification passes, the private orthogonal codewords corresponding to each receiver are... The filtering and decoding parameters related to the shared seed / key and the version identifier epoch are distributed to the corresponding receiving end through a secure channel and stored locally. S16. Parameter version maintenance: Maintain the version correspondence between the shared seed / key and the version identifier epoch, record the effective range of each version identifier epoch, and ensure that the sender and the unrevoked trusted receiver use consistent covert tag generation rules and parameter configurations within the same version identifier epoch.

3. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S2 specifically includes: S21. Message Alignment and Mapping: In the current version identifier epoch, the sender obtains a set of hidden messages for multiple receivers within the trusted set T. Each message is length aligned, symbol mapped, or grouped and encoded to form a standardized message vector adapted to joint encoding. S22. Joint Orthogonal Coding: Read the private orthogonal codeword sets corresponding to each receiver within the trusted set T. Construct a shared load vector ; S23. Scaling and Quantization: Introducing Scaling Factors For shared load vectors Perform quantization processing to obtain the quantized payload vector. , ; S24. Range Constraints and Rollback Strategies: For quantized load vectors Each component is subject to an effective range constraint; when a component goes out of bounds, at least one fallback strategy is executed: component truncation, adjustment of scaling factor. Remapping some message components or reselecting the payload fragment length until a quantized payload vector that meets the constraints is obtained; S25. Load fragmentation and cycle binding: Quantizing the load vector The organization is a payload sequence or a set of payload fragments, and is bound to the current version identifier epoch to ensure that the receiver can use the same round parameters to complete filtering and projection-based local decoding; when the payload length exceeds the capacity that a single UTXO-based encrypted transaction can carry, it is split into multiple UTXO-based encrypted transactions and sent in consecutive rounds.

4. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S3 specifically includes: S31. Output Structure Configuration: Set the quantization load vector , construct containing The UTXO output carries the encrypted transaction, making the first output... Each transaction output corresponds to a payload component. At the same time, compliant change output and transaction fees are configured to ensure that transactions maintain standard validity under the rules of amount conservation and on-chain verification. S32. Amount Mapping and Constraints: Mapping Load Components A linear mapping is used to represent the amount output by the corresponding transaction. The preferred mapping rule is... ,in For the base amount, The amount increment; simultaneously, on-chain compliance constraints are applied. This includes blockchain native rules such as minimum output amount and dust prevention transactions; when the mapped amount does not meet the boundary constraints, the amount step size Δ is adjusted or the process is rolled back to step S2 to re-execute the quantization process. S33. Stealth Tag Generation and Length Control: Based on the shared seed / key and version identifier epoch, for each output index... Generate corresponding hidden markers , where f( ) is a combination of pseudo-random function or message authentication code and encoding truncation; and a fixed-length tag suffix is ​​obtained through encoding and truncation, so that the hidden tag satisfies low collision or no collision constraints within the same version identifier epoch; S34. Address Bearing and Format Validity: Hidden Marks Embed the bearable location of the corresponding UTXO transaction output address to form a tagged output address. Embedding methods include embedding the hidden marker as an address suffix, or embedding the equivalent bearable character position of the address without violating the address's legality and transaction verification rules. S35, Constructing and Broadcasting Secret Transactions: As a transaction output pair, it completes the compliant construction of the UTXO-encrypted transaction and broadcasts it to the blockchain network, so that the transaction is represented as a standard UTXO transaction on the chain, which can be propagated and confirmed by the entire network as the block is completed.

5. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S4 specifically includes: S41. On-chain monitoring and preprocessing: The receiver continuously monitors new blocks and transaction pool transactions on the blockchain network, extracting the output set of each transaction. It also performs pre-filtering on non-standard outputs and outputs that do not meet format constraints; S42. Tag Matching and Filtering: Generate a corresponding set of hidden tags based on the locally stored shared seed / key and version identifier epoch, and apply this to the transaction output address. Perform suffix matching or equivalent matching to filter out transaction outputs carrying compliance hidden markers; S43. Candidate Decision and Fault Tolerance: When the number of outputs matching the hidden marker in the same transaction reaches a preset threshold... When the transaction is selected as a candidate UTXO-based transaction, the fault tolerance range can be set on the threshold and matching rules when there are output loss, reordering or noise on the chain. S44. Index Recovery: Based on the hidden markers and their generation rules, establish a mapping relationship between the hidden markers and the output indices, and recover the original index corresponding to each matching output. ; S45. Reordering and Reconstructing: Based on the restored original index. Sort the matching output in ascending / descending order to obtain an ordered sequence of amount fields, and remove duplicate or conflicting index entries; S46. Obtain the load by inverse mapping of amount: based on the preset base amount. With amount step size The sorted monetary sequence is inversely mapped to quantized payload components. This allows for the complete reconstruction of the quantized payload vector to be decoded. .

6. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S5 specifically includes: S51, Dequantization and Normalization: Based on the preset scaling factor The reconstructed quantized load vector y is dequantized to obtain the shared load vector. Simultaneously, normalization or offset removal processing can be performed on the shared payload vector to suppress decoding deviations caused by monetary mapping and rounding errors. S52, Projection Estimation: The receiver uses locally stored private orthogonal codewords. Calculate the projection estimate Based on the pairwise orthogonality of the private orthogonal codewords, the message components of other receivers are completely suppressed in this projection calculation. S53, Decision and Inverse Mapping: On the projection estimate Perform threshold judgment, rounding, or symbol demapping to restore the real value to the original message symbol or message component; when the original message uses block coding or error correction coding, further perform the corresponding decoding operation; S54. Locality and Covertness Constraints: The entire projection-based local decoding process relies solely on the private orthogonal codewords stored locally by the receiver. It shares the seed / key and version identifier epoch parameters, eliminating the need for any interaction with the sender or other receivers, and is compatible with passive listening reception models.

7. The method for covert communication of UTXO-type blockchain groups based on orthogonal codewords and revocable control as described in claim 1, characterized in that, Step S6 specifically includes: S61. Revocation Trigger and Status Update: When a recipient exhibits untrustworthy behavior, actively leaves the group, goes offline for an extended period beyond the custom time limit, poses a risk of key leakage, or meets the preset revocation policy for breach of trust, they are added to the revocation set. Synchronously update the trusted set ; S62. Codeword Removal: In subsequent rounds of joint orthogonal coding, only the trusted set is used. The private orthogonal codeword set corresponding to the internal member is used to construct a shared payload vector. The private orthogonal codeword of the revoked receiver no longer participates in the construction of the payload space, thus blocking its ability to recover the message through projection-based local decoding at the encoding level. S63, Seed / Epoch Rolling Update: Synchronously update the shared seed / key seed and version identifier epoch to the new seed' and epoch', so that the generation of covert markers and index mapping rules in subsequent rounds completely depend on the new seed' and epoch, blocking the revoked recipient's ability to locate subsequent UTXO-carrying transactions from the screening level; S64. Update Distribution and Security Isolation: The updated seed' and epoch' are distributed only to recipients within the trusted set T via off-chain secure channels, on-chain ciphertext delivery, or threshold sharing splitting. The on-chain ciphertext delivery method embeds the ciphertext of seed' as part of the new round of shared payload vector into the UTXO ciphertext transaction, which can only be decrypted and obtained by trusted recipients. The threshold sharing method performs threshold sharing splitting on seed' before distributing it to trusted recipients, preventing revoked recipients from piecing together the complete seed' and ensuring secure isolation of parameter updates. S65. Revocation effect guarantee: After the revocation process is completed, the revoked recipient shall meet at least one of the following effects in subsequent communication rounds: unable to generate new hidden markers to complete candidate transaction screening, unable to recover the output index to reconstruct the payload, and unable to recover the valid message through projection-type local decoding, thereby realizing the dynamic revocation of permissions and continuous blocking of communication capabilities of the distrusted member.

8. A UTXO-type blockchain group covert communication system based on orthogonal codewords and revocable control, characterized in that, include: The group security parameter maintenance module is used to maintain the group member set and the revocation set, and to maintain the validity status of members in real time. Generate and maintain a private orthogonal codeword dictionary, a shared seed / key and version identifier epoch, and perform parameter rotation updates after a preset parameter rotation period or a revocation event is triggered, providing full-process parameter support for off-chain joint encoding and receiver filtering and decoding; The joint orthogonal coding and payload construction module is used to aggregate a set of covert messages to be sent to multiple receivers within a trusted set; perform joint orthogonal coding and linear aggregation based on the private orthogonal codewords corresponding to each receiver to form a shared payload vector; and perform scaling quantization, range constraints and organization fragmentation on the shared payload vector to obtain an embeddable quantized payload vector, which serves as the payload input for subsequent transaction embedding. The transaction embedding and covert tag generation module is used to embed the quantized payload vector mapping into the standard fields of the UTXO transaction; it generates a covert tag associated with the output index based on the shared seed / key and version identifier epoch, and embeds the covert tag into the bearable position of the UTXO transaction output address; based on this, it constructs a compliant UTXO-based encrypted transaction and broadcasts it on the chain, so that the UTXO-based encrypted transaction always remains a valid standard UTXO transaction at the protocol layer; The transaction monitoring, filtering, and payload reconstruction module is used to continuously monitor on-chain transaction stream data; it generates covert marker matching rules based on the locally stored shared seed / key and version identifier epoch, and filters candidate UTXO-based cryptographic transactions according to the marker rules; it extracts the output address and amount fields from the candidate UTXO-based cryptographic transactions, performs output index recovery and sorting, and reconstructs the quantized payload vector to be decoded according to the amount inverse mapping rule, providing input for subsequent projection-based local decoding at the receiving end; The group dynamic management and revocation update module is used to monitor the status of group members and revocation trigger events. Based on the preset default judgment rules, it determines the defaulting objects that need to be removed and updates the set of trusted members. It triggers the rotation update of the shared seed / key and version identifier epoch and generates update parameters. At the same time, it drives the group security parameter maintenance module to complete the parameter synchronization of members in the trusted set. This enables subsequent joint encoding to remove the private orthogonal codewords corresponding to the revoked members and prevents the revoked members from continuing to generate covert markers to filter subsequent UTXO-carrying transactions and / or from completing projection-type local decoding. This achieves dynamic revocation and continuous control of group covert communication.

9. A computing device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes a computer program, it implements the method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1–7.

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