A Blockchain-Based Distributed Covert Data Reporting Method

Abstract

This invention relates to a distributed, covert data reporting method based on blockchain, belonging to the field of data security technology. To ensure the security of the data reporting process, this invention proposes a session key update method based on blockchain and Diffie-Hellman key exchange. Using symmetric cryptography, hash functions, and digital signature technology, it proposes a special data packet construction method. Each participating party periodically scans the blockchain for changes and pulls the new block to its local machine. This invention fundamentally eliminates the need for a handshake between the sender and receiver to establish a secure network communication channel, reducing the adverse effects of attacks such as DDoS attacks; it ensures the integrity and consistency of data packets; it provides data non-repudiation, tamper-proof, and anti-forgery characteristics; and it achieves low-maintenance key distribution and storage.

Description

Technical Field

[0001] This invention belongs to the field of data security technology, specifically relating to a distributed, covert data reporting method based on blockchain. Background Technology

[0002] Data reporting aims to transmit data from one system to another via networks or other communication methods. It typically requires the integration of cryptography, network security, and other technologies to maintain the consistency, integrity, confidentiality, and compliance of data from source to destination. With the development of information technology, data reporting has become an important part of the daily operations of industries and institutions such as governments, military, and finance that require regular data reporting.

[0003] However, traditional data reporting methods have several problems. First, traditional methods rely on one-time network communication. Successful data transmission depends on a network handshake between the sender and receiver to establish a secure communication channel, a process highly vulnerable to cyberattacks. While modern cryptography can prevent adversaries from accessing the secret data contained in the datagram, they can still disrupt this prerequisite using attacks such as Denial-of-Service (DDoS) attacks, preventing communication and hindering data reporting. Second, traditional methods focus solely on the transmission process, leaving the receiver in complete control after the data arrives at its destination. In scenarios with high data reporting frequency and high data confidentiality, this places a significant burden on the receiver's storage management, making them susceptible to targeted attacks, data corruption, and tampering, with the damage difficult to detect afterward. Third, traditional methods employ one-to-one or broadcast network communication, with clear identities of senders and receivers, explicit communication direction, and easily traceable message paths, failing to meet the demands of data reporting scenarios requiring high levels of covert communication. For example, in a military environment, this results in insufficient information concealment, making systems and units vulnerable to concentrated attacks and inadequate for future intelligent battlefield environments. Fourth, in covert communication scenarios, key distribution between the sender and receiver is quite difficult. Traditional methods require each participant to share a master key with each other in order to generate temporary session keys for encrypting datagrams in the future. This results in the master key space complexity, which reaches the quadratic level, making secure storage extremely difficult.

[0004] Blockchain technology is a decentralized distributed ledger technology that uses cryptographic algorithms to link data blocks in chronological order to form a chain structure, ensuring that the data is immutable and unforgeable, providing a new approach to solving the aforementioned problems. This invention aims to address the problems of traditional data reporting methods and provide a distributed, covert data reporting method based on blockchain technology. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The technical problem to be solved by this invention is how to provide a distributed, covert data reporting method based on blockchain to solve the above-mentioned problems of traditional data reporting methods.

[0007] (II) Technical Solution

[0008] To address the aforementioned technical problems, this invention proposes a distributed, covert data reporting method based on blockchain, which includes the following steps:

[0009] Step 1: Session Key Generation

[0010] First, all participants in the communication need to agree on a unified session key update strategy in advance, which specifies the conditions under which each participant will update the session key.

[0011] The key update server continuously checks whether the update conditions specified in the policy are met. If so, it generates a random number P and a generator G according to the Diffie-Hellman key exchange protocol and broadcasts them to all communication participants as a session key update instruction. Upon receiving the broadcast, each communication participant generates publicly available information and sends it to the key update server. The key update server aggregates the publicly available information from all communication participants and organizes it into a key update list. The key update server then submits the key update list as a transaction data to the blockchain for on-chain request. After the transaction broadcast and block consensus process, the key update list will be stored in plaintext in a specific block.

[0012] Each participant in the communication scans the blockchain for changes in real time and pulls newly added blocks; once a new key update list is detected, it is saved to the local cache; and a session key ssk is generated based on the key update list.

[0013] Step 2: Send datagram

[0014] The sender organizes the data into a raw datagram ORMSG. Then, based on the receiver's identity, the sender selects the session key ssk generated in step one to encrypt the datagram header H and data D of the raw datagram ORMSG, respectively, to obtain ciphertext C. The sender signs the ciphertext C. Finally, the sender uses the session key ssk to encrypt the digital signature to obtain the signed ciphertext Csig. Combining Csig and ciphertext C yields the datagram MSG.

[0015] The datagram is sent using a random forwarding network. The datagram MSG is packaged into a new transaction data and a request to be uploaded to the blockchain is submitted.

[0016] Step 3: Receive data packets

[0017] Each participating party periodically scans the blockchain for changes and pulls new blocks to its local machine. They discard blocks that clearly do not contain datagrams. For the remaining data, based on the MSG format, they extract the potentially ciphertext Chead and attempt to decrypt it using their respective session keys. Once decrypted using a session key ssk, if the receiving address RecvAddr matches their own address, it indicates that the datagram was received by themselves. The receiving party then decrypts the datagram to obtain the plaintext.

[0018] (III) Beneficial Effects

[0019] This invention proposes a distributed covert data reporting method based on blockchain. It also discloses a highly robust method for correcting labeled data and detecting events in the military field, with the main advantages being as follows:

[0020] (1) The data reporting process of this invention is based on blockchain, which separates the data packet sending and receiving processes. The sender only needs to put the data on the blockchain without considering the current network status of the receiver. The receiver can pull data packets from the blockchain at any time. This fundamentally eliminates the need for the sender and receiver to handshake to establish a secure network communication channel, and reduces the adverse effects of network attacks such as denial-of-service attacks (DDoS).

[0021] (2) This invention uses blockchain to distribute and store data packets, eliminating the need for local maintenance by the receiver. Because blockchain data is immutable and unforgeable, adversaries cannot corrupt the blocks on the chain, ensuring the integrity and consistency of the data packets.

[0022] (3) This invention uses a random forwarding network on the sender side, eliminating the correspondence between data packets and the sender for adversaries. Data packets are stored on the blockchain, and the receiver pulls new blocks and scans the message data, naturally eliminating the correspondence between data packets and the receiver. Based on this, this invention utilizes digital signatures and designs a special data packet format to provide data non-repudiation, tamper-proof, and forgery-proof characteristics while ensuring that the digital signature itself does not reveal the sender's identity.

[0023] (4) A session key generation method based on blockchain and Diffie-Hellman key exchange technology is proposed. Combining the advantages of the two technologies, key distribution and storage with low maintenance cost are realized. Attached Figure Description

[0024] Figure 1 This is a general framework diagram of the present invention;

[0025] Figure 2 This is a flowchart of the session key generation process of the present invention;

[0026] Figure 3 This is a schematic diagram of the sender's data processing.

[0027] Figure 4 This is a schematic diagram of the data processing by the receiving party. Detailed Implementation

[0028] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0029] This invention discloses a distributed, covert data reporting method based on blockchain. By utilizing technologies such as blockchain, symmetric cryptography, public-key cryptography, hash algorithms, and digital signatures, it achieves data reporting that is unforgeable, immutable, requires no network handshake between the sender and receiver, and ensures the identities of both parties are not revealed. The main problems this invention aims to solve are:

[0030] (1) The sending and receiving parties need to perform a network handshake and establish a secure communication channel. This process is vulnerable to network attacks, which may threaten the integrity, consistency and confidentiality of the data, or make it difficult to establish normal communication and hinder the normal data reporting.

[0031] (2) In scenarios with high data reporting frequency and high data confidentiality, since the data reporting process is a one-time communication, the data security depends on the receiver. Its storage is vulnerable to targeted attacks from adversaries, which can lead to data damage, tampering, and difficulty in detecting the damage.

[0032] (3) The identities of the sender and receiver are clear, the communication direction is clear, and the message transmission path is easy to be tracked, which cannot meet the data reporting scenarios with high requirements for covert communication.

[0033] (4) Under the premise of covert communication, there is a key distribution problem among the communication participants, and the key maintenance is difficult.

[0034] like Figure 1 The diagram shown is an overall framework diagram of a distributed covert data reporting method based on blockchain according to the present invention.

[0035] Step 1: Session Key Generation

[0036] To ensure the security of the data transmission process, it is necessary to periodically update the session keys of each participating party. This invention proposes a session key update method based on blockchain and Diffie-Hellman key exchange. The process framework is as follows: Figure 2 As shown.

[0037] First, all participants in the communication need to agree on a unified session key update strategy in advance. This strategy specifies the conditions under which each participant will update the session key, such as after a specific interval or when the number of blocks in the blockchain reaches a threshold. The strategy is relatively flexible and can be selected according to the actual situation.

[0038] Table 1 Key Update List

[0039] Contact address Timestamp Publicly available information <addr1> < / addr1> <timestamp1> < / timestamp1> G^R1modP <addr2> < / addr2> <timestamp2> < / timestamp2> G^R2modP <addr3> < / addr3> <timestamp3> < / timestamp3> G^R3modP … … …

[0040] The key update server continuously checks whether the update conditions specified in the policy are met. If so, it generates a random number P and a generator G according to the Diffie-Hellman key exchange protocol and broadcasts this to all communication participants as a session key update instruction. Upon receiving the broadcast, each communication participant generates a secret random number R (a random integer between 1 and P-2) locally and calculates G. R mod P is sent as publicly available information to the key update server. The key update server aggregates the publicly available information from all communication participants and, once complete, organizes it into a key update list, as shown in Table 1. The key update server then submits this key update list as a transaction to the blockchain, requesting it to be uploaded. After transaction broadcasting and block consensus processes, the key update list will be stored in plaintext in a specific block.

[0041]

[0042] Each participating party scans the blockchain for changes in real time and pulls newly added blocks (pulling list). Once a new key update list is detected, it is saved to the local cache. The calculation method for generating the session key based on the key update list is shown in Equation (1). Assume a participating party P... i Want to get with P j The session key, then according to P j Address Addr j Retrieve the key update list to obtain the corresponding publicly available information. Then, using the locally saved R i The session key is calculated by P. Similarly, participant P j The same method can also be used to obtain P i Same session key for communication Because adversary A is unaware of the secret random numbers R of each participant, it is unable to generate the correct session key.

[0043] The session key update method proposed in this invention combines blockchain and Diffie-Hellman key exchange, providing the following superior features:

[0044] (1) Reduced communication overhead: In traditional key distribution methods, the session key update synchronization task requires all n participants to communicate and negotiate with each other, resulting in a communication complexity of O(n^2). 2 This invention requires one key update server network broadcast and n one-to-one communication between the participants and the key update server, reducing the communication complexity to O(n).

[0045] (2) Guarantee of Information Correctness: This invention utilizes the immutability of blockchain to ensure that each participant receives correct key update information. In traditional key distribution methods, one-to-one communication between participants is vulnerable to network attacks, such as man-in-the-middle attacks, leading to the theft and substitution of session key-related update information. In this invention, there is no communication between any two participants; only communication exists between the participants and the key update server. First, the key update server can only obtain publicly available information from each participant. Even if the key update server is compromised by adversary A, no secret information will be leaked. Multiple key update servers can be set up to counter the aforementioned attacks. Second, adversary A may attempt to attack and tamper with the communication content between the participants and the key update server, but this method will not be effective because once an incorrect key update list is uploaded to the chain, the participants can immediately detect the errors in the relevant entries, thereby alerting other participants and the key update server. Furthermore, due to the immutability of blockchain, adversary A cannot manipulate the block itself.

[0046] (3) Low local key maintenance cost: In traditional methods, each participant needs to maintain keys between each other (depending on the method, this may include session keys, master keys, random seeds, etc.), resulting in a space complexity of O(n^2). 2 Here, n represents the total number of participants, and all of the above data needs to be encrypted and stored. In this invention, each participant needs to maintain a key update list locally, with a space complexity of O(n). This list is publicly available and does not require encrypted storage. Participants only need to encrypt and store a secret random number R, greatly reducing maintenance costs.

[0047] Step 2: Send datagram

[0048] This invention proposes a unique data packet construction method using symmetric cryptography, hash functions, and digital signature technology. This method provides anti-repudiation and anti-forgery characteristics while ensuring that confidential data packet information is not leaked and the sender's identity remains undiscovered. Specifically, the receiver can verify, either independently or to a third party, that the target data packet was generated and uploaded to the blockchain by a specific sender. To achieve these functional characteristics, this invention divides the task into a data packet construction stage and a random forwarding and blockchain uploading stage.

[0049] (1) Datagram Construction Stage

[0050] The sender organizes the data as follows: Figure 3 The raw datagram format shown is explained below:

[0051] ORMSG = (H, D)

[0052] H = (SendAddr, RecvAddr, r)

[0053] ORMSG represents the raw datagram, which can be broken down into a datagram header H and a data field D. The datagram header H can be further divided into a sender address (SendAddr), a receiver address (RecvAddr), and a random number (r). The sender and receiver addresses differ from the address concepts used in network transmission. In this invention, these two addresses merely serve as identifiers, allowing the data receiver to ascertain the message's origin and confirm its identity as the recipient; they do not participate in network routing or other network communication processes. The definition of the addresses is flexible and is agreed upon in advance by the sending and receiving parties, for example, using clearly identifiable composite fields such as names, identity IDs, or department names.

[0054] The data header H should also include a random number r to prevent adversaries from analyzing the sender's identity. First, the plaintext space for addresses SendAddr and RecvAddr may be small, and adversary A may know the prior distribution of these addresses, making the encrypted data header vulnerable to brute-force attacks. Second, without the random number r, data headers from the same sender and receiver will produce identical ciphertext data after encryption. This allows adversary A to gain additional knowledge without cracking the ciphertext, namely, knowing that certain data packets belong to the same sender-receiver pair, and thus analyzing the sender's identity based on global historical network traffic.

[0055] Subsequently, based on the receiver's identity, the sender selects the session key ssk generated in step one to encrypt the header H and data D of the original datagram ORMSG:

[0056] Chead:=Enc ssk (H)

[0057] Cd:=Enc ssk (D)

[0058] C := (Chead, Cd)

[0059] Where Chead represents the encrypted data header, Cd represents the encrypted data field, and C represents the encrypted original data packet after concatenating Chead and Cd. ssk This indicates that symmetric key encryption is used with the session key, employing secure symmetric cryptographic algorithms such as AES. The above operations ensure that the sender-receiver correspondence and the message data D are not leaked.

[0060] hash := SHA(C)

[0061] Sig: = Sign sk (hash)

[0062] Csig:=Enc ssk (Sig)

[0063] MSG: = (Csig, C)

[0064] This invention signs hash values, thereby supporting non-repudiation and non-forgery characteristics. That is, the sender cannot later deny its sender identity, and an adversary A cannot impersonate the sender to generate legitimate messages. Specifically, the sender uses a hash function such as SHA256 or SHA512 to calculate the hash value of the ciphertext C, and then signs it using its private key sk to generate a digital signature Sig for the hash value. The sender needs to generate a key pair (sk, pk) beforehand, where the private key sk is kept secret by the sender, and the public key pk is submitted to a public key infrastructure (PKI) for registration. Finally, the sender uses the session key ssk to encrypt the digital signature to obtain the signed ciphertext Csig. Concatenating Csig and the ciphertext C yields the datagram MSG.

[0065] Through the above operations, this invention enables the recipient to verify the digital signature or display the digital signature for third-party verification, while preventing adversary A from discovering the sender's identity by testing all public keys in the Public Key Infrastructure (PKI), thus ensuring the sender's privacy. This is because the digital signature is encrypted with the session key SSK, which can only be decrypted by the sender and receiver.

[0066] (2) Random forwarding and on-chain stage

[0067] To conceal the correspondence between the sender and the datagram MSG, this invention employs a random forwarding network. A random forwarding network is a network infrastructure composed of a large number of routers, each forwarding received packets to other routers in the network according to probability. After a certain number of random forwardings, the last router forwards the packet to a specific service node, which is responsible for packaging the datagram MSG into new transaction data and submitting a request to the blockchain for on-chain processing.

[0068] The above operations make it difficult for adversary A to trace the message path, thus preventing them from locating the data source. Furthermore, based on the nature of the MSG (Message Submission Group) datagram, adversary A cannot determine the sender's identity through the datagram. Ultimately, this achieves the concealment of the sender's identity.

[0069] Step 3: Receive data packets

[0070] Each participating party periodically scans the blockchain for changes and pulls new blocks to its local machine. Participants discard blocks that clearly do not contain datagrams. For the remaining data, the receiver... Figure 4 As shown, based on the format of the datagram MSG, the portion that is likely ciphertext Chead is extracted, and decryption is attempted using various session keys. Once decrypted using a session key ssk, the receiving address RecvAddr in the decryption result matches its own address, indicating that the datagram was received by itself. Due to the use of symmetric cryptography and the small size of Chead, the overall performance overhead is acceptable.

[0071] (Csig,Chead,Cd)←MSG

[0072] Sig:=Ded ssk (Csig)

[0073] hash := SHA(C)

[0074] Next, the receiver splits the datagram MSG into (Csig, Chead, Cd), where Csig is the ciphertext signature, Chead is the ciphertext header, and Cd is the ciphertext data field. The receiver inputs the session key ssk into the decryption algorithm Dec to decrypt Csig into the digital signature Sig, and then uses the same hash function SHA (pre-agreed upon by all communication participants) as the sender to obtain the hash value of the ciphertext C. The receiver obtains the sender's public key pk (located at SendAddr) from the public key infrastructure pki, and uses the hash and pk to verify the digital signature Sig. If the verification passes, it means that the message was indeed generated and uploaded to the blockchain by the sender at address SendAddr. If the verification fails, the datagram MSG is discarded.

[0075] D: = Dec ssk (Cd)

[0076] Finally, the receiver inputs the session key ssk into the decryption algorithm Dec to decrypt the ciphertext Cd of the data field, obtaining the plaintext D of the data field for subsequent processing. This completes the data transmission process.

[0077] In this invention, digital signatures also support third-party verification. Because the digital signature is encrypted as Csig to conceal the sender's identity, a third party cannot decrypt it to obtain the digital signature Sig. Therefore, the receiver needs to provide Sig and reveal the sender's identity so that the third party can obtain the corresponding public key pk from the public key infrastructure (PKI) to verify the signature. During this process, the receiver can provide the digital signature Sig to the third party, demonstrating that it is indeed the recipient of the datagram. If the third party verifies the signature, the correspondence between the datagram and the sender is confirmed. It is important to note that the receiver does not need to locally store the historical session keys corresponding to each datagram. The receiver can reconstruct the correct session key based on the historical key update list and the historical random number R generated locally in the Diffie-Hellman key exchange.

[0078] This invention discloses a method for correcting labeled data and detecting events in military fields under highly robust scenarios, with the main advantages being as follows:

[0079] (1) The data reporting process of this invention is based on blockchain, which separates the data packet sending and receiving processes. The sender only needs to put the data on the blockchain without considering the current network status of the receiver. The receiver can pull data packets from the blockchain at any time. This fundamentally eliminates the need for the sender and receiver to handshake to establish a secure network communication channel, and reduces the adverse effects of network attacks such as denial-of-service attacks (DDoS).

[0080] (2) This invention uses blockchain to distribute and store data packets, eliminating the need for local maintenance by the receiver. Because blockchain data is immutable and unforgeable, adversaries cannot corrupt the blocks on the chain, ensuring the integrity and consistency of the data packets.

[0081] (3) This invention uses a random forwarding network on the sender side, eliminating the correspondence between data packets and the sender for adversaries. Data packets are stored on the blockchain, and the receiver pulls new blocks and scans the message data, naturally eliminating the correspondence between data packets and the receiver. Based on this, this invention utilizes digital signatures and designs a special data packet format to provide data non-repudiation, tamper-proof, and forgery-proof characteristics while ensuring that the digital signature itself does not reveal the sender's identity.

[0082] (4) A session key generation method based on blockchain and Diffie-Hellman key exchange technology is proposed. Combining the advantages of the two technologies, key distribution and storage with low maintenance cost are realized.

[0083] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A distributed, covert data reporting method based on blockchain, characterized in that, The method includes the following steps: Step 1: Session Key Generation First, all participants in the communication need to agree on a unified session key update strategy in advance, which specifies the conditions under which each participant will update the session key. The key update server constantly checks whether the update conditions specified in the policy are met. If they are met, it generates a random number P and a generator G according to the Diffie-Hellman key exchange protocol and broadcasts them to all communication participants as a session key update instruction. After receiving the broadcast, each communication participant generates publicly available information and sends it to the key update server. The key update server collects all publicly available information from all communication participants and organizes it into a key update list once all information has been collected. The key update server submits the key update list as a transaction data to the blockchain and requests it to be uploaded to the blockchain. After the transaction broadcast and block consensus process, the key update list will be stored in plaintext in a certain block. Each participant in the communication scans the blockchain for changes in real time and pulls newly added blocks; once a new key update list is detected, it is saved to the local cache; and a session key ssk is generated based on the key update list. Step 2: Send datagram The sender organizes the data into a raw datagram ORMSG. Then, based on the receiver's identity, the sender selects the session key ssk generated in step one to encrypt the datagram header H and data D of the raw datagram ORMSG, respectively, to obtain ciphertext C. The sender signs the ciphertext C. Finally, the sender uses the session key ssk to encrypt the digital signature to obtain the signed ciphertext Csig. Combining Csig and ciphertext C yields the datagram MSG. The datagram is sent using a random forwarding network. The datagram MSG is packaged into a new transaction data and a request to be uploaded to the blockchain is submitted. Step 3: Receive data packets Each participating party periodically scans the blockchain for changes and pulls new blocks to its local machine. They discard blocks that clearly do not contain datagrams. For the remaining data, based on the MSG format, they extract the potentially ciphertext Chead and attempt to decrypt it using their respective session keys. Once decrypted using a session key ssk, if the receiving address RecvAddr matches their own address, it indicates that the datagram was received by themselves. The receiving party then decrypts the datagram to obtain the plaintext.

2. The distributed covert data reporting method based on blockchain as described in claim 1, characterized in that, The session key update strategy is to wait for a specific interval or until the number of blocks in the blockchain reaches a threshold.

3. The distributed covert data reporting method based on blockchain as described in claim 1, characterized in that, Each participating party generates publicly available information including: generating a secret random number R locally, where R is a random integer between 1 and P-2, and calculating G. R mod P is publicly available information.

4. The distributed covert data reporting method based on blockchain as described in claim 1, characterized in that, The generation of session keys based on the key update list includes: as shown in formula (1), assuming a certain communication participant P i Want to get with P j The session key, then according to P j Address Addr j Retrieve the key update list to obtain the corresponding publicly available information. Then, using the locally saved R i The session key is calculated by P. Similarly, participant P j The same method was used to obtain P. i Same session key for communication Because adversary A is unaware of the secret random numbers R of each participant, it is unable to generate the correct session key; 5. The distributed covert data reporting method based on blockchain as described in any one of claims 2-4, characterized in that, In step two, the sender organizes the data into the raw datagram ORMSG, including: The sender organizes the data into a raw datagram format, as described below: ORMSG = (H, D) H = (SendAddr, RecvAddr, r) ORMSG represents the raw datagram, which can be divided into a datagram header H and a data field D. The datagram header H can be divided into a send address SendAddr, a receive address RecvAddr, and a random number r. The send and receive addresses are different from the address concepts in network transmission. The above two addresses only serve as identifiers to help the data receiver know the source of the message and confirm that it is indeed the message receiver. They do not participate in the network routing and network communication process. The data header H should also contain a random number r to prevent adversaries from analyzing the sender's identity.

6. The distributed covert data reporting method based on blockchain as described in claim 5, characterized in that, In step two, the sender, based on the receiver's identity, selects the session key ssk generated in step one to encrypt the header H and data D of the original datagram ORMSG, resulting in ciphertext C, which includes: Based on the receiver's identity, the sender selects the session key ssk generated in step one to encrypt the header H and data D of the original datagram ORMSG. Permission: =Enc ssk (H) Cd:=Enc ssk (D) C := (Chead, Cd) Where Chead represents the ciphertext of the data header, Cd represents the ciphertext of the data fields, and C represents the original ciphertext of the data packet after concatenating Chead and Cd; Enc ssk This indicates that symmetric key encryption is used with the session key. The above operations ensure that the sender-receiver correspondence and the message data D are not leaked.

7. The distributed covert data reporting method based on blockchain as described in claim 6, characterized in that, In step two, the sender uses the session key ssk to encrypt the digital signature to obtain the signature ciphertext Csig; Concatenating Csig and ciphertext C yields the datagram MSG, which includes: hash := SHA(C) Say:=Sign sk (hash) Csig:=Enc ssk (Say) MSG:=(Csig,C) The sender uses a hash function to calculate the hash value of the ciphertext C, and then signs it using its private key sk to generate a digital signature Sig for the hash value. The sender needs to generate a key pair (sk, pk) in advance, where the private key sk is kept secret by the sender and the public key pk is submitted to the public key infrastructure pki for registration. Finally, the sender uses the session key ssk to encrypt the digital signature to obtain the signed ciphertext Csig. Combining Csig and the ciphertext C yields the datagram MSG.

8. The distributed covert data reporting method based on blockchain as described in claim 7, characterized in that, In step two, the random forwarding network is used to send data packets, package the data packet MSG into new transaction data, and submit an on-chain request to the blockchain. This includes: the random forwarding network is a network facility composed of a large number of routers, each router forwards the received packets to other routers in the network according to probability; after a certain number of random forwardings, the last router forwards the packet to a specific service node, which is responsible for packaging the data packet MSG into new transaction data and submitting an on-chain request to the blockchain.

9. The distributed covert data reporting method based on blockchain as described in claim 7, characterized in that, In step three, the receiver then decrypts the datagram to obtain the plaintext, including: (Csig,Chead,Cd)←MSG Say:=Dec ssk (Csig) hash := SHA(C) The receiver splits the datagram MSG into (Csig, Chead, Cd), where Csig is the ciphertext signature, Chead is the ciphertext header, and Cd is the ciphertext data field. The receiver inputs the session key ssk into the decryption algorithm Dec to decrypt Csig into the digital signature Sig, and then uses the same hash function SHA as the sender to obtain the hash value of the ciphertext C. The receiver obtains the sender's public key pk from the public key infrastructure pki and uses the hash and pk to verify the digital signature Sig. If the verification passes, it means that the message was indeed generated and uploaded to the blockchain by the sender at address SendAddr; if the verification fails, the datagram MSG is discarded. D:=Dec ssk (Cd) Finally, the receiver inputs the session key ssk into the decryption algorithm Dec to decrypt the ciphertext Cd of the data field, obtaining the plaintext D of the data field for subsequent processing. At this point, the data transmission process is complete.

10. The distributed covert data reporting method based on blockchain as described in claim 9, characterized in that, Digital signatures support third-party verification. Since the digital signature is encrypted as Csig, a third party cannot decrypt it to obtain the digital signature Sig on its own. Therefore, the recipient needs to provide the Sig and reveal the sender's identity so that the third party can obtain the corresponding public key pk from the public key infrastructure pki to verify the signature. During this process, the recipient can provide the digital signature Sig to the third party, demonstrating that it is indeed the recipient of the datagram. If the third party verifies the signature, the correspondence between the datagram and the sender is confirmed. The recipient does not need to secretly store the historical session keys corresponding to each datagram locally; the recipient can reconstruct the correct session key based on the historical key update list and the historical random number R generated locally in the Diffie-Hellman key exchange.

Images