Distributed hidden data submission method based on block chain

Abstract

The invention relates to a distributed hidden data submission method based on a block chain, and belongs to the technical field of data security. In order to guarantee the security of a data submission process, a session key updating method based on a block chain and Diffie-Hellman key exchange is provided, symmetric cryptography, a hash function and a digital signature technology are used, a special data message construction method is provided, and each communication participant periodically scans the change of the block chain and pulls a new block to the local. According to the invention, the demand of establishing a secure network communication channel by handshake between a receiving party and a transmitting party is eliminated fundamentally, and the adverse effect of DDos network attack is reduced; the integrity and the consistency of the datagram are ensured; the data anti-repudiation, anti-tampering and anti-forgery characteristics are provided; and key distribution and storage with low maintenance cost are realized.

Description

Technical Field

[0001] The present invention belongs to the field of data security technology, and specifically relates to a distributed hidden data reporting method based on blockchain. Background Art

[0002] Data reporting aims to transfer data from one system to another through the network or other communication methods. It usually requires the combination 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 government, military and finance that need to report data regularly.

[0003] However, there are many problems with traditional data transmission methods. First, the traditional method uses one-time network communication. The prerequisite for successful data transmission is that the sender and receiver conduct a network handshake and establish a secure communication channel. This process is extremely vulnerable to network attacks. Although the application of modern cryptography technology in network security can ensure that the enemy cannot obtain the secret data contained in the datagram, the enemy can use means such as denial of service attacks (DDos) to destroy the above prerequisites, making it impossible to establish communication and hindering the transmission of data. Second, the traditional method only focuses on the transmission process. After the data arrives at the destination, it will be fully managed by the receiver. In scenarios with high data transmission frequency and high data confidentiality, it will bring a heavy burden to the storage management of the receiver, and it is easy to be attacked by the enemy, resulting in data being destroyed and tampered, and the damage is difficult to find after it is caused. Third, the traditional method uses a one-to-one or broadcast network communication method. The identities of the sender and receiver are clear, the communication direction is obvious, and the message transmission path is easy to be tracked. It cannot meet the data transmission scenarios with high requirements for covert communication. For example, in a military environment, this will lead to insufficient information concealment, and systems and units are prone to concentrated attacks, which cannot cope with the future intelligent battlefield environment. Fourth, in the case of covert communication, it is difficult to distribute the keys between the sender and the receiver. The traditional method requires each communication participant to share the master key in order to generate a temporary session key in the future to encrypt the datagram. This results in the space complexity of the master key maintained locally by the communication participants reaching the quadratic level, and the difficulty of secure storage is relatively high.

[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, and ensures that the data cannot be tampered with or forged, providing a new idea for solving the above problems. The present invention aims to solve the problems of traditional data reporting methods and provide a distributed hidden data reporting method based on blockchain technology. Summary of the invention

[0005] 1. Technical issues to be resolved

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

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes a distributed hidden data reporting method based on blockchain, which comprises the following steps:

[0009] Step 1: Session key generation

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

[0011] The key update server checks at any time 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 session key update instructions. After receiving the broadcast, each communication participant generates publicly available information and sends it to the key update server. The key update server collects the publicly available information of all communication participants and organizes it into a key update list after it is fully collected. The key update server uses the key update list as a transaction data and submits a request to the blockchain to be uploaded. After the transaction broadcast and block consensus process, the key update list will be saved in plain text in a certain block.

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

[0013] Step 2: Send datagram

[0014] The sender organizes the data into the original datagram ORMSG. Then, according to the identity of the receiver, the sender selects the session key ssk generated in step 1 to encrypt the data header H and data D of the original datagram ORMSG respectively to obtain the 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. The datagram MSG can be obtained by combining Csig and the ciphertext C.

[0015] Use a random forwarding network to send datagrams, package the datagram MSG into a new transaction data, and submit a request to the blockchain;

[0016] Step 3: Receive datagram

[0017] Each communication participant regularly scans blockchain changes and pulls new blocks to the local area; the participants eliminate blocks that obviously do not contain datagrams, and for the remaining data, according to the format of the datagram MSG, intercept the part that may be the ciphertext Chead, and try to decrypt it with each session key; once decrypted by a certain session key ssk, it is found from the decryption result that the receiving address RecvAddr matches its own address, indicating that the recipient of the datagram is itself; the recipient then decrypts the datagram to obtain the plaintext.

[0018] (III) Beneficial effects

[0019] The present invention proposes a distributed hidden data reporting method based on blockchain. The present invention discloses a method for correcting labeled data and detecting events in the military field under a highly robust scenario. The main advantages are reflected in the following aspects:

[0020] (1) The data reporting process of the present invention is based on blockchain, which separates the data report sending and receiving processes. The sender only needs to upload the data to the blockchain without considering the current network status of the receiver. The receiver can pull the data from the blockchain at any time. This fundamentally eliminates the need for the sender and receiver to shake hands to establish a secure network communication channel, reducing the adverse effects of network attacks such as denial of service attacks (DDos).

[0021] (2) The present invention uses blockchain to store datagrams in a distributed manner, without the need for local maintenance by the recipient. Since blockchain data is tamper-proof and unforgeable, adversaries cannot destroy blocks on the chain, thus ensuring the integrity and consistency of datagrams.

[0022] (3) The present invention uses a random forwarding network on the sender side, which eliminates the correspondence between the datagram and the sender for the adversary. The datagram is stored on the chain, and the receiver pulls the newly added block and scans the message data, which naturally eliminates the correspondence between the datagram and the receiver. On this basis, the present invention uses digital signatures and designs a special datagram format to provide data anti-repudiation, anti-tampering, and anti-forgery characteristics while ensuring that the digital signature itself does not disclose the identity of the sender.

[0023] (4) A session key generation method based on blockchain and Diffie-Hellman key exchange technology is proposed, which combines the advantages of the two technologies and realizes key distribution and storage with low maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the overall framework diagram of the present invention;

[0025] Figure 2 A flow chart for generating a session key of the present invention;

[0026] Figure 3 This is a schematic diagram of data processing at the sender;

[0027] Figure 4 Schematic diagram of data processing on the receiving side. DETAILED DESCRIPTION

[0028] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0029] The present invention discloses a distributed hidden data reporting method based on blockchain. Through blockchain, symmetric encryption, public key encryption, hash algorithm, digital signature and other technologies, data reporting is achieved in which data cannot be forged or tampered with, no network handshake between the sender and the receiver is required, and the identities of both parties are not disclosed. The main problems to be solved by the present invention are:

[0030] (1) The sender and receiver need to conduct 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, thus hindering the normal transmission of data.

[0031] (2) In scenarios where data reporting frequency is high and data confidentiality is high, since the data reporting process is a one-time communication, the data security depends on the recipient, and its storage is vulnerable to targeted attacks from the adversary, causing the data to be destroyed and tampered with, and the damage is difficult to detect.

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

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

[0034] like Figure 1 Shown is an overall framework diagram of a distributed hidden data reporting method based on blockchain of the present invention.

[0035] Step 1: Session key generation

[0036] In order to ensure the security of the data reporting process, it is necessary to regularly update the session keys of each communication participant. This invention proposes a session key update method based on blockchain and Diffie-Hellman key exchange. The process framework is as follows: Figure 2 shown.

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

[0038] Table 1 Key update list

[0039] Address of correspondent 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 checks at any time 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 a secret random number R (a random integer between 1 and P-2) locally and calculates G. R mod P is sent to the key update server as public information. The key update server collects the public information of all communication participants and organizes it into a key update list after it is fully collected, as shown in Table 1. The key update server uses the key update list as a transaction data and submits a request to the blockchain. After the transaction broadcast and block consensus process, the key update list will be saved in plain text in a block.

[0041]

[0042] Each communication participant scans the blockchain changes in real time and pulls the newly added blocks (pull 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 formula (1). Assume that a communication participant P i Want to get with P j The session key is P j Address j Retrieve the key update list and obtain the corresponding publicly available information Then use the locally saved R i , P calculates the session key Similarly, participant P j The same method can also be used to obtain i Same session key for communication Since the adversary A does not know the secret random number R of each participant, he cannot generate the correct session key.

[0043] The session key update method proposed in the present invention combines blockchain with Diffie-Hellman key exchange and provides the following advantages:

[0044] (1) Reduce communication overhead: In the traditional key distribution method, the session key update synchronization task requires all n participants to communicate and negotiate with each other, and the communication complexity is O(n 2 ). The present invention requires one network broadcast of the key update server and n one-to-one communications between the participants and the key update server, and the communication complexity is reduced to O(n).

[0045] (2) Guarantee of correctness of update information: The present invention utilizes the immutability of blockchain to ensure that all participants can obtain 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, which can lead to the theft and substitution of session key related update information. In the present invention, there is no communication process between participants, and there is only communication between 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 groups of key update servers can be set up to resist the above attacks. Second, adversary A may attack and tamper with the communication content between the participant and the key update server, but this method will not work because once the wrong key update list is uploaded to the chain, the participant can immediately find that the relevant entry is wrong, thereby alerting other participants and the key update server. And due to the immutability of blockchain, adversary A cannot manipulate the block itself.

[0046] (3) Low local key maintenance cost: In the traditional method, each participant needs to maintain the key between each other (depending on the method, it may maintain the session key, master key, random seed and other information between each other), and the space complexity is O(n 2 ), n is the total number of participants, and all the above data need to be encrypted and stored. In the present invention, each participant needs to maintain a key update list locally, and its space complexity is O(n). The list is open to the public and does not need to be encrypted and stored. The participants only need to encrypt and save the secret random number R, which greatly reduces the maintenance cost.

[0047] Step 2: Send datagram

[0048] The present invention uses symmetric encryption, hash functions, and digital signature technology to propose a special datagram construction method that can provide anti-repudiation and anti-forgery characteristics while ensuring that the confidential information of the datagram is not leaked and the identity of the sender is invisible, that is, the receiver can verify by itself or prove to a third party that the target datagram is generated and uploaded to the chain by a specific sender. Specifically, in order to meet the above functional characteristics, the present invention divides the task into the datagram construction stage, random forwarding, and chaining stage.

[0049] (1) Datagram construction phase

[0050] The sender organizes the data into Figure 3 The original datagram format shown is described as follows:

[0051] ORMSG=(H,D)

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

[0053] ORMSG represents the original datagram, which can be divided into a datagram header H and a data field D. Among them, the datagram header H can be divided into a sending address SendAddr, a receiving address RecvAddr, and a random number r. The sending and receiving addresses are different from the concept of addresses in network transmission. In the present invention, the above two addresses only serve as identifiers to facilitate the data receiver to know the source of the message and determine that it is indeed the message receiver, and do not participate in network communication processes such as network routing. The definition rules of the address are relatively flexible and are agreed upon in advance by the sending and receiving parties. For example, composite fields with clear directionality such as name, identity ID, and department name are used.

[0054] The data header H should also contain a random number r to prevent the adversary from analyzing the identity of the sender. First, the plaintext space of the addresses SendAddr and RecvAddr may be small, and the adversary A may know the prior distribution of the addresses, which may lead to the threat of exhaustive attacks after the data header is encrypted. Secondly, if the random number r is not introduced, the encrypted ciphertext data generated by the data headers generated by the same sender and receiver are exactly the same, so that the adversary A can obtain additional knowledge without cracking the ciphertext, that is, it can know that some datagrams belong to the same sender and receiver, and thus analyze the sender's identity based on the global historical traffic situation in the network.

[0055] Subsequently, the sender selects the session key ssk generated in step 1 according to the identity of the receiver to encrypt the data header H and data D of the original datagram ORMSG respectively:

[0056] Chead:=Enc ssk (H)

[0057] Cd:=Enc ssk (D)

[0058] C:=(Chead,Cd)

[0059] Among them, Chead represents the data header ciphertext, Cd represents the data field ciphertext, and C represents the original data packet ciphertext after Chead and Cd are combined. ssk It indicates that the session key is used for symmetric key encryption, and a secure symmetric encryption algorithm such as AES can be used. The above operation ensures that the corresponding relationship between the sender and the receiver 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] The present invention signs the hash value to support anti-repudiation and anti-forgery characteristics, that is, the sender cannot deny its identity as the sender afterwards, and the adversary A cannot pretend to be the sender to generate a legitimate message. Specifically, the sender uses a hash function such as SHA256, SHA512, etc. to calculate the ciphertext hash value hash of the ciphertext C, and then signs it with the private key sk it holds to generate a digital signature Sig for the hash value. The sender needs to generate a key pair (sk, pk) in advance, in which the private key sk is kept secretly 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. The datagram MSG can be obtained by combining Csig and the ciphertext C.

[0065] Through the above operations, the present invention can support the receiver to verify the digital signature, or display the digital signature to the outside for third-party verification, while preventing the adversary A from knowing the sender's identity by testing all public keys in the public key infrastructure pki, thereby ensuring the sender's privacy. This is because the digital signature is encrypted by the session key ssk, and only the sender and receiver can decrypt it.

[0066] (2) Random forwarding and chaining stage

[0067] In order to conceal the correspondence between the sender and the datagram MSG, the present invention adopts a random forwarding network. The random forwarding network is a network facility composed of a large number of routers, each of which forwards the received message to other routers in the network according to probability. After a certain number of random forwardings, the last router forwards the message to a specific service node, which is responsible for packaging the datagram MSG into a new transaction data and submitting a request to the blockchain.

[0068] The above operation makes it difficult for adversary A to track the message path, and thus cannot locate the source of the data. At the same time, according to the nature of the datagram MSG, adversary A cannot learn the identity of the sender through the datagram. Ultimately, the identity of the sender is hidden.

[0069] Step 3: Receive datagram

[0070] Each communication participant regularly scans blockchain changes and pulls new blocks to the local area. The participants eliminate blocks that obviously do not contain datagrams. For the remaining data, the receiver Figure 4 As shown in the figure, according to the format of the datagram MSG, the part that may be the ciphertext Chead is intercepted and decrypted using various session keys. Once decrypted using a session key ssk, it is found from the decryption result that the receiving address RecvAddr matches its own address, indicating that the recipient of the datagram is itself. Since symmetric encryption is used and the size of Chead is very small, 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 the form of (Csig, Chead, Cd), where Csig is the signature ciphertext, Chead is the datagram header ciphertext, and Cd is the data field ciphertext. The receiver inputs the session key ssk into the decryption algorithm Dec, decrypts Csig into the digital signature Sig, and then uses the same hash function SHA as the sender (agreed in advance by all communication participants) to obtain the hash value hash of the ciphertext C. The receiver obtains the public key pk of the sender (address is SendAddr) from the public key infrastructure pki, and uses hash and pk to verify the digital signature Sig. If the verification is successful, it means that the message is indeed generated and uploaded to the chain by the sender with the 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 data field ciphertext Cd and obtain the data field plaintext D for subsequent processing. At this point, the data reporting process is completed.

[0077] In the present invention, the digital signature also supports third-party verification. Since the digital signature is encrypted as Csig in order to hide the identity of the sender, the third party cannot decrypt it by itself to obtain the digital signature Sig. Therefore, the receiver needs to provide Sig for it and reveal the identity of the sender so that the third party can obtain the corresponding public key pk from the public key infrastructure pki to verify the signature. In this process, the receiver can provide the digital signature Sig to the third party, indicating that it is indeed the receiver of the datagram. If the third party passes the signature verification, the corresponding relationship between the datagram and the sender is determined. It should be noted that the receiver does not need to secretly store the historical session keys corresponding to each datagram locally. 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] The present invention discloses a method for correcting labeled data and detecting events in the military field under a highly robust scenario, the main advantages of which are reflected in the following aspects:

[0079] (1) The data reporting process of the present invention is based on blockchain, which separates the data report sending and receiving processes. The sender only needs to upload the data to the blockchain without considering the current network status of the receiver. The receiver can pull the data from the blockchain at any time. This fundamentally eliminates the need for the sender and receiver to shake hands to establish a secure network communication channel, reducing the adverse effects of network attacks such as denial of service attacks (DDos).

[0080] (2) The present invention uses blockchain to store datagrams in a distributed manner, without the need for local maintenance by the recipient. Since blockchain data is tamper-proof and unforgeable, adversaries cannot destroy blocks on the chain, thus ensuring the integrity and consistency of datagrams.

[0081] (3) The present invention uses a random forwarding network on the sender side, which eliminates the correspondence between the datagram and the sender for the adversary. The datagram is stored on the chain, and the receiver pulls the newly added block and scans the message data, which naturally eliminates the correspondence between the datagram and the receiver. On this basis, the present invention uses digital signatures and designs a special datagram format to provide data anti-repudiation, anti-tampering, and anti-forgery characteristics while ensuring that the digital signature itself does not disclose the identity of the sender.

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

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A distributed hidden data reporting method based on blockchain, characterized in that: The method comprises the following steps: Step 1: Session key generation First, all communication participants need to agree in advance on a unified session key update policy, which specifies the conditions under which each participant updates the session key; The key update server checks at any time 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 session key update instructions. After receiving the broadcast, each communication participant generates publicly available information and sends it to the key update server. The key update server collects the publicly available information of all communication participants and organizes it into a key update list after all information is collected; The key update server uses the key update list as a transaction data and submits a request to the blockchain. After the transaction broadcast and block consensus process, the key update list will be saved in a block in plain text. Each communication participant scans the blockchain changes in real time and pulls the newly added blocks; once a new key update list is detected, it is saved to the local cache; and the session key ssk is generated based on the key update list; Step 2: Send datagram The sender organizes the data into the original datagram ORMSG. Then, according to the identity of the receiver, the sender selects the session key ssk generated in step 1 to encrypt the data header H and data D of the original datagram ORMSG respectively to obtain the 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. The datagram MSG can be obtained by combining Csig and the ciphertext C. Use a random forwarding network to send datagrams, package the datagram MSG into a new transaction data, and submit a request to the blockchain; Step 3: Receive datagram Each communication participant regularly scans blockchain changes and pulls new blocks to the local area; the participants eliminate blocks that obviously do not contain datagrams, and for the remaining data, according to the format of the datagram MSG, intercept the part that may be the ciphertext Chead, and try to decrypt it with each session key; once decrypted by a certain session key ssk, it is found from the decryption result that the receiving address RecvAddr matches its own address, indicating that the recipient of the datagram is itself; the recipient then decrypts the datagram to obtain the plaintext.

2. The distributed hidden data reporting method based on blockchain as claimed in claim 1, characterized in that: The session key update strategy is to update after a certain interval or when the number of blocks in the blockchain reaches a threshold.

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

4. The distributed hidden data reporting method based on blockchain as claimed in claim 1, characterized in that: The generating of the session key according to the key update list includes: As shown in formula (1), assuming that a communication participant P i Want to get with P j The session key is P j Address j Retrieve the key update list and obtain the corresponding publicly available information Then use the locally saved R i , P calculates the session key Similarly, participant P j The same method is used to obtain i Same session key for communication Since the adversary A does not know the secret random number R of each participant, it cannot generate the correct session key; 5. The distributed hidden data reporting method based on blockchain according to any one of claims 2 to 4, characterized in that: In step 2, the sender organizes the data into an original datagram ORMSG including: The sender organizes the data into raw datagram form, as follows: ORMSG = (H, D) H=(SendAddr,RecvAddr,r) ORMSG represents the original datagram, which can be divided into a datagram header H and a data field D; the datagram header H can be divided into a sending address SendAddr, a receiving address RecvAddr, and a random number r; the sending and receiving addresses are different from the address concepts in network transmission. The above two addresses only serve as identifiers to facilitate the data receiver to know the source of the message and determine that it is indeed the message receiver, and do not participate in network communication processes such as network routing; The datagram header H should also contain a random number r to prevent the adversary from analyzing the sender's identity.

6. The distributed hidden data reporting method based on blockchain as claimed in claim 5, characterized in that: In step 2, the sender selects the session key ssk generated in step 1 according to the identity of the receiver to encrypt the data header H and data D of the original datagram ORMSG respectively, and the ciphertext C obtained includes: The sender selects the session key ssk generated in step 1 according to the identity of the receiver to encrypt the data header H and data D of the original datagram ORMSG respectively: Permission: =Enc ssk (H) Cd:=Enc ssk (D) C: = (Chead, Cd) Among them, Chead represents the data header ciphertext, Cd represents the data field ciphertext, and C represents the original data ciphertext after Chead and Cd are combined; Enc ssk It indicates that the session key is used for symmetric key encryption. The above operation ensures that the correspondence between the sender and the receiver and the message data D are not leaked.

7. The distributed hidden data reporting method based on blockchain as claimed in claim 6 is characterized in that: In the step 2, the sender uses the session key ssk to encrypt the digital signature to obtain the signature ciphertext Csig; Combining Csig and ciphertext C will yield 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 ciphertext hash value hash of the ciphertext C, and then signs it with 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 secretly 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; Csig and ciphertext C are combined to obtain the datagram MSG.

8. The distributed hidden data reporting method based on blockchain as claimed in claim 7 is characterized in that: In the step 2, a random forwarding network is used to send datagrams, the datagram MSG is packaged into a new transaction data, and a request for on-chain is made to the blockchain, including: the random forwarding network is a network facility composed of a large number of routers, and each router forwards the received message to other routers in the network according to probability; after a certain number of random forwardings, the last router forwards the message to a specific service node, which is responsible for packaging the datagram MSG into a new transaction data and making a request for on-chain to the blockchain.

9. The distributed hidden data reporting method based on blockchain as claimed in claim 7, characterized in that: In step 3, 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 the form of (Csig, Chead, Cd), where Csig is the signature ciphertext, Chead is the datagram header ciphertext, and Cd is the data field ciphertext; the receiver inputs the session key ssk into the decryption algorithm Dec, decrypts Csig into the digital signature Sig, and then uses the same hash function SHA as the sender to obtain the hash value hash of the ciphertext C; the receiver obtains the sender's public key pk from the public key infrastructure pki, and uses hash and pk to verify the digital signature Sig; if the verification is successful, it means that the message is indeed generated and uploaded to the chain by the sender with the 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 data field ciphertext Cd and obtains the data field plaintext D for subsequent processing. At this point, the data reporting process is completed.

10. The distributed hidden data reporting method based on blockchain as claimed in claim 9, characterized in that: Digital signatures support third-party verification. Digital signatures are encrypted as Csig, so third parties cannot decrypt them by themselves to obtain the digital signature Sig. Therefore, the receiver needs to provide Sig and reveal the identity of the sender so that the third party can obtain the corresponding public key pk from the public key infrastructure pki to verify the signature. In this process, the receiver can provide the digital signature Sig to the third party, indicating that it is indeed the receiver of the datagram. If the third party passes the signature verification, the correspondence between the datagram and the sender is determined. The receiver does not need to secretly store the historical session keys corresponding to each datagram locally. 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.

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