TWI704794B - System and implement method for signing and verifying contract in a block chain network - Google Patents

Abstract

A blockchain-based contract signing and verification system and its implementation method. The system includes a hash module, an encryption module, and a verification module. The hash module can verify an electronic contract before and after signing an electronic contract. The text and attribute information respectively perform hash calculations to calculate a corresponding original hash value and a sign-off hash value; the encryption module can digitally sign each sign-off hash value with the private key of the sign-off end to generate encryption After signing the hash value, the original hash value and the encrypted signing hash value are published to a blockchain network; thereby, the electronic contract before and after the signing and its signing process are undeniable Features such as flexibility, unforgeability, and irreversibility, and the verification module can also verify the electronic contract uploaded by the user to confirm the authenticity of the contract.

Description

Block chain-based contract signing and verification system and its implementation method

The present invention relates to the field of Internet technology, in particular to an application of blockchain technology (Blockchain), so that the electronic contracts before and after signing and the signing process (Electronic Contracts) have the characteristics of non-repudiation, non-forgeability, and irreversible modification, etc. "Blockchain-based contract signing and verification system and its implementation method" that can verify the authenticity of the contract.

At present, contract signing is mainly realized by encrypting and decrypting an electronic contract through a hash algorithm and a public key cryptographic algorithm. Among them, the hash function is mainly based on an electronic contract to generate a hash value. , And public-key cryptography is mainly used by the sender to sign with its own private key to generate an electronic sign-off value based on the sign-off hash value (that is, the encrypted sign-off hash Value), whereby the receiving end can decrypt the public key of the sending end to verify that the electronic sign-off value is indeed issued by the sending end.

However, in the above conventional contract signing technology, the electronic contract before and after the signing must be stored in a centralized third-party organization to prove that both parties to the contract have indeed completed the signing of the electronic contract. In the future, if the third-party organization is invaded by a person with intent, the content of the contract before and after the signing may be improperly tampered with, which will affect the trust of both parties to the third-party organization; and related known technologies can be found in the invention patents Announcement No. TWI388184 “Online Simulation Signature System and Method”, Republic of China Invention Patent Announcement No. TWI392321 “Electronic Document Digital Signing System and Method”, US Invention Patent Publication No. US20080052519A1 “System and method for signing a contract electronically" and other previous cases.

In summary, in terms of how to effectively prevent the contract from being improperly altered, concealed or destroyed, how to ensure the integrity of the contract data, and how to ensure the non-repudiation and irreversibility of the contract data and its signing process, the current contract signing technology is still Needs to be improved.

In view of the above problems, the present invention provides a data integrity, non-repudiation, and data irreversible change characteristics of the contract, can prevent the content of the contract from being improperly modified, and can improve the traceability of the contract signing process (Traceability). Blockchain-based contract signing and verification system and its implementation method".

To achieve the above objective, the present invention provides a blockchain-based contract signing and verification system and its implementation method. The system mainly includes: a processing module, a communication module, a hash module, a sign-off module, and An encryption module, where the hash module is used to perform a hash calculation on a content information and an attribute information of an electronic contract to calculate a corresponding original hash value; the sign-off module is used for a sign-off end device Perform a sign-off operation on the electronic contract to generate a signed electronic contract. The sign-off module also allows a second sign-off end device to sign-off the signed electronic contract to generate a second signed electronic contract. Electronic contract; the hash module is also used to perform a second hash calculation on the content and attribute information of the signed electronic contract to calculate the corresponding hash value of the signature. The hash module also provides 2. Perform the second hash calculation on the content and attribute information of the signed electronic contract to calculate the corresponding second sign hash value; the encryption module is used to verify the private value of each sign device. The key is digitally signed (Digital Signature), and an encrypted sign-off hash value is generated. The encryption module is also used to digitally sign each second sign-off hash value with the private key of the second sign-off end device, and Generate encrypted second sign-off hash values; the communication module is used to publish each original hash value, each encrypted sign-off hash value, and each encrypted second sign-off hash value to a blockchain network.

In one embodiment of the present invention, if the sign-off end device does not generate an electronic handwritten signature in the sign-off area of the electronic contract after the sign-off module is executed (for example, an "AAA" electronic handwritten signature) is not allowed The second sign-off end device performs sign-off operations (such as generating an electronic handwritten signature of "BBB"), and A second signed electronic contract, and the hash module can also perform hash calculations on electronic handwritten signatures to calculate a handwritten signature hash value and publish it to the blockchain network.

In one embodiment of the present invention, the hash module can also perform hash calculation on at least one biometric parameter sent by the signer end device and the second signer end device to generate at least one biometric hash value, which is associated with Both the sign-off end device and the biometric hash value of the second sign-off end device can be published to the blockchain network.

In summary, after the contract signing and verification technology provided by the present invention is implemented, due to the above hash value and the encrypted hash value, both can be published to a highly reliable and decentralized blockchain network And the time stamp of contract signing will not be tampered with in the record of the blockchain. Therefore, the system in this case can achieve irreversible modification of the electronic contract data and the signing process, difficult to be forged and tampered, and not to be signed. The beneficial effect denied.

In order for your reviewer to have a clear understanding of the purpose, technical features and effects of the present invention after implementation, the following descriptions and illustrations are used for explanation, please refer to them.

10: Blockchain-based contract signing and verification system

101: Processing Module

102: Communication module

103: Hash Module

104: Sign-off module

105: encryption module

106: database

107: Verification Module

20: Sign-off device

20’: The second sign-off device

30: Internet

40: Blockchain network

50: Verify the demand side device

D1: Electronic contract

Hash(D1): Original hash value

D2: Electronic contract has been signed

Hash(D2): sign-off hash value

En(Hash(D2)): The signed hash value after encryption

Hash (D2, Biometrics): biometric hash value

D3: The second signed electronic contract

Hash(D3): hash value of the second sign

En(Hash(D3)): The second sign-off hash value after encryption

Hash (D3, Biometrics): the second biometric hash value

D4: Electronic contract to be verified

Hash(D4): hash value to be verified

S: Implementation method of contract signing and verification system based on blockchain

S1: Receive the electronic contract before signing

S2: Perform hash calculation based on contract content and attributes

S3: Receive the signed electronic contract

S4: Perform the second hash calculation based on the content and attributes of the contract

S5: Encrypt the sign-off hash value

S6: Publish to the blockchain network

Figure 1 is a system architecture diagram of the present invention.

Figure 2 is a flowchart of the system implementation of the present invention.

Figure 3 is a schematic diagram (1) of the information flow of the present invention.

Figure 4 is a schematic diagram (1) of the information flow of the present invention.

Figure 5 is a schematic diagram (1) of the information flow of another embodiment (1) of the present invention.

Figure 6 is a schematic diagram (2) of the information flow of another embodiment (1) of the present invention.

Figure 7 is a system architecture diagram of another embodiment (2) of the present invention.

Figure 8 is a schematic diagram of the information flow of another embodiment (2) of the present invention.

Figure 9 is a schematic diagram of the information flow of another embodiment (3) of the present invention.

Please refer to "Figure 1", which is a system architecture diagram of the present invention. The present invention discloses a blockchain-based contract signing and verification system 10 for an approving end device 20 to establish an information link through a network 30. The system includes: a processing module 101, a communication module 102, a hash module 103, a sign-off module 104 and an encryption module 105 are respectively coupled to the processing module 101.

(1) The processing module 101 can run the blockchain-based contract signing and verification system 10 and control the execution of the above modules, and has functions such as logical operations, temporary storage of operation results, and storage of execution instruction positions. It can be A central processing unit (CPU).

(2) The communication module 102 can establish a communication connection with the sign-off end device 20. The network 30 can be a public or private network, such as a wireless network (for example, 3G, 4G LTE, Wi-Fi), and a wired network. Road, local area network (LAN), wide area network (WA), etc., but not limited to this.

(3) The hash module 103 can perform a hash calculation on a content information and an attribute information of an electronic contract to calculate a corresponding original hash value. The content and attribute information of the above electronic contract are both Belongs to a clear text (Cleartext).

(4) The sign-off module 104 can allow the sign-off end device 20 to perform a sign-off operation on the electronic contract to generate a signed electronic contract; among them, the form of the sign-off operation performed by the sign-off module 104 can refer to A sign-off area of the electronic contract generates an electronic signature stamp or an electronic handwritten signature.

(5) The hash module 103 can also perform a second hash calculation on the content information and attribute information of the signed electronic contract to calculate a corresponding sign hash value.

(6) The encryption module 105 can digitally sign each sign-off hash value with the private key of the sign-off end device 20, that is, execute an encryption algorithm to generate an encrypted sign-off hash value. All belong to a ciphertext (Ciphertext).

(7) The database 106 can store the content information and attribute information of the electronic contract, the original hash value of the electronic contract, the content information and attribute information (plain text) of the signed electronic contract, and the signed hash of the signed electronic contract Value, and the signed hash value of the signed electronic contract after encryption.

(8) The communication module 102 can also publish the original hash value of the electronic contract and the signed hash value of the signed electronic contract to a blockchain network 40.

Among them, the above-mentioned attribute information may be a user account of the approving terminal device 20, a name of an approver, an approving time, an approving location, a file modification time, a file size, a number of characters, and one line. One or a combination of number, paragraph number, page number, file creation time, file editing time, and annotation information, but not limited to this.

Among them, the above-mentioned hash calculation can be one-way hash algorithms such as SHA-0, SHA-1, SHA-2, SHA-3, MD5, BLAKE2, but not limited to this.

Among them, the aforementioned encryption algorithm may be RSA, ECC, ElGamal, Rabin, etc. public key cryptographic algorithms, but it is not limited to this.

Among them, the format of the above electronic contract can be PDF, DOC or XLS format, but it is not limited to this.

The above-mentioned sign-off device 20 can be a workstation, a personal computer, a notebook computer, a smart phone, etc., but is not limited to this.

Among them, the blockchain-based contract signing and verification system 10 uses a web service as a communication interface with the network 30.

Please refer to "Figure 2", which is the flow chart of the system implementation of the present invention. Please also refer to the information flow diagrams of "Figure 3" ~ "Figure 4" and "Figure 1". The present invention discloses a system based on The implementation method S of the blockchain contract signing and verification system includes the following steps:

(1) Receive an electronic contract before signing (step S1): a communication module 102 sends an electronic contract D1 to an approving terminal device 20 through a network 30;

(2) Perform a hash calculation based on the content and attributes of the contract (step S2): a hash module 103 performs a hash calculation on a content information and an attribute information of the electronic contract D1 to calculate the corresponding original hash value Hash (D1), and it can be the hash value Hash(D1,Content) corresponding to the content information and the hash value Hash(D1,Attribute) corresponding to the attribute information, as shown in "Figure 4";

(3) Receive a signed electronic contract (step S3): The communication module 102 receives an signed electronic contract D2 from the sign-off end device 20, which has been signed. In addition, in this embodiment, in a better case, When this step is executed, the form of the signed electronic contract D2 is that after the sign-off end device 20 executes a sign-off module 104, an electronic signature stamp or an electronic handwritten signature is generated in an sign-off area of the electronic contract D1, namely Such as "AAA" shown in "Figure 4", and can be stored in the database 106.

(4) Perform a second hash calculation based on the content and attributes of the contract (step S4): A hash module 103 performs a second hash calculation on the content and attribute information of the signed electronic contract D2 to calculate the corresponding Sign the hash value Hash(D2), and it can be the hash value Hash(D2,Content) corresponding to the content information and the hash value Hash(D2,Attribute) corresponding to the attribute information, as shown in "Figure 4" Shown

(5) Encrypt the sign-off hash value (step S5): an encryption module 105 digitally signs each sign-off hash value Hash (D2) with the private key of the sign-off end device 20, and generates an encrypted signature The kernel hash value En(Hash(D2)), and it can be respectively the encrypted hash value En(Hash(D2,Content)) corresponding to the content information and the encrypted hash value En(Hash(D2) corresponding to the attribute information ,Attribute)), as shown in "Figure 4";

(6) Publish to the blockchain network (step S6): The communication module 102 converts the original hash value Hash(D1) of the electronic contract D1 and the signed hash value En( Hash(D2)), published to the N network nodes of a blockchain network 40, that is, "on the chain" shown in "Figure 4".

Please refer to "Figure 5" ~ "Figure 6" for a schematic diagram of the information flow of another embodiment (1) of the present invention, and please refer to "Figure 1" in conjunction with this embodiment and "Figure 1" to " The technologies shown in Figure 4 are similar, but the main differences are:

(1) When step S4 is executed (execute the second hash calculation based on the contract content and attributes), the hash module 103 can also extract a second signed electronic contract that has been signed by a second signer device 20' D3. Perform a second hash calculation on the content information and attribute information of the second signed electronic contract D3 to calculate a corresponding second signed hash value Hash(D3), which can be respectively corresponding to the content The hash value Hash (D3, Content) of the information and the hash value Hash (D3, Attribute) corresponding to the attribute information.

(2) When step S5 is executed (encrypting the sign-off hash value), the encryption module 105 can further digitally sign each second sign-off hash value Hash (D3) with the private key of the second sign-off end device 20' Chapter, to generate the encrypted second sign-off hash value En(Hash(D3)), which can be the encrypted hash value En(Hash(D3,Content)) corresponding to the content information and the attribute information Encrypted hash value En(Hash(D3,Attribute)).

(3) Continuing, when step S6 is executed (published to the blockchain network), the communication module 102 can also publish the encrypted second sign-off hash value En(Hash(D3)) to the blockchain network Road 40.

In addition, in this embodiment, in a preferred case, before step S4 is executed (the second hash calculation is performed according to the contract content and attributes), if the sign-off end device 20 executes the sign-off module 104, the electronic contract D1 is not signed If the verification area generates an electronic handwritten signature, that is, "AAA" as shown in "Figure 6", the processing module 101 does not allow the second sign-off end device 20' to use the sign-off module 104 when the electronic contract has been signed A second sign-off area of D2 performs the sign-off operation, that is, it is not allowed to generate another electronic handwritten signature in a second sign-off area of the signed electronic contract D2, and the second signed electronic contract D2 is generated and stored To the database 106, that is, "BBB" as shown in "Figure 6". In addition, the hash module 103 can also perform the electronic handwritten signature of the signer device 20 and the electronic handwritten signature of the second signer device 20' Perform hash calculation to calculate a handwritten signature hash value, and each of the aforementioned handwritten signature hash values can be issued to the blockchain network 40 by the communication module 102, whereby each handwritten signature hash value can be stored in the block The chain network 40, therefore, the signer device 20 and the second signer device 20' will not deny that the electronic contract is signed by them.

Please refer to "Figure 7", which is a system architecture diagram of another embodiment (2) of the present invention, and please refer to "Figure 1" together. The technologies of the embodiments shown in Figures 5 to 6 are the same. The main difference is that the blockchain-based contract signing and verification system 10 disclosed in the present invention may further include a processing module 101 A verification module 107, please continue to refer to "Figure 8", which is a schematic diagram of the information flow of another embodiment (2) of the present invention. When this embodiment is implemented, the verification module 107 can connect the communication module 102 A to-be-verified electronic contract D4 received from a verification request-side device 50 is used as an input parameter, and the processing module 101 drives the hash module 103 to perform hash calculations on the content information and attribute information of the electronic contract D4 to be verified respectively. To generate a hash value Hash(D4) to be verified, and it can be a hash value Hash(D4,Content) corresponding to the content information and a hash value Hash(D4,Attribute) corresponding to the attribute information, and then verify The module 107 can perform encryption on each second sign-off hash value En(Hash(D3)) stored in the blockchain network 40 according to the public key of the second sign-off end device 20' (by the second sign-off Sent by the end device 20') perform decryption to decrypt the corresponding second sign-off hash value Hash (D3), and then, the verification module 107 will verify the hash value Hash (D4) and the second sign-off hash value Hash (D3) For comparison, it can be verified whether the electronic contract D4 to be verified is actually signed by the second signatory terminal device 20', and the contract content of the electronic contract to be verified D4 can be verified compared to the second signed electronic contract D3, is there any improper tampering?

In addition, this embodiment can also be applied to the embodiment shown in "Figures 1 to 4". When this embodiment is implemented according to this embodiment, after the hash module 103 generates the hash value Hash (D4) to be verified, the verification module The group 107 can perform the encrypted hash value En(Hash(D2)) stored in the blockchain network 40 according to the signature The public key of the core device 20 decrypts to decrypt the corresponding sign-off hash value Hash(D2), and then, the verification module 107 performs the verification of the hash value Hash(D4) and the sign-off hash value Hash(D2) By comparison, it can be verified whether the electronic contract D4 to be verified is actually signed by the approving end device 20, and it can be verified whether the contract content of the electronic contract D4 to be verified is improperly tampered with compared to the signed electronic contract D2.

Please refer to "Figure 9", which is a schematic diagram of the information flow of another embodiment (3) of the present invention. Please also refer to "Figure 1" for this embodiment and "Figures 5 to 6". The embodiments are similar in technology, and the main difference is that the database 106 of the blockchain-based contract signing and verification system 10 of the present invention can also store the data sent by the signer device 20 and the second signer device 20 At least one biometric parameter. Therefore, when this embodiment is implemented, the hash module 103 can perform a hash calculation on the biometric parameters associated with the signed electronic contract D2 and the approving terminal device 20 to generate a biometric hash The value Hash (D2, Biometrics), and the biometric hash value Hash (D2, Biometrics) can be issued to the blockchain network 40 by the communication module 102, whereby the biometric hash value Hash (D2, Biometrics) can be encrypted The later sign-off hash value En(Hash(D2)) is also stored in the blockchain network 40, so the sign-off end device 20 cannot deny that the signed electronic contract D2 was signed by it.

In continuation, please continue to refer to "Figure 9". Similarly, when this embodiment is implemented, the hash module 103 can also be associated with the signed electronic contract D3, and the biometric parameters of the second approving terminal device 20' perform hash calculation to generate a second biometric hash value Hash (D3, Biometrics), and the second biometric hash value Hash (D3, Biometrics) can also be used It is published by the communication module 102 to the blockchain network 40, whereby the second biometric hash value Hash(D3, Biometrics) can be combined with the encrypted second sign-off hash value En(Hash(D3)) It is stored in the blockchain network 40, so the second approving end device 20' cannot deny that the second signed electronic contract D3 was signed by it.

Among them, the above-mentioned biometric parameter can be the original data of a fingerprint image, a face image, an iris image, etc., but is not limited to this.

In summary, after the contract signing and verification technology disclosed in this case is implemented, it starts from the electronic contract that has not yet been signed to the electronic contract that has been signed by the sign-off end device or the second sign-off end device. All the sign-off process of the contract can be recorded in the blockchain network with decentralized characteristics, and will not be stored in the hands of one party, so that the parties to the contract are more legally equal, while ensuring the electronic contract The content will not be tampered with, concealed or destroyed. At the same time, the electronic contract stored on the blockchain and its signing process are both undeniable and irreversible.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention; anyone who is familiar with this technique, Equal changes and modifications made without departing from the spirit and scope of the present invention should all be covered by the patent scope of the present invention.

In summary, the present invention has patent requirements such as "industrial applicability", "novelty" and "advancedness"; the applicant filed an application for a patent for invention with the Bureau in accordance with the provisions of the Patent Law.

10: Blockchain-based contract signing and verification system

101: Processing Module

102: Communication module

103: Hash Module

104: Sign-off module

105: encryption module

106: database

20: Sign-off device

30: Internet

40: Blockchain network

Claims (8)

A blockchain-based contract signing and verification system, comprising: a processing module, a communication module, a hash module, a signing module and an encryption module are respectively coupled to the processing module, the The processing module is used to control the above-mentioned modules; the hash module is used to perform a hash calculation on a content information and an attribute information of an electronic contract to calculate a corresponding original hash value; the sign-off module For a sign-off end device to perform a sign-off operation on the electronic contract to generate an signed electronic contract, the sign-off module is also used by a second sign-off end device to sign the signed electronic contract Operation to generate a second signed electronic contract; the hash module is also used to perform a second hash calculation on the content and attribute information of the signed electronic contract to calculate the corresponding one To verify the hash value, the hash module is also used to perform the second hash calculation on the content information and the attribute information of the second signed electronic contract to calculate a corresponding second sign hash value; The encryption module is used to digitally sign each of the sign-off hash values with the private key of the sign-off end device to generate the encrypted sign-off hash value; the encryption module is also used to verify each second The sign-off hash value is digitally signed with the private key of the second sign-off end device to generate the encrypted second sign-off hash value; and The communication module is used for publishing each original hash value, each encrypted signoff hash value, and each encrypted second signoff hash value to a blockchain network. For example, the blockchain-based contract sign-off and verification system of claim 1, wherein if the sign-off end device does not generate an electronic handwritten signature in the electronic contract, the second sign-off end device is not allowed to use the sign-off The module performs the sign-off operation, and the hash module is also used to perform the hash calculation on the electronic handwritten signature to calculate a handwritten signature hash value, and the handwritten signature hash value is for publishing to the blockchain network . For example, the blockchain-based contract signing and verification system of claim 1, wherein the hash module is also used to execute at least one biometric parameter sent by the signer device or the second signer device The hash calculation generates at least one biometric hash value, and the biometric hash value associated with the sign-off end device or the second sign-off end device is for publishing to the blockchain network. For example, the blockchain-based contract signing and verification system of claim 1, further includes a verification module coupled to the processing module, and the verification module is used to input the communication module from a verification request-side device A received electronic contract to be verified causes the hash module to perform hash calculations on the content and attribute information of the electronic contract to be verified to respectively generate a hash value to be verified corresponding to the content and attribute information. The verification module Group is also available for storage Each of the encrypted second sign-off hash values of the blockchain network is decrypted to further compare the to-be-verified hash value with the decrypted second sign-off hash value to verify the to-be-verified electronic Whether the contract is actually signed by the second signatory end device, and whether the contract content of the electronic contract to be verified is verified compared to the second signed electronic contract stored in the blockchain network. Tamper. A method for implementing a blockchain-based contract signing and verification system includes: a hash calculation step based on the content and attributes of the contract: a hash module performs a hash on a content information and an attribute information of the electronic contract Calculation to calculate the corresponding original hash value; one executes the second hash calculation step according to the content and attributes of the contract: the hash module extracts a signed electronic contract that has been signed by the sign-off end device, and then The content information and the attribute information of the signed electronic contract perform a second hash calculation to calculate a corresponding sign-off hash value, and the hash module further extracts a second sign-off end device for the signed A second signed electronic contract after the signed electronic contract is verified, and then the second hash calculation is performed on the content information and the attribute information of the second signed electronic contract to calculate the corresponding one Two sign-off hash values; a pair of sign-off hash values are encrypted. Steps: an encryption module digitally signs each sign-off hash value with the private key of the sign-off end device to generate the encrypted sign-off hash Value, the encryption module also hashes each of the second signatories The value is digitally signed with the private key of the second sign-off end device to generate the encrypted second sign-off hash value; and a step of publishing to the blockchain network: a communication module sends each original The hash value, the encrypted hash value of each signature, and the hash value of each second signature are published to a blockchain network. For example, the implementation method of the blockchain-based contract signing and verification system of claim 5, wherein, before the execution of the second hash calculation step according to the content and attributes of the contract, if the sign-off end device is not generated in the electronic contract An electronic handwritten signature does not allow the second approving end device to perform an approving operation to generate the second signed electronic contract, and the hash module can perform the hash calculation on the electronic handwritten signature to calculate a handwritten signature Signature hash value, the handwritten signature hash value is published to the blockchain network when the step of publishing to the blockchain network is executed. For example, the implementation method of the blockchain-based contract signing and verification system of claim 5, wherein, when the second hash calculation step is executed according to the content and attributes of the contract, the hash module further performs the verification end device, Or the at least one biometric parameter sent by the second signer end device performs the hash calculation to generate at least one biometric hash value, which is associated with the signer end device or the biological feature of the second signer end device The feature hash value is released to the blockchain network when the step of publishing to the blockchain network is executed. For example, in the implementation method of the blockchain-based contract signing and verification system of claim 5, a verification module causes the hash module to perform hash calculations on the content and attribute information of an electronic contract to be verified to respectively generate corresponding For a hash value to be verified in the text and attribute information, the verification module also decrypts each encrypted second sign-off hash value stored in the blockchain network, and further the hash value to be verified is combined with The decrypted second sign-off hash value is compared to verify whether the electronic contract to be verified is actually signed by the second sign-off end device, and to verify that the contract content of the electronic contract to be verified is compared to stored in Whether the second signed electronic contract of the blockchain network has been tampered with.

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