Fair electronic contract signing methods, storage media, devices and systems for multiple parties

Abstract

This invention provides a method, storage medium, device, and system for fair multi-party electronic contract signing. If a signatory receives incorrect hidden information from the signatures of other signatories, it proposes to terminate the agreement with the other negotiating parties. In this case, all negotiating parties receive nothing, ensuring fairness. When all signatories agree to continue the contract signing process, they resend their electronic contract signatures to the other signatories. Simultaneously, with the assistance of a trusted center, each signatory receives what they desire, further guaranteeing fairness. This invention is applicable to scenarios involving multi-party electronic contract signing, ensuring information security and fairness among the parties, and guaranteeing the smooth and secure signing of electronic contracts.

Description

Technical Field

[0001] This invention belongs to the field of encrypted communication technology of quantum cryptography networks, specifically relating to a method, storage medium, device and system for signing electronic contracts fairly among multiple parties. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the development of computer technology and automated office technology, electronic contracts are becoming increasingly popular. This method of contract signing has changed the traditional practice of using paper as the original document, and contracts are concluded electronically, reaching agreements under network conditions.

[0004] According to the inventor, the core technology of current electronic contract signing systems is PKI technology. However, PKI technology uses RSA asymmetric keys to achieve non-repudiation signatures. In the face of the foreseeable research and construction of quantum computers, cryptographic systems based on computational complexity are insecure and pose security risks. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method, storage medium, device, and system for signing electronic contracts fairly among multiple parties. This invention is applicable to scenarios involving the signing of electronic contracts by multiple parties, ensuring information security and fairness among them, and guaranteeing the smooth and secure signing of electronic contracts.

[0006] According to some embodiments, the present invention adopts the following technical solution:

[0007] A fair and equitable method for signing electronic contracts among multiple parties includes the following steps:

[0008] Each electronic contract signatory applies to the Trust Center for the electronic contract signature information and related hidden information of the contract to be signed. The Trust Center verifies the application and returns the data to the corresponding signatory. Any signatory can send its hidden information to other electronic contract signatories.

[0009] Each signatory to an electronic contract verifies the correctness of the hidden information sent by other signatories. If correct, the signatory sends a signature message indicating that the signing process continues; otherwise, the signing process is stopped.

[0010] After receiving the signature message indicating that the signing process continues, each electronic contract signatory sends its own electronic contract signature information or a signature message indicating that it is abandoning the signing process to other signatories.

[0011] After each electronic contract signatory receives the electronic contract signature information sent by all other signatories, it verifies the electronic contract signature information. If all signatures are correct, the contract is successfully signed; otherwise, it sends a ruling to the Trust Center.

[0012] The Trust Center verifies the correctness of the ruling information based on any signatory's ruling information. If correct, it generates electronic contract signature information based on the signature hiding information in the ruling information and sends it to the signatory who sent the ruling information.

[0013] As an alternative implementation method, the specific process of the Trusted Center verifying the application includes: the Trusted Center receives a signature request, a signature information encryption request and data sent by a signer, reads the shared key corresponding to the key sequence number in the signature request, if the shared key has been used, the corresponding signer's request is rejected; otherwise, the correctness of the data is verified, and if it is correct, the identity authentication of the corresponding signer is passed, and the shared key is marked as used.

[0014] As an alternative implementation method, the specific process of the trusted center feeding back data to the corresponding signatory includes: the trusted center reads another unused key from the signature key library to perform symmetric key signing on the contract hash value H(C), obtaining HMAC(H(C)||Pi||TP||TSi||SNi1;SKi1), where TSi is the timestamp of the signature and SNi1 is the sequence number of the signature key SNi1. DSi=Pi||TP||TSi||SNi1||HMAC(H(C)||Pi||TP||TSi||SNi1;SKi1) is used as the signature information of Pi of the electronic contract C. DSi is encrypted using SNi1 to obtain ciphertext E(DSi). SNi1||E(DSi) is used as the hidden information of the Pi signature. The trusted center uses the shared key with Pi to calculate the message authentication code of DSi||SNi1||E(DSi). DSi||SNi1||E(DSi) and its message authentication code are sent to the corresponding electronic contract signatory.

[0015] As an alternative implementation method, the specific process by which any signatory sends its signature-hidden information to other signatories of the electronic contract includes:

[0016] After each signatory receives the signature information and its message authentication code from the Trusted Center, it verifies the legitimacy of the signature information using the message authentication code. If the verification is successful, it obtains the signature information and hidden information, saves the signature information, and sends the hidden information to each of the other signatories. After receiving the data, the other signatories go to the Trusted Center to verify whether the hidden information is the encrypted ciphertext of the signature information of the signatory of the electronic contract corresponding to the correct sequence key.

[0017] As an alternative implementation, the specific process by which each signatory to an electronic contract verifies the correctness of hidden information sent by other signatories includes:

[0018] If any signatory has received the hidden signature messages sent by all other signing methods within the specified time and verified that they are all valid, it applies to the Trusted Center and obtains a signature message indicating that it agrees to continue executing the agreement regarding the signature key sequence number. The signatory then broadcasts the signature message to all other signatories. Otherwise, the signatory suspends the signing process or broadcasts a signature message indicating the termination of this exchange.

[0019] As an alternative implementation, the specific process of sending a signature message indicating that the signing process continues to the other signatories, if correct, includes:

[0020] Within a specified time period, if a signatory has received all the signed messages and verified the correctness of each message authentication code, and if all are correct and all agree to continue execution, the signatory will send the signature information to each other signing method; otherwise, the signatory will suspend the signing process or broadcast a signature message indicating the termination of the signature information exchange.

[0021] As an alternative implementation method, the specific process by which the Trusted Center verifies the correctness of the ruling information based on the ruling information of any signatory includes:

[0022] When all signatories agree to continue with the contract signing, they send their electronic contract signatures to the other signatories. If a signatories do not receive an electronic contract signature from another signatories or receive an incorrect signature, they send a ruling to the Trust Center.

[0023] As an alternative implementation method, the specific process by which the trusted center generates electronic contract signature information based on the signature hiding information in the adjudication information and sends it to the signatory who sent the adjudication information includes: decrypting the signature hiding information in the adjudication information using a signature key with a matching serial number to obtain the signature information; verifying the correctness of the signature information; if correct, decrypting the signature key with a matching serial number in the signature hiding information to obtain the signature information of other signatories; verifying the correctness of the signature information of other signatories; if correct, exchanging the signature information of the signatories; and each signatory, after receiving the signature information of other signatories, verifying its correctness; and if correct, saving the signature information respectively.

[0024] A computer-readable storage medium storing a plurality of instructions adapted for loading and execution by a processor of a terminal device of the steps in a method for signing a multi-party fair electronic contract.

[0025] A terminal device includes a processor and a computer-readable storage medium, the processor being configured to implement instructions; the computer-readable storage medium being configured to store multiple instructions adapted for loading by the processor and executing steps in the aforementioned method for signing a fair multi-party electronic contract.

[0026] A multi-party equitable electronic contract signing system, comprising:

[0027] Multiple client devices, each executing instructions from different electronic contract signatories, are configured to request signature information and related hidden information of the contract to be signed from the Trusted Center, receive verification information, send the hidden information of the contract signatories to other electronic contract signatories, verify the correctness of the hidden information sent by other signatories, and if correct, send a signature message indicating that the signing process continues to other signatories; otherwise, stop the signing process. After receiving the signature message indicating that the signing process continues, each device sends its own electronic contract signature information or a signature message indicating that it abandons the signing process to other signatories, verifies the electronic contract signature information, and if both are correct, the contract is successfully signed; otherwise, a ruling message is sent to the Trusted Center.

[0028] The Trust Center is configured to verify applications from different electronic contract signatories and return data to the corresponding signatories for electronic contract signing; based on the ruling information of any signatories, it verifies whether the ruling information is correct; if correct, it generates electronic contract signature information based on the signature hiding information in the ruling information and sends it to the signatories who sent the ruling information.

[0029] In this invention, the client serves as the implementation device for each signatory.

[0030] As an alternative implementation, the trusted center and each client device obtain a shared key through quantum key distribution.

[0031] When the shared key between the trusted center and the client devices is about to run out, the client devices use the unused shared key to authenticate with the trusted center. After successful authentication, the trusted center distributes quantum keys to the client devices through the quantum secure channel of the quantum cryptography network. The trusted center and each client device encrypt the newly distributed quantum key using the unused key, and use the ciphertext as the new shared key. The new shared key is then divided and sequentially numbered.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] In this invention, if the hidden signature information received by a signatory from other signatories is incorrect, the signatory proposes to terminate the execution of the agreement. At this point, none of the signatories receive anything, thus ensuring fairness. When all signatories agree to continue executing the contract signing, they resend their electronic contract signatures to the other signatories. With the help of a trusted center, each signatory receives what they desire, ensuring fairness.

[0034] This invention uses symmetric key digital signature technology in every encryption, decryption, and information exchange process. The signature uses the signer's shared key, and the trusted center verifies the signer's identity through the shared key before signing. Therefore, it is impossible for any signer to forge the message, which helps to ensure information security.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 A diagram illustrating the parties involved in the signing process;

[0038] Figure 2 This is a diagram illustrating the signing process. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] Symmetric-key algorithms are cryptographic algorithms that use the same secret key for both encryption and decryption. This cryptosystem is characterized by low mathematical computation, fast encryption speed, and ease of processing, but distributing the symmetric key is relatively difficult. The emergence of quantum cryptography networks has solved the problem of symmetric key distribution. Through quantum cryptography networks, both parties can easily obtain a shared symmetric key using quantum key distribution.

[0043] This embodiment relies on the abundant symmetric key resources of quantum cryptography networks to provide a fair multi-party electronic contract signing method. First, it introduces the parties involved in the process, such as... Figure 1 As shown, this includes a trusted third-party organization, the Trusted Center, which is responsible for digital signatures of electronic contracts, identity registration of electronic contract signatories, identity authentication of signatories during electronic contract signing, and acting as a trusted third party to resolve disputes related to electronic contract signing. A true random number digital signature keystore is established within the Trusted Center for digital signatures of electronic contract data. The keys in the keystore are divided according to the length used for each digital signature, and the divided keys are sequentially numbered.

[0044] The signatories of the electronic contract are those who sign electronic contracts through a trusted center. Before signing the electronic contract, the signatories submit an identity registration application to the trusted center via a quantum cryptography network terminal using a quantum secure channel. The quantum secure channel refers to a communication link in the quantum cryptography network that can generate a shared key.

[0045] After receiving the identity registration application from the signatory, the Trusted Center reviews the materials submitted by the signatory. Upon successful review, the Trusted Center distributes the shared key to the signatory through the quantum secure channel of the quantum cryptography network. The Trusted Center stores the signatory's identity registration information and the shared key in its database. The signatory securely stores the shared key and, together with the shared key in the Trusted Center's database, divides the shared key according to the length required for each use and synchronizes the sequential numbering.

[0046] This embodiment is a multi-party electronic contract signing method. Assume the n parties involved in the electronic contract signing are P1, P2, ..., P... n (P i (i = 1, 2, ..., n) represent the identification codes of the contract signatories, P i (i = 1, 2, ..., n) have already completed identity registration at the trusted center), P i (i = 1, 2, ..., n) The contract to be signed is C (Pi has already agreed on the contents of C in advance). For example... Figure 2 As shown, the details are as follows:

[0047] Each contract signatory applies to the Trust Center for electronic contract signature information and hidden information related to the electronic contract signature.

[0048] Each electronic contract signatory P i (i∈{1,2,…,n}) Calculate the hash value H(C) of contract C, and use the unused shared key Ki1 of the trusted center to calculate the message authentication code HMAC(P) associated with the key. i ||TP||H(C)||Ni1;Ki1)(TP is the identification code of the trusted center, Ni1 represents the serial number of the key Ki1, and || represents the data concatenation operation), Pi sends an electronic contract signing request and a signature information encryption request to the trusted center, and sends P i TP, Ni1, H(C) and HMAC(P) i ||TP||H(C)||Ni1;Ki1) is sent to the trusted center, and the key Ki1 is marked as used.

[0049] The Trusted Center received P i The signature request, signature information encryption request, and data P sent by (i∈{1,2,…,n}) i TP, Ni1, H(C) and HMAC(P) i After ||TP||H(C)||Ni1;Ki1), retrieve the sequence number Ni1 from the database and P. i If the shared key Ki1 is already in use, then P is rejected. i Request, otherwise verify HMAC(P) i The correctness of ||TP||H(C)||Ni1;Ki1), if correct then P i After successful identity authentication, the key Ki1 is marked as used. The trusted center reads the unused key STi1 with sequence number SNi1 from the signature key store and performs a symmetric key signature on the contract hash value H(C), obtaining the data HMAC(H(C)||P). i ||TP||TSi||SNi1;SKi1), where TSi is the timestamp of the signature, SNi1 is the sequence number of the signature key SNi1, and DS i =P i ||TP||TSi||SNi1||HMAC(H(C)||P i ||TP||TSi||SNi1;SKi1) as P of electronic contract C i The signature data is encrypted using SKi1 DS. i Obtain the ciphertext E(DS) i ), and SNi1||E(DS) i ) as P i Hidden information in the signature, used by the Trust Center with P i Shared key computation DS i||SNi1||E(DS i The message authentication code will be used by DS. i ||SNi1||E(DS i ) and its message authentication code are sent to P i .

[0050] Each contract signatory sends its own electronic contract signature hiding information to the other signatories, and each signatory verifies the correctness of the electronic contract signature hiding information sent by the other signatories.

[0051] Each signatory P i (i∈{1,2,…,n}) receive DS i ||SNi1||E(DS i After obtaining the message authentication code, the data DS is verified using the message authentication code. i ||SNi1||E(DS i The validity of the data is verified, and if the verification is successful, the data DS is obtained. i and SNi1||E(DS) i Save DS i , SNi1||E(DS i )Sent to each of the other signatories P j (j∈{1,2,…,n}, j≠i), P j After receiving the data, P j Verify SNi1||E(DS) at a trusted center i The correctness of E(DS) (verification) i Is it the P key of the trusted central signature key repository key pair of contract C with serial number SNi1? i (The encrypted ciphertext of the signature information).

[0052] If any contract signatory receives and verifies the signature hiding information sent by all other contract signatories, it sends a signature message to the other signatories to continue the signing process; otherwise, it suspends the signing process or sends a signature message to abandon the signing process.

[0053] For any i∈{1,2,…,n}, within the specified time interval [t1,t2], P i All other signatories P have been received j (j∈{1,2,…,n},j≠i) The signed hidden message SNj1||E(DS) sent to him j If all of them are verified to be valid, then the signature data HMAC(P) is requested from the Trusted Center and obtained. i ||TP||“process i"||SNi2;SKi2)(where SNi2 is the signature key of the trusted center, SNi2 is the sequence number of the signature key SNi2, process i P represents i (Agreed that the agreement will continue to be implemented), P i Sign the message me i2 ={HMAC(P i ||TP||“process i "||SNi2;SKi2), process i P i TP, [t2, t3]} is broadcast to all other signatories P j (j∈{1,2,…,n}, j≠i);

[0054] Otherwise, P i Pause, or broadcast the signature message me i2 ={HMAC(P i ||TP||“abort i "||SNi2;SKi2), abort i P i ,TP,[t2,t3]}(where HMAC(P i ||TP||“abort i "||SNi2;SKi2) is P i The signature data requested from the Trusted Center, abort i P represents i This exchange will be terminated), [t2,t3] represents the exchange between the signatories. i2 Time limit.

[0055] If any signatory receives a signature message from all other signatories indicating that the signing process should continue, then the signatory shall send its electronic contract signature information to all other signatories; otherwise, the signing process shall be suspended or a signature message indicating that the signing process is abandoned shall be sent.

[0056] For any i ∈ {1, 2, ..., n}, within the specified time [t2, t3], P i All me have been received j2 ={HMAC(P j ||TP||“process j "||SNj2;SKj2), process j P j ,TP,[t2,t3]}(j∈{1,2,…,n},j≠i),P i Verify each HMAC(P) j ||TP||“processj The correctness of (||SNj2; SKj2) is such that if they are both correct and both agree to continue execution, then P i me i3 ={DS i P i TP, [t3, t4]} is sent to each other signatory; otherwise P i Pause, or broadcast abort i (if abort was previously) i If not broadcast), [t3,t4] represents the exchange of me between the signatories. i3 Time limit.

[0057] Once any signatory receives electronic contract signature information from all other signatories, it verifies the correctness of the electronic contract signature information. If all signatures are correct, the contract is successfully signed; otherwise, it sends a ruling to the Trust Center.

[0058] For any i ∈ {1, 2, ..., n}, within the specified time interval [t3, t4], P i All me have been received j3 ={DS j P j , TP, [t3,t4]} (j∈{1,2,…,n},j≠i), and verify all DS j If all are correct, the contract is successfully signed. If P i I have already i3 ={DS i P i ,TP,[t3,t4]} are sent to P j But I haven't received it yet. j3 ={DS j P j , TP, [t3,t4]}, then P i me i4 ={SNj1||E(DS) j ), me 12 me 22 , ..., me i2 , ..., me n2 DS i ,SNi1||E(DS i ), TP, [t4,t5]} are sent to the trusted center, where [t4,t5] is the time limit for the signer to send to the trusted center, where each, me i4 This is information related to the ruling.

[0059] The Trust Center verifies the correctness of the ruling information sent by the signatory who has not received the signature information, generates electronic contract signature information based on the signature hidden information in the ruling information, and sends the signature information to the signatory who has not received the signature information.

[0060] If the Trusted Center receives me i4 ={SNj1||E(DS) j ), me 12 me 22 , ..., me i2 , ..., me n2 DS i ,SNi1||E(DS i ), TP, [t4, t5]}, the trusted center first verifies all me 12 me 22 , ..., me i2 , ..., me n2 If correct, then check the correctness of SNi1||E(DS). i E(DS) i ) Use the signature key with serial number SNi1 to decrypt and obtain DS i Verify DS i The correctness of SNj1||E(DS) is as follows: If correct, then for SNj1||E(DS) j E(DS) j ) Use the signature key with serial number SNj1 to decrypt and obtain DS j Verify DS j The correctness of DS, if correct, will be... j Send to P i DS i Send to P j P i and P j Received DS respectively j and DS i Verify their correctness separately. If correct, save the DS. j and DS i .

[0061] A fair exchange protocol is a fundamental security protocol that must be followed in the electronic contract signing process. It primarily ensures the security and fairness of information exchange and related matters in a network environment. A fair exchange protocol ensures that the parties involved exchange information in a equitable manner, so that either either party receives the other's information, or neither party receives the other's information. In other words, if the transaction proceeds normally, the protocol guarantees that both parties receive the information they need; if the protocol terminates abnormally, it should ensure that both parties are on equal footing, with neither party having any advantage.

[0062] In the first step of the electronic contract signing method in this embodiment, each negotiating party calculates its own electronic contract signature information and contract signature hidden information, which does not involve fairness.

[0063] In the second and third steps of the electronic contract signing method in this embodiment, if the signing party P i If the signatures received from other signatories contain incorrect hidden information, the agreement can be terminated by requesting the other negotiating parties to do so. In this case, all negotiating parties receive nothing, and fairness is guaranteed.

[0064] In steps four and five of the electronic contract signing method in this embodiment, when all signatories agree to continue with the contract signing, each signatory sends its electronic contract signature to the other signatories. When a signatory P... i No other signatory P was received j If the electronic contract signature or the received signature is incorrect, then P i Send the ruling information to the trusted center. i4 ={SNj1||E(DS) j ), me 12 me 22 , ..., me i2 , ..., me n2 DS i ,SNi1||E(DS i ), TP, [t4, t5]}.

[0065] In the sixth step of the electronic contract signing method in this embodiment, the trusted center first uses me 12 me 22 , ..., me i2 , ..., me n2 Confirm that each signatory has received the correct signature hiding information from the other signatories, and confirm DS. i Correctness, then through P j The signature hides the information SNj1||E(DS) j ) Obtain P j Electronic contract signing, P j The electronic contract signature is sent to P i At the same time, P i The electronic contract signature is sent to P j In this situation, with the help of the Trust Center, P i and P j Since they both get what they want, fairness still holds.

[0066] Because symmetric key digital signature technology is used in each of the above steps, it is impossible for any signer to forge the message {the signer's shared key is used when signing, and the trusted center verifies the signer's identity through the shared key before signing}.

[0067] In conclusion, this electronic contract signing method complies with the fair exchange agreement.

[0068] The Trusted Center and the electronic contract signatories obtain a shared key through quantum key distribution. When their shared key is about to run out, the electronic contract signatories use the unused shared key to authenticate each other with the Trusted Center. After successful authentication, the Trusted Center distributes a quantum key to the electronic contract signatories through the quantum secure channel of the quantum cryptography network. The Trusted Center and the electronic contract signatories use the unused key to encrypt the newly distributed quantum key, use the ciphertext as the new shared key, and divide and number the new shared key sequentially.

[0069] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0071] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0072] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0074] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A fair electronic contract signing method for multiple parties, characterized by: Includes the following steps: Each electronic contract signatory applies to the Trust Center for the electronic contract signature information and related hidden information of the contract to be signed. The Trust Center verifies the application and returns the data to the corresponding signatory. Any signatory can send its hidden information to other electronic contract signatories. Each signatory to an electronic contract verifies the correctness of the hidden information sent by other signatories. If correct, the signatory sends a signature message indicating that the signing process continues; otherwise, the signing process is stopped. After receiving the signature message indicating that the signing process continues, each electronic contract signatory sends its own electronic contract signature information or a signature message indicating that it is abandoning the signing process to other signatories. After each electronic contract signatory receives the electronic contract signature information sent by all other signatories, it verifies the electronic contract signature information. If all signatures are correct, the contract is successfully signed; otherwise, it sends a ruling to the Trust Center. The Trust Center verifies the correctness of the ruling information based on any signatory's ruling information. If correct, it generates electronic contract signature information based on the signature hiding information in the ruling information and sends it to the signatory who sent the ruling information. The specific process by which any signatory sends their hidden signature information to other signatories of an electronic contract includes: After each signatory receives the signature information and its message authentication code from the Trusted Center, it verifies the legitimacy of the signature information using the message authentication code. If the verification is successful, it obtains the signature information and hidden information, saves the signature information, and sends the hidden information to each of the other signatories. After receiving the data, the other signatories go to the Trusted Center to verify whether the hidden information is the encrypted ciphertext of the signature information of the signatory of the electronic contract corresponding to the correct sequence key.

2. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: it is trustworthy. The specific process by which the center verifies an application includes: the trusted center receives a signature request, a signature information encryption request, and data from a signer; it reads the shared key corresponding to the key sequence number in the signature request; if the shared key has been used, the corresponding signer's request is rejected; otherwise, the correctness of the data is verified; if correct, the identity authentication of the corresponding signer is passed, and the shared key is marked as used.

3. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: it is trustworthy. The specific process by which the trusted center provides data feedback to the relevant signatory includes: the trusted center reading the contract hash value from another unused key pair in the signature keystore. H ( C Perform symmetric key signing to obtain HMAC ( H ( C )|| Pi || TP || TSi || SNi 1; SKi 1), among which, HMAC Message authentication code Pi A unique identifier for each party signing the electronic contract. TP This is the identification code for the trusted center. TSi For the timestamp of the signature, SNi 1 is the signing key SKi The sequence number 1 will DSi = Pi || TP || TSi || SNi 1|| HMAC ( H ( C )|| Pi || TP || TSi || SNi 1; SKi 1) As an electronic contract C of Pi The signature information, using SKi 1 Encryption DSi Obtain the ciphertext E ( DSi ),Will SNi 1|| E ( DSi As Pi Hidden information in signatures, used by Trust Centers Pi Shared key computation DSi || SNi 1|| E ( DSi The message authentication code will DSi || SNi 1|| E ( DSi The electronic contract signatory sends the electronic contract and its authentication code to the corresponding electronic contract signatory.

4. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: The specific process by which each signatory to an electronic contract verifies the correctness of hidden messages sent by other signatories includes: If any signatory has received the hidden signature messages sent by all other signing methods within the specified time and verified that they are all valid, it applies to the Trusted Center and obtains a signature message indicating that it agrees to continue executing the agreement regarding the signature key sequence number. The signatory then broadcasts the signature message to all other signatories. Otherwise, the signatory suspends the signing process or broadcasts a signature message indicating the termination of this exchange.

5. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: If correct, the specific process of sending a signature message indicating that the signing process continues to the other signatories includes: Within a specified time period, if a signatory has received all the signature information and verified the correctness of each message authentication code, and if all are correct and all agree to continue execution, the signatory will send the signature information to each of the other signatories; otherwise, the signatory will suspend the signing process or broadcast a signature message indicating the termination of the current exchange of signature messages.

6. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: it is trustworthy. The specific process by which the center verifies the accuracy of the ruling information based on any signatory's ruling information includes: When all signatories agree to continue with the contract signing, they send their electronic contract signatures to the other signatories. If a signatories do not receive an electronic contract signature from another signatories or receive an incorrect signature, they send a ruling to the Trust Center.

7. The method for signing a fair electronic contract among multiple parties as described in claim 1, characterized in that: it is trustworthy. The specific process by which the center generates electronic contract signature information based on the signature-hidden information in the ruling information and sends it to the signatory who sent the ruling information includes: decrypting the signature-hidden information in the ruling information using a signature key with a matching serial number to obtain the signature information; verifying the correctness of the signature information; if correct, decrypting the signature key with a matching serial number in the signature-hidden information to obtain the signature information of other signatories; verifying the correctness of the signature information of other signatories; if correct, exchanging the signature information of the signatories; and each signatory, after receiving the signature information of other signatories, verifying its correctness; and if correct, saving the signature information respectively.

8. A computer-readable storage medium, characterized in that: it stores... There are multiple instructions adapted to be loaded by the processor of the terminal device and executed in any one of the claims 1-7 of the method for signing a multi-party fair electronic contract.

9. A terminal device, characterized in that: It includes a processor and a computer-readable storage medium, the processor being used to implement various instructions; the computer-readable storage medium being used to store multiple instructions adapted for loading by the processor and executing the steps of a multi-party fair electronic contract signing method according to any one of claims 1-7.

10. A multi-party fair electronic contract signing system, employing a multi-party fair electronic contract signing method as described in any one of claims 1-7, characterized in that: include: Multiple client devices, each executing instructions from different electronic contract signatories, are configured to request signature information and related hidden information of the contract to be signed from the Trusted Center, receive verification information, send the hidden information of the contract signatories to other electronic contract signatories, verify the correctness of the hidden information sent by other signatories, and if correct, send a signature message indicating that the signing process continues to other signatories; otherwise, stop the signing process. After receiving the signature message indicating that the signing process continues, each device sends its own electronic contract signature information or a signature message indicating that it abandons the signing process to other signatories, verifies the electronic contract signature information, and if both are correct, the contract is successfully signed; otherwise, a ruling message is sent to the Trusted Center. The Trust Center is configured to verify applications from different electronic contract signatories and return data to the corresponding signatories for electronic contract signing; based on the ruling information of any signatories, it verifies whether the ruling information is correct; if correct, it generates electronic contract signature information based on the signature hiding information in the ruling information and sends it to the signatories who sent the ruling information.

11. A multi-party fair electronic contract signing system as described in claim 10, characterized in that: The trusted center and each client device obtain a shared key through quantum key distribution.

12. A multi-party fair electronic contract signing system as described in claim 10, characterized in that: When the shared key between the trusted center and the client devices is about to run out, the client devices use the unused shared key to authenticate each other with the trusted center. After successful authentication, the trusted center distributes quantum keys to the client devices through the quantum secure channel of the quantum cryptography network. The trusted center and each client device encrypt the newly distributed quantum key using the unused key, and use the ciphertext as the new shared key. The new shared key is then divided and sequentially numbered.

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