Quantum computing-resistant digital currency dual offline transaction method and system with anonymous sender

Abstract

The present invention discloses a method and system for dual offline transactions of digital currency with anti-quantum computing in which the payee is anonymous. The method comprises the following steps: S1, preparation stage: issuing a private key based on ID cryptography, digital currency with anti-quantum computing and a digital certificate to the payee terminal / payee terminal respectively; S2, dual offline transaction stage: the payee terminal and the payee terminal complete the dual offline transaction through an offline transaction method in an offline state; S3, online transaction stage: confirm the transaction through commercial banks and the central bank in an online state. Beneficial effects: The present invention designs a digital currency equipped with a private key, which can realize a dual offline transaction method of digital currency with an anonymous payee, protect the identity information of the payee from being exposed; and the method of the present invention can carry out various transactions between digital currencies, including dual offline transactions; and can realize anti-quantum computing.

Description

Technical Field

[0001] The present invention relates to the field of digital currency, and in particular to a quantum computing-resistant digital currency dual offline transaction method and system with anonymous payee. Background Art

[0002] As most people know, quantum computers have great potential in password cracking. Most of the current mainstream asymmetric (public key) encryption algorithms, such as the RSA encryption algorithm, are based on two mathematical problems: factorization of large integers or calculation of discrete logarithms over finite fields. The difficulty of their cracking depends on the efficiency of solving these problems. On traditional computers, solving these two mathematical problems takes exponential time (that is, the cracking time increases exponentially with the increase of the length of the public key), which is unacceptable in practical applications. The Shor algorithm, which is tailor-made for quantum computers, can perform integer factorization or discrete logarithm calculation in polynomial time (that is, the cracking time increases with the increase of the length of the public key at a rate of k, where k is a constant independent of the length of the public key), thus making it possible to crack the RSA and discrete logarithm encryption algorithms.

[0003] The core elements of the digital currency D-RMB system of the People's Bank of China are one currency, two types of libraries and three centers. One currency, namely "D-RMB" (DC / EP), referred to as D currency, specifically refers to a string of encrypted digital strings representing a specific amount signed by the central bank. Two types of libraries: the D-RMB issuance library and the bank library (central bank digital currency database, commercial bank digital currency database). Digital currency in the issuance library is the central bank's digital currency fund; digital currency in the bank library is the commercial bank's inventory of digital cash. Three centers: one is the registration center (recording the entire process of currency generation, circulation, counting and verification, and extinction); the other two are certification centers, namely CA certification center (based on the PKI system, centralized management of institutional and user certificates, such as CFCA) and IBC certification center [that is, the certification center established based on identity-based cryptographic technology (Identity-Based Cryptograph)]. Two tables can be designed in the registration center, one is the digital currency ownership registration table, which records the ownership of digital currency, and the other is the transaction flow table.

[0004] The D-RMB system is a hierarchical system, which is jointly built by the central bank and commercial banks. The central bank digital currency system is a computer system operated and maintained by the central bank or an institution designated by the central bank to process information about digital currency. Its main functions include being responsible for the issuance and verification monitoring of digital currency. The commercial bank digital currency system is a computer system operated and maintained by commercial banks or institutions designated by commercial banks to process information about digital currency. It performs various currency-related functions of existing banks, namely banking functions, mainly including being directly responsible for meeting various needs of providing digital currency circulation services to the society after applying for digital currency from the central bank.

[0005] Patent CN201911053809 proposes an anonymous transaction method and system based on digital currency, but this method and system have some problems: only online transactions can be carried out, and the user's temporary identity can only be used for subsequent transaction processes when it is recognized by its own server. When the user cannot communicate with its own server, the payee of this method cannot use the user's temporary identity to verify its digital signature for the transaction (in a mathematical signature based on a digital certificate, since the user needs to hide his true identity, he cannot provide a digital certificate containing his true identity, and cannot prove the association between his temporary identity and his digital certificate, so he cannot use his digital certificate to verify his digital signature for the transaction; in a mathematical signature based on ID cryptography, since the user needs to hide his true identity, he cannot provide his true identity, and cannot prove the association between his temporary identity and his true identity, so he cannot use his true identity to verify his digital signature for the transaction). Therefore, the payee cannot recognize the legitimacy of the transaction and complete the entire transaction process without receiving any identity credentials from the sender.

[0006] Based on the above analysis, the existing technology of digital currency communication system has the following defects:

[0007] 1. Most of the existing digital currency transaction methods based on digital certificates or user IDs expose the user's identity;

[0008] 2. The existing digital currency anonymous transaction methods based on digital certificates or user IDs can ensure the anonymous identity of users but cannot perform anonymous transactions when both the payee and the payee are offline (i.e., double offline);

[0009] 3. Existing digital currency transaction methods cannot resist quantum computing. Summary of the invention

[0010] In response to the problems in the related technology, the present invention proposes a quantum computing-resistant digital currency dual offline transaction method and system with anonymous payee to overcome the above-mentioned technical problems existing in the existing related technology.

[0011] To this end, the specific technical solution adopted by the present invention is as follows:

[0012] According to one aspect of the present invention, a quantum computing-resistant digital currency dual offline transaction method with anonymity of the sender is provided, the method comprising the following steps:

[0013] S1. Preparation stage: issuing private keys based on ID cryptography, quantum-resistant digital currency and digital certificates to the payee terminal / payee terminal respectively;

[0014] S2, dual offline transaction stage: the payee terminal and the payee terminal complete the dual offline transaction through an offline transaction method in an offline state;

[0015] S3, online transaction stage: transactions are confirmed online by commercial banks and the central bank;

[0016] Among them, S1 includes using the key management server to issue a private key based on ID cryptography to the payee terminal / payee terminal, and using the central bank to issue quantum computing-resistant digital currency and digital certificates to the payee terminal / payee terminal.

[0017] Furthermore, the issuance of quantum computing-resistant digital currency by the central bank to the payee terminal / payee terminal in S1 specifically includes the following steps:

[0018] The payee terminal / payee terminal generates a set of public-private key pairs based on the RSA or ECC cryptographic system, and sends the public key to the corresponding commercial bank. The corresponding commercial bank sends the public key to the central bank. The central bank generates quantum computing-resistant digital currencies of various values ​​and ID cryptography-based private keys corresponding to the ID of the digital currency based on the public key and currency value, and sends the digital currency and the ID cryptography-based private key to the corresponding commercial bank. The corresponding commercial bank then sends the digital currency and the ID cryptography-based private key to the corresponding user terminal.

[0019] Furthermore, the payment sender terminal and the payment receiver terminal in S2 complete the dual offline transaction by using an offline transaction method in an offline state, including the following steps:

[0020] S21, the payee terminal verifies the identity of the payee terminal using an identity verification method;

[0021] S22, the payee terminal sends the transaction to the payee terminal through a preset communication method;

[0022] S23, the payee terminal receives the transaction and performs decryption verification, and after successful verification, sends a message confirming the transaction to the payee terminal.

[0023] Furthermore, the identity verification of the payee terminal by the payee terminal using the identity verification method in S21 specifically includes the following steps:

[0024] S211, the payee terminal sends information requesting the payee terminal to verify its identity, and the payee terminal sends its quantum computing-resistant digital certificate to the payee terminal;

[0025] S212. The sender terminal receives the digital certificate of quantum computing, uses the public key of the central bank to decrypt the encrypted signature in the digital certificate, and verifies the decrypted signature. If the verification is successful, the identity of the sender terminal is confirmed and the transaction continues. If the verification fails, the transaction fails.

[0026] Furthermore, the sending terminal of the payee sends the transaction to the payee terminal through a preset communication method in S22, which specifically includes the following steps:

[0027] S221, the payee terminal takes out a digital currency with a currency value equal to the value of this transaction, obtains the current timestamp, and combines the current timestamp, the payee's identity ID, the payee's identity ID and the digital currency to obtain the transaction, wherein the payee's identity ID is the identity ID of the payee's commercial bank, so the payee only knows the commercial bank to which the payee belongs, and is not clear about the specific identity of the payee;

[0028] S222. Use the RSA or ECC private key corresponding to the digital currency to sign the transaction to obtain a transaction signature, and calculate the symmetric key between the digital currency ID and the payee terminal identity ID;

[0029] S223. Use the symmetric key to encrypt the transaction and transaction signature to obtain encrypted information, and send the current timestamp, encrypted information and digital currency ID together to the payee terminal.

[0030] Furthermore, the payee terminal in S23 receives the transaction information and performs decryption verification, and after successful verification, sends a message confirming the transaction to the payee terminal, which specifically includes the following steps:

[0031] S231, the payee terminal receives the current timestamp, encrypted information and digital currency ID, calculates the symmetric key between the payee terminal identity ID and the digital currency ID, and uses the symmetric key to decrypt the transaction and transaction signature;

[0032] S232, the payee terminal takes out the encrypted public key in the digital currency, and decrypts it with the public key of the central bank stored by the payee to obtain the RSA or ECC public key therein, and uses the public key to verify the transaction signature. After successful verification, the digital currency is verified. If the verification is successful, the transaction is trusted, and the payee terminal encrypts the transaction confirmation message and the payee terminal's signature based on ID cryptography with a symmetric key and sends them to the payee terminal;

[0033] S234, the payee terminal receives the message and uses the symmetric key to decrypt it to obtain a message confirming the transaction and a signature of the payee terminal based on ID cryptography, and verifies the digital signature at the same time. After checking that the message confirming the transaction is successful, the digital currency and its private key are deleted.

[0034] Furthermore, the online confirmation of the transaction by the commercial bank and the central bank in S3 includes the following steps:

[0035] S31, the payee terminal sends the transaction to the payee commercial bank, and the payee commercial bank receives the transaction and forwards it to the central bank;

[0036] S32: The central bank receives the message, verifies and decrypts it, and forwards the generated confirmation message to the payee terminal through the payee commercial bank.

[0037] Furthermore, in S31, the beneficiary terminal sends the transaction to the beneficiary commercial bank, and the beneficiary commercial bank receives the transaction and forwards it to the central bank, which specifically includes the following steps:

[0038] S311, the payee terminal encrypts the confirmed transaction with the public key of the payee commercial bank to obtain a first ciphertext, signs it to obtain a first signature, and sends the first ciphertext and the first signature to the payee commercial bank corresponding to the payee terminal;

[0039] S312: The payee commercial bank receives the message and verifies the first signature. If the verification is successful, the payee commercial bank uses the private key to decrypt the message to obtain the transaction.

[0040] S313. The payee commercial bank encrypts the public key of the central bank used for the transaction to obtain a corresponding second ciphertext, signs the second ciphertext to obtain a second signature, and sends the second ciphertext and the second signature to the central bank.

[0041] Furthermore, the central bank receives the message in S32 for verification and decryption, and forwards the generated confirmation message to the payee terminal through the payee commercial bank, which specifically includes the following steps:

[0042] S321, the central bank receives the message and verifies the second signature. If the verification is successful, the central bank uses the private key of the central bank to decrypt the transaction and confirm the transaction. At the same time, the central bank records the transaction and generates a confirmation message, encrypts it to obtain a third ciphertext, and signs the third ciphertext to obtain a third signature and sends it to the payee terminal;

[0043] S322: The payee terminal receives the message, verifies the third signature, decrypts it to obtain a confirmation message, and records the transaction locally;

[0044] S323, the central bank sends a confirmation message to the payee commercial bank, which receives the message and verifies it, and records the transaction locally, finds the corresponding lender terminal according to the digital currency in the transaction, and sends the real identity of the payee terminal to the central bank;

[0045] S324. The payee commercial bank encrypts the confirmation message to obtain a fourth ciphertext, and signs the fourth ciphertext to obtain a fourth signature and sends them to the payee terminal. The payee terminal receives the message, verifies the signature, and then decrypts it to obtain a confirmation message, confirming that the digital currency of the transaction is valid, and the transaction is completed.

[0046] According to another aspect of the present invention, a quantum computing-resistant digital currency dual offline transaction system with anonymity of the payee is provided, the system comprising a central bank digital currency system, a payee commercial bank, a payee commercial bank, a payee terminal and a payee terminal, wherein the payee commercial bank corresponds to the payee terminal, and the payee commercial bank corresponds to the payee terminal;

[0047] The central bank digital currency system has a public-private key pair based on the RSA cryptographic system, and the private key is stored in the central bank, and the public key is issued to all commercial banks and user terminals and stored in the corresponding hardware wallet;

[0048] The central bank digital currency system is also equipped with a key management server based on ID cryptography, and the key management server is used to issue system private keys for the central bank digital currency system, and is also used to issue private keys based on ID cryptography for all objects with IDs.

[0049] The beneficial effects of the present invention are as follows: the present invention designs a digital currency equipped with a private key, which can realize a digital currency dual offline transaction method in which the sender is anonymous, thereby protecting the identity information of the sender from being exposed; and the method of the present invention can carry out various transactions between digital currencies including dual offline transactions; and can realize anti-quantum computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 Flow chart of a quantum computing-resistant digital currency dual offline transaction method with anonymous sender according to an embodiment of the present invention;

[0052] Figure 2 This is a data structure diagram of quantum-resistant digital currency in a quantum computing-resistant digital currency dual offline transaction method with anonymous sender according to an embodiment of the present invention;

[0053] Figure 3 It is a flowchart of the digital currency dual offline transaction steps involved in the quantum computing resistant digital currency dual offline transaction method with anonymous sender according to an embodiment of the present invention;

[0054] Figure 4 It is a basic structural diagram of the central bank digital currency system in the quantum computing-resistant digital currency dual offline transaction system with anonymous sender according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0056] According to an embodiment of the present invention, a quantum computing-resistant digital currency dual offline transaction method and system with anonymous payee are provided.

[0057] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. Figure 1-3 As shown, according to one embodiment of the present invention, a quantum computing-resistant digital currency dual offline transaction method with anonymous sender is provided, and the method comprises the following steps:

[0058] S1. Preparation stage: issuing private keys based on ID cryptography, quantum-resistant digital currency and digital certificates to the payee terminal / payee terminal respectively;

[0059] Among them, S1 includes using a key management server (KMS) to issue a private key based on ID cryptography to the payee terminal (PT) / payee terminal (CT), and using a central bank (SS) to issue quantum computing-resistant digital currency and digital certificates to the payee terminal / payee terminal.

[0060] Specifically, SS has a public-private key pair PK based on the RSA cryptographic system. SS / SK SS , where the private key SK SS Saved by SS, public key PK SS It is issued to all commercial banks and user terminals and stored in their hardware wallets, and is never made public. SS also maintains a key management server KMS based on ID cryptography, which issues system private keys SKMS to SS and issues private keys based on ID cryptography to all objects with IDs (including commercial banks, user terminals and digital currencies), such as issuing SK to the payee terminal CT. CT , issue SK to the sender terminal PT PT There is a public-private key correspondence SK CT =SKMS*PK CT and SK PT =SKMS*PK PT , and PK CT =H1(IDCT) and PK PT =H1(IDPT).

[0061] The process of the central bank SS issuing quantum computing-resistant digital currency to user terminals is as follows: the payee terminal PT generates a set of public-private key pairs based on the RSA or ECC cryptographic system, and sends the public key to the corresponding commercial bank PS, which sends the public key to the central bank SS. SS generates quantum computing-resistant digital currency of various currency values ​​and the ID-based cryptography private key corresponding to the digital currency ID based on the public key and currency value, and sends the digital currency and the ID-based cryptography private key to PS, which then sends the digital currency and the ID-based cryptography private key to PT. The central bank also issues digital currency and the corresponding ID-based cryptography private key to the payee terminal CT in the same way.

[0062] The data structure of the quantum computing-resistant digital currency issued by SS is as follows Figure 2 As shown, it includes ID, currency value, encrypted public key and encrypted signature. The public key carried by the digital currency (that is, the public key involved in generating digital currency mentioned above) is encrypted using the true random number parameter RPK to obtain {public key} RPK, and then the private key SK of SS is used to encrypt the public key carried by the digital currency (that is, the public key involved in generating digital currency mentioned above). SS Encryption parameter RPK to get {RPK}SK SS , combine the two to get {public key}RPK||{RPK}SK SS, which is the encrypted public key in the digital currency data structure. To obtain the public key, use PK SS Decrypt {RPK}SK SS Get RPK, and then use RPK to decrypt {public key}RPK to get the public key. Use the true random number parameter RS ​​to encrypt the signature of the digital currency to get {signature}RS, and then use SS's private key SK SS Encrypt parameter RS ​​to get {RS}SK SS , combining the two to get {signature}RS||{RS}SK SS , which is the encrypted signature in the digital currency data structure. To obtain the signature, use PK SS Decrypt {RS}SK SS Get RS, and then use RS to decrypt {signature} RS to get the signature. After the public key and signature are symmetrically encrypted, they can resist quantum computing.

[0063] In the present invention, the central bank SS also issues a quantum computing-resistant digital certificate based on ID cryptography to the user terminal. The data structure corresponding to the digital certificate is different from that of an ordinary digital certificate in the following ways: the certificate owner field contains the ID of the digital certificate owner, the certificate public key field is empty, the public key algorithm field is based on ID cryptography, and the certificate signature field is an encrypted signature. The structure of the encrypted signature is as described above.

[0064] S2, dual offline transaction stage: the payee terminal and the payee terminal complete the dual offline transaction through an offline transaction method in an offline state;

[0065] Wherein, the S2 comprises the following steps:

[0066] S21, the payee terminal PT verifies the identity of the payee CT (the payee terminal verifies the identity of the payee terminal using an identity verification method);

[0067] PT requests CT to verify its identity information. Since the payee is usually a merchant and does not need to hide his identity, this patent does not hide the identity of the payee. CT will send its quantum computing-resistant digital certificate CERTC T Sent to PT.

[0068] After PT receives it, it uses SS's public key PK SS Decryption CERT CT The encrypted signature in the PT is obtained and the decrypted signature is verified. If the PT verification is successful, the identity of the CT is confirmed and the subsequent steps are performed. Otherwise, the subsequent steps are not performed.

[0069] S22, the payee terminal PT sends a transaction (the payee terminal sends the transaction to the payee terminal via a preset communication method);

[0070] T takes out a digital currency PM with a value equal to the value of this transaction, obtains the current timestamp T2, and combines T2, the sender information IDPS, the payee identity IDCT and PM into a transaction TX, that is, TX = {T2||IDPS||IDCT||PM}. Since the sender information is represented by IDPS, the payee only knows the commercial bank to which the sender belongs, and does not know the specific identity of the sender. Use the RSA or ECC private key corresponding to the digital currency PM to sign TX to obtain TXS, and then calculate the symmetric key TXK between IDPM and IDCT: According to the formula PK CT =H1(IDCT) calculates PK CT , take out PM's ID cryptography-based private key SK PM , calculate the symmetric key TXK between the two = FTX(T2, e(SK PM , PK CT )), where FTX(T, K) is an arbitrary function, such as a message authentication function or a concatenation function. TX||TXS is encrypted with TXK to obtain {TX||TXS}TXK, and T2||{TX||TXS}TXK and IDPM are sent to CT together.

[0071] S23, the payee terminal CT receives the transaction (the payee terminal receives the transaction and performs decryption verification, and after successful verification, sends a message confirming the transaction to the payee terminal);

[0072] After receiving the message, T obtains T2||{TX||TXS}TXK and IDPM. CT calculates the symmetric key TXK′ between IDCT and IDPM: According to the formula PK PM =H1(IDPM) calculates PK PM , take out CT's private key SK based on ID cryptography CT , calculate the symmetric key TXK′=FTX(T2, e(SK CT , PK PM )). According to ID cryptography, we can get:

[0073] e(SK CT , PK PM )=e(SKMS*PK CT , PK PM )=e(SKMS*PK PM , PK CT )=e(SK PM , PK CT ),

[0074] So TXK′=TXK. Decrypt {TX||TxS}TXK with TXK′ to get TX||TXS. CT takes out the encrypted public key in the digital currency PM and uses the PK stored by itself SS Decrypt to get the RSA or ECC public key, and then use the public key to verify the signature TXS. After successful verification, verify the digital currency PM, such as verifying the currency value and the central bank signature. If the verification is successful, the transaction is trusted. CT will confirm the transaction message RET CT The signature of CT based on ID cryptography is encrypted with TXK′ and sent to PT.

[0075] After PT receives the message, it decrypts it with TXK to get RET CT And CT's signature based on ID cryptography, verify the digital signature, view RET CT After the transaction is successful, the digital currency PM and its private key will be deleted. Since the private key corresponds to the digital currency one by one, the private key also needs to be destroyed after the digital currency is issued. After the digital currency is received by the recipient, it becomes an ordinary digital currency without a private key.

[0076] S3, online transaction stage (transactions are confirmed online by commercial banks and the central bank);

[0077] During the online transaction stage, SS and CS, SS and PS can communicate confidentially through a quantum secure communication system based on QKD key distribution. CS and CT, PS and PT can communicate confidentially through a key card system based on a symmetric key pool or an asymmetric key pool. All messages sent during the online transaction stage are encrypted by the quantum computing-resistant confidential communication mechanism between the two parties.

[0078] Wherein, the S3 comprises the following steps:

[0079] S31, the payee terminal CT sends a transaction (the payee terminal sends the transaction to the payee commercial bank, and the payee commercial bank receives the transaction and forwards it to the central bank);

[0080] CT encrypts the previously confirmed transaction TX with CS's public key to obtain a ciphertext (the first ciphertext), then signs the ciphertext and sends the ciphertext and signature (the first signature) to its corresponding commercial bank CS. CS verifies the signature. If the verification is successful, it decrypts the transaction TX with CS's private key.

[0081] CS encrypts TX with SS's public key to obtain a ciphertext (the second ciphertext), then signs the ciphertext and sends the ciphertext and signature (the second signature) to the central bank SS.

[0082] S32, the central bank SS sends a confirmation message (the central bank receives the message for verification and decryption, and forwards the generated confirmation message to the payee terminal through the payment-issuing commercial bank);

[0083] SS verifies the signature. If the verification is successful, SS uses its private key to decrypt the transaction TX and confirms TX. SS records TX and generates a confirmation message RET SS , for RET SS The ciphertext is encrypted to obtain the third ciphertext, and then the ciphertext is signed and sent to the CS together with the ciphertext and the signature (third signature).

[0084] CS verifies the signature and decrypts it to get the confirmation message, then records the transaction TX locally. SS sends the confirmation message to PS in the same way, and PS also records the transaction TX after verification, finds the corresponding user PT based on the digital currency in TX, and sends the real identity of PT to the central bank.

[0085] CS acknowledges the message RET SS The ciphertext is encrypted (the fourth ciphertext), and then the ciphertext is signed and sent to CT together with the ciphertext and the signature (the fourth signature). After CT verifies the signature, it decrypts and obtains a confirmation message, confirming that the digital currency of the transaction is valid, and the transaction is completed.

[0086] In addition to supporting dual offline transactions, the transaction process in the present invention also supports transactions where the payee is online and the payee is offline, transactions where the payee is offline and the payee is online, and transactions where the payee is online and the payee is online, that is, the process supports all types of transactions. In the present invention, the digital currency has an encrypted public key and an encrypted signature, and the digital certificate is combined with the ID cryptography theory to achieve the effect of anti-quantum computing in the offline transaction stage; at the same time, in the online transaction stage, confidential communications between the central bank and commercial banks, and between commercial banks and user terminals are also carried out to resist quantum computing.

[0087] According to another aspect of the present invention, taking the operation example of the central bank digital currency as an example, Figure 4As shown, the basic structure of the digital currency system mainly includes the central bank digital currency system, the commercial bank digital currency system (in practice, it can be multiple commercial bank digital currency systems) and users. Among them, the central bank digital currency system is used to generate and issue digital currency, as well as to register the ownership of digital currency; the commercial bank digital currency system is used to perform banking functions for digital currency; the user is the main body of digital currency use, and in the present invention, the user holds a terminal to conduct digital currency transactions. In the present invention, an anti-quantum computing communication system is deployed between the central bank digital currency system and the commercial bank digital currency system, and between the commercial bank digital currency system and the user terminal, which can ensure anti-quantum computing communication between them. For example, a quantum secure communication system based on QKD key distribution is deployed between the central bank digital currency system and the commercial bank digital currency system, and a key card system based on a symmetric key pool or an asymmetric key pool is deployed between the commercial bank digital currency system and the user terminal.

[0088] Specifically, the present invention provides an anonymous quantum computing-resistant digital currency dual offline transaction system based on the digital currency system. The system includes the central bank (i.e., the central bank digital currency system) SS, the sender commercial bank (i.e., the commercial bank digital currency system) PS and its corresponding sender terminal PT, the payee commercial bank CS and its corresponding payee terminal CT, and their corresponding IDs are IDSS, IDPS, IDPT, IDCS and IDCT respectively.

[0089] SS has a public-private key pair PK based on the RSA cryptographic system SS / SK SS , where the private key SK SS Saved by SS, public key PK SS Issued to all commercial banks and user terminals and stored in their hardware wallets, and never made public. SS also maintains a key management server KMS based on ID cryptography, which issues system private keys SKMS to SS and issues private keys based on ID cryptography to all objects with IDs (including commercial banks, user terminals and digital currencies).

[0090] In summary, with the aid of the above technical solution of the present invention, the present invention designs a digital currency equipped with a private key, which can realize a digital currency dual offline transaction method in which the sender is anonymous, thereby protecting the identity information of the sender from being exposed; and the method of the present invention can carry out various types of transactions between digital currencies including dual offline transactions; and can realize anti-quantum computing.

[0091] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A quantum computing-resistant digital currency dual offline transaction method with anonymity of the sender, characterized in that: The method comprises the following steps: S1. Preparation stage: issuing private keys based on ID cryptography, quantum-resistant digital currency and digital certificates to the payee terminal / payee terminal respectively; S2, dual offline transaction stage: the payee terminal and the payee terminal complete the dual offline transaction through an offline transaction method in an offline state; S3, online transaction stage: transactions are confirmed online by commercial banks and the central bank; Wherein, the S1 includes using a key management server to issue a private key based on ID cryptography to the payee terminal / payee terminal, and using a central bank to issue a quantum computing-resistant digital currency and a digital certificate to the payee terminal / payee terminal; and the quantum computing-resistant digital currency is a digital currency containing an ID, a currency value, an encrypted public key and an encrypted signature, and the quantum computing-resistant digital certificate is a digital certificate containing a certificate owner field, the certificate owner field contains the ID of the digital certificate owner, the certificate public key field is vacant, the public key algorithm field is based on ID cryptography, and the certificate signature field is an encrypted signature; In S2, the sender terminal and the payee terminal complete the dual offline transaction by using the offline transaction method in an offline state, including the following steps: S21, the payee terminal verifies the identity of the payee terminal using an identity verification method; S22, the payee terminal sends the transaction to the payee terminal through a preset communication method; S23, the payee terminal receives the transaction and performs decryption verification, and after successful verification, sends a message confirming the transaction to the payee terminal.

2. The method for double offline transactions of quantum computing-resistant digital currency with anonymity of the sender according to claim 1 is characterized in that: The use of the central bank to issue quantum computing-resistant digital currency to the payee terminal in S1 specifically includes the following steps: The payee terminal / payee terminal generates a set of public-private key pairs based on the RSA or ECC cryptographic system, and sends the public key to the corresponding commercial bank. The corresponding commercial bank sends the public key to the central bank. The central bank generates quantum computing-resistant digital currencies of various values ​​and ID cryptography-based private keys corresponding to the ID of the digital currency based on the public key and currency value, and sends the digital currency and the ID cryptography-based private key to the corresponding commercial bank. The corresponding commercial bank then sends the digital currency and the ID cryptography-based private key to the corresponding user terminal.

3. The anonymous quantum computing-resistant digital currency dual offline transaction method according to claim 1 is characterized in that: The step S21 in which the sender terminal uses the identity verification method to verify the identity of the payee terminal specifically includes the following steps: S211, the payee terminal sends information requesting the payee terminal to verify its identity, and the payee terminal sends its quantum computing-resistant digital certificate to the payee terminal; S212. The sender terminal receives the digital certificate of quantum computing, uses the public key of the central bank to decrypt the encrypted signature in the digital certificate, and verifies the decrypted signature. If the verification is successful, the identity of the sender terminal is confirmed and the transaction continues. If the verification fails, the transaction fails.

4. The method for double offline transaction of quantum computing-resistant digital currency with anonymous payment party according to claim 1 is characterized in that: The sending terminal of the payee sends the transaction to the payee terminal through a preset communication method in S22, which specifically includes the following steps: S221, the payee terminal takes out a digital currency with a currency value equal to the value of this transaction, obtains the current timestamp, and combines the current timestamp, the payee's identity ID, the payee's identity ID and the digital currency to obtain the transaction, wherein the payee's identity ID is the identity ID of the payee's commercial bank, so the payee only knows the commercial bank to which the payee belongs, and is not clear about the specific identity of the payee; S222. Use the RSA or ECC private key corresponding to the digital currency to sign the transaction to obtain a transaction signature, and calculate the symmetric key between the digital currency ID and the payee terminal identity ID; S223. Use the symmetric key to encrypt the transaction and transaction signature to obtain encrypted information, and send the current timestamp, encrypted information and digital currency ID together to the payee terminal.

5. The method for double offline transaction of quantum computing-resistant digital currency with anonymous payment party according to claim 1 is characterized in that: In S23, the payee terminal receives the transaction information and performs decryption verification, and after successful verification, sends a message confirming the transaction to the payee terminal, which specifically includes the following steps: S231, the payee terminal receives the current timestamp, encrypted information and digital currency ID, calculates the symmetric key between the payee terminal identity ID and the digital currency ID, and uses the symmetric key to decrypt the transaction and transaction signature; S232, the payee terminal takes out the encrypted public key in the digital currency, and decrypts it with the public key of the central bank stored by the payee to obtain the RSA or ECC public key therein, and uses the public key to verify the transaction signature. After successful verification, the digital currency is verified. If the verification is successful, the transaction is trusted, and the payee terminal encrypts the transaction confirmation message and the payee terminal's signature based on ID cryptography with a symmetric key and sends them to the payee terminal; S234, the payee terminal receives the message and uses the symmetric key to decrypt it to obtain a message confirming the transaction and a signature of the payee terminal based on ID cryptography, and verifies the digital signature at the same time. After checking that the message confirming the transaction is successful, the digital currency and its private key are deleted.

6. The anonymous quantum computing-resistant digital currency dual offline transaction method according to claim 1 is characterized in that: The online confirmation of transactions by commercial banks and the central bank in S3 includes the following steps: S31, the payee terminal sends the transaction to the payee commercial bank, and the payee commercial bank receives the transaction and forwards it to the central bank; S32: The central bank receives the message, verifies and decrypts it, and forwards the generated confirmation message to the payee terminal through the payee commercial bank.

7. The method for double offline transactions of quantum computing-resistant digital currency with anonymity of the sender according to claim 6 is characterized in that: In S31, the beneficiary terminal sends the transaction to the beneficiary commercial bank, and the beneficiary commercial bank receives the transaction and forwards it to the central bank, which specifically includes the following steps: S311, the payee terminal encrypts the confirmed transaction with the public key of the payee commercial bank to obtain a first ciphertext, signs it to obtain a first signature, and sends the first ciphertext and the first signature to the payee commercial bank corresponding to the payee terminal; S312: The payee commercial bank receives the message and verifies the first signature. If the verification is successful, the payee commercial bank uses the private key to decrypt the message to obtain the transaction. S313. The payee commercial bank encrypts the public key of the central bank used for the transaction to obtain a corresponding second ciphertext, signs the second ciphertext to obtain a second signature, and sends the second ciphertext and the second signature to the central bank.

8. The method for double offline transactions of quantum computing-resistant digital currency with anonymity of the sender according to claim 6 is characterized in that: In S32, the central bank receives the message, verifies and decrypts it, and forwards the generated confirmation message to the payee terminal through the payee commercial bank, which specifically includes the following steps: S321, the central bank receives the message and verifies the second signature. If the verification is successful, the central bank uses the private key of the central bank to decrypt the transaction and confirm the transaction. At the same time, the central bank records the transaction and generates a confirmation message, encrypts it to obtain a third ciphertext, and signs the third ciphertext to obtain a third signature and sends it to the payee terminal; S322: The payee terminal receives the message, verifies the third signature, decrypts it to obtain a confirmation message, and records the transaction locally; S323, the central bank sends a confirmation message to the payee commercial bank, which receives the message and verifies it, and records the transaction locally, finds the corresponding lender terminal according to the digital currency in the transaction, and sends the real identity of the payee terminal to the central bank; S324. The payee commercial bank encrypts the confirmation message to obtain a fourth ciphertext, and signs the fourth ciphertext to obtain a fourth signature and sends them to the payee terminal. The payee terminal receives the message, verifies the signature, and then decrypts it to obtain a confirmation message, confirming that the digital currency of the transaction is valid, and the transaction is completed.

9. A quantum computing-resistant digital currency dual offline transaction system with anonymity of the payee, used to implement the steps of the quantum computing-resistant digital currency dual offline transaction method with anonymity of the payee as described in any one of claims 1 to 8, characterized in that: The system includes a central bank digital currency system, a payee commercial bank, a payee commercial bank, a payee terminal and a payee terminal, wherein the payee commercial bank corresponds to the payee terminal, and the payee commercial bank corresponds to the payee terminal; The central bank digital currency system has a public-private key pair based on the RSA cryptographic system, and the private key is stored in the central bank, and the public key is issued to all commercial banks and user terminals and stored in the corresponding hardware wallet; The central bank digital currency system is also equipped with a key management server based on ID cryptography, and the key management server is used to issue system private keys for the central bank digital currency system, and is also used to issue private keys based on ID cryptography for all objects with IDs.

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