Two-Party Anonymous Anti-Quantum Computing Digital Currency Double-Offline Transaction Method and System

Abstract

The present invention discloses a method and system for double-offline transactions of quantum-resistant computing digital currency with both parties anonymous. The method includes that the remitting commercial bank / receiving commercial bank issues digital currency based on ID cryptography to the remitting terminal / receiving terminal; uses a communication method to achieve double-anonymous transactions between the remitting terminal and the receiving terminal in a double-offline state; and confirms the transactions through the central bank in an online state. Beneficial effects: The present invention designs digital currency equipped with private keys, which can realize a method for double-offline transactions of digital currency with both parties anonymous, protects the identity information of the remitting party and the receiving party, and prevents the real identities of users from being exposed; moreover, the method of the present invention can conduct various transactions including double-offline transactions between digital currencies; the method for double-offline transactions of digital currency of the present invention has the ability to resist quantum computing and is difficult to be broken by a quantum computer.

Description

Technical Field

[0001] The present invention relates to the field of digital currency transactions, and specifically to a method and system for double-offline transactions of quantum-resistant digital currency with double anonymity for both parties. Background Art

[0002] Digital currency, abbreviated as DIGICCY, is the abbreviation of "Digital Currency" in English and is an alternative currency in the form of electronic currency. Digital gold coins and cryptographic currencies both belong to digital currency (DIGICCY).

[0003] Generally, digital currency is an unregulated, digital currency, usually issued and managed by developers, and accepted and used by members of a specific virtual community. The European Banking Authority defines virtual currency as: a digital representation of value, not issued by a central bank or authority, not pegged to a fiat currency, but since it is accepted by the public, it can be used as a means of payment and can also be transferred, stored or traded in electronic form.

[0004] DCEP (Digital Currency Electronic Payment), the Chinese version of the digital currency project, that is, digital currency and electronic payment tools, is the legal digital currency under research by the People's Bank of China and is a type of DIGICCY (digital currency).

[0005] Digital RMB is issued by the People's Bank of China, participated in operation by designated operating institutions and exchanged to the public. Based on a broad account system, it supports the loose coupling function of bank accounts, is equivalent to banknotes and coins, and has the characteristics of value and legal compensation and is a controllable anonymous payment tool. At present, regarding the research progress, top-level design, standard formulation, function research and development, joint debugging and testing and other work have been completed, and internal closed pilot testing started in April 2020. Although the specific time point for the market is still uncertain, what we can be sure of is that a cashless society is a future trend, and China can be said to be the country closest to a cashless society at present. Mobile electronic payment has undoubtedly changed our lives and made transactions more efficient, convenient and safe. Facing the constantly changing society and the increasingly updated technology, as technology developers, they should always maintain curiosity and sensitivity to the application of new technologies in order to create better value in the future industry wave.

[0006] However, with the needs of different scenarios, some buyers and sellers will require anonymous transactions for their own privacy or account security, but the existing digital currency transaction methods based on digital certificates or user IDs expose the user's identity.

[0007] Patent CN201911053809 discloses an anonymous transaction method and system based on digital currency. However, there are some problems with this method and system: it can only conduct online transactions. The temporary identity of the user can only proceed with the subsequent transaction process if it is recognized by its own server. When the user is unable to communicate with its own server, the payee of this method cannot use the user's temporary identity to verify the digital signature of the transaction (in the mathematical signature based on digital certificates, since the user needs to hide their real identity, they cannot provide a digital certificate containing their real identity, and cannot prove the association between their temporary identity and their digital certificate. Therefore, they cannot use their digital certificate to verify the digital signature of the transaction; in the mathematical signature based on ID cryptography, since the user needs to hide their real identity, they cannot provide their real identity, and cannot prove the association relationship between their temporary identity and their real identity. Therefore, they cannot use their real identity to verify the digital signature of the transaction). Therefore, without receiving any identity credentials from the payer, the payee cannot recognize the legitimacy of this transaction and complete the entire transaction process.

[0008] Now, all countries are developing quantum computers. As the next-generation computer, quantum computers have very great advantages. The powerful computing power and unique algorithms of quantum computers will completely collapse the current asymmetric cryptosystem. Therefore, with the rapid development of quantum computers, the existing asymmetric cryptosystem will face huge communication security risks. Digital currency systems mainly based on the asymmetric cryptography system will all face the risk of being cracked.

[0009] Based on the above analysis, the existing technologies of digital currency communication systems have the following defects:

[0010] 1. Most of the existing digital currency transaction methods based on digital certificates or user IDs expose the user's identity;

[0011] 2. The existing digital currency anonymous transaction methods based on digital certificates or user IDs can ensure the anonymous identity of users but cannot conduct anonymous transactions where both the payer and the payee are offline (i.e., double offline);

[0012] 3. The existing digital currency systems do not have the ability to resist quantum computing and have no security in the face of quantum computers. Summary of the Invention

[0013] In view of the problems in the related technologies, the present invention proposes a double-offline transaction method and system for quantum-computing-resistant digital currency with mutual anonymity to overcome the above-mentioned technical problems existing in the existing related technologies.

[0014] To this end, the specific technical solutions adopted by the present invention are as follows:

[0015] According to one aspect of the present invention, there is provided a method for double-offline transaction of a two-party anonymous quantum-resistant computing digital currency, the method comprising the following steps:

[0016] S1. The remitting bank / commercial bank of the payee issues digital currency based on ID cryptography to the remitting terminal / payee terminal;

[0017] S2. Use a communication method to achieve a double-anonymous transaction between the remitting terminal and the payee terminal in a double-offline state;

[0018] S3. Confirm the transaction through the central bank in an online state;

[0019] Wherein, the specific steps of the remitting bank / commercial bank of the payee issuing digital currency based on ID cryptography to the remitting terminal / payee terminal in the step S1 are as follows:

[0020] S11. The remitting terminal / payee terminal generates a pair of public and private key pairs, and packages the public key into a digital currency issuance request, and sends it to the corresponding commercial bank in an encrypted form. The corresponding commercial bank decrypts the request and verifies the validity of the request. After passing the verification, the corresponding commercial bank forwards the public key to the central bank;

[0021] S12. After receiving the request, the central bank generates digital currency with the corresponding currency value according to the public key and the currency value in the message. The central bank generates a corresponding ID cryptography private key based on the ID of the digital currency, and the central bank sends the digital currency and the ID cryptography private key based on the ID of the digital currency to the corresponding commercial bank;

[0022] S13. The corresponding commercial bank issues the digital currency and the private key based on the ID of the digital currency to the corresponding terminal.

[0023] Further, the steps of using a communication method to achieve a double-anonymous transaction between the remitting terminal and the payee terminal in a double-offline state in the step S2 are as follows:

[0024] S21. The remitting terminal takes out the digital currency of the remitting terminal directly issued by the remitting bank, and sends the ID of the digital currency of the remitting terminal as the anonymous ID of the remitting terminal to the payee terminal;

[0025] S22. The payee terminal calculates a first symmetric key and first signature information, obtains first encrypted information through the first signature information and the first symmetric key, combines the digital currency ID of the payee terminal and the first encrypted information to obtain a first combined information, and sends the first combined information to the remitting terminal;

[0026] S23. The payment terminal calculates the second symmetric key, decrypts and verifies the digital currency of the receiving terminal and the first signature information in the first encrypted information;

[0027] S24. The payment terminal withdraws the digital currency of the payment terminal directly issued by the commercial bank of the payer, generates a transaction, obtains the second signature information through the transaction, obtains the second encrypted information through the transaction and the second signature information, combines the digital currency ID of the payment terminal and the second encrypted information to obtain the second combined information, and sends the second combined information to the receiving terminal;

[0028] S26. The receiving terminal verifies the second signature information, decrypts and verifies the digital currency of the payment terminal;

[0029] S26. The receiving terminal verifies the second signature information, decrypts and verifies the digital currency of the payment terminal;

[0030] S27. The receiving terminal encrypts and sends the confirmation message to the payment terminal using the first symmetric key. The payment terminal decrypts the encrypted information using the second symmetric key to obtain the confirmation message, approves the completion of the transaction, and deletes the digital currency of the payment terminal, the private key of the digital currency of the payment terminal, and the private key of the digital currency of the payment terminal based on ID cryptography.

[0031] Further, the steps of the receiving terminal calculating the first symmetric key and the first signature information in S22, obtaining the first encrypted information through the first signature information and the first symmetric key, combining the digital currency ID of the receiving terminal and the first encrypted information to obtain the first combined information, and sending the first combined information to the payment terminal specifically include the following steps:

[0032] S221. After receiving the message, the receiving terminal calculates the public key of the digital currency of the payment terminal based on ID cryptography according to the digital currency ID of the payment terminal, selects a digital currency of the receiving terminal from the digital currencies directly issued by the commercial bank of the payee, and uses the ID of this digital currency as the payee ID, that is, the anonymous ID;

[0033] S222. The receiving terminal calculates the first symmetric key using the private key of the digital currency of the receiving terminal based on ID cryptography and the public key of the digital currency of the payment terminal based on ID cryptography;

[0034] S223. The receiving terminal calculates the first signature information using the private key of the digital currency of the receiving terminal based on ID cryptography for the digital currency of the receiving terminal, encrypts the digital currency of the receiving terminal and the first signature information using the first symmetric key to obtain the first encrypted information, and the receiving terminal combines the digital currency ID of the receiving terminal and the first encrypted information to obtain the first combined information and sends it to the payment terminal.

[0035] Further, the steps for the payment terminal in S23 to calculate the second symmetric key, decrypt, and verify the digital currency of the receiving terminal and the first signature information in the first encrypted information are specifically as follows:

[0036] S231: After receiving the message, the payment terminal calculates the public key of the receiving terminal's digital currency based on ID cryptography according to the digital currency ID of the receiving terminal, retrieves the private key of the payment terminal's digital currency based on ID cryptography, and calculates the second symmetric key using this private key and the public key.

[0037] S232: The payment terminal uses the second symmetric key to decrypt the first encrypted information to obtain the receiving terminal's digital currency and the first signature information, and uses the public key of the receiving terminal's digital currency based on ID cryptography to verify the first signature information. After successful verification, it recognizes this ID as a valid receiving ID.

[0038] S233: The payment terminal decrypts the encrypted signature and the encrypted public key in the receiving terminal's digital currency respectively through the public key of the central bank to obtain the digital signature and the public key of the receiving terminal's digital currency.

[0039] S234: The payment terminal uses the public key of the central bank to verify the digital signature of the digital currency. After successful verification, at the same time, the payment terminal confirms that this message is a legal message, and retains the digital currency ID as the anonymous ID of the receiving terminal and retains the public key of the digital currency in the receiving terminal's digital currency.

[0040] Further, the steps for the payment terminal in S24 to retrieve the digital currency of the payment terminal directly issued by the payer's commercial bank, generate a transaction, obtain the second signature information through the transaction, obtain the second encrypted information through the transaction and the second signature information, combine the digital currency ID of the payment terminal and the second encrypted information to obtain the second combined information, and send the second combined information to the receiving terminal are specifically as follows:

[0041] S241: The payment terminal retrieves the digital currency of the payment terminal directly issued by the payer's commercial bank and generates a transaction, and uses the private key of the payment terminal's digital currency to sign this transaction to obtain the second signature information.

[0042] S242: The payment terminal uses the second symmetric key to encrypt the transaction and the second signature information to obtain the second encrypted information, combines the digital currency ID of the payment terminal and the second encrypted information to obtain the second combined information, and sends the second combined information to the receiving terminal.

[0043] Further, the steps for the receiving terminal in S26 to verify the second signature information, decrypt, and verify the digital currency of the payment terminal are specifically as follows:

[0044] S261. The receiving terminal judges the reasonableness of the time in the transaction, extracts the public key in the digital currency of the sending terminal in the transaction, and uses it to verify the second signature information;

[0045] S262. The receiving terminal decrypts the encrypted signature and the encrypted public key in the digital currency of the sending terminal through the public key of the central bank to obtain the digital signature and the public key of the digital currency of the sending terminal, and the receiving terminal uses this public key to verify the digital signature of the digital currency. The receiving terminal trusts this transaction and stores the transaction and the second signature information.

[0046] Further, the confirmation of the transaction by the central bank in the online state in S3 includes the following steps:

[0047] S31. The receiving terminal sends the transaction and the second signature information to the receiving party's commercial bank, and the receiving party's commercial bank encrypts and sends the receiving terminal ID, the transaction and the second signature information to the central bank;

[0048] S32. After registering the transaction, the central bank generates a confirmation message and encrypts and sends the confirmation message to the receiving terminal through the receiving party's commercial bank;

[0049] S33. The receiving terminal decrypts and verifies to obtain the confirmation message, confirms that the digital currency of the transaction is valid, and the digital currency in the transaction is marked as available for normal use, and the transaction ends.

[0050] Further, the specific steps of the receiving terminal sending the transaction and the second signature information to the receiving party's commercial bank in S31, and the receiving party's commercial bank encrypting and sending the receiving terminal ID, the transaction and the second signature information to the central bank include the following steps:

[0051] S311. The receiving terminal uses the ID of the digital currency of the receiving terminal as the anonymous ID of the receiving terminal, encrypts the transaction and the second signature information and sends them to the receiving party's commercial bank;

[0052] S312. The receiving party's commercial bank decrypts and verifies the message to obtain the transaction and the second signature information, and finds its corresponding terminal according to the ID of the digital currency of the receiving terminal, that is, the receiving terminal;

[0053] S313. The receiving party's commercial bank encrypts and sends the receiving terminal ID, the transaction and the second signature information to the central bank through the quantum communication network.

[0054] Further, the specific steps of the central bank generating a confirmation message after registering the transaction in S32 and encrypting and sending the confirmation message to the receiving terminal include the following steps:

[0055] S321. After receiving the receiving terminal ID, the transaction, and the second signature information, the central bank verifies the transaction and the second signature information, registers the transaction, generates a confirmation message, and encrypts and sends the transaction and the second signature information to the remitting commercial bank according to the remitting commercial bank ID in the transaction;

[0056] S322. After verifying the transaction and the digital currency and confirming the transaction, the remitting commercial bank finds its corresponding terminal according to the digital currency of the remitting terminal, that is, the remitting terminal, records the remitting terminal ID and the transaction as a transaction entry, and encrypts and sends the entry to the central bank;

[0057] S323. After receiving and verifying the message, the central bank records the remitting terminal ID, the receiving terminal ID, and the transaction as a transaction entry, and encrypts and sends the transaction confirmation message to the receiving commercial bank;

[0058] S324. The receiving commercial bank records the receiving terminal ID and the transaction as a transaction entry, and encrypts and sends the confirmation message to the receiving terminal.

[0059] According to another aspect of the present invention, a quantum-computing-resistant digital currency two-offline transaction system with two-way anonymity is provided. The system includes a central bank digital currency system, a commercial bank digital currency system, and users. The users are the main bodies of digital currency use, and the users hold terminals to conduct digital currency transactions;

[0060] Among them, the commercial bank digital currency system includes a remitting commercial bank and a receiving commercial bank. The user terminals include a remitting terminal and a receiving terminal. The remitting commercial bank corresponds to the remitting terminal, and the remitting terminal is equipped with a digital currency hardware wallet issued by the remitting commercial bank. The receiving commercial bank corresponds to the receiving terminal, and the receiving terminal is equipped with a digital currency hardware wallet issued by the receiving commercial bank;

[0061] The central bank and the commercial banks have established a quantum communication service station and access the quantum communication network through the quantum communication service station to achieve quantum-computing-resistant secure communication. The user terminals connect to the quantum communication service stations of their respective deposit-taking commercial banks through the equipped digital currency hardware wallets;

[0062] The central bank digital currency system is used to generate and issue digital currency, and conduct ownership registration of digital currency; the commercial bank digital currency system is used to perform banking functions for digital currency

[0063] The beneficial effects of the present invention are:

[0064] 1. The present invention designs a digital currency equipped with a private key, which can implement a method for two-party anonymous digital currency double-offline transactions, protecting the identity information of the payer and the payee, and preventing the exposure of the user's true identity; moreover, the method of the present invention can conduct various transactions including double-offline transactions between digital currencies.

[0065] 2. The digital currency double-offline transaction method of the present invention has the ability to resist quantum computing and is difficult to be broken by a quantum computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0067] Figure 1 It is a schematic diagram of two-party anonymous quantum-resistant digital currency double-offline transaction of the present invention;

[0068] Figure 2 It is a schematic diagram of the digital currency data structure of the quantum-resistant digital currency system of the present invention;

[0069] Figure 3 It is a network structure block diagram of the quantum-resistant digital currency system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] The following will further illustrate the present invention in conjunction with the drawings and specific embodiments. However, it should be understood that the present invention can be implemented in various forms. Some exemplary and non-limiting embodiments presented in the following drawings and described below are not intended to limit the present invention to the specific embodiments described.

[0071] It should be understood that, when technically feasible, the technical features listed for different embodiments above can be combined with each other to form additional embodiments within the scope of the present invention. In addition, the specific examples and embodiments described in the present invention are non-limiting, and corresponding modifications can be made to the structures, steps, and sequences described above without departing from the protection scope of the present invention.

[0072] According to an embodiment of the present invention, a method and system for two-party anonymous quantum-resistant digital currency double-offline transaction are provided.

[0073] The present invention will be further described in conjunction with the accompanying drawings and specific embodiments. According to an embodiment of the present invention, a method for two-party anonymous anti-quantum computing digital currency dual-offline transaction is provided. The participating objects of this method include the central bank (i.e., the central bank digital currency system) SS, commercial bank PS, commercial bank CS, payment terminal PT, and receiving terminal CT. Among them, the opening bank of the payment terminal PT is commercial bank PS, so the payment terminal PT is equipped with a digital currency hardware wallet issued by commercial bank PS. Similarly, the opening bank of the receiving terminal CT is commercial bank CS, so the receiving terminal CT is equipped with a digital currency hardware wallet issued by commercial bank CS. In this embodiment, let the ID of the central bank SS be IDSS, the ID of commercial bank PS be IDPS, the ID of commercial bank CS be IDCS, the ID of payment terminal PT be IDPT, and the ID of receiving terminal CT be IDCT.

[0074] Specifically, as Figure 1-2 shown, this method includes the following steps:

[0075] S1. The paying commercial bank / receiving commercial bank issues digital currency based on ID cryptography to the payment terminal / receiving terminal;

[0076] Specifically, the public and private keys of the central bank SS are based on the RSA cryptosystem. Let its RSA public and private key pair be PK SS / SK SS . The central bank SS also establishes an algorithm system based on ID cryptography for issuing public and private key pairs based on ID cryptography algorithms for the IDs in this system. The parameters of the ID cryptography algorithm are set as follows:

[0077] (1) Let q be a large prime number, generate G1 and G2. G1 and G2 are respectively an additive cyclic group and a multiplicative cyclic group of order q. The mapping G1×G1→G2 becomes a bilinear mapping. Randomly select a generator P of G1;

[0078] (2) Define a hash function H: {0, 1} * →G1 * ;

[0079] (3) Set other system parameters ad_paras;

[0080] (4) Randomly take s∈Z q * as the master key of this algorithm system. s is only stored in the key management server KS, and calculate the system public key P pub =s·P.

[0081] The algorithm parameters are

[0082] In this embodiment, the digital currency hardware wallet stores the RSA public key PK of the central bank SS SS and cannot be read, that is, the public key is not publicly disclosed to prevent it from being cracked by a quantum computer and obtaining the private key. The digital currency hardware wallet also stores the system parameters of the ID-based cryptography algorithm and cannot be read either.

[0083] In this embodiment, the method for obtaining the symmetric key between two parties through ID-based cryptographic calculation is as follows:

[0084] Taking A and B of the two communicating parties as an example, let the public-private key pair of A be PK A / SK A , and the public-private key pair of B be PK B / SK B . A can obtain the symmetric key with B by obtaining the public key of B B can obtain the symmetric key with A by obtaining the public key of A According to ID-based cryptography, we have:

[0085] This embodiment realizes the process of two-party anonymous quantum-computing-resistant double-offline transfer from the payment terminal PT to the receiving terminal CT. The specific steps are as follows:

[0086] S1. Issuing digital currency stage (the issuing commercial bank of the payer / the receiving commercial bank issues digital currency based on ID-based cryptography for the payment terminal / the receiving terminal)

[0087] The payment terminal PT generates a pair of public-private key pairs, and packs the public key into a digital currency issuance request and sends it to its bank, i.e., the commercial bank PS, in an encrypted form. The commercial bank PS decrypts the request and verifies the validity of the request. After verification, the commercial bank PS forwards the public key to the central bank SS.

[0088] Upon receiving the request, the central bank SS will generate digital currency with the corresponding currency value according to the public key and the currency value in the message. The data structure of the digital currency is as Figure 2 shown. The composition of the digital currency is: digital currency ID, digital currency value, encrypted public key, encrypted digital currency central bank signature. Among them, the encrypted public key is {public key}RPK||{RPK}SK SS , the public key is the public key sent by the payment terminal PT, and RPK is the truly random number generated by the central bank SS; the encrypted signature is {signature}RS||{RS}SK SS , the signature is that the central bank SS uses its own private key SK SSObtained by performing signature calculation on the digital currency, where RS is the true random number generated by the central bank SS. In the above text, the form {m}k represents the ciphertext obtained by encrypting m with the key k, but {public key}RPK is symmetric encryption, and {RPK}SK SS is asymmetric encryption. The central bank SS will generate the corresponding ID cryptographic private key based on the ID of the digital currency. The central bank SS sends the digital currency and the ID cryptographic private key based on the ID of the digital currency to the commercial bank PS. The method of decrypting the encrypted public key is to use the public key PK of the central bank SS SS to decrypt {RPK}SK SS to obtain RPK, and then use RPK to decrypt {public key}RPK to obtain the public key; the method of decrypting the encrypted signature is to use the public key PK of the central bank SS SS to decrypt {RS}SK SS to obtain RS, and then use RS to decrypt {signature}RS to obtain the signature.

[0089] The commercial bank PS issues the digital currency and the private key based on the ID of the digital currency to the PT. In the above process, the commercial bank PS will deduct an equal amount from the online banking account corresponding to the payment terminal PT.

[0090] The receiving terminal CT also obtains the issuance of the digital currency from the commercial bank CS in the same way.

[0091] S2. Double-offline transaction stage (realize double-anonymous transaction between the payer and the payee in the double-offline state by using communication methods)

[0092] For the sake of simplicity in description, assume that the digital currency of the payment terminal PT in this transaction is PM, the digital currency ID is IDPM, and the public-private key pair of the digital currency is PKT PM / SKT PM , the public-private key pair of the digital currency based on ID cryptography is PKID PM / SKID PM , PKID PM =H(IDPM), SKID PM =s*PKID PM ; the digital currency of the receiving terminal CT is CM, the digital currency ID is IDCM, and the public-private key pair of the digital currency is PKT CM / SKT CM , the public-private key pair of the digital currency based on ID cryptography is PKID CM / SKID CM , PKID CM =H(IDCM), SKID CM =s*PKID CM .

[0093] The payment terminal PT withdraws the digital currency PM directly issued by the commercial bank PS, and the value of PM is equal to the amount of this transaction. The payment terminal PT sends the ID of the digital currency PM, that is, IDPM, as an anonymous ID to the receiving terminal CT.

[0094] After receiving the message, the receiving terminal CT calculates the public key PKID of the digital currency PM based on ID cryptography according to IDPM. PM The receiving terminal CT selects a digital currency CM from the digital currencies directly issued by the commercial bank CS, and uses the ID of this digital currency, that is, IDCM, as the payee ID, that is, the anonymous ID. The receiving terminal CT uses the private key SKID of the digital currency CM based on ID cryptography. CM and the public key PKID PM to calculate the symmetric key with the payment terminal PT through the ID cryptography algorithm (the first symmetric key). The receiving terminal CT uses the private key SKID based on the digital currency ID CM to perform a signature algorithm calculation on the digital currency CM to obtain the signature SCM (the first signature information). The receiving terminal CT encrypts the digital currency CM and the signature SCM using the key TXK to obtain {CM||SCM}TXK (the first encrypted information). The receiving terminal packs to obtain IDCM||{CM||SCM}TXK (the first combined information) and sends it to the payment terminal PT. Since the transaction content is encrypted by the symmetric key, the transaction content is confidential and can resist quantum computing; since the digital signature is encrypted by the symmetric key, the digital signature can resist quantum computing.

[0095] After receiving the message, the payment terminal PT calculates the public key PKID of the digital currency CM based on ID cryptography according to IDCM. CM The payment terminal PT withdraws the private key SKID of the digital currency PM based on ID cryptography. PM and the public key PKID CM to calculate the symmetric key with the receiving terminal CT through the ID cryptography algorithm (the second symmetric key). The payment terminal PT uses the key TXK to decrypt {CM||SCM}TXK to obtain the digital currency CM and the signature SCM of the message. The payment terminal PT uses the public key PKID CM to verify the signature SCM in the message. After the verification passes, it recognizes this ID as a valid receiving ID. The payment terminal PT decrypts the encrypted signature in the digital currency CM through the public key PK of the central bank SS to obtain the digital signature. The payment terminal PT decrypts the encrypted public key in the digital currency CM through the public key PK of the central bank SS to obtain the public key PKT of the digital currency CM. CM The payment terminal PT uses the public key PK SSVerify the digital signature of the digital currency. After successful verification, at the same time, the payment terminal PT confirms that the message is legal and retains the digital currency ID as the anonymous ID of the receiving terminal CT and retains the public key PKT of the digital currency in the digital currency CM. CM 。

[0096] The payment terminal PT retrieves the digital currency PM directly issued by the commercial bank PS. The value of PM is equal to the amount of this transaction. The payment terminal PT generates a transaction Tx, and the transaction Tx includes the current transaction time, the payer information IDPS, the payee information IDCM, and the digital currency PM. The payment terminal PT uses the private key SKT of the digital currency PM PM to sign the transaction Tx to obtain TxS (the second signature information). The payment terminal PT encrypts Tx||TxS using the key TXK to obtain {Tx||TxS}TXK (the second encrypted information), and packages it to obtain IDPM||{Tx||TxS}TXK (the second combined information). The payment terminal PT sends IDPM||{Tx||TxS}TXK to the receiving terminal CT.

[0097] After receiving the message, the receiving terminal CT decrypts {Tx||TxS}TXK using the symmetric key TXK to calculate Tx||TxS.

[0098] The receiving terminal CT judges the rationality of the time in the transaction Tx and retrieves the public key PKT in PM in Tx PM , and uses it to verify TxS. The receiving terminal CT decrypts the encrypted signature in the digital currency PM through the public key PK of the central bank SS to obtain the digital signature. The receiving terminal CT decrypts the encrypted public key in the digital currency PM through the public key PK of the central bank SS to obtain the public key PKT of the digital currency PM. PM 。The receiving terminal CT uses the public key PK SS to verify the digital signature of the digital currency. The receiving terminal CT trusts this transaction and stores Tx||TxS. However, since the online transaction has not been completed, the digital currency in Tx is marked as unavailable.

[0099] The receiving terminal CT encrypts the confirmation message using the key TXK and sends it to the payment terminal PT. The payment terminal PT decrypts the message using the key TXK to obtain the confirmation message. The payment terminal PT approves the completion of the transaction and deletes the digital currency PM, the private key of the digital currency PM, and the private key of the digital currency PM based on ID cryptography.

[0100] S3. Online transaction stage (confirm the transaction through the central bank in the online state)

[0101] The payment collection terminal CT uses the ID of the digital currency CM, i.e., IDCM, as the anonymous ID. The payment collection terminal CT encrypts the transaction Tx||TxS and sends it to the commercial bank CS. The commercial bank CS decrypts and verifies the message to obtain the transaction Tx||TxS. CS finds the corresponding terminal as CT according to IDCM. The commercial bank CS encrypts and sends the transaction IDCT||Tx||TxS to the central bank SS through the quantum communication network.

[0102] The central bank SS receives the transaction message IDCT||Tx||TxS from the commercial bank CS. The central bank SS confirms Tx||TxS. After registering the transaction Tx, SS generates a confirmation message and encrypts and sends Tx||TxS to the commercial bank PS according to the IDPS in Tx. After verifying the transaction and the digital currency and confirming the transaction, PS finds the corresponding terminal as PT according to PM, records IDPT||Tx as a transaction entry, and encrypts and sends this entry to SS, that is, PS knows the real identity of the sender but does not know the real identity of the recipient. After receiving and verifying the message from PS, the central bank SS records IDPT||IDCT||Tx as a transaction entry, that is, SS knows the real identity of the sender and also knows the real identity of the recipient. SS encrypts and sends the transaction confirmation message to the commercial bank CS. The commercial bank CS records IDCT||Tx as a transaction entry, that is, CS does not know the real identity of the sender but knows the real identity of the recipient. The commercial bank CS encrypts and sends the confirmation message to the payment collection terminal CT.

[0103] After decrypting and verifying, the payment collection terminal CT obtains the confirmation message, confirms that the digital currency of the transaction is valid, the digital currency in Tx is marked as available for normal use, and the transaction ends. Since CT does not have the private key of the received digital currency PM and the private key of the digital currency PM based on ID cryptography, the digital currency PM can be used as an ordinary digital currency by CT subsequently.

[0104] According to another aspect of the present invention, as Figure 3 shown, a two-party anonymous quantum-computing-resistant digital currency double-offline transaction system is provided;

[0105] Taking the operation instance of the central bank digital currency as an example, the basic structure of the digital currency system mainly includes the central bank digital currency system, the commercial bank digital currency system (which can be multiple commercial bank digital currency systems in practice), and users. Among them, the central bank digital currency system is used to generate and issue digital currency and register the ownership of the digital currency; the commercial bank digital currency system is used to perform banking functions for digital currency; users are the main body of digital currency use. In the present invention, users hold terminals to conduct transactions of digital currency.

[0106] The digital currency system network of the two-party anonymous anti-quantum computing digital currency double-offline transaction method of the present invention is as follows Figure 3 shown. In the digital currency system network of the present invention, there are three types of objects: the People's Bank of China, i.e., the central bank, commercial banks, and user terminals. Among them, the central bank and commercial banks have established quantum communication service stations and can access the quantum communication network through the quantum communication service stations to achieve secure communication against quantum computing. The user terminals are connected to the quantum communication service stations of the commercial banks where they open accounts through the equipped digital currency hardware wallets. The digital currency hardware wallets equipped by the user terminals are issued by the quantum communication service stations of the commercial banks where the users open accounts. The digital currency hardware wallets in the present invention store a symmetric key pool or an asymmetric key pool issued by the quantum communication service station, and in the form of a key card, help the user terminals and the quantum communication service stations to achieve secure communication against quantum computing. The method for secure communication against quantum computing based on the symmetric key pool is described in the patent with the application number "201610845826.7"; the method for secure communication against quantum computing based on the asymmetric key pool is described in the patent with the application number "201910325032.1".

[0107] In addition to supporting double-offline transactions, this embodiment also supports transactions where the payer is online and the payee is offline, transactions where the payer is offline and the payee is online, and transactions where the payer is online and the payee is online, that is, this process supports all types of transactions.

[0108] In summary, the present invention designs a digital currency with a private key, which can realize a two-party anonymous digital currency double-offline transaction method, protecting the identity information of the payer and the payee, and preventing the exposure of the users' true identities; moreover, the method of the present invention can conduct various transactions including double-offline transactions between digital currencies. The digital currency double-offline transaction method of the present invention has the ability to resist quantum computing and is difficult to be broken by quantum computers.

[0109] The above specific embodiments only describe the preferred embodiments of the present invention, rather than limiting the protection scope of the present invention. Without departing from the design concept and spirit of the present invention, various deformations, substitutions, and improvements made by those of ordinary skill in the art to the technical solutions of the present invention based on the written description and drawings provided by the present invention shall fall within the protection scope of the present invention. The protection scope of the present invention is determined by the claims.

Claims

1. A method for double-offline transactions of quantum-computing-resistant digital currency with both parties anonymous, characterized in that, The method includes the following steps: S1. The remitting commercial bank / receiving commercial bank issues digital currency based on ID cryptography to the remitting terminal / receiving terminal; S2. Use a communication method to achieve double-anonymous transactions between the remitting terminal and the receiving terminal in a double-offline state; S3. Confirm the transaction through the central bank in an online state; Among them, the specific steps for the remitting commercial bank / receiving commercial bank to issue digital currency based on ID cryptography to the remitting terminal / receiving terminal in S1 are as follows: S11. The remitting terminal / receiving terminal generates a pair of public and private key pairs, packs the public key into a digital currency issuance request, and sends it to the corresponding commercial bank in an encrypted form. The corresponding commercial bank decrypts the request and verifies the validity of the request. After verification, the corresponding commercial bank forwards the public key to the central bank; S12. After receiving the request, the central bank generates digital currency with the corresponding currency value according to the public key and the currency value in the message. The central bank generates a corresponding ID cryptography private key based on the ID of the digital currency, and the central bank sends the digital currency and the ID cryptography private key based on the ID of the digital currency to the corresponding commercial bank; S13. The corresponding commercial bank issues the digital currency and the private key based on the ID of the digital currency to the corresponding terminal; The steps for using a communication method to achieve double-anonymous transactions between the remitting terminal and the receiving terminal in a double-offline state in S2 are as follows: S21. The remitting terminal takes out the digital currency of the remitting terminal directly issued by the remitting commercial bank, and sends the ID of the digital currency of the remitting terminal as the anonymous ID of the remitting terminal to the receiving terminal; S22. The receiving terminal calculates the first symmetric key and the first signature information, obtains the first encrypted information through the first signature information and the first symmetric key, combines the digital currency ID of the receiving terminal and the first encrypted information to obtain the first combined information, and sends the first combined information to the remitting terminal; S23. The remitting terminal calculates the second symmetric key, and decrypts and verifies the digital currency of the receiving terminal and the first signature information in the first encrypted information; S24. The remitting terminal takes out the digital currency of the remitting terminal directly issued by the remitting commercial bank, generates a transaction, obtains the second signature information through the transaction, obtains the second encrypted information through the transaction and the second signature information, combines the digital currency ID of the remitting terminal and the second encrypted information to obtain the second combined information, and sends the second combined information to the receiving terminal; S25. After receiving the message, the receiving terminal decrypts the second encrypted information using the first symmetric key to obtain the transaction and the second signature information; S26. The receiving terminal verifies the second signature information, and decrypts and verifies the digital currency of the remitting terminal; S27. The receiving terminal encrypts the confirmation message using the first symmetric key and sends it to the remitting terminal. The remitting terminal decrypts the encrypted information using the second symmetric key to obtain the confirmation message, recognizes the completion of the transaction, and deletes the digital currency of the remitting terminal, the private key of the digital currency of the remitting terminal, and the ID cryptography private key based on the digital currency of the remitting terminal.

2. The method for double-offline transaction of two-party anonymous anti-quantum computing digital currency according to claim 1, characterized in that In S22, the receiving terminal calculates a first symmetric key and a first signature information, obtains a first encrypted information through the first signature information and the first symmetric key, combines the digital currency ID of the receiving terminal and the first encrypted information to obtain a first combined information, and sends the first combined information to the sending terminal, which specifically includes the following steps: S221. After receiving the message, the receiving terminal calculates the ID-cryptography-based public key of the digital currency of the sending terminal according to the digital currency ID of the sending terminal, selects a digital currency of the receiving terminal directly issued by the receiving party's commercial bank, and uses the ID of this digital currency as the receiving party ID, that is, the anonymous ID; S222. The receiving terminal calculates the first symmetric key by using the ID-cryptography-based private key of the digital currency of the receiving terminal and the ID-cryptography-based public key of the digital currency of the sending terminal; S223. The receiving terminal calculates the first signature information by using the ID-cryptography-based private key of the digital currency of the receiving terminal for the digital currency of the receiving terminal, encrypts the digital currency of the receiving terminal and the first signature information by using the first symmetric key to obtain the first encrypted information, and the receiving terminal combines the digital currency ID of the receiving terminal and the first encrypted information to obtain the first combined information and sends it to the sending terminal.

3. The method for double-offline transaction of two-party anonymous quantum-resistant digital currency according to claim 1, characterized in that In S23, the sending terminal calculates a second symmetric key, and decrypts and verifies the digital currency of the receiving terminal and the first signature information in the first encrypted information, which specifically includes the following steps: S231. After receiving the message, the sending terminal calculates the ID-cryptography-based public key of the digital currency of the receiving terminal according to the digital currency ID of the receiving terminal, retrieves the ID-cryptography-based private key of the digital currency of the sending terminal, and calculates the second symmetric key by using this private key and this public key; S232. The sending terminal decrypts the first encrypted information by using the second symmetric key to obtain the digital currency of the receiving terminal and the first signature information, and verifies the first signature information by using the ID-cryptography-based public key of the digital currency of the receiving terminal. After the verification passes, it recognizes this ID as a valid receiving ID; S233. The sending terminal decrypts the encrypted signature and the encrypted public key in the digital currency of the receiving terminal by using the public key of the central bank to obtain the digital signature and the public key of the digital currency of the receiving terminal; S234. The sending terminal verifies the digital signature of the digital currency by using the public key of the central bank. After the verification passes, at the same time, the sending terminal confirms that this message is a legal message, and retains the digital currency ID as the anonymous ID of the receiving terminal and retains the public key of the digital currency in the digital currency of the receiving terminal.

4. The method for two-party anonymous anti-quantum computing digital currency double-offline transaction according to claim 1, wherein In S24, the sending terminal retrieves the digital currency of the sending terminal directly issued by the sending party's commercial bank, generates a transaction, obtains a second signature information through the transaction, obtains a second encrypted information through the transaction and the second signature information, combines the digital currency ID of the sending terminal and the second encrypted information to obtain a second combined information, and sends the second combined information to the receiving terminal, which specifically includes the following steps: S241. The payment terminal retrieves the digital currency of the payment terminal directly issued by the commercial bank of the payer, generates a transaction, and signs the transaction using the private key of the digital currency of the payment terminal to obtain the second signature information; S242. The payment terminal encrypts the transaction and the second signature information using the second symmetric key to obtain the second encrypted information, combines the digital currency ID of the payment terminal and the second encrypted information to obtain the second combined information, and sends the second combined information to the receiving terminal.

5. The method for two-party anonymous anti-quantum computing digital currency double-offline transaction according to claim 1, characterized in that, In step S26, the steps for the receiving terminal to verify the second signature information, decrypt, and verify the digital currency of the payment terminal are as follows: S261. The receiving terminal judges the rationality of the time in the transaction, retrieves the public key in the digital currency of the payment terminal in the transaction, and uses it to verify the second signature information; S262. The receiving terminal decrypts the encrypted signature and the encrypted public key in the digital currency of the payment terminal through the public key of the central bank to obtain the digital signature and the public key of the digital currency of the payment terminal, and the receiving terminal uses this public key to verify the digital signature of the digital currency. The receiving terminal trusts this transaction and stores the transaction and the second signature information.

6. The method for two-party anonymous anti-quantum computing digital currency double-offline transaction according to claim 1, wherein In step S3, the steps for the central bank to confirm the transaction in the online state are as follows: S31. The receiving terminal sends the transaction and the second signature information to the commercial bank of the payee. The commercial bank of the payee encrypts and sends the receiving terminal ID, the transaction, and the second signature information to the central bank; S32. After registering the transaction, the central bank generates a confirmation message and encrypts and sends the confirmation message to the receiving terminal through the commercial bank of the payee; S33. The receiving terminal decrypts and verifies to obtain the confirmation message, confirms that the digital currency of the transaction is valid, and the digital currency in the transaction is marked as being available for normal use, and the transaction ends.

7. The method for two-party anonymous anti-quantum computing digital currency double-offline transaction according to claim 6, wherein In step S31, the steps for the receiving terminal to send the transaction and the second signature information to the commercial bank of the payee, and the commercial bank of the payee to encrypt and send the receiving terminal ID, the transaction, and the second signature information to the central bank are as follows: S311. The receiving terminal uses the ID of the digital currency of the receiving terminal as the anonymous ID of the receiving terminal, encrypts the transaction and the second signature information, and sends them to the commercial bank of the payee; S312. The commercial bank of the payee decrypts and verifies the message to obtain the transaction and the second signature information, and finds its corresponding terminal according to the ID of the digital currency of the receiving terminal, that is, the receiving terminal; S313. The commercial bank of the payee encrypts and sends the receiving terminal ID, the transaction, and the second signature information to the central bank through the quantum communication network.

8. The method for double-offline transaction of two-party anonymous quantum-resistant digital currency according to claim 6, characterized in that, In step S32, the steps for the central bank to generate a confirmation message after registering the transaction and encrypt and send the confirmation message to the receiving terminal through the commercial bank of the payee are as follows: S321. After receiving the receiving terminal ID, the transaction, and the second signature information, the central bank confirms the transaction and the second signature information, registers this transaction, generates a confirmation message, and encrypts and sends the transaction and the second signature information to the commercial bank of the payer according to the ID of the commercial bank of the payer in the transaction; S322. After the paying commercial bank verifies the transaction and the digital currency and confirms the transaction, it finds its corresponding terminal according to the digital currency of the paying terminal, that is, the paying terminal, records the paying terminal ID and the transaction as a transaction entry, and encrypts and sends this entry to the central bank; S323. After receiving and verifying the message, the central bank records the paying terminal ID, the receiving terminal ID and the transaction as a transaction entry, and encrypts and sends the transaction confirmation message to the receiving commercial bank; S324. The receiving commercial bank records the receiving terminal ID and the transaction as a transaction entry, and encrypts and sends the confirmation message to the receiving terminal.

9. A two-party anonymous anti-quantum computing digital currency double-offline trading system for implementing the steps of the anti-quantum computing digital currency communication method based on ID cryptography according to any one of claims 1-8, characterized in that, The system includes a central bank digital currency system, a commercial bank digital currency system and users, and the users are the main body of digital currency use. Users hold terminals to conduct digital currency transactions; Among them, the commercial bank digital currency system includes the paying commercial bank and the receiving commercial bank. The user terminal includes the paying terminal and the receiving terminal. The paying commercial bank corresponds to the paying terminal, and the paying terminal is equipped with a digital currency hardware wallet issued by the paying commercial bank. The receiving commercial bank corresponds to the receiving terminal, and the receiving terminal is equipped with a digital currency hardware wallet issued by the receiving commercial bank; The central bank and commercial banks have established quantum communication service stations and can access the quantum communication network through the quantum communication service stations to achieve quantum-computing-resistant secure communication. The user terminal connects to the quantum communication service stations of the commercial banks of their respective deposit-taking institutions through the equipped digital currency hardware wallets; The central bank digital currency system is used to generate and issue digital currency and conduct ownership registration of digital currency; the commercial bank digital currency system is used to perform banking functions for digital currency.

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