Anonymous dual offline transaction method and system based on trusted intermediary and one-time certificate

Abstract

The present invention discloses an anonymous dual offline transaction method and system based on a trusted intermediary and a one-time certificate, the method comprising a preparation stage: using a communication method to achieve close distance communication between the trusted intermediary and the payee and the payee; a dual offline transaction stage: using a communication method to achieve close distance communication between the payee and the payee, and completing the offline transaction through the trusted intermediary in an offline state; an online transaction stage: confirming the transaction through a commercial bank and a central bank in an online state. Beneficial effects: Compared with the prior art, the present invention can better protect the privacy information of users and make transactions (especially dual offline transactions) safer.

Description

Technical Field

[0001] The present invention relates to the field of information technology, and in particular to an anonymous dual offline transaction method and system based on a trusted intermediary and a one-time certificate. Background Art

[0002] At present, with the rapid development of the times, digital currency payment methods are favored by more and more people. Digital currency payment tools (DC / EP, Digital Currency and Electronic Payment) as a digital alternative to cash banknotes are of great significance to building a cashless society.

[0003] Patent No. CN201911053809 discloses an anonymous transaction method and system based on digital currency. The problem with this patent is that it can only conduct online transactions. The user's temporary identity can only be recognized by its own server before the subsequent transaction process can be carried out. 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 digital 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 digital 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 this transaction and complete the entire transaction process without receiving any identity credentials from the payee, that is, the problem with this patent method is that dual offline transactions cannot be carried out. Dual offline transactions are transactions in which both the payee and the payee are offline. Summary of the invention

[0004] In view of the problems in the related art, the present invention proposes an anonymous dual offline transaction method and system based on a trusted intermediary and a one-time certificate to overcome the above technical problems existing in the existing related art.

[0005] To this end, the specific technical solution adopted by the present invention is as follows:

[0006] According to one aspect of the present invention, an anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate is provided, the method comprising the following steps:

[0007] S1. Preparation phase: Use communication methods to achieve close-range communication between the trusted intermediary and the sender and receiver;

[0008] S2, dual offline transaction stage: use the communication method to achieve close communication between the sender and the receiver, and complete the offline transaction through a trusted intermediary in an offline state;

[0009] S3. Online transaction stage: The transaction is confirmed online by commercial banks and the central bank.

[0010] Furthermore, the use of the communication method in S1 to achieve short-distance communication between the trusted intermediary and the payee and the payee includes the following steps:

[0011] S11. Using a communication method to achieve close distance communication between the sender and the trusted intermediary;

[0012] S12. Use a communication method to achieve short-distance communication between the payee and the trusted intermediary.

[0013] Furthermore, it is characterized in that the use of the communication method in S11 to achieve short-distance communication between the payee and the trusted intermediary specifically includes the following steps:

[0014] S111, the trusted intermediary obtains the first timestamp, generates the first combination information and sends it to the payee, the payee verifies the certificate, the first timestamp and the signature of the trusted intermediary, if the verification fails, the transaction fails, if the verification succeeds, the payee recognizes the trusted intermediary as the owner of the trusted intermediary certificate;

[0015] S112. The payee generates a one-time anonymous identity and temporary public and private keys of the payee, and generates a second combination of information and sends it to the trusted intermediary. The trusted intermediary uses its own private key to decrypt and obtain the payee certificate, and verifies the payee certificate, the first timestamp and the signature. At the same time, the trusted intermediary generates a one-time payee certificate corresponding to the one-time anonymous identity of the payee based on the one-time anonymous identity of the payee or the temporary public key of the payee, wherein the digital signature of the one-time payee certificate is completed by the trusted intermediary.

[0016] Furthermore, the use of the communication method in S12 to achieve short-distance communication between the payee and the trusted intermediary specifically includes the following steps:

[0017] S121, the trusted intermediary obtains the second timestamp, generates the third combination information and sends it to the payee, the payee verifies the certificate, the second timestamp and the signature of the trusted intermediary, if the verification fails, the transaction fails, if the verification succeeds, the payee recognizes the trusted intermediary as the owner of the trusted intermediary certificate;

[0018] S122. The payee generates a one-time anonymous identity of the payee and temporary public and private keys of the payee, and generates a fourth combination of information and sends it to the trusted intermediary. The trusted intermediary uses its own private key to decrypt and obtain the payee certificate, and verifies the payee certificate, the second timestamp and the signature. At the same time, the trusted intermediary generates a one-time certificate of the payee corresponding to the one-time anonymous identity of the payee based on the one-time anonymous identity of the payee or the temporary public key of the payee, wherein the digital signature of the one-time certificate of the payee is completed by the trusted intermediary.

[0019] Furthermore, the communication method used in S2 realizes close distance communication between the payee and the payee, and completes the offline transaction through a trusted intermediary in an offline state, specifically including the following steps:

[0020] S201, the payee obtains the third timestamp, uses the payee's temporary private key to sign the third timestamp and the payee's one-time anonymous identity to obtain the first signature information, and generates the fifth combination information and sends it to the payee. The payee verifies the payee's one-time certificate, the third timestamp and the signature. If the verification fails, the transaction fails. If the verification succeeds, the payee recognizes the user with the payee's one-time anonymous identity as the payee. At the same time, the payee generates new second combination information, generates the first sending information and sends it to the payee's commercial bank. The payee combines the transaction time, the payee's one-time anonymous identity, the payee's one-time anonymous identity and the digital currency to obtain the sixth combination information, and uses the payee's temporary private key to sign the sixth combination information and the first sending information to obtain the second signature information. The payee sends the seventh combination information to the payee;

[0021] S202. The payee verifies the payee's one-time certificate, transaction time and signature. If the verification fails, the transaction fails. If the verification succeeds, a new fourth combination of information is generated, and a second sending message is generated from the sixth combination of information and the first sending message. The new fourth combination of information and the second sending message are stored at the same time, and the digital currency in the sixth combination of information is taken out and stored, and marked as not confirmed by the central bank.

[0022] Furthermore, the sending method of the seventh combination information sent by the payee in S201 includes but is not limited to sending in plain text and sending encrypted with the public key of the receiver.

[0023] Furthermore, the online confirmation of the transaction by the commercial bank and the central bank in S3 specifically includes the following steps:

[0024] S301, the payee performs identity authentication with the payee commercial bank and obtains a session key;

[0025] S302, the payee generates and sends a new fourth combination of information, the second sending information and a signature on the two to the payee's commercial bank;

[0026] S303, the payee's commercial bank verifies the signature and the new fourth combination of information. If the verification fails, the transaction fails. If the verification succeeds, the payee's true identity is confirmed, and the second sending information and the payee's true identity are sent to the central bank;

[0027] S304, the central bank stores the real identity of the payee and the sixth combination of information, and sends the second sending information to the payee's commercial bank;

[0028] S305, the commercial bank of the payee decrypts the first transmission information to obtain the new second combination information, and verifies the new second combination information. If the verification fails, the transaction fails. If the verification succeeds, the real identity of the payee is known, and the real identity of the payee, the one-time anonymous identity of the payee and the sixth combination information are combined into a complete transaction entry and stored. The commercial bank of the payee sends the transaction result and the real identity of the payee to the central bank.

[0029] S306, the central bank combines the real identity of the payee, the real identity of the payee and the sixth combination of information into a complete transaction entry and stores it, and sends the transaction result to the payee's commercial bank;

[0030] S307, the payee's commercial bank combines the payee's one-time anonymous identity, the payee's real identity and the sixth combination of information into a complete transaction entry and stores it, and sends the transaction result to the payee;

[0031] S308. After the payee confirms that the transaction is successful, the stored new fourth combination information and the second sending information are deleted, and the digital currency in the stored sixth combination information is found and marked as confirmed by the central bank.

[0032] According to another aspect of the present invention, an anonymous dual offline transaction system based on a trusted intermediary and a one-time certificate is provided, the system comprising a central bank, a payee commercial bank, a payee commercial bank, a payee, a payee and a trusted intermediary, the payee corresponds to the payee commercial bank, the payee corresponds to the payee commercial bank, the trusted intermediary communicates with the payee and the payee through short-range communication, the payee and the payee carry digital certificates, the real identities of the members are stored in the digital certificates, and the digital certificates of the payee commercial bank and the payee commercial bank are stored in the trusted intermediary.

[0033] Furthermore, the trusted intermediary is a trusted infrastructure that does not have networking capabilities, and the trusted infrastructure includes but is not limited to digital currency ATMs, digital currency POS machines, and digital currency trading equipment held by trusted merchants.

[0034] The beneficial effects of the present invention are as follows: through the use of the present invention, anonymous dual offline transactions of digital currency can be realized, so that the payee and the payee can use a trusted intermediary to complete anonymous identity transactions in the dual offline transaction stage, and then use commercial banks and central banks to confirm the transactions in the online transaction stage. The payee can use the digital currency obtained in the offline transaction, and by setting a one-time certificate and a one-time anonymous identity for the payee and the payee, the privacy of the user can be better protected. Compared with the prior art, the present invention can better protect the privacy information of the user and make transactions (especially dual offline transactions) safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] 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.

[0036] Figure 1 is a flow chart of an anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to an embodiment of the present invention;

[0037] Figure 2 4 is a schematic diagram of the structure of an anonymous dual offline transaction system based on a trusted intermediary and a one-time certificate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] 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.

[0039] According to an embodiment of the present invention, an anonymous dual offline transaction method and system based on a trusted intermediary and a one-time certificate are provided.

[0040] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to one embodiment of the present invention, an anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate is provided, and the method includes the following steps:

[0041] S1. Preparation stage: Use communication methods to achieve short-range communication between M (trusted intermediary) and A (sender) and B (recipient); and M is a trusted infrastructure, including digital currency ATMs, digital currency POS machines, and digital currency transaction equipment held by trusted merchants.

[0042] Wherein, the S1 comprises the following steps:

[0043] S11. Use a communication method to achieve close distance communication between A (sender) and M (trusted intermediary);

[0044] The S11 specifically includes the following steps:

[0045] S111, M obtains the timestamp TA (first timestamp), generates MA = TA||IDM||SIGN(TA||IDM,SKM)||CertM (first combined information) and sends it to A, where SIGN(m,sk) is the signature of the message m using the private key sk, the same below. A verifies CertM (trusted intermediary certificate), timestamp TA and signature. If A fails to verify, the transaction fails. If A succeeds in verification, A recognizes M as the owner of CertM and a trusted intermediary;

[0046] S112. A generates IDA (a one-time anonymous identity of the payee, preferably a true random number that does not repeat each time, i.e., the identity is a one-time identity) and PKA' / SKA' (temporary public and private keys of the payee), and generates AM=TA||IDA||PKA'||SIGN(TA||IDA||PKA',SKA)||ENC(CertA,PKM) (second combined information) and sends it to M, where ENC(m, pk) is the encryption of the message m using the public key pk, the same below. M uses SKM (private key) to decrypt and obtain CertA (payee certificate), and verifies CertA, timestamp TA and signature. M generates CertA' (one-time certificate) of the payee corresponding to IDA based on IDA / PKA' (the one-time anonymous identity of the payee and the temporary public key of the payee), where the digital signature of CertA' is completed by a trusted intermediary.

[0047] S12, using a communication method to achieve close distance communication between B (payee) and M (trusted intermediary);

[0048] The S12 specifically includes the following steps:

[0049] S121, M obtains the timestamp TB (second timestamp), generates MB=TB||IDM||SIGN(TB||IDM,SKM)||CertM (third combination information) and sends it to B, B verifies CertM, timestamp TB and signature, if B fails to verify, the transaction fails, if B succeeds, then B recognizes M as the owner of CertM;

[0050] S122, B generates IDB (a one-time anonymous identity of the payee, preferably a true random number, which is not repeated each time, that is, the identity is a one-time identity) and PKB' / SKB' (temporary public and private keys of the payee), and generates BM=TB||IDB||PKB'||SIGN(TB||IDB||PKB', SKB)||ENC (the fourth combined information) and sends it to M. M uses SKM to decrypt and obtain CertB (the payee's certificate), and verifies CertB, timestamp TB and signature. M generates CertB' (the payee's one-time certificate) corresponding to IDB based on IDB / PKB' (the payee's one-time anonymous identity and the payee's temporary public key), where the digital signature of CertB' is completed by M.

[0051] S2, dual offline transaction stage: use the communication method to achieve close communication between A (sender) and B (recipient), and complete the offline transaction through a trusted intermediary in an offline state;

[0052] Wherein, the S2 specifically includes the following steps:

[0053] S201. B obtains timestamp T (third timestamp), uses SKB' to sign timestamp T and IDB to obtain SIGN(T||IDB, SKB') (first signature information), and generates MBA=T||IDB||SIGN(T||IDB, SKB')||CertB' (fifth combined information) and sends it to A. S verifies CertB', timestamp T and signature. If A fails to verify, the transaction fails. If the verification succeeds, A recognizes IDB as the payee. A generates AM'=TA||IDA||SIGN(TA||IDA, SKA)||CertA (new second Combined information), and generate MAS=ENC(AM',PKAS) (first sending information) and send it to AS (the sender's commercial bank), A combines the transaction time T, IDA, IDB and digital currency to obtain TX (sixth combined information), and uses SKA' to sign TX and MAS to obtain SIGN(TX||MAS,SKA') (second signature information), A sends TX||MAS||SIGN(TX||MAS,SKA')||CertA' (seventh combined information) to B, and the seventh combined information is implemented by sending in plain text or encrypting with the recipient's public key;

[0054] S202, B verifies CertA', transaction time T and signature. If the verification fails, the transaction fails. If the verification succeeds, the transaction continues. B generates BM'=TB||IDB||SIGN(TB||IDB,SKB)||CertB (new fourth combination information), sets MBtx=TX||MAS (the sixth combination information and the first sending message are combined into the second sending message), and stores BM'||MBtx. Then, the digital currency in TX is taken out and stored, and marked as confirmed by the central bank.

[0055] S3, online transaction stage: the transaction is confirmed online by commercial banks and S (central bank).

[0056] Wherein, the S3 specifically includes the following steps:

[0057] S301, B and BS (the payee commercial bank) perform identity authentication and obtain the session key;

[0058] S302, B generates and sends BM'||MBtx||SIGN(BM'||MBtx, SKB) to BS;

[0059] S303, BS verifies the signature and BM'. If the verification fails, the transaction fails. Otherwise, the transaction continues. BS confirms B's IDBTRUE (real identity) and sends MBtx||IDBTRUE to S (central bank).

[0060] S304, S stores IDBTRUE||TX, and sends MBtx to AS;

[0061] S305, AS decrypts MAS to get AM', and verifies AM'. If the verification fails, the transaction fails, otherwise the transaction continues. AS learns A's IDATRUE, combines IDATRUE||IDB||TX into a complete transaction entry and stores it. At this time, AS does not know B's true identity. AS sends RET||IDATRUE (transaction result and sender's true identity) to S, and RET indicates success or failure.

[0062] S306, S combines IDATRUE||IDBTRUE||TX into a complete transaction entry and stores it, that is, S knows the true identities of A and B, and S sends RET to BS;

[0063] S307, BS combines IDA||IDBTRUE||TX into a complete transaction entry and stores it. At this time, BS does not know the true identity of A, and BS sends RET to B;

[0064] S308. After B confirms that the transaction is successful, he deletes the stored BM'||MBtx, finds the digital currency in the stored TX, marks it as confirmed by the central bank, and can be used normally later.

[0065] According to another aspect of the present invention, Figure 2 As shown, an anonymous dual offline transaction system based on a trusted intermediary and a one-time certificate is provided, which includes S (central bank), AS (sender's commercial bank), BS (receiver's commercial bank), A (sender), B (receiver) and M (trusted intermediary), A corresponds to AS, B corresponds to BS, and M communicates with A and B through short-distance communication. The trusted intermediary M has a digital certificate issuance function. Each member of A, B and M carries a digital certificate, which stores the real identity of the member; M stores the digital certificates of various commercial banks such as AS and BS. M is a trusted infrastructure without networking function. The trusted infrastructure does not store the received certificates to prevent user information leakage. The trusted infrastructure includes but is not limited to digital currency ATMs, digital currency POS machines, and digital currency transaction equipment held by trusted merchants.

[0066] In summary, through the use of the present invention, anonymous dual offline transactions of digital currency can be realized, so that the payee and the payee can use a trusted intermediary to complete anonymous identity transactions in the dual offline transaction stage, and then use commercial banks and central banks to confirm the transaction in the online transaction stage. The payee can use the digital currency obtained in the offline transaction, and by setting a one-time certificate and a one-time anonymous identity for the payee and the payee, the user's privacy can be better protected. Compared with the prior art, the present invention can better protect the user's privacy information and make transactions (especially dual offline transactions) safer.

[0067] 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.

[0068] 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. An anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate, characterized in that: The method comprises the following steps: S1. Preparation phase: Use communication methods to achieve close-range communication between the trusted intermediary and the sender and receiver; S2, dual offline transaction stage: use the communication method to achieve close communication between the sender and the receiver, and complete the offline transaction through a trusted intermediary in an offline state; S3, online transaction stage: transactions are confirmed online by commercial banks and the central bank; In S2, a communication method is used to achieve close distance communication between the payee and the payee, and offline transactions are completed through a trusted intermediary in an offline state, specifically including the following steps: S201, the payee obtains the third timestamp, uses the payee's temporary private key to sign the third timestamp and the payee's one-time anonymous identity to obtain the first signature information, and generates the fifth combination information and sends it to the payee. The payee verifies the payee's one-time certificate, the third timestamp and the signature. If the verification fails, the transaction fails. If the verification succeeds, the payee recognizes the user with the payee's one-time anonymous identity as the payee. At the same time, the payee generates new second combination information, generates the first sending information and sends it to the payee's commercial bank. The payee combines the transaction time, the payee's one-time anonymous identity, the payee's one-time anonymous identity and the digital currency to obtain the sixth combination information, and uses the payee's temporary private key to sign the sixth combination information and the first sending information to obtain the second signature information. The payee sends the seventh combination information to the payee; S202, the payee verifies the payee's one-time certificate, transaction time and signature. If the verification fails, the transaction fails. If the verification succeeds, a new fourth combination of information is generated, and a second transmission message is generated from the sixth combination of information and the first transmission message. The new fourth combination of information and the second transmission message are stored at the same time, and the digital currency in the sixth combination of information is taken out and stored, and marked as unconfirmed by the central bank; The sending method of the seventh combination information sent by the payee in S201 includes but is not limited to sending in plain text and sending encrypted with the public key of the receiver.

2. The anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to claim 1 is characterized in that: The communication method used in S1 to implement short-distance communication between the trusted intermediary and the payee and the payee includes the following steps: S11. Using a communication method to achieve close distance communication between the sender and the trusted intermediary; S12. Use a communication method to achieve short-distance communication between the payee and the trusted intermediary.

3. The anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to claim 2 is characterized in that: The use of the communication method in S11 to achieve short-distance communication between the sender and the trusted intermediary specifically includes the following steps: S111, the trusted intermediary obtains the first timestamp, generates the first combination information and sends it to the payee, the payee verifies the certificate, the first timestamp and the signature of the trusted intermediary, if the verification fails, the transaction fails, if the verification succeeds, the payee recognizes the trusted intermediary as the owner of the trusted intermediary certificate; S112. The payee generates a one-time anonymous identity and temporary public and private keys of the payee, and generates a second combination of information and sends it to the trusted intermediary. The trusted intermediary uses its own private key to decrypt and obtain the payee certificate, and verifies the payee certificate, the first timestamp and the signature. At the same time, the trusted intermediary generates a one-time payee certificate corresponding to the one-time anonymous identity of the payee based on the one-time anonymous identity of the payee or the temporary public key of the payee, wherein the digital signature of the one-time payee certificate is completed by the trusted intermediary.

4. The anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to claim 2 is characterized in that: The use of the communication method in S12 to achieve short-distance communication between the payee and the trusted intermediary specifically includes the following steps: S121, the trusted intermediary obtains the second timestamp, generates the third combination information and sends it to the payee, the payee verifies the certificate, the second timestamp and the signature of the trusted intermediary, if the verification fails, the transaction fails, if the verification succeeds, the payee recognizes the trusted intermediary as the owner of the trusted intermediary certificate; S122. The payee generates a one-time anonymous identity of the payee and temporary public and private keys of the payee, and generates a fourth combination of information and sends it to the trusted intermediary. The trusted intermediary uses its own private key to decrypt and obtain the payee certificate, and verifies the payee certificate, the second timestamp and the signature. At the same time, the trusted intermediary generates a one-time certificate of the payee corresponding to the one-time anonymous identity of the payee based on the one-time anonymous identity of the payee or the temporary public key of the payee, wherein the digital signature of the one-time certificate of the payee is completed by the trusted intermediary.

5. The anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to claim 1 is characterized in that: The trusted intermediary in S1 is a trusted infrastructure, including but not limited to digital currency ATMs, digital currency POS machines, and digital currency transaction equipment held by trusted merchants.

6. The anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to claim 1 is characterized in that: The online confirmation of the transaction by the commercial bank and the central bank in S3 specifically includes the following steps: S301, the payee performs identity authentication with the payee commercial bank and obtains a session key; S302, the payee generates and sends a new fourth combination of information, the second sending information and a signature on the two to the payee's commercial bank; S303, the payee's commercial bank verifies the signature and the new fourth combination of information. If the verification fails, the transaction fails. If the verification succeeds, the payee's true identity is confirmed, and the second sending information and the payee's true identity are sent to the central bank; S304, the central bank stores the real identity of the payee and the sixth combination of information, and sends the second sending information to the payee's commercial bank; S305, the commercial bank of the payee decrypts the first transmission information to obtain the new second combination information, and verifies the new second combination information. If the verification fails, the transaction fails. If the verification succeeds, the real identity of the payee is known, and the real identity of the payee, the one-time anonymous identity of the payee and the sixth combination information are combined into a complete transaction entry and stored. The commercial bank of the payee sends the transaction result and the real identity of the payee to the central bank. S306, the central bank combines the real identity of the payee, the real identity of the payee and the sixth combination of information into a complete transaction entry and stores it, and sends the transaction result to the payee's commercial bank; S307, the payee's commercial bank combines the payee's one-time anonymous identity, the payee's real identity and the sixth combination of information into a complete transaction entry and stores it, and sends the transaction result to the payee; S308. After the payee confirms that the transaction is successful, the stored new fourth combination information and the second sending information are deleted, and the digital currency in the stored sixth combination information is found and marked as confirmed by the central bank.

7. An anonymous dual offline transaction system based on a trusted intermediary and a one-time certificate, used to implement the steps of the anonymous dual offline transaction method based on a trusted intermediary and a one-time certificate according to any one of claims 1 to 6, characterized in that: The system includes a central bank, a payee commercial bank, a payee commercial bank, a payee, a payee and a trusted intermediary. The payee corresponds to the payee commercial bank, and the payee corresponds to the payee commercial bank. The trusted intermediary communicates with the payee and the payee through short-distance communication. The payee and the payee have digital certificates that store the real identity of the member. The trusted intermediary stores the digital certificates of the payee commercial bank and the payee commercial bank.

8. The anonymous dual offline transaction system based on a trusted intermediary and a one-time certificate according to claim 7, characterized in that: A trusted intermediary is a trusted infrastructure that does not have networking capabilities. This trusted infrastructure includes but is not limited to digital currency ATMs, digital currency POS machines, and digital currency trading equipment held by trusted merchants.

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