Blockchain-implemented systems and methods

Abstract

The present invention provides a novel and advantageous method and corresponding system. The invention is implemented by means of a distributed electronic ledger (blockchain). The invention is applicable for the exchange or transfer of assets, for example, digital assets, for example, tickets, etc. (but not limited thereto). One embodiment provides a computer-implemented method for transferring assets between a first user and a second user by means of a blockchain, the method comprising: generating a first blockchain transaction comprising at least one first output representing at least one first asset, wherein the at least one first asset is for exchange for at least one second asset represented by at least one second output of a second blockchain transaction.

Description

[0001] This application is a divisional application of the PCT national phase application filed on July 21, 2017, with application number 201780042358.2 and entitled "System and Method for Implementing Blockchain". Technical Field

[0002] This invention generally relates to distributed ledger technology (e.g., blockchain-related technology), and particularly to solutions for the secure transfer (and / or exchange) of assets between parties. Secure peer-to-peer exchange methods and / or systems can be provided, implemented through blockchain platforms or protocols. This invention is particularly suitable for the secure transfer of assets, such as digital or electronic assets, between parties with no prior relationship or trust. Background Technology

[0003] In this document, we use the term 'blockchain' for convenience and ease of reference, as it is currently the most widely known term in this field. The term is used herein to encompass all forms of electronic, computer-based distributed ledgers, including consensus-based blockchains, alternative chains, sidechains and transaction chain technologies, permissioned and permissionless ledgers, private or public ledgers, shared ledgers, and their variations.

[0004] A blockchain is an electronic ledger implemented as a decentralized, distributed, computer-based system of blocks, each consisting of a transaction. Each transaction (Tx) includes at least one input and at least one output. Each block contains the hash of the previous block, and these blocks are chained together to create a permanent, immutable record of all transactions since the blockchain's inception. Transactions contain applets called scripts, which are embedded in their inputs and outputs. These applets specify how and by whom the transaction's outputs are accessed. On some platforms, these scripts are written using stack-based scripting languages.

[0005] In order for a transaction to be written into the blockchain, the transaction must i) be verified by the first node that receives the transaction, and if the transaction is successfully verified, the node will relay the transaction to other nodes in the network; ii) be added to a new block; and iii) be mined, that is, added to the public ledger of past transactions.

[0006] It should be noted that alternative blockchain implementations are also within the scope of this invention.

[0007] Recently, digital entrepreneurs have begun exploring the use of cryptographically secure systems and data that can be stored on blockchains to enable new systems.

[0008] One area of ​​current interest and research is utilizing blockchain to realize "smart contracts." These are computer programs designed to automatically execute the terms of contracts or agreements. Unlike traditional contracts written in natural language, smart contracts are machine-executable programs that include rules that can process input to produce results, which can then prompt actions to be taken based on those results.

[0009] Another area of ​​interest related to blockchain is using 'tokens' to represent and transfer real-world entities via the blockchain. Potentially sensitive or secretive items can be represented by tokens, which have no discernible meaning or value. Therefore, tokens act as identifiers that allow referencing real-world items. Summary of the Invention

[0010] The invention is defined in the appended claims.

[0011] This invention provides a computer-implemented method and corresponding system. It can be described as a method for implementing or performing operations via blockchain. It can also be described as a method for exchanging or transferring assets via blockchain. One or both assets can be of any type, such as physical, electronic, or digital assets. These may be tokenized assets.

[0012] This method provides a computer-based approach for controlling the transfer and / or exchange of at least one asset between a first user and a second user via blockchain. The method can control the manner and timing of asset transfers.

[0013] The method may include: Generate a first blockchain transaction, comprising at least one first output representing at least one first asset, the first output being exchangeable by providing any of the following: (i) unlock data; or (ii) a cryptographic signature of a first user and a cryptographic signature of a second user, wherein the at least one first asset is exchanged for at least one second asset represented by at least one second output of a second blockchain transaction, the at least one second output being exchangeable by providing any of the following: (i) the unlock data; or (ii) a cryptographic signature of a first user and a cryptographic signature of a second user.

[0014] By providing first unlock data to redeem at least one second output, the first unlock data can be used to redeem at least one first output.

[0015] The term "exchange" can refer to spending (i.e., exchanging) the output contained in a blockchain transaction.

[0016] The above method enables mutually guaranteed asset transfers via blockchain, providing the advantages of secure asset transfer and the creation and maintenance of immutable transfer records.

[0017] Therefore, this invention provides a mechanism for secure asset exchange via blockchain between parties without prior trust. This is achieved using cryptography, a time-locking mechanism to control transaction mining time, and the concept of "revealable" data. Creating interdependence between transactions means implementing control over asset transfers through the creative application of blockchain protocols. Thus, this invention provides a more secure asset exchange solution for the advantageous use of blockchain between trustless parties.

[0018] By providing the cryptographic signatures of the first user and the second user to exchange the first blockchain transaction, at least one first output can be returned to the first user.

[0019] This allows the first asset to be returned to the first user when both the first and second users' signatures are provided, thus offering the advantage of preventing the first user from losing the asset.

[0020] The method may also include the step of generating a third blockchain transaction, which, in response to the elapsed first lock time, enables the exchange of at least one first output by providing a cryptographic signature from a first user and a cryptographic signature from a second user.

[0021] This provides a time period to prevent the first user from redeeming the first output, thus providing the advantage of preventing the first user from requesting the first output in addition to the second output during that time period.

[0022] The third blockchain transaction may include an unlocking script, which includes the cryptographic signatures of the first user and the second user.

[0023] This prevents third parties from demanding the first output, thus providing the advantage of increased security for the method.

[0024] The step of generating a third blockchain transaction may include sending an incomplete third blockchain transaction to a second user, the incomplete third blockchain transaction being used to receive the second user's cryptographic signature before it is returned to the first user in a complete state.

[0025] This provides the advantage of a simple and secure mechanism for collecting cryptographic signatures.

[0026] The first lock-in time may be longer than the second lock-in time associated with the fourth blockchain transaction, wherein the fourth blockchain transaction is used to exchange at least one second output by providing the cryptographic signatures of the first user and the second user in response to the elapsed second lock-in time.

[0027] This provides a buffer period equal to the difference between the first and second lock times, during which the second user can redeem the first output, but the first user is prohibited from redeeming the first and second outputs by not submitting a third blockchain transaction to the blockchain.

[0028] The unlocking data may include displayable data selected by the first user, which is unknown to the second user prior to the redemption of the third blockchain transaction. The displayable data may be (initially) secret, preferably known only to the first user until the third blockchain transaction is spent. The displayable data may become public, or it may be "displayed" by providing the displayable data in the unlocking script to make it available from the blockchain. This could be a locking script for unlocking the third transaction. The second user is then able to see and use the displayable data and provide it to another locking script.

[0029] This provides the advantage of establishing mutual trust between the first and second users, where the display of displayable data enables the first user to redeem the second output and the second user to redeem the first output. It also provides the further advantage that by not displaying the displayable data, the first and second users can regain the corresponding assets represented by the corresponding first and second transactions.

[0030] The unlocked data may also include a second user's encrypted signature.

[0031] This ensures that the exchange of the first output requires a cryptographic signature from a second user, thus providing the advantage of increased method security.

[0032] According to a second aspect of the invention, a computer-implemented method for transferring assets between a first user and a second user is provided, the method comprising: generating a second blockchain transaction, the second blockchain transaction including at least one second output representing at least one second asset, the second output being redeemable by providing any one of: (i) unlocking data; or (ii) a cryptographic signature of the first user and a cryptographic signature of the second user, wherein the at least one second asset is exchanged for at least one first asset represented by at least one first output of the first blockchain transaction, the at least one first output being redeemable by providing any one of: (i) the first unlocking data; or (ii) the cryptographic signature of the first user and a cryptographic signature of the second user, wherein redeeming the second output by providing the first unlocking data makes the first unlocking data available for redeeming the first output.

[0033] By providing the cryptographic signatures of the first user and the second user to exchange for the second blockchain transaction, the second output can be returned to the second user.

[0034] This allows the second asset to be returned to the second user when the signatures of the first and second users are provided, thus providing the advantage of preventing the second user from losing the asset.

[0035] The method may also include the step of generating a fourth blockchain transaction, which, in response to the elapsed second lock time, enables the exchange of at least one second output by providing the cryptographic signatures of a first user and a second user.

[0036] This provides a time period to prevent a second user from exchanging for a second output, thus providing the advantage of preventing a second user from requesting a second output in addition to the first output during that time period.

[0037] The fourth blockchain transaction may include an unlocking script, which includes the cryptographic signatures of the first user and the second user.

[0038] The step of generating the fourth blockchain transaction may include sending an incomplete fourth blockchain transaction to a first user, the incomplete fourth blockchain transaction being used to receive the first user's cryptographic signature before it is returned to the second user in a complete state.

[0039] The method may also include steps for monitoring third-party blockchain transactions on the blockchain.

[0040] This provides the advantage of enabling the second user to redeem the first output in a timely manner.

[0041] The method may also include the step of generating a fifth blockchain transaction comprising at least one third output, which can be redeemed by providing a cryptographic signature from a first user, thereby returning at least one first output to the first user.

[0042] This enables the implementation of a refund mechanism on the blockchain, where the first asset is returned to the first user, thus providing the advantage of increasing the user-friendliness of the method.

[0043] The method may also include the step of broadcasting the fifth blockchain transaction to the blockchain in response to a determination that the asset has not been provided to the first user.

[0044] This offers the advantage of further reducing the possibility of losing first-time users.

[0045] The fifth blockchain transaction can be sent to a third party, and the third party can perform the judgment and broadcast it.

[0046] This provides the further advantage of increasing the automation of the method. Attached Figure Description

[0047] Figure 1The diagram shows a blockchain transaction representing a first asset transferred from a first user to a second user in exchange for a second asset; Figure 2 The example illustrates a tokenized blockchain transaction, representing a second asset provided by a second user to a first user in exchange for a first asset. Figure 3 This illustrates a blockchain transaction that could potentially be used to lock up the device after the first lock-up period has elapsed. Figure 1 The transaction output is returned to the first user; Figure 4 The blockchain transaction shown is used to potentially lock up the device after the second lock-up period has elapsed. Figure 2 The transaction output is returned to the second user; Figure 5 This shows a blockchain transaction indicating that the first asset was returned to the first user; and Figure 6 A flowchart showing the steps taken by the first and second users is provided. Detailed Implementation

[0048] We now provide an explanation of embodiments of the invention, which is for illustrative purposes only. In this illustrative scenario, a method for transferring a second asset in the form of an event ticket in exchange for a first asset in the form of payment via blockchain is described. The use of blockchain provides inherent advantages of this technology. These advantages include tamper-proof recording of events and more secure currency exchange. Although this illustration relates to tickets, other types of assets can also be transferred and still fall within the scope of this invention. The invention does not limit the types of assets involved.

[0049] Alice is considering buying tickets to an event sometime in the future. Bob is offering tickets for this event in the form of tokenized blockchain transactions.

[0050] refer to Figure 1 and Figure 6 Alice generates the first blockchain transaction (S100) representing payment for the many tickets she wants to buy from Bob. From this point on, for clarity, this first blockchain transaction can be referred to as a payment transaction.

[0051] The payment transaction has the following output scripts: OP_IF OP_HASH160<hash160(X)> OP_EQUALVERIFY OP_DUP OP_HASH160<hash160(Bob’s public key)> OP_EQUALVERIFY OP_CHECKSIG OP_ELSE OP_2<Alice’s public key><Bob’s public key> OP_2 OP_CHECKMULTISIG OP_ENDIF. Payment transactions can be unlocked by submitting any of the following unlock scripts to the payment transaction's locking script: <Bob’s signature><Bob’s public key> <x>OP_1 <Alice’s signature><Bob’s signature> OP_0 X includes data in a form available in blockchain transactions, selected by Alice and used to ensure the security of payment transactions. X can be a digital version of biometric information, such as a fingerprint or iris scan. X can contain randomly or pseudo-randomly generated data. (The above unlocking script...)<Bob’s signature><Bob’s public key> <x>The content, including X, may be referred to as "unlock data". This unlock data may include Bob's signature and Bob's public key, or it may simply include data X, or it may include any suitable combination thereof. In this illustrative embodiment, the unlock data includes Bob's signature, Bob's public key, and a password X chosen by Alice. Therefore, X may be referred to as "displayable data".

[0052] Redemption can be achieved by providing either: Bob's cryptographic signature, Bob's public key, and X; or Alice's cryptographic signature and Bob's cryptographic signature. (Note that the first data element (OP_0, OP_1) selects the stage currently in use. If the top stack value is not 0, an IF statement is executed, and the top stack value is removed.) Alice submits the payment transaction to the blockchain for verification and broadcast. Bob can monitor the blockchain to process the payment transaction and read the hash of X from the payment transaction (S102). Alice can also transmit the hash of X and / or other information about the payment transaction to Bob by any suitable means, such as by email or text message (S102).

[0053] refer to Figure 2 and Figure 6 Bob generates a second blockchain transaction (S104) indicating that the tickets Alice wants to purchase will be sent to Alice after payment. Before Bob generates this second blockchain transaction representing the tickets, the quantity and type of tickets Alice wants to purchase may have already been sent to Bob by any suitable means, such as via email, through an application on a mobile device or PC, an online store, or transaction metadata embedded in the previous blockchain transaction. From this point on, for clarity, the second blockchain transaction can be referred to as the "ticket transaction".

[0054] Ticket transactions have the following lock script output: OP_IF OP_HASH160<hash160(X)> OP_EQUALVERIFY OP_HASH160<hash160(redeem script)> OP_EQUAL OP_ELSE OP_2<Alice’s public key><Bob’s public key> OP_2 OP_CHECKMULTISIG OP_ENDIF. In the above locking script, the redemption script is: OP_1<metadata(reference ticket1)><metadata(reference ticket2)><Alice’s public key> OP_2 OP_CHECKMULTISIG. Ticket transactions can be unlocked by submitting any of the following unlock scripts to the ticket transaction's lock script: <Alice’s signature><redeem script> <x>OP_1 <Alice’s signature><Bob’s signature> OP_0 Here, X is the password chosen by Alice and kept secret by her until she provides it to the ticket transaction's locking script to redeem the ticket, as shown in the redemption script above. In other words, the ticket can be redeemed by providing either: Alice's cryptographic signature, the redemption script (containing Alice's public key), and X; or Alice's cryptographic signature and Bob's cryptographic signature.

[0055] Bob submits ticket transactions to the blockchain for verification and broadcast. Alice can monitor the blockchain for ticket transactions. Bob can also send information about ticket transactions to Alice by any suitable means, such as email or text message.

[0056] refer to Figure 3 and Figure 6 Alice also generates a third blockchain transaction (S200) (which can henceforth be called the payment return transaction), used to redeem the payment transaction by providing Alice's signature and Bob's signature to the locking script of the payment transaction. Alice sets this transaction to have a 48-hour lock time. This means that the transaction can be verified by the first node that receives it, and the transaction can be added to the storage pool. The transaction cannot be added to the blockchain until the amount of time defined by the lock time (48 hours in this illustrative example) has elapsed.

[0057] To generate the payment refund transaction, Bob must provide his signature to create the unlocking script for the transaction. To do this, Alice can generate an incomplete version of the payment refund transaction without Bob's signature and send it to Bob, who then provides his signature to the locking script of the incomplete transaction (S204) and returns the complete version of the payment refund transaction to Alice.

[0058] refer to Figure 4 and Figure 6 Bob also generates a fourth blockchain transaction (S202) (hereafter referred to as the "Ticket Refund Transaction"), which is used to redeem the tokenized output of the ticket transaction by providing Alice's signature and Bob's signature to the locking script of the ticket transaction. Bob sets this transaction to have a 24-hour lock-up period. This means that the transaction can be verified by the first node that receives it, and the transaction can be added to the storage pool. The transaction cannot be added to the blockchain until the amount of time defined by the lock-up period (the 24-hour period in this illustrative example) has elapsed. It should be understood that while the above lock-up periods are chosen as 48 hours and 24 hours, any suitable lock-up period can be chosen, although it is advantageous for the lock-up period of the payment refund transaction to be longer than that of the ticket refund transaction for reasons described later in the application.

[0059] To generate the payment refund transaction, Alice must provide her signature to create the unlocking script for the transaction. To do this, Bob can generate an incomplete version of the payment refund transaction without Alice's signature and send it to Alice, who then provides her signature to the locking script of the incomplete transaction (S204) and returns the complete version of the payment refund transaction to Bob.

[0060] Once payment and ticket transactions are added to the blockchain, Alice can choose to provide her signature, public key, and X to the locking script for the ticket transaction in order to redeem the tickets. In doing so, Alice must expose X (make X public on the blockchain) as a requirement for unlocking the ticket transaction. Once Bob knows X, he can then provide his signature, his public key, and X to the locking script for the payment transaction in order to redeem the payment for those tickets.

[0061] Alice must wait until the ticket refund transaction lockout time expires to provide X. After that, Bob is able to provide his signature to the ticket refund transaction lockout script and add the ticket refund transaction to the blockchain. This allows Alice's signature and Bob's signature to be provided to the ticket transaction lockout script, thereby returning the tokenized output of the ticket transaction to Bob.

[0062] Alice can then wait until the lock time for the payment return transaction expires before providing her signature to the lock script for the payment return transaction and adding the payment return transaction to the blockchain. This allows Alice's signature and Bob's signature to be provided to the lock script for the payment transaction, thus returning the payment transaction to Alice.

[0063] If Alice provides X before the ticket refund transaction lockout period expires, Bob must wait until the refund transaction lockout period expires before providing X to the lockout script for the payment transaction to request payment for the tickets Alice redeemed. If Bob fails to request X before the lockout period expires, Alice will be able to sign the refund transaction once the lockout period has passed.

[0064] The payment refund transaction lockout time was chosen to be longer than the ticket refund transaction lockout time, so that Bob would have a reasonable minimum time to request payment from the moment Alice requested the ticket. This minimum time is equal to the difference between the two lockout times. In this illustrative example, this minimum time is therefore 24 hours.

[0065] refer to Figure 5 Bob generates a fifth blockchain transaction, referred to below as a refund transaction. Bob can do this if the event for which the purchased tickets were purchased is canceled, or if Alice decides to refund the tickets for a refund or for any other suitable reason. Bob sends the refund transaction to a third party, such as a third user of the blockchain or an independent service provider offering such intermediary services. The third party can monitor the exchange and / or the event and can determine whether the event is taking place as planned; an example of the latter is event cancellation, and a refund is returned to Alice upon confirmation of cancellation.

[0066] For any other suitable reason, a third party may be instructed or configured to execute the refund (by publishing the refund transaction to the blockchain). Legitimate grounds may be specified in the terms and conditions of the exchange, i.e., grounds that satisfy Bob and / or the third party, as legitimate criteria for the refund to Alice. These terms and conditions may be transmitted between Alice, Bob, and the third party prior to the exchange, and may be stored on the blockchain in the form of a tokenized contract or on a resource connected to the internet.< / x> < / x> < / x>

Claims

1. A computer-implemented device configured for transferring assets between a first user and a second user via a blockchain, said device comprising: A generation module is configured to generate a first blockchain transaction, the first blockchain transaction including at least one first output, the at least one first output representing at least one first asset, the at least one first output being locked by a locking script, the locking script including a hash of secret data selected by a first user, the at least one first output being redeemable by providing unlocking data, the unlocking data including secret data selected by the first user; as well as An exchange module configured to exchange at least one second asset for the at least one first asset, wherein the at least one second asset is represented by at least one second output of a second blockchain transaction. Wherein, the at least one second output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one second output can be redeemed by providing the unlocking data, the unlocking data comprising the secret data selected by the first user, and Specifically, by providing the unlock data to redeem the at least one second output, the unlock data can be used by the second user to redeem the at least one first output.

2. The computer-implemented device according to claim 1, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the first blockchain transaction, at least one first output is returned to the first user.

3. The computer-implemented device according to claim 1 or claim 2, wherein, The generation module is also configured to generate a third blockchain transaction, which, in response to the elapsed first lock time, can be redeemed for at least one first output by providing the cryptographic signatures of the first user and the second user.

4. The computer-implemented device according to claim 1, wherein, The unlocked data includes displayable data selected by the first user, wherein the displayable data is unknown to the second user prior to the redemption of the third blockchain transaction.

5. A computing device, comprising: processor; and The memory is configured to store instructions executable by the processor. The processor is configured to execute instructions stored in the memory to perform a method for transferring assets between a first user and a second user via a blockchain, the method comprising: Generate a first blockchain transaction, the first blockchain transaction including at least one first output, the at least one first output representing at least one first asset, the at least one first output being locked by a locking script, the locking script including a hash of secret data selected by a first user, the at least one first output being redeemable by providing unlocking data, the unlocking data including secret data selected by the first user; and The at least one first asset is exchanged for at least one second asset, wherein the at least one second asset is represented by at least one second output of the second blockchain transaction. Wherein, the at least one second output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one second output can be redeemed by providing the unlocking data, the unlocking data comprising the secret data selected by the first user, and Specifically, by providing the unlock data to redeem the at least one second output, the unlock data can be used by the second user to redeem the at least one first output.

6. The computing device according to claim 5, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the first blockchain transaction, at least one first output is returned to the first user.

7. The computing device according to claim 5 or claim 6, wherein, The method further includes the step of generating a third blockchain transaction, which, in response to the elapsed first lock time, is capable of redeeming at least one first output by providing the cryptographic signatures of the first user and the second user.

8. The computing device according to claim 5, wherein, The unlocked data includes displayable data selected by the first user, wherein the displayable data is unknown to the second user prior to the redemption of the third blockchain transaction.

9. A computer-readable storage medium having a computer program stored thereon, the computer program, when executed by a computer, causing the computer to perform a method for transferring assets between a first user and a second user via a blockchain, the method comprising: Generate a first blockchain transaction, the first blockchain transaction including at least one first output, the at least one first output representing at least one first asset, the at least one first output being locked by a locking script, the locking script including a hash of secret data selected by the first user, the at least one first output being redeemable by providing unlocking data, the unlocking data including secret data selected by the first user; as well as The at least one first asset is exchanged for at least one second asset, wherein the at least one second asset is represented by at least one second output of the second blockchain transaction. Wherein, the at least one second output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one second output can be redeemed by providing the unlocking data, the unlocking data comprising the secret data selected by the first user, and Specifically, by providing the unlock data to redeem the at least one second output, the unlock data can be used by the second user to redeem the at least one first output.

10. The computer-readable storage medium according to claim 9, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the first blockchain transaction, at least one first output is returned to the first user.

11. The computer-readable storage medium according to claim 9 or claim 10, wherein, The method further includes the step of generating a third blockchain transaction, which, in response to the elapsed first lock time, is capable of redeeming at least one first output by providing the cryptographic signatures of the first user and the second user.

12. The computer-readable storage medium according to claim 9, wherein, The unlocked data includes displayable data selected by the first user, wherein the displayable data is unknown to the second user prior to the redemption of the third blockchain transaction.

13. A computer-implemented device configured for transferring assets between a first user and a second user, said device comprising: A generation module is configured to generate a second blockchain transaction, the second blockchain transaction including at least one second output, the at least one second output representing at least one second asset. The second output is locked by a locking script, which includes a hash of secret data selected by the first user, and the second output can be redeemed by providing unlocking data, which includes the secret data selected by the first user. Wherein, the at least one second asset is used to exchange for at least one first asset, and the at least one first asset is represented by at least one first output of the first blockchain transaction. Wherein, the at least one first output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one first output can be redeemed by providing unlocking data, the unlocking data comprising secret data selected by the first user, and Specifically, by providing the unlocking data for the first user to exchange for the second output, the unlocking data can be used by the second user to exchange for the at least one first output.

14. The computer-implemented device according to claim 13, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the second blockchain transaction, the second output is returned to the second user.

15. The computer-implemented apparatus according to claim 13 or claim 14, wherein, The generation module is also configured to generate a fourth blockchain transaction, which, in response to the elapsed second lock time, is capable of redeeming at least one second output by providing the cryptographic signatures of the first user and the second user.

16. A computing device, comprising: processor; and The memory is configured to store instructions executable by the processor. The processor is configured to execute instructions stored in the memory to perform a method for transferring assets between a first user and a second user, the method comprising: A second blockchain transaction is generated, the second blockchain transaction including at least one second output, the at least one second output representing at least one second asset. The second output is locked by a locking script, which includes a hash of secret data selected by the first user, and the second output can be redeemed by providing unlocking data, which includes the secret data selected by the first user. Wherein, the at least one second asset is used to exchange for at least one first asset, and the at least one first asset is represented by at least one first output of the first blockchain transaction. Wherein, the at least one first output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one first output can be redeemed by providing unlocking data, the unlocking data comprising secret data selected by the first user, and Specifically, by providing the unlocking data for the first user to exchange for the second output, the unlocking data can be used by the second user to exchange for the at least one first output.

17. The computing device according to claim 16, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the second blockchain transaction, the second output is returned to the second user.

18. The computing device according to claim 16 or claim 17, wherein, The method further includes the step of generating a fourth blockchain transaction, which, in response to the elapsed second lock time, is capable of redeeming at least one second output by providing the cryptographic signatures of the first user and the second user.

19. A computer-readable storage medium having a computer program stored thereon, the computer program, when executed by a computer, causing the computer to perform a method for transferring assets between a first user and a second user, the method comprising: A second blockchain transaction is generated, the second blockchain transaction including at least one second output, the at least one second output representing at least one second asset. The second output is locked by a locking script, which includes a hash of secret data selected by the first user, and the second output can be redeemed by providing unlocking data, which includes the secret data selected by the first user. Wherein, the at least one second asset is used to exchange for at least one first asset, and the at least one first asset is represented by at least one first output of the first blockchain transaction. Wherein, the at least one first output is locked by a locking script, the locking script comprising a hash of secret data selected by the first user, and the at least one first output can be redeemed by providing unlocking data, the unlocking data comprising secret data selected by the first user, and Specifically, by providing the unlocking data for the first user to exchange for the second output, the unlocking data can be used by the second user to exchange for the at least one first output.

20. The computer-readable storage medium according to claim 19, wherein, By providing the cryptographic signatures of the first user and the second user to exchange the second blockchain transaction, the second output is returned to the second user.

21. The computer-readable storage medium according to claim 19 or claim 20, wherein, The method further includes the step of generating a fourth blockchain transaction, which, in response to the elapsed second lock time, is capable of redeeming at least one second output by providing the cryptographic signatures of the first user and the second user.

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