Computer-implemented systems and methods for controlling or enforcing the execution of transfers made on a blockchain

Abstract

To provide a method and system for generating and enforcing an agreed set of conditions ruling transfers on a blockchain.SOLUTION: The computer-implemented method includes the steps of providing a recipient with a representation of at least one rule for transfers made on a blockchain network, receiving, from a sender, a redemption script including a representation and a script address including a hash of the redemption script, and generating a hash of the redemption script to compare the same to the script address. If the hash matches the script address, the sender can use the script address in the locking script associated with the output of the blockchain transaction, knowing with satisfaction that the rule will be enforced to unlock the asset.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates generally to distributed computing networks, and more particularly to distributed ledger technology (blockchain). The present invention provides advantages related to security, enforcement, and control of transfers and communications between participants on a blockchain network. The present invention provides a solution for enforcing how future transfers on the network can be performed, thus solving a problem previously thought to be impossible in the art. It is suitable for use in, but not limited to, machine-executable smart contracts. [Background technology]

[0002] In this document, the term "blockchain" is used to include all forms of electronic, computer-based distributed ledgers. These include consensus-based blockchain and transaction chain technologies, permissioned and unpermissioned ledgers, shared ledgers, and variations thereof. The most widely known application of blockchain technology is the Bitcoin® ledger, although other blockchain implementations have been proposed and developed. While Bitcoin may be referenced herein for convenience and illustrative purposes, it should be noted that the present invention is not limited to use with the Bitcoin blockchain, and alternative blockchain implementations and protocols are within the scope of the present invention. The term "Bitcoin" is used herein to refer to any version or variation of the protocol derived from the Bitcoin protocol. The term "user" may refer herein to a human or processor-based resource.

[0003] A blockchain is a peer-to-peer electronic ledger implemented as a computer-based, decentralized, distributed system composed of blocks, which are in turn composed of transactions. Each transaction is a data structure that encodes the transfer of control of digital assets between participants in the blockchain system and includes at least one input and at least one output. Each block contains a hash of the previous block, allowing blocks to be chained together to create a permanent, immutable record of all transactions written to the blockchain since its inception. Transactions contain small programs, known as scripts, embedded in their inputs and outputs that specify how and who can access the transaction's outputs. In the Bitcoin platform, these scripts are written using a stack-based scripting language.

[0004] For a transaction to be written to the blockchain, it must be "validated." Network nodes (miners) perform the work to ensure that each transaction is valid, and invalid transactions are rejected by the network. A software client installed on the node performs this validation by running its locking and unlocking scripts against unspent transactions (UTXOs). If the execution of the locking and unlocking scripts evaluates to TRUE, the transaction is valid and the transaction is written to the blockchain. Thus, for a transaction to be written to the blockchain, it must i) be verified by the first node that receives the transaction; if the transaction is verified, the node relays it to other nodes in the network; ii) be added to a new block constructed by miners; and iii) be mined, i.e., added to the public ledger of past transactions.

[0005] While blockchain technology is most widely known for its use in implementing cryptocurrencies, digital entrepreneurs are beginning to explore the use of both the cryptographic security system upon which Bitcoin is based and the data that can be stored on the blockchain to realize new systems. It would be significantly advantageous if blockchain could be used for automated tasks and processes that are not limited to the cryptocurrency realm. Such solutions would be more versatile in their application while also being able to take advantage of the benefits of blockchain (e.g., permanent, tamper-proof record of events, distributed processing, etc.). One such area of ​​research and interest is the use of blockchain for the implementation of "smart contracts," for example.

[0006] To provide a more versatile blockchain platform, it would be advantageous to be able to control or influence how "onward" transfers of assets occur on the network following an initial transfer of assets between participants, Alice and Bob. In many different types of scenarios and for many different reasons, it is desirable to establish rules (i.e., conditions or criteria) that govern subsequent transfers of assets from Bob to one or more others without the need for trust between the parties. Until now, it has been considered impossible within the technical community to impose binding constraints on future blockchain transactions. Summary of the Invention

[0007] Applicants have devised an invention that addresses at least this need, the invention being defined in the claims appended hereto.

[0008] According to one embodiment of the present invention, generating a representation of at least one rule (r) for transfers to be made on the blockchain network; generating a redeem script (R) containing the expression (r) and a script address containing a hash (HR) of the redeem script (R); comparing a hash (H) of the redeem script (R) with (against) the script address; If the hash (H) matches the script address, using the script address in a locking script associated with the output (UTXO) of the blockchain transaction (TX0); A computer-implemented method may be provided, comprising:

[0009] Additionally or alternatively, providing the recipient with a representation of at least one rule (r) for transfers to be made on the blockchain network; receiving from a sender a redeem script (R) containing a representation (r) and a script address containing a hash (HR) of the redeem script (R); generating a hash (H) of the redeem script (R) and comparing it with the script address; If the hash (H) matches the script address, using the script address in a locking script associated with the output of the blockchain transaction (TX0); A computer-implemented method may be provided, comprising:

[0010] Additionally or alternatively, receiving from a sender a representation of at least one rule (r) for transfers to be made on the blockchain network; sending a redeem script (R) containing the expression (r) and a script address containing a hash (HR) of the redeem script (R) to the sender; providing a redeem script (R) in a further blockchain transaction (TX1) configured to unlock an output in the blockchain transaction (TX0) locked to a script address; A computer-implemented method may be provided, comprising:

[0011] The blockchain network may be the Bitcoin network or a variant thereof, or may be another (non-Bitcoin) blockchain network. The method may include generating a hash of a redeem script. The method may include creating, updating, and / or completing a blockchain transaction (TX0).

[0012] Embodiments of the present disclosure may further include any steps included in FIG. 1 or in the description provided below.

[0013] One or more embodiments may include: generating and / or consuming a further blockchain transaction (TX1) including an unlocking script configured to use the script address to unlock the locking script of the transaction (TX0); It may further include:

[0014] Preferably, transaction TX0 and / or further transaction TX1 are of a transaction type that allows cryptocurrency to be sent / associated / locked with a script hash in the output's locking script and requires the user to provide a script matching the script hash in the unlocking script and data that causes the script to evaluate to true in order to obtain (unlock) the cryptocurrency. If the blockchain network is the Bitcoin network or a variant thereof, this may be a Pay-to-script-hash (P2SH) transaction. If the blockchain network is not the Bitcoin network or a variant thereof, the transaction may be of a functionally equivalent / similar transaction type according to another (non-Bitcoin) blockchain protocol.

[0015] Preferably, the expression (r) is a reference to or an identifier of a location where at least one rule can be accessed, such as a blockchain script, or a portion / snippet of code written in a blockchain scripting language, a text file, a smart contract, an image, and / or the like.

[0016] Preferably, at least one rule relates to how or to whom subsequent transfers may be made on the blockchain network.

[0017] Preferably, the representation (r) of at least one rule is provided to the recipient as part of an incomplete blockchain transaction or as a snippet of blockchain script code.

[0018] Preferably, the script address is provided as part of the blockchain transaction.

[0019] Preferably, the method further comprises the step of submitting the transaction to a blockchain network.

[0020] Preferably, at least one rule specifies a cryptographic signature that must be provided to unlock an asset on the blockchain.

[0021] The present disclosure further provides a computer-implemented system, the system comprising: Processor and a memory containing executable instructions that, when executed by a processor, cause the system to perform any embodiment of the computer-implemented methods described herein; Includes.

[0022] The present disclosure further provides a non-transitory computer-readable storage medium having stored thereon executable instructions that, when executed by a processor of a computer system, cause the computer system to perform at least the embodiments of the present invention described herein. [Brief explanation of the drawings]

[0023] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. One embodiment of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] 1 shows a flowchart illustrating at a high level one embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram illustrating a computing environment in which various embodiments may be implemented. DETAILED DESCRIPTION OF THE INVENTION

[0024] Embodiments of the present disclosure provide a novel and advantageous mechanism for controlling electronic transfers over a blockchain network. Traditionally, it has been thought that it is impossible to constrain, compel, influence, or control forward (“downstream”) exchanges made through subsequent transactions on a blockchain network. For example, when Alice makes a transfer to Bob through a blockchain transaction, it has traditionally been thought that Alice cannot direct or control the transfers that Bob (or other recipients further down the chain of transfers) then makes. Once Bob receives the assets transferred from Alice, he is free to act as he chooses. This is undesirable in many situations because it is not uncommon for users to want their communications routed in a particular way or to impose constraints on how and / or who handles the transfer of their electronic assets, data, and communications.

[0025] The present disclosure addresses this problem by providing a cryptographically enforced mechanism by which parties can inject conditions, constraints, and rules into initial transfers for the impact of onward propagation. This is done using a mathematically enforced control approach that allows secure, immutable, visible, and traceable conditions to be associated with future actions that still need to be performed on the blockchain network.

[0026] Before providing a detailed example of one embodiment, merely by way of technical background, a brief summary of some of the known techniques that may be used to advantage by the present disclosure is provided.

[0027] [Pay-To-Script-Hash (P2SH)] Unlike standard blockchain transactions within the Bitcoin protocol, which allow payments against the hash of a 'public key', P2SH transactions allow the sender to pay against the hash of a 'script'. In a traditional transaction, the output contains a (locking) script, which must evaluate to TRUE when a spend attempt is made. The locking script dictates who must sign to unlock the associated output. In a P2SH transaction, on the other hand, the output does not contain the script itself, only the hash of the locking script. P2SH addresses can therefore be identified because they contain the hashed script, which begins with a 3 (as opposed to a public key hash address, which begins with a 1).

[0028] Instead of requiring a would-be recipient of funds to provide a signature that matches a public key specified in the locking script of an unspent output (UTXO), a P2SH transaction requires the recipient to provide a 'script' (known as a redeem script, referred to herein as R) that hashes to the same hash in the locking script, and to further provide data required to satisfy the conditions set in the locking script that will cause the script to evaluate to TRUE. If these redeem script hashes match and the correct data is provided to enable the locking script to evaluate to TRUE, the funds associated with the output are unlocked and control is transferred to the recipient. Note that according to embodiments of the present disclosure implemented using a different (non-Bitcoin-based) blockchain protocol, the transaction type may be called something other than "P2SH." However, the functionality is essentially the same in that a potential recipient of the transaction's locked funds must provide a script that, when hashed, matches the hash provided in the transaction output's locking script. However, for ease of reference, the term "P2SH" will be used to refer to such transaction types having this functionality / characteristics.

[0029] [Smart Contract] A smart contract is a computer program designed to automate the execution of the terms of a machine-readable contract or agreement. Unlike traditional contracts, which are written in natural language, a smart contract is a machine-readable and executable program containing rules that can process inputs to produce results and then cause actions to be performed depending on those results.

[0030] One exemplary embodiment provides an overview of the present disclosure. Assume Alice owns a certain amount of cryptocurrency or tokenized assets or other resources on the blockchain. She creates a set of conditions or rules r that dictate the terms under which her assets should be transferred and / or accessed. The set of rules is formulated in the Bitcoin scripting language, Script, in a Bitcoin-related implementation, or possibly in some other language if a different blockchain protocol is used.

[0031] Alice wants to transfer her assets to Bob and wants to ensure that when Bob unlocks her assets on the blockchain, he also follows these rules. For example, rule r might be that her assets can only be unlocked if Eve's signature is also provided. In Bitcoin script, this condition is expressed as: r = OP_DUP OP_HASH160 <H(P E )> OP_EQUALVERIFY OP_CHECKSIGVERIFY (1) where P E is Eve's public key. This script takes the input r input = <Sig P E > <P E > will evaluate to TRUE only if

[0032] Now consider the following scenario: [Table 1] Alice imposes rule r on the first transaction, tx1, from herself to Bob. Alice may also impose that the next transaction from Bob to Charlie also follows the same rules: spending output UTXO1 from tx1 is subject to the same rule r as spending output UTXO0. This is done as follows: 1. Alice sends a set of rules r to Bob. Recall that the rules are expressed as blockchain script snippets, e.g., as shown in (1). 2. Bob creates a redeem script R that includes rule r along with his own rules (e.g., his own signature requirements). R B = r + Checksig P B 3. Bob runs the redeem script R B Create a Pay to Script Hash (P2SH) address P1 based on 4. Bob sends his P2SH address P1 to the redeem script R B and send it to Alice. 5. Alice sends Bob's P2SH address P1 to the redeem script R B Check that the hash of

[0033] Alice can now be sure that when she creates transaction tx1 locked to Bob's P2SH address, it will be subject to rule r. In order for Bob to unlock the assets by creating a further transaction tx2, rule r must be satisfied in Bob's unlocking script; otherwise, the result will be FALSE and the output will not be unlocked.

[0034] [Step-through example of using the present invention] To facilitate the reader's understanding, reference will now be made to FIG. 1, which provides a more detailed step-through example of one exemplary embodiment in which the present invention may be used.

[0035] In step 101, two or more parties, e.g., Alice and Bob, decide on a course of action governed by a set of conditions, rules, or criteria (hereafter simply referred to as "rules," r). This can be any type of action, such as the transfer of cryptocurrency or tokens held on a blockchain, or the purchase / rental / provision of some equipment, good, or service. Similarly, a condition can be any constraint on the execution of an action, e.g., Alice will transfer a tokenized entity on the blockchain to Bob upon confirmation of a specified event.

[0036] Alice (or some other person) creates a representation of the rule r. The representation can take any form, such as a text file, or an image, or a sound file, or a script. It is essentially a record of agreed-upon actions and the conditions / rules / criteria that govern the execution of those actions. In some embodiments, it may be a smart contract, as known in the art and described above. In a preferred embodiment, the conditions are expressed in the Bitcoin scripting language Script, or some other blockchain-compatible and executable language. Thus, r may be a snippet or portion of (blockchain script) code.

[0037] In step 102, Bob uses Alice's script snippet r to generate a redeem script R. Thus, the redeem script R includes the rule r. Bob may also include some additional rules of his own.

[0038] In step 103, Bob uses the redeem script R to generate a hash H(R), which he can use as his P2SH address.

[0039] In step 104, Bob sends his P2SH address and redeem script R to Alice. This can be done in any suitable way. Alice can then be sure that the redeem script R contains her rule r.

[0040] In steps 105 and 106, Alice checks that the P2SH provided by Bob is a hash of Bob's redeem script. This is a quick and computationally simple process. If they don't match, Alice can choose to terminate the transaction or query it. However, if they match, she can proceed knowing that her rules will be included and enforced, and therefore she generates blockchain transaction TX0, which she submits to the network in step 107 for validation and to be mined into a block.

[0041] In step 108, when Bob wants to access the assets locked by Alice in TX0, he generates a spend transaction tx1 that includes an output (UTXO) that will provide the redeem script R needed by the locking script in TX0 to release the assets. For that to happen, snippet r must evaluate to TRUE, which ensures that rule r originally specified by Alice is enforced.

[0042] In an alternative embodiment, the above process may be performed by generating an incomplete partial transaction. This can be done by Alice inserting snippet r into the locking script of the partially complete P2SH transaction TX0. The locking script is associated with TX0's unspent output UTXO and determines how the UTXO can be unlocked by a further subsequent transaction, tx1. TX0 is incomplete because it does not yet contain a P2SH address, which will be supplied by Bob.

[0043] According to step 103, the partial transaction TX0 (containing snippet r) is communicated to Bob. This can be achieved in a variety of ways: Bob can check that the rules in r match the rules that Alice and Bob agreed to in step 101.

[0044] According to step 103, Bob creates a redeem script R containing rule r, then creates a hash of R to generate his P2SH address. In step 104, Bob's redeem script R and the P2SH are communicated to Alice by Bob inserting his P2SH address into transaction TX0 and sending it back to Alice. R can be transmitted via any suitable method. From Bob's updated version of TX0, Alice can check that the P2SH address he provided matches the hash of the redeem script R containing rule r.

[0045] In step 107, Alice submits TX0 to the blockchain network as described above, where it is validated and mined into a block according to known methods. Of course, Bob wants to spend the UTXO in TX0, and therefore must unlock it in step 108. To unlock the UTXO, he needs to provide the necessary hash for the UTXO's redeem script, and therefore he creates a spend transaction TX1 that includes TX1's unlocking script. TX1 is then submitted to the blockchain, validated, and mined, which results in the hash being presented to the redeem script in TX0, unlocking the output, and effecting the transfer of the asset (e.g., cryptocurrency, a portion of a token, etc.). Bob now owns the asset.

[0046] Thus, the present invention provides a solution to a problem previously thought to be unsolvable in the art, allowing for the control, enforcement, and constraints of subsequent transfers between parties in a blockchain network through the use of mathematical and cryptographic techniques.

[0047] Referring now to FIG. 2 , an exemplary simplified block diagram of a computing device 2600 that may be used to implement at least one embodiment of the present disclosure is provided. In various embodiments, the computing device 2600 may be used to implement any of the systems illustrated and described above. For example, the computing device 2600 may be configured for use as a data server, a web server, a portable computing device, a personal computer, or any electronic computing device. As shown in FIG. 2 , the computing device 2600 may include one or more processors (collectively labeled 2602) having one or more levels of cache memory and a memory controller, which may be configured to communicate with a storage subsystem 2606 that includes a main memory 2608 and persistent storage 2610. The main memory 2608 may include dynamic random access memory (DRAM) 2618 and read-only memory (ROM) 2620, as shown. The storage subsystem 2606 and cache memory 2602 may be used for storage of information such as details associated with transactions and blocks as described in this disclosure. The processor 2602 may be utilized to provide the steps or functionality of any of the embodiments described in this disclosure.

[0048] The processor 2602 may also be in communication with one or more user interface input devices 2612 , one or more user interface output devices 2614 , and a network interface subsystem 2616 .

[0049] The bus subsystem 2604 may provide a mechanism that allows the various components and subsystems of the computing device 2600 to communicate with each other as intended. Although the bus subsystem 2604 is shown generally as a single bus, alternative embodiments of the bus subsystem may utilize multiple buses.

[0050] The network interface subsystem 2616 may provide an interface to other computing devices and networks. The network interface subsystem 2616 may act as an interface for receiving data from other systems and transmitting data from the computing device 2600 to other systems. For example, the network interface subsystem 2616 may allow a data technician to connect the device to a network, so that the data technician can send data to and receive data from the device while at a remote location, such as a data center.

[0051] User interface input devices 2612 may include one or more user input devices, such as a keyboard; a pointing device, such as an integrated mouse, trackball, touchpad, or graphics tablet; a scanner; a barcode scanner; a touchscreen integrated into a display; audio input devices, such as a voice recognition system, a microphone, and other types of input devices. In general, use of the term "input device" is intended to encompass all possible types of devices and mechanisms for inputting information into computing device 2600.

[0052] The one or more user interface output devices 2614 may include a display subsystem, a printer, or a non-visual display such as an audio output device. The display subsystem may be a flat panel device such as a cathode ray tube (CRT), a liquid crystal display (LCD), a light emitting diode (LED) display, or a projection or other display device. In general, use of the term "output device" is intended to include all possible types of devices and mechanisms that output information from computing device 2600. The one or more user interface output devices 2614 may be used, for example, to present a user interface and facilitate user interaction with applications that perform the described processes and variations thereof, when such interaction may be appropriate.

[0053] Storage subsystem 2606 may provide a computer-readable storage medium that stores basic programming and data constructs that may provide the functionality of at least one embodiment of the present disclosure. Applications (programs, code modules, instructions), which when executed by one or more processors, may provide the functionality of one or more embodiments of the present disclosure, may be stored in storage subsystem 2606. These application modules or instructions may be executed by one or more processors 2602. Storage subsystem 2606 may also provide a repository for storing data used in accordance with the present disclosure. For example, main memory 2608 and cache memory 2602 may provide volatile storage for programs and data. Persistent storage 2610 may provide persistent (non-volatile) storage for programs and data and may include flash memory, one or more solid-state drives, one or more magnetic hard disk drives, one or more floppy disk drives with associated removable media, one or more optical drives (e.g., CD-ROM, DVD, or Blue-Ray) with associated removable media, and other similar storage media. Such programs and data may include programs that perform the steps of one or more embodiments described in this disclosure, and data associated with the transactions and blocks described in this disclosure.

[0054] Computing device 2600 may be of various types, including a portable computing device, a tablet computer, a workstation, or any other device described below. Additionally, computing device 2600 may include another device that may be connected to computing device 2600 through one or more ports (e.g., USB, headphone jack, Lightning connector, etc.). A device that may be connected to computing device 2600 may include multiple ports configured to accept fiber optic connectors. Thus, the device may be configured to convert optical signals into electrical signals that may be transmitted to computing device 2600 through ports that connect the device to computing device 2600 for processing. Due to the ever-changing nature of computers and networks, the description of computing device 2600 shown in FIG. 2 is intended merely as a specific example for purposes of illustrating a preferred embodiment of the device. Many other configurations are possible, having more or fewer components than the system shown in FIG. 2 .

[0055] It should be noted that the above-described embodiments illustrate rather than limit the invention, and that those skilled in the art can design many alternative embodiments without departing from the scope of the invention as defined by the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the scope of the claim. The words "comprise" and "comprises", and the like, do not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. In this specification, "comprise" means "comprises or consists of", and "comprising" means "includes or consists of". The singular reference of an element does not exclude the plural reference of such elements, and vice versa. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used to advantage.

Claims

1. 1. A computer-implemented method executed at a first party, the method comprising: generating a representation of at least one rule for transfers made on a blockchain network and inserting the at least one rule into a locking script of the partially completed transaction; sending the partially completed transaction to a second party; receiving from the second party a completed version of the transaction, the completed version including a redeem script that includes the representation and a script address that includes a hash of the redeem script; submitting the transaction to the blockchain network; A method comprising:

2. The method further comprises: comparing a hash of the redeem script with the script address; The method of claim 1 , comprising:

3. If the hash matches the script address, submitting the transaction to the blockchain network is performed. The method of claim 2.

4. The method further comprises: terminating the transaction if the hash does not match the script address; The method of claim 2 , comprising:

5. 1. A computer-implemented method executed at a second party, the method comprising: receiving, from a first party, a partially completed transaction that includes a snippet of a locking script that includes an expression of at least one rule regarding transfers that occur on a blockchain network; sending the first party a completed version of the transaction, including a redeem script containing the expression and a script address containing a hash of the redeem script; providing the redeem script in a further blockchain transaction configured to unlock a blockchain transaction output locked to the script address; A method comprising:

6. The further blockchain transaction: an unlocking script configured to use the script address to unlock the locking script of the transaction; The method of claim 5.

7. The method further comprises: submitting the blockchain transaction to the blockchain network; 7. The method of claim 5 or 6, comprising:

8. the transaction and / or the further blockchain transaction is a Pay-to-Script-Hash (P2SH) transaction type or a functionally similar / equivalent transaction type in another blockchain protocol; 8. The method according to any one of claims 5 to 7.

9. the representation is a blockchain script, or a portion of code written in a blockchain scripting language, a text file, a smart contract, an image, a reference to or an identifier of a location where the at least one rule can be accessed; 9. The method according to any one of claims 1 to 8.

10. the at least one rule relates to how or to whom subsequent transfers may be made on the blockchain network; 10. The method according to any one of claims 1 to 9.

11. the at least one rule specifies a cryptographic signature that must be provided to unlock an asset on the blockchain network; 11. The method according to any one of claims 1 to 10.

12. the at least one rule comprises a set of actions and associated conditions agreed upon by the first party and the second party; 12. The method according to any one of claims 1 to 11.

13. 1. A computer-implemented system comprising: a processor; a memory storing executable instructions; Execution of the instructions by the processor results in the system: Carrying out the method according to any one of claims 1 to 12 system.

14. storing executable instructions which, when executed by a processor of a computer system, cause the computer system to perform at least the method of any one of claims 1 to 12; A non-transitory computer-readable storage medium.

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