Moving cryptocurrency from a remotely restricted wallet

Abstract

The present disclosure provides systems, devices, and methods for transferring cryptocurrency from a limited-access cryptocurrency wallet. The limited-access cryptocurrency wallet can pre-create one or more pseudo accounts, each assigned to one or more recipients, and transfer a predetermined amount of cryptocurrency from an associated account associated with the limited-access cryptocurrency wallet to the one or more pseudo accounts. The limited-access cryptocurrency wallet can further pre-generate multiple signed transactions for transferring multiple predetermined partial amounts of cryptocurrency from the one or more pseudo accounts to one or more receiving accounts associated with the one or more recipients, and transmit the multiple signed transactions to a network-connected device. The network-connected device can then transmit one or more of the multiple signed transactions in real time for transferring the cryptocurrency from the one or more pseudo accounts to the one or more receiving accounts without physical involvement with the limited-access cryptocurrency wallet.

Description

Technical Field

[0001] Related Applications This application claims the benefit of priority of U.S. Patent Application No. 16 / 989,939, filed on August 11, 2020. The entire content of this U.S. Patent Application is incorporated herein by reference.

[0002] In some embodiments, the present invention relates to the transfer of cryptocurrency funds from a cryptocurrency wallet, and more particularly, to transferring cryptocurrency funds from a restricted-access cryptocurrency wallet without physically interacting with the restricted-access cryptocurrency wallet, but not limited thereto.

Background Art

[0003] In modern times, financial transactions are mainly carried out using digital-based transaction instructions to transfer fiat currency (cash), which has replaced the conventional physical money transactions.

[0004] In recent years, the introduction of blockchain-based cryptocurrencies has opened up a way to make more use of digital currencies. In particular, cryptocurrencies are virtual currencies that are not controlled by any single entity such as a country, a central bank, and / or others.

[0005] While having many advantages, such cryptocurrencies are inherently vulnerable to malicious attacks and are controlled by a large-scale computer network, so using cryptocurrencies may pose significant security concerns. For transactions using cryptocurrencies, it is basically necessary to connect a digital wallet, which is an electronic device storing user accounts, to a network, making it more vulnerable to such malicious attacks carried out by malicious actors trying to seize control of the cryptocurrencies stored in the accounts.

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to a first aspect of the present invention, a method is provided for moving cryptocurrency from an access-restricted cryptocurrency wallet, the method comprising using one or more processors of an access-restricted cryptocurrency wallet having network connectivity limited to sending. The one or more processors are used as follows:

[0007] Create one or more temporary accounts, each assigned to one or more recipients.

[0008] Send one or more transactions to move a predetermined total amount of cryptocurrency from an account associated with an access-restricted cryptocurrency wallet to one or more virtual accounts. One or more transactions are recorded on a blockchain managed by multiple network-connected computer nodes.

[0009] Generate multiple signed transactions to transfer multiple default amounts of cryptocurrency from one or more temporary accounts to one or more receiving accounts associated with one or more recipients. The sum of the multiple default amounts will not exceed the default total amount.

[0010] Send multiple signed transactions to a network-connected device configured to send one or more multiple signed transactions to move cryptocurrency from one or more virtual accounts to one or more receiving accounts, respectively, without physically engaging with an access-restricted cryptocurrency wallet.

[0011] According to a second aspect of the present invention, an access-restricted cryptocurrency wallet device is provided, comprising a non-temporary storage medium for storing code and one or more processors connected to the non-temporary storage medium. The one or more processors execute the code. The code includes the following:

[0012] A code instruction to create one or more temporary accounts, each assigned to one or more recipients.

[0013] A code instruction to send one or more transactions to move a predetermined total amount of cryptocurrency from an account associated with an access-restricted cryptocurrency wallet to one or more virtual accounts. The one or more transactions are recorded on a blockchain managed by multiple network-connected computer nodes.

[0014] A code instruction to generate multiple signed transactions to transfer multiple default fractional amounts of cryptocurrency from one or more temporary accounts to one or more receiving accounts associated with one or more recipients. The sum of the multiple default fractional amounts does not exceed the default total amount.

[0015] A code instruction for sending multiple signed transactions to a network-connected device configured to send one or more multiple signed transactions to move cryptocurrency from one or more virtual accounts to one or more receiving accounts, respectively, without physically engaging with an access-restricted cryptocurrency wallet.

[0016] In an optional implementation of the first and / or second embodiment, an access-restricted cryptocurrency wallet is used by multiple computer nodes that generate multiple signed transactions using one or more multi-party computation (MPC) protocols.

[0017] In further realizations of the first and / or second aspects, multiple predetermined fractions are effective simultaneously.

[0018] In further implementations of the first and / or second embodiment, the network-connected device is implemented by a subset of network-connected computer nodes that send one or more signed transactions to one or more receiving accounts using one or more multi-party computing (MPC) protocols.

[0019] In an optional implementation of the first and / or second embodiment, one or more processors are further configured to generate a plurality of signed excess transactions used to move cryptocurrency from one or more temporary accounts to accounts associated with an access-restricted cryptocurrency wallet. A network-connected device is configured to send one or more of the plurality of signed excess transactions to the account associated with the access-restricted cryptocurrency wallet if there is an excess in the transaction to be sent to the receiving account.

[0020] In an optional implementation of the first and / or second embodiment, one or more processors are further configured for the following purposes:

[0021] Multiple temporary accounts are created, and each temporary account is assigned to the corresponding recipient from among multiple recipients.

[0022] Send one or more transactions to move a predetermined amount of cryptocurrency from the account associated with the access-restricted cryptocurrency wallet to each of several virtual accounts.

[0023] Generate multiple signed transactions of multiple default fractional amounts of cryptocurrency from one or more of multiple virtual accounts to one or more other of multiple virtual accounts.

[0024] In further implementations of the first and / or second embodiment, one or more of the temporary accounts are created by an access-restricted cryptocurrency wallet as a Payment Channel 2-2 multisig account and recorded on the blockchain, and each transaction from one or more temporary accounts to one or more receiving accounts is further signed by one or more recipients. Multiple signed transactions are set up to move a predetermined portion of a predetermined total amount, which increases in stages.

[0025] In a further implementation of the first and / or second aspect, the network connection device sends a plurality of signed transactions that are not signed by one or more recipients respectively and are not recorded on the blockchain to transfer cryptocurrency from one or more virtual accounts to one or more recipient accounts, and replaces the previously sent signed transaction sent to one or more recipient accounts with each of the plurality of signed transactions using the transaction identifier (ID) of the previously sent signed transaction. Each of the signed transactions to be sent includes the amount of cryptocurrency that is the sum of the amount of cryptocurrency transferred in this signed transaction and the cryptocurrency transferred in the previous signed transaction.

[0026] In a further implementation of the first and / or second aspect, the most recent signed transaction sent by the network connection device to transfer cryptocurrency from one or more virtual accounts to one or more recipient accounts is recorded on the blockchain if each of one or more recipients signs the most recent signed transaction to be sent.

[0027] In an optional implementation of the first and / or second aspect, the payment channel 2-2 multisig account is a time-limited account associated with a deadline. If each of one or more recipients fails to sign the most recent signed transaction sent to transfer cryptocurrency from one or more virtual accounts to one or more recipient accounts within the deadline, the amount of cryptocurrency stored in the payment channel 2-2 multisig account is returned to the account associated with the access-restricted cryptocurrency wallet.

[0028] In the first and / or second optional implementation, if one or more receiving accounts are associated with the corresponding cryptocurrency wallets of one or more recipients that are not configured to support Payment Channel 2-2 Multisig accounts, the Payment Channel 2-2 Multisig accounts are configured such that each signed transaction sent to move cryptocurrency from one or more temporary accounts to one or more receiving accounts and recorded on the blockchain requires the signature of another network-connected device associated with one or more recipients.

[0029] In an optional implementation of the first and / or second embodiment, the access-restricted cryptocurrency wallet closes one or more temporary accounts by sending instructions to a network-connected device to jointly close a Payment Channel 2-2 multisignature account with each of the one or more recipients.

[0030] In further implementations of the first and / or second embodiment, one or more temporary accounts are created by the access-restricted cryptocurrency wallet as new cryptocurrency accounts associated with the access-restricted cryptocurrency wallet.

[0031] In further realizations of the first and / or second aspects, if the cryptocurrency is an account-based cryptocurrency and each transaction includes a nonce indicating the number of previous transactions, the access-restricted cryptocurrency wallet generates a plurality of signed transactions such that each of the plurality of signed transactions includes a corresponding nonce from a plurality of valid nonces and a corresponding default fraction, constituting a uniform distribution of default total amounts according to a default granularity.

[0032] In further implementations of the first and / or second embodiment, when a specific amount of cryptocurrency is moved to one or more receiving accounts, the network-connected device selects one or more signed transactions that include a default fraction that is greater than or equal to the specific amount. All other signed transactions that include the same nonce and other default fractions are discarded.

[0033] In the optional implementations of the first and / or second embodiment, one or more processors are further configured to generate a plurality of signed transactions for moving each of the default fractions to one of a plurality of receiving accounts, each of the plurality of signed transactions comprising a default fraction of the default total, each default fraction of the default total, and each of the plurality of receiving accounts.

[0034] In an optional implementation of the first and / or second embodiment, one or more processors are further configured to send one or more signed transactions for a network-connected device to move cryptocurrency to an account associated with an access-restricted cryptocurrency wallet, by defining the account associated with the access-restricted cryptocurrency wallet as one of a plurality of receiving accounts.

[0035] In an optional implementation of the first and / or second embodiment, the access-restricted cryptocurrency wallet closes one or more virtual accounts by sending instructions to a network-connected device to close the account-based virtual accounts.

[0036] In an optional implementation of the first and / or second aspect, the access-restricted cryptocurrency wallet closes one or more temporary accounts by sending one or more transactions, which are recorded on the blockchain and include one or more nonces of multiple signed transactions and a cryptocurrency amount of zero, to move the cryptocurrency to an account associated with the access-restricted cryptocurrency wallet.

[0037] In further realizations of the first and / or second aspects, where the cryptocurrency is a transaction-based cryptocurrency (UTXO) and each transaction includes one or more input amounts of cryptocurrency, tracing back to the corresponding output amounts of previous transactions, the access-restricted cryptocurrency wallet generates multiple signed transactions such that each signed transaction is derived from a signed transaction in a higher layer and constitutes a hierarchical directed acyclic graph (DAG) comprising multiple signed transactions, each containing a transaction ID (TXID). The hierarchical DAG is configured to distribute a predetermined total amount according to a predetermined granularity.

[0038] In further realizations of the first and / or second embodiment, the DAG is configured as a hierarchical tree.

[0039] In further implementations of the first and / or second embodiment, when transferring a specific amount of cryptocurrency to one or more receiving accounts, the network-connected device selects at least a portion (segment) of a hierarchical DAG that includes one or more signed transactions containing a predetermined fraction that is greater than or equal to the specific amount. Each signed transaction in a segment that is not sent is marked as unavailable.

[0040] In an optional implementation of the first and / or second embodiment, the remaining balance of available cryptocurrency in one or more unavailable transactions is notified to the access-restricted cryptocurrency wallet by inserting one or more strings of limited length into the access-restricted cryptocurrency wallet via a capacity-restricted input interface of the access-restricted cryptocurrency wallet configured to accept one or more strings of limited length.

[0041] In an optional implementation of the first and / or second embodiment, an access-restricted cryptocurrency wallet derives the balance from an index known to the access-restricted cryptocurrency wallet that first generated multiple signed transactions containing one or more unavailable transactions, by including an index of unavailable transactions containing one or more unavailable transactions.

[0042] In an optional implementation of the first and / or second aspect, the access-restricted cryptocurrency wallet sends a transaction to an account associated with the access-restricted cryptocurrency wallet, which includes the cumulative sum of the fractional amounts of cryptocurrency contained in one or more unusable signed transactions recorded on the blockchain.

[0043] In an optional implementation of the first and / or second embodiment, if each of one or more recipients uses a different access-restricted cryptocurrency wallet, the amount of cryptocurrency to be moved to the receiving account associated with the other access-restricted cryptocurrency wallet is notified to the other access-restricted cryptocurrency wallet by inserting one or more strings of limited length into the other access-restricted cryptocurrency wallet via the capacity-restricted input interface of the other access-restricted cryptocurrency wallet. One or more strings include a description of the first signed transaction of a plurality of signed transactions sent to the receiving account of the other access-restricted cryptocurrency wallet, the structure of a hierarchical DAG, and the index of the last signed transaction of the plurality of signed transactions sent to move cryptocurrency to the receiving account of the other access-restricted cryptocurrency wallet.

[0044] In the optional implementations of the first and / or second embodiment, if the fee needs to be distributed to one or more computer nodes that record one or more signed transactions on the blockchain, the access-restricted cryptocurrency wallet expands each of the multiple signed transactions into a corresponding set of signed transactions and assigns a fee of each amount of cryptocurrency to each signed transaction in the set. The network-connected device selects one of the transactions from the set according to the fee amount.

[0045] In an optional implementation of the first and / or second embodiment, if a fee needs to be allocated to one or more of several computer nodes that record one or more signed transactions on the blockchain, an access-restricted cryptocurrency wallet generates one or more fee-allocating transactions containing a dedicated amount of cryptocurrency for the fee, sends one or more fee-allocating transactions to move the cryptocurrency to an account associated with a network-connected device, and the network-connected device sends one or more fee-allocating transactions to move the cryptocurrency to one or more computing nodes that have recorded one or more signed transactions. One or more fee-allocating transactions contain an amount of cryptocurrency sufficient to cover the fees for both one or more signed transactions and one or more fee-allocating transactions.

[0046] In an optional implementation of the first and / or second embodiment, if the fee needs to be distributed among one or more computer nodes that record one or more signed transactions on the blockchain, the access-restricted cryptocurrency wallet establishes an arrangement with at least one partner computer node among the multiple computer nodes, which arranges that at least one partner computer node records each of the multiple signed transactions sent by a network-connected device to move cryptocurrency from one or more virtual accounts to one or more receiving accounts.

[0047] In an optional implementation of the first and / or second embodiment, the signature of each of a plurality of signed transactions is encrypted using at least one secret, and the network-attached device decrypts the signature of at least one signed transaction using at least one secret before transmitting at least one signed transaction.

[0048] In further realizations of the first and / or second embodiment, at least one piece of sensitive information used to decrypt the signature of at least one signed transaction is obtained from a portable storage device associated with an access-restricted cryptocurrency wallet device.

[0049] In further realizations of the first and / or second embodiment, at least one piece of confidential information used to decrypt the signature of at least one signed transaction is provided by at least one user associated with an access-restricted cryptocurrency wallet device.

[0050] In further implementations of the first and / or second embodiment, at least one secret information used to decrypt the signature of at least one signed transaction is reconstructed from multiple secret information shares using at least one secret sharing algorithm.

[0051] In the optional implementations of the first and / or second embodiment, the signature of each of the multiple signed transactions is encrypted using one of the corresponding secrets from among the multiple secrets.

[0052] In an optional implementation of the first and / or second embodiment, identification data of at least one signed transaction is presented to enable the identification of at least one signed transaction and, accordingly, to obtain the respective secret information used to encrypt the signature of at least one signed transaction.

[0053] Other systems, methods, features, and effects of the disclosure will be apparent, or will become apparent, to those skilled in the art upon consideration of the following drawings and detailed description. All such further systems, methods, features, and effects are contained in this description, are within the scope of the disclosure, and are intended to be protected by the appended claims.

[0054] Unless otherwise specified, all technical and / or scientific terms used in this disclosure have the same meaning as those commonly understood by those skilled in the art relating to the present invention. Methods and materials similar to or equivalent to those described in this disclosure may be used in carrying out or testing embodiments of the present invention, but the following descriptions are illustrative methods and / or materials. In case of any conflict, the patent specification, including definitions, shall prevail. In addition, the materials, methods and examples are illustrative and not intended to necessarily impose limitations.

[0055] Implementation of the methods and / or systems of the embodiments of the present invention may include performing or completing predetermined tasks manually, automatically, or in combination thereof. Furthermore, through the actual instrumentation and installation of embodiments of the methods and / or systems of the present invention, several predetermined tasks can be performed by hardware, software, firmware, or an operating system in combination thereof.

[0056] For example, hardware that performs a defined task according to an embodiment of the present invention can be implemented as a chip or circuit. As software, a defined task according to an embodiment of the present invention can be implemented as a set of software instructions executed by a computer using any suitable operating system. In exemplary embodiments of the present invention, one or more tasks according to exemplary embodiments of the methods and / or systems described herein are performed by a data processing device such as a computer platform that executes a set of instructions. Optionally, the data processor includes volatile memory for storing instructions and / or data, and / or non-volatile storage for storing instructions and / or data, such as a magnetic hard disk and / or removable media. Optionally, network connectivity may also be provided. Optionally, a display and / or user input devices such as a keyboard and mouse may also be provided.

[0057] Hereinafter, several embodiments of the present invention will be described only as examples, with reference to the accompanying drawings. Hereafter, the drawings will be specifically referenced in detail, emphasizing that the details shown are for illustrative purposes only, illustrating embodiments of the present invention. In this regard, the description accompanied by the drawings will make it clear to those skilled in the art how embodiments of the present invention can be carried out.

[0058] The following is included in the drawing. [Brief explanation of the drawing]

[0059] [Figure 1] The flowchart shows an exemplary process performed by an access-restricted cryptocurrency wallet and a network-connected device that moves cryptocurrency funds from an account associated with the access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device, according to some embodiments of the present invention. [Figure 2]This is a schematic diagram of an exemplary system, according to some embodiments of the present invention, for transferring cryptocurrency funds from an account associated with an access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device. [Figure 3] This is a schematic diagram of an exemplary sequence of transferring cryptocurrency funds from an account associated with an access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device, according to some embodiments of the present invention. [Figure 4] This is a schematic diagram of an exemplary configuration of a plurality of pre-generated signed cryptocurrency transactions for a payment channel temporary account, according to some embodiments of the present invention. [Figure 5] This is a schematic diagram illustrating an exemplary configuration of a plurality of signed cryptocurrency transactions pre-generated according to a predetermined flat distribution used in an account-based cryptocurrency service according to some embodiments of the present invention. [Figure 6] This is a schematic diagram illustrating an exemplary structure of multiple virtual accounts in a hierarchical (layered) structure used in an account-based cryptocurrency service according to some embodiments of the present invention. [Figure 7A] This is a schematic diagram of an exemplary hierarchical tree configuration of multiple signed cryptocurrency transactions that are pre-generated according to a default tree distribution used in a transaction-based cryptocurrency service according to some embodiments of the present invention. [Figure 7B] This is a schematic diagram of an exemplary hierarchical tree configuration of multiple signed cryptocurrency transactions that are pre-generated according to a default tree distribution used in a transaction-based cryptocurrency service according to some embodiments of the present invention. [Figure 8A] This is a schematic diagram illustrating an exemplary use of an exemplary hierarchical tree configuration for transferring cryptocurrency funds to a receiving account, according to some embodiments of the present invention. [Figure 8B]This is a schematic diagram illustrating an exemplary use of an exemplary hierarchical tree configuration for transferring cryptocurrency funds to a receiving account, according to some embodiments of the present invention. [Figure 9] This is a schematic diagram of an exemplary hierarchical structure constructed to move cryptocurrency funds to one or more receiving accounts using a reduced number of signed transactions, according to some embodiments of the present invention. [Modes for carrying out the invention]

[0060] In some embodiments, the present invention relates to the transfer of cryptocurrency funds from a cryptocurrency wallet, and in particular to the transfer of cryptocurrency funds from an access-restricted cryptocurrency wallet without physically engaging with the access-restricted cryptocurrency wallet, but is not limited thereto.

[0061] According to some embodiments of the present invention, methods, systems, and computer program products are provided for moving cryptocurrency funds from an account associated with an access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device. The access-restricted cryptocurrency wallet device may be, for example, a cold wallet that cannot receive data from the network, an offline hot wallet, a group of offline computer nodes, and / or others, and such an access-restricted cryptocurrency wallet device can be stored in a secure location for security reasons, such as a vault, a location with restricted access, and / or others, thereby making it inaccessible. A cryptocurrency platform, or cryptocurrency service, such as Bitcoin, Bitcoin Cash, Ethereum, Ripple, etc., is a blockchain-based platform governed by a plurality of independent computer nodes that manage a distributed ledger according to one or more protocols defined by the cryptocurrency platform.

[0062] An access-restricted cryptocurrency wallet can be operated to generate provisions and means for moving cryptocurrency funds to one or more receiving accounts associated with one or more specific recipients to which the owner (user) of the access-restricted cryptocurrency wallet may want to move cryptocurrency in the future. An access-restricted cryptocurrency wallet, in particular a cold wallet, may be an isolated device equipped with a one-way transmitter that facilitates a send-only communication interface, such as a one-way send-only communication channel with one or more other resources connected to the network. In another example, even if an access-restricted cryptocurrency wallet is a hot wallet that can receive network data, when stored in a secure location, the hot wallet is disconnected from the network. Thus, an access-restricted cryptocurrency wallet can be made unable to receive data from the network and can be highly evasive of malicious attacks on the network.

[0063] An access-restricted cryptocurrency wallet can be configured to generate reserves for moving large amounts of cryptocurrency through multiple transactions, each containing a predetermined fractional amount of cryptocurrency, over the period during which the access-restricted cryptocurrency wallet is securely stored and inaccessible.

[0064] Specifically, an access-restricted cryptocurrency wallet can be configured and operated to create one or more provisional accounts, each assigned to one or more recipients to whom the user may potentially want to transfer cryptocurrency funds in the future. Because provisional accounts are temporary accounts intended for specific uses, they are assigned to specific recipients only for a limited period. After creation, the access-restricted cryptocurrency wallet can send one or more transactions to move a predetermined total amount of cryptocurrency (usually a sufficient amount of cryptocurrency) from the account associated with the access-restricted cryptocurrency wallet to each provisional account.

[0065] The access-restricted cryptocurrency wallet can then generate multiple cryptocurrency transactions from each temporary account to receiving accounts associated with one or more recipients. Each of the multiple signed transactions generated by the access-restricted cryptocurrency wallet can be configured to move a default portion of the total amount of cryptocurrency such that the sum of multiple default portions does not exceed the default total amount of cryptocurrency initially moved to the temporary account. Thus, each signed transaction includes at least the account identifier (ID) of each temporary account, the account ID of each receiving account, the amount of cryptocurrency, and the signature of the access-restricted cryptocurrency wallet device. One or more signed transactions may further include one or more additional data items, fields, flags, etc., as determined by the cryptocurrency used. The access-restricted cryptocurrency wallet may sign each signed transaction with its own private key, and can calculate the hash value of each transaction using one or more hash functions, for example, as known in the art. A signed transaction becomes a valid cryptocurrency transaction from a temporary account to the respective receiving account, and since the private key can only be used in an access-restricted cryptocurrency wallet, no one else can generate and / or duplicate a signed transaction.

[0066] An access-restricted cryptocurrency wallet can then send multiple signed transactions to a network-connected device, such as a hot wallet connected to the network and associated with the user. A network-connected device can be utilized by a single device connected to the network, or by a group of computer nodes that can participate in one or more multi-party computing (MPC) sessions acting together as a network-connected device. Signed transactions are not recorded on the blockchain, but rather are stored only by the network-connected device.

[0067] From this point forward, access-restricted cryptocurrency wallets are no longer necessary, and the cryptocurrency funds stored in them may be stored in a secure location, such as a safe or a location with restricted access, to ensure their safety. Since access-restricted cryptocurrency wallets are stored remotely, they are physically inaccessible and therefore cannot be physically operated and / or involved with by the user (owner) associated with them.

[0068] Even in such cases, it is possible to move cryptocurrency funds and / or a portion thereof that have been previously moved from an account associated with an access-restricted cryptocurrency wallet to one or more temporary accounts to one or more receiving accounts associated with each of the one or more designated recipients. This can be done by instructing, configuring, and / or otherwise operating a network-connected device to send one or more pre-generated signed transactions in real time. Specifically, in response to an instruction to move a specific amount of cryptocurrency to a particular receiving account, the network-connected device can select one or more signed transactions that include a portion of the specific amount of cryptocurrency to be moved that is cumulatively equal to or exceeds that amount.

[0069] This means that a network-connected device can be manipulated to move cryptocurrency funds (not exceeding the total amount moved to each temporary account) that were initially moved from the account associated with the access-restricted cryptocurrency wallet, without physically engaging with the access-restricted cryptocurrency wallet itself, which remains in a secure storage location.

[0070] Optionally, the signatures of multiple signed transactions sent from an access-restricted cryptocurrency wallet to a network-connected device may be encrypted using one or more pieces of secret information, such as a secret value, secret string, secret number, etc. Therefore, when instructed and / or operated to send one or more signed transactions to one or more receiving accounts, the network-connected device must first decrypt the signatures of one or more signed transactions before sending them. The one or more pieces of secret information used to encrypt the signed transactions can be stored securely in one or more ways, for example, by being securely held by one or more users, or by being securely stored in one or more storage devices, typically protected devices requiring authentication for access. Furthermore, one or more pieces of secret information can be distributed across multiple secret information shares distributed among a group of computer nodes, and the group of computer nodes can engage in one or more MPC sessions to jointly decrypt one or more signed transactions using the corresponding secret information shares.

[0071] As will be detailed later, various embodiments of the present invention can create, generate, configure and / or coordinate temporary accounts and signed transactions to implement all kinds of cryptocurrency systems, i.e., cryptocurrency services, including, for example, account-based cryptocurrencies such as Ethereum and Ripple, and transaction-based (UTXO) cryptocurrencies such as Bitcoin and Bitcoin Cash.

[0072] Furthermore, in a preliminary stage, an access-restricted cryptocurrency wallet can be made to operate in a way that creates multiple signed excess transactions to return at least a portion of the amount to the account associated with the access-restricted cryptocurrency wallet.

[0073] Moving cryptocurrency funds from accounts associated with an access-restricted cryptocurrency wallet, without physically engaging with the wallet itself, can yield numerous benefits and advantages.

[0074] Firstly, a predetermined specific amount of cryptocurrency funds stored in an access-restricted cryptocurrency wallet can be used for transfers without involving the access-restricted cryptocurrency wallet, while the remaining portion of the cryptocurrency funds stored in the access-restricted cryptocurrency wallet can be highly secure by storing the access-restricted cryptocurrency wallet in a secure location.

[0075] Furthermore, since the total amount of cryptocurrency funds transferred to each temporary account can be limited and / or capped, the risk of losing cryptocurrency funds held in one or more temporary accounts is limited to the restricted total amount transferred to each of those temporary accounts. In addition, since signed transactions are pre-signed to transfer cryptocurrency funds from one or more temporary accounts to one or more receiving accounts associated with one or more specific recipients, these cryptocurrency funds cannot be misused for other purposes.

[0076] Furthermore, because signed transactions are pre-signed to move cryptocurrency funds from one or more temporary accounts to one or more receiving accounts associated with one or more specific recipients, a potential malicious actor attempting to divert cryptocurrency funds held in one or more temporary accounts to one or more other accounts cannot alter these signed transactions. In the worst-case scenario, a malicious actor might cause one or more signed transactions to be sent to one or more receiving accounts. However, since these one or more receiving accounts are typically long-term trading partners and therefore associated with specific, trusted recipients, the transferred funds will not be lost.

[0077] Furthermore, encrypting the signatures of signed transactions requires active user intervention and participation in the transmission of each signed transaction, adding an additional level of security and safety, thus further enhancing the security and robustness of signed transactions. This means that even if a malicious actor succeeds in compromising one or more network-connected devices or receiving accounts, the increased security requiring user intervention will prevent the malicious actor from sending one or more signed transactions to the compromised receiving accounts.

[0078] In addition to the foregoing, the methods, systems, and devices described herein can be configured to support a wide range of cryptocurrencies. Thus, for most, if not all, of the popular and commonly used cryptocurrencies, it is easy to apply and adopt the method of moving cryptocurrency funds from accounts associated with an access-restricted cryptocurrency wallet without physically engaging with the access-restricted cryptocurrency wallet itself.

[0079] Furthermore, cryptocurrency funds can be automatically sent from one or more virtual accounts without human intervention. Specifically, a network-connected device can automatically send one or more signed transactions in response to one or more trigger events, such as a predetermined scheduled time, an action performed by one or more recipients, a transaction detected on the blockchain network, and / or other events.

[0080] Before describing in detail at least one embodiment of the present invention, it should be understood that the present invention is not necessarily limited to the details of the configuration and arrangement and / or methods of the components described and / or shown in the following description and / or drawings and / or examples. Other embodiments of the present invention are possible, and the present invention can be carried out or implemented in various ways.

[0081] As will be understood by those skilled in the art, aspects of the present invention may be implemented as systems, methods, or computer program products. Accordingly, aspects of the present invention may take the form of a hardware embodiment as a whole, a software embodiment (including firmware, resident software, microcode, etc.), or a combination of a software embodiment and a hardware embodiment, which in this disclosure may often be referred to as "circuits," "modules," or "systems." Furthermore, aspects of the present invention may take the form of a computer program product implemented on one or more computer-readable media having computer-readable program code implemented on the computer-readable media.

[0082] Any combination of one or more computer-readable media may be used. A computer-readable storage medium may be a tangible device capable of holding and storing instructions used by an instruction execution device. A computer-readable media may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. More specific examples (exemplary list) of computer-readable storage media include electrical connections with one or more wires, portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM, i.e., flash memory), optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the context as used herein, a computer-readable storage medium may be any tangible medium that contains or can store programs used by or in connection with an instruction execution system, instruction execution unit, or instruction execution device.

[0083] A computer-readable signal medium may include propagating data signals, for example, propagated as part of a baseband or carrier wave, into which computer-readable program code is embodied. Such propagating signals may take any of various forms, including but not limited to electromagnetic, optical, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium other than a computer-readable storage medium that is capable of communicating, propagating, or carrying programs used by or in connection with an instruction execution system, instruction execution unit, or instruction execution device.

[0084] Computer program code, including computer-readable program instructions materialized on a computer-readable medium, may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cables, RF, and any suitable combination thereof.

[0085] The program code used to perform the operation of the aspects of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java®, Smalltalk, and C++, and conventional procedural programming languages ​​such as the C programming language or similar programming languages.

[0086] The program code may run entirely on the user's computer as a standalone software package, partially on the user's computer, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or wide area network (WAN), or the connection may be made to an external computer (for example, via the Internet using an Internet service provider). The program code can be downloaded from a computer-readable storage medium to each computer / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network.

[0087] Hereinafter, embodiments of the present invention will be described with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It can be seen that each block in the flowchart and / or block diagram, and combinations of blocks in the flowchart and / or block diagram, can be implemented by computer-readable program instructions.

[0088] The flowcharts and block diagrams in the figures illustrate the architecture, functions, and operation of possible embodiments of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, segment, or portion of an instruction set comprising one or more executable instructions used to perform one or more defined logical functions. In some other embodiments, the functions described in a block may be performed in an order different from the order shown in the figure. For example, if two consecutive blocks are shown, they may actually be executed almost simultaneously, or in some cases, the blocks may be executed in reverse order depending on the functions involved. It can also be seen that each block in the block diagram and / or flowchart diagram, and combinations of blocks in the block diagram and / or flowchart diagram, can be implemented by a system based on dedicated hardware that performs defined functions or operations or realizes combinations of dedicated hardware and computer instructions.

[0089] Referring to the drawings, Figure 1 shows a flowchart of an exemplary process performed by an access-restricted cryptocurrency wallet and a network-connected device that moves cryptocurrency funds from an account associated with the access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device, according to some embodiment of the present invention.

[0090] An exemplary process 110 can be carried out by an access-restricted cryptocurrency wallet 102, which is a device used as a digital wallet for cryptocurrencies such as Bitcoin, Bitcoin Cash, Ethereum, Ripple, etc., which are governed by a network of computer nodes that control cryptocurrencies, for example, a blockchain network that manages a blockchain.

[0091] In particular, the access-restricted cryptocurrency wallet 102 may typically be disconnected from the network, which enables access restriction and allows it to be stored in a secure location (e.g., a safe) that is physically inaccessible and inoperable by the user concerned. While the access-restricted cryptocurrency wallet 102 is inaccessible and physically inoperable, there may be a strong need to move cryptocurrency funds from one or more cryptocurrency accounts associated with the access-restricted cryptocurrency wallet 102 to one or more other accounts of one or more recipients (hereinafter referred to as receiving accounts) without physically engaging with (accessing) the access-restricted cryptocurrency wallet 102.

[0092] To achieve this objective, the access-restricted cryptocurrency wallet 102 can perform a process 110 that pre-generates means and reserves to enable the transfer of cryptocurrency to one or more receiving accounts.

[0093] The access-restricted cryptocurrency wallet 102 may be configured to create one or more temporary accounts, each of which is assigned to each recipient to whom the user may potentially want to move cryptocurrency funds in the future. The access-restricted cryptocurrency wallet 102 can move a predetermined amount of cryptocurrency, typically an equivalent amount, to one or more of the temporary accounts. The amount of cryptocurrency moved to each temporary account is referred to as the total amount.

[0094] The access-restricted cryptocurrency wallet 102 can then generate multiple cryptocurrency transactions from each temporary account to the corresponding receiving account. Each of these transactions is properly signed by the access-restricted cryptocurrency wallet 102 using its unique private key, so that each transaction becomes a valid cryptocurrency transaction from the temporary account to one or more receiving accounts. The access-restricted cryptocurrency wallet 102 can generate multiple signed transactions used to move a predetermined portion of the total amount of the initially moved cryptocurrency, such that the sum of the multiple predetermined portions does not exceed the predetermined total amount.

[0095] The access-restricted cryptocurrency wallet 102 can then send multiple signed transactions to the network-connected device 104, which may be used by a single device connected to the network, or by a group of computer nodes that can participate in one or more multi-party computing (MPC) sessions to operate together as the network-connected device 104.

[0096] A network-connected device 104 performing an exemplary process 120 can receive multiple signed transactions. The network-connected device 104 can further move one or more signed transactions to one or more receiving accounts. Specifically, a user associated with an access-restricted cryptocurrency wallet 102 can instruct the network-connected device 104 to move one or more cryptocurrency transactions to a receiving account. In response to the instruction, the network-connected device 104 can send one or more signed transactions pre-created by the access-restricted cryptocurrency wallet 102 to move the cryptocurrency to the receiving account. Specifically, the network-connected device 104 can send signed transactions selected such that the portion amount is equal to or greater than the amount instructed by the user to move, depending on the portion amount of the one or more signed transactions.

[0097] Therefore, without physically engaging with the access-restricted cryptocurrency wallet 102, a network-connected device 104 that functions as a hot wallet can be operated to send one or more pre-created signed transactions, allowing cryptocurrencies stored in one or more accounts controlled by the access-restricted cryptocurrency wallet 102 to be moved to other accounts in real time at a later date. Furthermore, by using signed transactions, cryptocurrency funds can be moved only to one or more recipients defined and designated by the access-restricted cryptocurrency wallet 102.

[0098] Referring also to Figure 2, this is a schematic diagram of an exemplary system, according to some embodiments of the present invention, for moving cryptocurrency funds from an account associated with an access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with an access-restricted cryptocurrency wallet device.

[0099] An exemplary system 200 may include an access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102 configured to store the cryptocurrency funds of an associated user 202.

[0100] Cryptocurrency services can be governed by a community network comprising multiple computer nodes 204, such as a blockchain network that manages a distributed ledger blockchain for tracking, logging, and recording cryptocurrency transactions.

[0101] Computer nodes 204, such as computers, servers, processing nodes, network nodes, cloud computing resources, smartphones, tablets, etc., can communicate with each other via one or more wired and / or wireless networks, including network 206 such as a local area network (LAN), wide area network (WAN), municipal area network (MAN), wireless LAN (WLAN), cellular network, the internet, etc.

[0102] According to some embodiments of the present invention, the access-restricted cryptocurrency wallet 102 may be an isolated device, for example, a proprietary device, a custom device, etc., isolated from network 206 in particular in terms of receiving data from network 206. In particular, being an isolated device can facilitate the function of a cold wallet associated with one or more accounts of user 202 that store the cryptocurrency funds of the associated user 202. Since the cold wallet is an isolated device that is isolated by being disconnected from network 230 at least on the receiving end, the cold wallet can be highly resistant to network-based malicious attacks that would attempt to infiltrate the cold wallet in order to seize access and control of the one or more accounts it stores and, in some cases, move the cryptocurrency funds out of the cold wallet and steal the cryptocurrency funds.

[0103] The access-restricted cryptocurrency wallet 102 may also be an isolated device with a transmission-only communication function, and therefore the access-restricted cryptocurrency wallet 102 may comprise a unidirectional transmitter 210 that facilitates the operation of a one-way secure communication channel with one or more other devices, one or more processors 212 that execute processes such as process 110, and storage 214 (program storage) for storing program code and / or data. The isolated device may further include one or more interfaces for receiving data, specifically a secure capacity-limited input interface 216 that accepts limited data, typically very small amounts of data.

[0104] The unidirectional transmitter 210 may include one or more wired interfaces, wireless interfaces, and / or optical transmitting interfaces configured solely for data transmission and therefore unable to receive data. The unidirectional transmitter 210 may be physically tamper-resistant so that data transmitted from the unidirectional transmitter 210 is impossible to compromise and / or detectable and reported. For example, the unidirectional transmitter 210 may include an optical-based transmitter (e.g., infrared, laser, etc.) configured to optically encode data. In particular, the unidirectional transmitter 210 may transmit a directional optical pattern directed to a specific receiver that cannot be intercepted by a potentially malicious (eavesdropping) device. In another example, the unidirectional transmitter 210 may include wired and / or wireless transmitters, for example, serial transmitters, radio frequency (RF) transmitters configured to transmit data using wires and / or wirelessly. In another example, the unidirectional transmitter 210 may include a display, such as a screen or projector, that displays QR code® encoded data that can be scanned and restored for transmission to one or more computer nodes 204. In yet another example, the unidirectional secure communication channel may be implemented using a hardware storage medium, such as a CD-ROM disk, preferably a single-use disk. In such a case, the unidirectional transmitter 210 may include a media access interface suitable for writing, burning, and / or programming data to the hardware storage medium. The burned hardware storage medium can then be provided to one or more computer nodes 204 so that data can be securely moved from the isolation device 202 to the computer nodes 204.

[0105] Furthermore, since the unidirectional transmitter 210 can transmit encrypted data, it is possible to form a reliable and secure unidirectional (one-way) communication channel.

[0106] One or more processors 212 (homogeneous or heterogeneous processors) may include one or more processing nodes configured to perform parallel processing as a cluster and / or as one or more multi-core processors. The storage 214 may include one or more non-temporary memory devices, i.e., persistent non-volatile devices such as ROM, flash arrays, hard drives, SSDs, magnetic disks, etc., and / or one or more volatile devices such as RAM device cache memory.

[0107] One or more processors 212 may execute one or more software modules, such as processes, scripts, applications, agents, utilities, or tools. Each software module may be stored in a non-temporary medium (program storage) such as storage 214 and may have multiple program instructions that are executed by one or more processors such as processor 212.

[0108] Furthermore, the account management unit 220 may utilize and / or support one or more hardware elements integrated with and / or connected to the isolation device 202, such as circuits, components, integrated circuits (ICs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), etc. In one example, the account management unit 220 may use a random number generator to create one or more cryptographic keys, for example, an asymmetric encryption key pair including a private key and a public key, as is known in this technology. In another example, the account management unit 220 may use a Hardware Security Module (HSM) to utilize one or more functions, for example, message signing, key injection, database encryption, etc.

[0109] Therefore, one or more processors 212 can execute one or more functional modules utilized by one or more software modules, one or more hardware modules, and / or a combination thereof. For example, one or more processors 212 can execute the account management application 220 in order to execute process 110.

[0110] The capacity-limited input interface 216 may be configured to accept a limited amount of data, typically a very small amount of data, which can be inserted manually and / or automatically. In one example, the capacity-limited input interface 216 may include one or more user interfaces, such as a keyboard or touch screen, to interact with a user 202 and receive a string of data entered by the user 202. In another example, the capacity-limited input interface 216 may include a computer-punched card reader configured to read data, such as a string of data encoded on one or more punched cards inserted manually and / or automatically. The user interface may further include one or more output interfaces, such as a display, speaker, earphones, etc., to output data to the user 202.

[0111] On the other hand, according to some embodiments of the present invention, an access-restricted cryptocurrency wallet 102 may be implemented using a hot wallet device associated with one or more accounts of user 202, such as a computer, server, smartphone, tablet, and / or any other computer device having one or more processors, in order to store the cryptocurrency funds of the associated user 202. The access-restricted cryptocurrency hot wallet 102 is, with some exceptions, very similar to a network-connected device 104. For example, since it is naturally assumed that it communicates with a network 206, the access-restricted cryptocurrency hot wallet 102 may include a two-way network interface that communicates with one or more computer nodes 204, for example, to send data to and receive data from the network 206. However, for some reason, user 202 may disconnect the hot wallet from the network 206 in order to secure the hot wallet, for example, by placing the hot wallet in a secure and inaccessible location where the hot wallet is separated from the network 206. In another example, the access-restricted cryptocurrency hot wallet 102 may include one or more high-capacity interfaces for sending and / or receiving large amounts of data, such as a Universal Serial Bus (USB) port, an RF interface, etc.

[0112] Furthermore, according to some embodiments of the present invention, the access-restricted cryptocurrency wallet 102 can be utilized and / or implemented by a group of computer nodes, such as computer node 204, which can participate in one or more MPC sessions to execute process 100 using one or more MPC protocols known in the art, such as Shamir secret sharing, in order to execute process 120. In particular, after executing process 100, the group of computer nodes utilizing the access-restricted cryptocurrency wallet 102 can be disconnected from the network 206 in order to protect the computer nodes, for example, by placing them in a secure and inaccessible location where the computer nodes are isolated from the network 206.

[0113] The system may further include network-connected devices such as a network-connected device 104, which is connected to the network 206 and has one or more processors, such as a computer, server, smartphone, tablet, and / or any other computer device. The network-connected device 104 may be associated with user 202. For example, the network-connected device 104 may be user 202's hot wallet. In another example, the network-connected device 104 may simply be a network-connected device used and operated by user 202.

[0114] The network connection device 104 is a network interface that connects to the network 206 and may include a network interface that communicates with one or more network connection resources connected to the network 206, such as one or more computer nodes 204. The network connection device 104 may also include one or more processors, such as one or more processors 212 that execute process 120, and storage, such as storage 214 (program storage) that stores code and / or data. The network connection device 104 may further include one or more hardware modules, such as circuits, components, ICs, ASICs, FPGAs, DSPs, etc.

[0115] Therefore, the network-connected device 104, specifically one or more processors of the network-connected device 104, can execute one or more software modules, one or more hardware modules, and / or one or more functional modules utilized by a combination thereof. For example, the network-connected device 104 can execute a transaction controller 222 to execute process 120.

[0116] 204 subsets of network-connected computer nodes may optionally be configured such that the network-connected device 104 is involved in one or more MPC sessions using one or more known MPC protocols to perform a process 120, such as the Shamir secret sharing scheme.

[0117] As described above, data transmitted by the access-restricted cryptocurrency wallet 102 using a unidirectional secure communication channel supported by the unidirectional transmitter 210 can be encrypted. By applying one or more encryption schemes, the access-restricted cryptocurrency wallet 102 can establish a unidirectional secure and reliable channel with one or more network-connected resources connected to the network 206, such as one or more computer nodes 204. For example, the access-restricted cryptocurrency wallet 102 may encrypt data transmitted to each computer node 204 using an encryption-decryption key pair uniquely associated with each of at least some of the computer nodes 204. The access-restricted cryptocurrency wallet 102 may be associated with such an encryption-decryption key pair to enable the computer nodes 204 to verify and / or authenticate the data transmitted by the access-restricted cryptocurrency wallet 102, as is known in the art. The encryption-decryption key pair may include, for example, an asymmetric cryptographic key pair including a private key and a public key. The public key of the asymmetric cryptographic key pair associated with each computing node 204 and the access-restricted cryptocurrency wallet 102 is made public and shared, while the private key of the asymmetric cryptographic key pair is kept secret. Therefore, only the device using that private key can use it, and thus, this device is the only device that can decrypt messages addressed to that device.

[0118] For the sake of brevity, in this specification, processes 110 and 120 and system 200 are described in terms of one access-restricted cryptocurrency wallet 102 associated with one user 202 and one network-connected device 104 supporting the access-restricted cryptocurrency wallet 102. However, this should not be interpreted restrictively, and processes 110 and 120 and system 200 can be extended to support multiple access-restricted cryptocurrency wallets 102 associated with the corresponding user 202 and supported by one or more network-connected devices 104.

[0119] Furthermore, for clarification, it is later described that the access-restricted cryptocurrency wallet 102 and the network connection device 104 execute processes 110 and 120, respectively. However, it is clear that the account management unit 220, executed by one or more processors 212 of the access-restricted cryptocurrency wallet 102, is the functional module that actually executes process 110, while the transaction controller 222, executed by one or more processors of the network connection device 104, is the functional module that actually executes process 120.

[0120] As shown in 112, the process 110 performed by the access-restricted cryptocurrency wallet 102 begins with creating one or more temporary accounts, each temporary account being assigned to each recipient to whom user 202 may potentially want to transfer cryptocurrency funds in the future.

[0121] A temporary account, by its very nature, is a temporary account intended for a specific purpose, and is therefore assigned (associated) with a specific recipient only for a limited period. However, the access-restricted cryptocurrency wallet 102 may optionally set up one or more existing accounts (principal accounts) associated with the access-restricted cryptocurrency wallet 102 as one or more temporary accounts. In such a case, the access-restricted cryptocurrency wallet 102 does not need to create a new account, and only needs to use one or more existing accounts associated with the access-restricted cryptocurrency wallet 102 as one or more temporary accounts.

[0122] As shown in 114, the access-restricted cryptocurrency wallet 102 can send a transaction of a predetermined total amount of cryptocurrency from one or more accounts (original accounts) associated with the access-restricted cryptocurrency wallet 102 to each virtual account. The transaction of the predetermined total amount is recorded by computer node 204 in the blockchain.

[0123] Typically, the total amount can be quite large, because the total amount can be used to move cryptocurrency funds to their respective recipients over a relatively long period of time while the restricted access cryptocurrency wallet 102 is isolated and stored in a secure location, such as a safe or a restricted location, where the restricted access cryptocurrency wallet 102 is physically inaccessible, i.e., where the user has no physical involvement with the restricted access cryptocurrency wallet 102.

[0124] As shown in 116, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions to move multiple default amounts of cryptocurrency from each temporary account to each receiving account assigned to each recipient. This means that for each temporary account assigned to each recipient, the access-restricted cryptocurrency wallet 102 can generate each of the sets of multiple signed transactions to move a default amount of cryptocurrency from each temporary account to each receiving account.

[0125] Each of the multiple signed transactions generated by the access-restricted cryptocurrency wallet 102 can be configured to move a predetermined portion of the total amount of cryptocurrency initially moved to each temporary account, such that the sum of multiple predetermined portions does not exceed a predetermined total amount. Each signed transaction may include at least the account identifier (ID) of each temporary account, the account ID of each receiving account, a predetermined portion of the cryptocurrency, and the signature of the access-restricted cryptocurrency wallet device 102. One or more signed transactions may further include one or more additional data items, fields, flags, etc., as determined by the cryptocurrency used. The access-restricted cryptocurrency wallet 102 may sign each signed transaction with a private key unique to it, and for example, the hash value of each transaction can be calculated using one or more hash functions, as is known in the art. Thus, the signed transactions are valid cryptocurrency transactions from the temporary accounts to their respective receiving accounts, and since the private key can only be used by the access-restricted cryptocurrency wallet, they cannot be generated and / or copied by any other party.

[0126] The multiple fractional amounts allocated to each temporary account may be determined according to one or more rules, for example, according to a predetermined granularity of fractional amounts, such as one cryptocurrency unit, two cryptocurrency units, three cryptocurrency units, and so on, up to a reasonably large number of cryptocurrency units. Furthermore, as will be described in detail later, multiple predetermined fractional amounts may be valid simultaneously until one or more signed transactions are sent to their respective receiving accounts. However, the sum of the multiple fractional amounts moved from each temporary account to each receiving account cannot exceed the total amount of cryptocurrency held in each temporary account.

[0127] Furthermore, the access-restricted cryptocurrency wallet 102 may generate multiple signed excess transactions to return one or more predetermined amounts of cryptocurrency from one or more temporary accounts to the account associated with the access-restricted cryptocurrency wallet 102. This allows cryptocurrency funds held in one or more temporary accounts, such as excess amounts, surplus amounts, final balances, etc., to be returned to the account of the access-restricted cryptocurrency wallet 102.

[0128] If the access-restricted cryptocurrency wallet 102 optionally creates multiple temporary accounts and each temporary account is assigned to a corresponding receiving account among multiple receiving accounts, the access-restricted cryptocurrency wallet 102 may further generate multiple signed transactions to move a predetermined amount of cryptocurrency from one or more temporary accounts to another or more temporary accounts. This allows the access-restricted cryptocurrency wallet 102 to dynamically move cryptocurrency funds between temporary accounts without having to generate additional signed transactions.

[0129] The transfer of cryptocurrency between virtual accounts may be carried out using one or more methods, techniques and / or embodiments. For example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions to transfer a predetermined amount of cryptocurrency from one or more specific virtual accounts to one or more other virtual accounts.

[0130] For example, suppose there are three temporary accounts, each assigned to a different recipient. The access-restricted cryptocurrency wallet 102 may generate multiple signed transactions to move a predetermined amount of cryptocurrency from the first temporary account to the second and third temporary accounts. The access-restricted cryptocurrency wallet 102 may further generate multiple signed transactions to move a predetermined amount of cryptocurrency from the second temporary account to the first and third temporary accounts, and further generate multiple signed transactions to move a predetermined amount of cryptocurrency from the third temporary account to the first and second temporary accounts. While such point-to-point implementation can increase flexibility, the access-restricted cryptocurrency wallet 102 may generate a very large number of signed transactions.

[0131] In another example, the access-restricted cryptocurrency wallet 102 may apply a technique such as Token Ring, in which the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions to move a predetermined amount of cryptocurrency from a first virtual account to a second virtual account, from the second virtual account to a third virtual account, and then back from the third virtual account to the first virtual account. This Token Ring embodiment can significantly reduce the number of signed transactions generated by the access-restricted cryptocurrency wallet 102, while it may be necessary to move cryptocurrency funds between virtual accounts in real time through multiple transactions. For example, to move a predetermined amount of cryptocurrency from the first virtual account to the third virtual account, one or more signed transactions can be sent to move the cryptocurrency from the first virtual account to the second virtual account, and then one or more further signed transactions can be sent to move the cryptocurrency from the second virtual account to the third virtual account.

[0132] The access-restricted cryptocurrency wallet 102 can reduce the number of signed transactions generated to move cryptocurrency between multiple virtual accounts by setting the fractional amount of these signed transactions to a relatively coarse granularity. While coarser granularity may reduce the flexibility of the amount that can be moved between virtual accounts, since all of these virtual accounts are associated with and owned by the access-restricted cryptocurrency wallet 102, this can be considered a minor restriction compared to the signed transactions generated to move cryptocurrency to one or more receiving accounts, which may require a finer granularity and greater flexibility.

[0133] Optionally, the access-restricted cryptocurrency wallet 102 may generate at least a portion of multiple signed transactions in a stepwise process. For example, before one or more receiving accounts are notified, the access-restricted cryptocurrency wallet 102 may create a signed transaction, set the input and output amounts, and optionally set one or more additional data items, such as fields or flags, as defined by the cryptocurrency service protocol. For example, once a receiving account is provided by user 202, the access-restricted cryptocurrency wallet 102 may complete the generation of the signed transaction by including the receiving account ID, such as a public key, and then sign the signed transaction. Generating signed transactions stepwise without user intervention in the initial step can significantly reduce the time required to complete the generation of signed transactions after the details of one or more receiving accounts have been provided.

[0134] As shown in 118, the access-restricted cryptocurrency wallet 102 can send multiple signed transactions generated for each temporary account to the network-connected device 104. The signed transactions are not recorded on the blockchain, but rather are stored only by the network-connected device 104. Subsequently, when an operation, command and / or request is made to move cryptocurrency funds to one or more receiving accounts, the network-connected device 104 can send one or more signed transactions in real time to perform the cryptocurrency transfer. This will be further explained in detail below.

[0135] The access-restricted cryptocurrency wallet 102 can send multiple signed transactions to the network-connected device 104 via the secure unidirectional transmitter 210.

[0136] As described above, the network-connected device 104 can be used by a single device connected to the network 206. Optionally, the network-connected device 104 may be used by a group of computer nodes, such as computer nodes 204, connected to the network 206. This group of computer nodes may participate in one or more multi-party computing (MPC) sessions, jointly execute process 120, and send one or more signed transactions to move cryptocurrency funds from one or more temporary accounts to one or more receiving accounts. The group of computer nodes 204 may participate in one or more MPC sessions using one or more known MPC algorithms, protocols, and / or techniques, such as Shamir secret sharing. By implementing the network-connected device 104 as a group of computer nodes 204, it is possible to prevent any single device from sending any of the signed transactions independently without the consent of the group, thereby significantly increasing the security and attack resistance of cryptocurrency funds stored in one or more temporary accounts.

[0137] Therefore, if the network-connected device 104 is used by one device, the access-restricted cryptocurrency wallet 102 can send signed transactions to the network-connected device 104, which is one device, either by sending them via a secure channel established with the network-connected device 104 using the network 206, and / or by directly connecting to the network-connected device 104. If the network-connected device 104 is used by a group of computer nodes, the access-restricted cryptocurrency wallet 102 can send signed transactions via a secure unidirectional transmitter 210 connected to the network 206 that connects the group of computer nodes 204.

[0138] From this point forward, the access-restricted cryptocurrency wallet 102 is no longer necessary, and it may be stored in a location with restricted access, such as a safe or a restricted location, to ensure the security of the cryptocurrency funds stored in the access-restricted cryptocurrency wallet 102. Since the access-restricted cryptocurrency wallet 102 is stored in remote isolation, it can be made physically inaccessible, and therefore, the user 202 cannot physically operate and / or interact with it.

[0139] As shown in 122, the process 120 performed by the network-connected device 104 begins by receiving multiple signed transactions generated by the access-restricted cryptocurrency wallet 102 to move cryptocurrency funds, specifically multiple predetermined fractional amounts, into one or more temporary accounts that are assigned to one or more receiving accounts.

[0140] As shown in 124, the network-connected device 104 can send one or more signed transactions to move cryptocurrency funds from one or more temporary accounts to each of one or more receiving accounts associated with each of one or more recipients.

[0141] For example, the network-connected device 104 may send one or more signed transactions in response to instructions received from user 202 associated with an access-restricted cryptocurrency wallet 102 that wants to move cryptocurrency to one or more recipients. In another example, the network-connected device 104 may automatically send one or more signed transactions in response to one or more trigger events, such as a predetermined scheduled time, an action taken by one or more recipients, a transaction detected on the blockchain network, and / or other events.

[0142] The network-connected device 104 may choose to send one or more signed transactions in proportion to one or more fractional amounts of one or more signed transactions selected for a specific amount of cryptocurrency that the network-connected device 104 is requested to move to each receiving account. In particular, the network-connected device 104 may select one or more signed transactions that include a default fractional amount, specifically, a cumulative default fractional amount greater than or equal to the specific amount of cryptocurrency that needs to be moved.

[0143] Referring to Figure 3, this is a schematic diagram of an exemplary sequence of moving cryptocurrency funds from an account associated with an access-restricted cryptocurrency wallet to one or more other accounts without physically engaging with the access-restricted cryptocurrency wallet device, according to some embodiments of the present invention.

[0144] An exemplary sequence 300 shows a sequence in which an access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102, executes a process such as process 110, which pre-generates reserves and means for moving cryptocurrency funds to a specific receiving account 314 in the future without physical access to or operation of the access-restricted cryptocurrency wallet 102. A network-connected device, such as a network-connected device 104, which executes a process such as process 120, can later (in real time) receive instructions from a user, such as user 202, to use the reserves and means generated by the access-restricted cryptocurrency wallet 102 to move cryptocurrency funds to a specific receiving account 314 without requiring physical involvement or operation of the access-restricted cryptocurrency wallet 102.

[0145] As can be seen from sequence 300, first, the access-restricted cryptocurrency wallet 102 can send one or more transactions to move the total amount of cryptocurrency from the original account 310 associated with the access-restricted cryptocurrency wallet 102 to a temporary account 312 assigned to a specific recipient, as shown in steps 112 and 114 of process 110 (320). These transactions can typically be recorded on a blockchain 304 which is managed to govern the cryptocurrency service.

[0146] Subsequently, as shown in steps 116 and 118 of process 110, the access-restricted cryptocurrency wallet 102 can send multiple signed transactions generated to transfer a predetermined portion of the total amount from the temporary account 312 to the receiving account 314 associated with a specific recipient to the network-connected device 104 (322). Specifically, the receiving account 314 can be associated and managed by the cryptocurrency wallet 302 used by the specific recipient.

[0147] As shown in step 124 of process 120, a network-connected device 104, which is normally associated with a user, may later receive instructions, triggers, and / or other operations from, for example, user 202, via a scheduled trigger event, etc., to send one or more of these signed transactions (330) to move the respective fractional amounts determined by the signed transactions from the temporary account 312 to the receiving account 314. One or more of these transactions may be recorded on the blockchain 304. However, in some embodiments of the present invention, for example, when intermediate signed transactions are generated for the payment channel 2-2 multisig temporary account 312, some of the transactions do not need to be recorded on the blockchain 304, and some of the transactions may replace the previously sent intermediate transactions, as detailed above.

[0148] If the temporary account 312 is optionally closed, the network-connected device 104 sends one or more pre-generated signed excess transactions by the access-restricted cryptocurrency wallet 102 to move the excess cryptocurrency remaining in the temporary account 312 to an account associated with the access-restricted cryptocurrency wallet 102, for example, the original account 310 (332).

[0149] It is clear that steps 320 and 322 may be performed in advance by the access-restricted cryptocurrency wallet 102 to generate reserves and means for future transfers of cryptocurrency funds to the receiving account 314. However, steps 330 and 332 may also be performed later, in real time, by a network-connected device 104 configured to use the reserves generated for transferring cryptocurrency to the receiving account 314, without requiring physical access, involvement, and / or operation of the access-restricted cryptocurrency wallet 102, and thus allowing the access-restricted cryptocurrency wallet 102 to be stored in a secure location.

[0150] One or more temporary accounts may be created in accordance with one or more technologies, algorithms, regulations and / or features applicable to (i.e., available and supported) each cryptocurrency service applied by the access-restricted cryptocurrency wallet 102 of System 200. Furthermore, signed transactions may be generated accordingly based on one or more operating parameters, configuration parameters and / or functional parameters, features and / or attributes of the temporary accounts and / or cryptocurrency services used in System 200. Furthermore, signed transactions sent to move cryptocurrency funds from one or more temporary accounts to a receiving account may be selected according to the configuration, settings and / or execution of the signed transactions.

[0151] In a first exemplary embodiment, the access-restricted cryptocurrency wallet 102 may create one or more temporary accounts using payment channels known in the art, particularly 2-2 multisignature accounts (wallets), in which the access-restricted cryptocurrency wallet 102 is one signer and each recipient is the other signer. Each 2-2 multisignature account requires that each transaction created from its respective temporary account for a receiving account associated with each recipient and recorded on the blockchain be signed by both the sender, i.e., the access-restricted cryptocurrency wallet 102, and the recipient, i.e., each recipient.

[0152] Optionally, the access-restricted cryptocurrency wallet 102 configures one or more payment channel 2-2 multi-signature accounts as time-limited accounts, each associated with a predetermined expiration date. This means that after the expiration date, the access-restricted cryptocurrency wallet 102 itself can withdraw the funds remaining in the payment channel of one or more transactions without requiring each recipient to sign the one or more transactions recorded on the blockchain.

[0153] There is also a scenario in which one or more receiving accounts are associated with each recipient's corresponding cryptocurrency wallet that is not configured to support Payment Channel 2-2 multisig accounts. Examples include other wallets that do not have network connectivity, such as stored cold wallets, hot wallets disconnected from the network, or wallets not configured to support multisig, etc. For this reason, the access-restricted cryptocurrency wallet 102 can optionally be configured such that one or more Payment Channel 2-2 multisig temporary accounts are associated with each of the one or more recipients and managed by a different network-connected device used by each. This means that each recipient can use their other network-connected device, such as a computer, laptop, smartphone, tablet, etc., to sign one or more transactions sent to move cryptocurrency from the Payment Channel 2-2 multisig account to the receiving account associated with each recipient.

[0154] The 2-2 multisignature account protocol stipulates that a transaction from an originating account to a receiving account is recorded on the blockchain only if both the sender associated with the originating account and the recipient associated with the receiving account sign the transaction. Therefore, one or more transactions to move cryptocurrency from a 2-2 multisignature account to a receiving account may be sent without being signed by the recipient, who is one of the signers. Consequently, such transactions are not recorded on the blockchain, and no fees are charged that could be allocated to one or more computer nodes (minors) that record transactions on the blockchain.

[0155] This means that one or more intermediate transactions can be sent to move cryptocurrency from a 2-2 multisignature account to a receiving account, thereby replacing one or more previously sent intermediate transactions that are not recorded on the blockchain. This can be done by ensuring that the current intermediate transaction contains the same identification (ID) data as the preceding intermediate transaction. The similar identification data between the current transaction and the preceding previous transaction may differ depending on the cryptocurrency, and may include, for example, the same transaction ID, the same nonce in account-based cryptocurrencies such as Ethereum, or the same one or more input IDs in transaction-based cryptocurrencies such as Bitcoin. Since the preceding previous transaction is replaced by the current (this) transaction, the amount of cryptocurrency moved in the current intermediate transaction is the sum of the amount of cryptocurrency moved in the preceding intermediate transaction plus the amount of cryptocurrency requested to be moved in the current transaction.

[0156] Therefore, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions so as to include multiple signed transactions that cannot coexist, i.e., multiple signed transactions that include the same ID data (e.g., transaction ID, nonce, one or more input IDs, etc.) and progressively increasing amounts of cryptocurrency. Thus, as described below, one or more of these transactions can be sent as intermediate transactions that replace previously sent intermediate transactions containing smaller amounts of cryptocurrency.

[0157] As described above in process 110, after generation, the access-restricted cryptocurrency wallet 102 can send multiple signed transactions to the network-connected device 104.

[0158] To transfer cryptocurrency funds from the Payment Channel 2-2 multi-signature temporary account to each recipient account, the network-connected device 104 may send one or more signed transactions to each recipient, specifically to the cryptocurrency wallet device used by each recipient. The network-connected device 104 may select one or more sent signed transactions depending on one or more parameters, for example, the amount of cryptocurrency to be moved relative to the fractional amounts defined in the multiple signed transactions.

[0159] For example, if a specific payment channel 2-2 multisignature virtual account is requested or instructed to send a specific amount of cryptocurrency to each receiving account, the network-connected device 104 may select one of the signed transactions that includes a fractional amount of cryptocurrency greater than or equal to the specific amount requested to be moved.

[0160] Furthermore, since this is permitted in Payment Channel 2-2 multi-signature accounts, it is possible that the recipient may not have signed a previously sent signed transaction to the receiving account. In such a case, the previously sent signed transaction can be considered an intermediate transaction. In such a case, the network-connected device 104 can select one of the signed transactions to replace the preceding signed transaction that was sent in order to move a second amount of cryptocurrency to the receiving account. Specifically, the network-connected device 104 can select one of the signed transactions that has the same transaction ID as the preceding signed transaction and has a fractional amount that is greater than or equal to the sum of the second amount (the amount sent in the preceding signed transaction) and a specific amount requested to be moved in the current signed transaction.

[0161] 2-2 To withdraw the cryptocurrency stored in the multi-signature temporary account, each recipient simply needs to sign the most recent signed transaction sent by the network-connected device 104 to move the cryptocurrency from each temporary account to each receiving account. Once each recipient signs the most recently sent signed transaction, this signed transaction is recorded on the blockchain.

[0162] If a recipient signs a specific signed transaction, and that specific signed transaction is recorded on the blockchain, and it is necessary to send subsequent signed transactions to move the cryptocurrency to each recipient, the connected cryptocurrency wallet 104 needs to select and send subsequent signed transactions that have a different transaction ID from the one or more transactions that have been signed by each recipient and recorded on the blockchain.

[0163] Furthermore, since one or more of the 2-2 multisig temporary accounts may be associated with an expiration date, if each recipient fails to sign one or more signed transactions sent to their associated receiving account within the expiration date, particularly the most recently sent signed transaction, the cryptocurrency funds held in each 2-2 multisig account may be returned to the account associated with the access-restricted cryptocurrency wallet 102.

[0164] Furthermore, if, accordingly, one or more of the Payment Channel 2-2 multisig temporary accounts are configured by the access-restricted cryptocurrency wallet 102 to support the signing of transactions by another network-connected device, each recipient may use their other network-connected device to sign one or more signed transactions sent by the network-connected device 104 in order to move cryptocurrency from each 2-2 multisig temporary account to the receiving account associated with each recipient.

[0165] Referring to Figure 4, this is a schematic diagram of an exemplary configuration of multiple signed cryptocurrency transactions pre-generated for a payment channel temporary account according to some embodiments of the present invention.

[0166] An exemplary default transaction set 400 created by an access-restricted cryptocurrency wallet, such as access-restricted cryptocurrency wallet 102, for one or more temporary accounts created as 2-2 multisig accounts, may contain N signed transactions created according to a default granularity. Since the 2-2 multisig protocol supports sending one or more intermediate transactions that may not be signed by each recipient and therefore not recorded on the blockchain, access-restricted cryptocurrency wallet 102 can generate a transaction set 400 that contains multiple signed transactions that cannot coexist, for example, multiple signed transactions with the same transaction ID. A network-connected device 104 can therefore send one or more signed transactions that replace previously sent intermediate signed transactions.

[0167] Furthermore, the access-restricted cryptocurrency wallet 102 can generate signed transactions that include progressively increasing fractional amounts of cryptocurrency. For example, fractional amount 2 defined in signed transaction 2 may exceed fractional amount 1 defined in signed transaction 1, fractional amount 3 defined in signed transaction 3 may exceed fractional amount 2 defined in signed transaction 2, and similarly, fractional amount N defined in signed transaction N may exceed fractional amount (N-1) defined in signed transaction (N-1).

[0168] Therefore, the signed transaction sent by the network-connected device 104, which replaces the previously sent intermediate signed transaction, may include the sum of the cryptocurrency contained in the previously sent intermediate signed transaction and the additional amount of cryptocurrency required for the current cryptocurrency transfer to the receiving account.

[0169] In a second exemplary embodiment, the access-restricted cryptocurrency wallet 102 may create one or more temporary accounts as each new standard cryptocurrency account associated with the access-restricted cryptocurrency wallet 102. However, different cryptocurrencies (services, platforms) may be implemented in different ways and therefore may use different operating parameters, configuration parameters and / or functional parameters, features and / or attributes. Thus, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions depending on the cryptocurrency being used.

[0170] For example, some cryptocurrencies, such as Ethereum and Ripple, are built and implemented as account-based cryptocurrency platforms or services. Account-based cryptocurrency transactions are configured to include a nonce indicating the number of previous transactions, the amount of cryptocurrency to be moved, and one or more other parameters, flags, etc. Therefore, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions such that each signed transaction includes a corresponding nonce indicating the number of transactions preceding this signed transaction, and a default fractional amount of cryptocurrency.

[0171] However, since the access-restricted cryptocurrency wallet 102 pre-generates signed transactions, it is unaware of the amount of cryptocurrency sent from each temporary account and the order of the transactions. Therefore, the access-restricted cryptocurrency wallet 102 may not be able to determine which nonce and which fractional amounts should be included in each of the generated signed transactions.

[0172] To support the high flexibility of the cryptocurrencies being sent and their order, the access-restricted cryptocurrency wallet 102 can generate a set of signed transactions for one or more virtual accounts, such that each of the multiple signed transactions includes a corresponding nonce from among multiple valid nonces and a corresponding default portion of the default total amount, as a flat distribution of default total amounts according to a default granularity.

[0173] Referring to Figure 5, this is a schematic diagram of an exemplary configuration of a plurality of pre-generated signed cryptocurrency transactions according to a predetermined uniform distribution, used in an account-based cryptocurrency service according to some embodiments of the present invention.

[0174] An exemplary default uniform distribution 500 created by an access-restricted cryptocurrency wallet, such as access-restricted cryptocurrency wallet 102, for one or more temporary accounts may include a uniform distribution of M signed transactions created according to a default granularity. Since the nonce contained in each signed transaction indicates the number of preceding transactions, the order of the signed transactions is determined according to the transaction nonce, starting from transaction 1 up to transaction M.

[0175] Multiple fractional amounts 1 to N can be defined according to a predetermined granularity, and the sum of these together does not exceed the predetermined total amount of cryptocurrency initially moved to each temporary account by the access-restricted cryptocurrency wallet 102. To support the flexibility of the amount that cryptocurrency fractional amounts can send from each temporary account to each receiving account, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions, each containing multiple subsets of signed transactions, all containing the same nonce, but each containing a predetermined fractional amount. The nonce determines the order of each signed transaction, and each fractional amount determines the amount moved by each signed transaction.

[0176] For example, the access-restricted cryptocurrency wallet 102 may generate multiple first transactions, all of which include a first nonce (nonce 1), each of which includes a fractional amount from 1 to N, such that the first first signed transaction (1,1) includes nonce 1 and fractional amount 1, the second first signed transaction (1,2) includes nonce 1 and fractional amount 2, and so on, up to the Nth first signed transaction (1,N) which includes nonce 1 and fractional amount N. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple second transactions, all of which include a second nonce (nonce 2), each of which includes one of the fractional amounts from 1 to N, such that the first second signed transaction (2,1) includes nonce 2 and fractional amount 1, the second second signed transaction (2,2) includes nonce 2 and fractional amount 2, and so on, up to the Nth second signed transaction (2,N) which includes nonce 2 and fractional amount N. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple M transactions, all of which contain an M nonce (nonce M), each M transaction containing one of the fractional amounts 1 to N, the first M signed transaction (M,1) containing nonce M and fractional amount 1, the second M signed transaction (M,2) containing nonce M and fractional amount 2, and so on, up to the Nth M signed transaction (M,N) containing nonce M and fractional amount N.

[0177] As described above, the access-restricted cryptocurrency wallet 102 can create multiple temporary accounts associated with multiple recipients. In such cases, the access-restricted cryptocurrency wallet 102 generates multiple default uniform distributions, such as a default uniform distribution 500, and each uniform distribution is used for one of the multiple temporary accounts. The access-restricted cryptocurrency wallet 102 can generate different default uniform distributions 500 so as to contain common distributions with similar fractional amounts. On the other hand, the access-restricted cryptocurrency wallet 102 may customize each of the multiple default uniform distributions 500 according to their respective parameters, such as their respective granularity, respective total amounts, the number of different fractional amounts in each, etc. Each parameter can reflect the requirements and / or patterns of cryptocurrency transfers from each temporary account to each receiving account associated with each recipient to which each temporary account is assigned.

[0178] Furthermore, the access-restricted cryptocurrency wallet 102 can extend the default uniform distribution 500 of the default total amount to move each signed transaction to one of several receiving accounts associated with each recipient. For example, the access-restricted cryptocurrency wallet 102 can generate the default uniform distribution 500 as a multidimensional distribution by duplicating each signed transaction (transaction(m,n)(m=1,…,M; n=1,…,N)), and extend each signed transaction to specify one of J receiving accounts. Thus, each signed transaction can take the form of transaction(m,n,j), where j=1,…,J represents each of the J receiving accounts, for example, the address (e.g., public key) of each receiving account. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple, J default uniform distributions 500, each assigned to each of the J receiving accounts.

[0179] Optionally, the access-restricted cryptocurrency wallet 102 generates one or more extended default uniform distributions 500 that include an account associated with the access-restricted cryptocurrency wallet 102 as one of the receiving accounts. This means that the access-restricted cryptocurrency wallet 102 generates one or more extended default uniform distributions 500 that include multiple signed excess transactions that enable the cryptocurrency funds stored in one or more temporary accounts, such as excess amounts, surplus amounts, final balances, etc., to be returned to the account of the access-restricted cryptocurrency wallet 102.

[0180] As described above in process 110, after generation, the access-restricted cryptocurrency wallet 102 can send multiple signed transactions to the network-connected device 104.

[0181] Optionally, the access-restricted cryptocurrency wallet 102 may transmit only partial data describing multiple signed transactions, which is sufficient for the network-connected device 104 to derive all the information about all the signed transactions. For example, suppose a temporary account is created as an account-based cryptocurrency account, and the access-restricted cryptocurrency wallet 102 generates multiple signed transactions according to a default uniform distribution, such as a default uniform distribution 500. In such a case, it is sufficient for the access-restricted cryptocurrency wallet 102 to transmit only very limited information describing the structure of the default uniform distribution 500, which is linked to the signatures of all signed transactions, such as granularity, minimum portion amount, maximum portion amount, etc. The network-connected device 104 can then use the received structure information to reconstruct the default uniform distribution 500 for comparing the multiple signed transactions.

[0182] When required to send a specific amount of cryptocurrency from a specific temporary account to each receiving account, the network connection device 104 can select one of the signed transactions that includes a sufficient partial cryptocurrency amount, that is, a partial amount greater than the specific amount required to be transferred.

[0183] Specifically, the network connection device 104 can select one of the signed transactions according to the number of signed transactions that have already been sent. For example, if the network connection device 104 is instructed to send the first signed transaction for moving cryptocurrency to each receiving account for the first time, the network connection device 104 can select a signed transaction that includes a sufficient cryptocurrency amount from the set of the first signed transactions (1,1) to (1,N).

[0184] Furthermore, when the network connection device 104 sends the selected signed transaction, since the first nonce is used, all other first signed transactions, that is, all transactions including the first nonce (for example, nonce 1), are no longer valid and are thus discarded. In another example, if the network connection device 104 is instructed to send the i-th signed transaction (1 < i < M) for moving cryptocurrency to each receiving account for the first time, the network connection device 104 may select a signed transaction that includes a sufficient cryptocurrency amount from the set of the i-th signed transactions (i,1) to (i,N). Furthermore, when the network connection device 104 sends the selected signed transaction, since the i-th nonce is used, all other i-th signed transactions, that is, all transactions including the i-th nonce (for example, nonce i), are no longer valid and are thus discarded.

[0185] Optionally, the access-restricted cryptocurrency wallet 102 may create multiple virtual accounts in a hierarchical (layered) structure. This means that the access-restricted cryptocurrency wallet 102 may pre-create one or more higher-level virtual accounts and send one or more transactions to move the total amount of cryptocurrency to each of these higher-level virtual accounts. The access-restricted cryptocurrency wallet 102 may further create one or more lower-level virtual accounts. The access-restricted cryptocurrency wallet 102 may further generate multiple signed transactions from one or more higher-level virtual accounts to one or more lower-level virtual accounts. The access-restricted cryptocurrency wallet 102 may then send the signed transactions to the network-connected device 104. In real time (while the access-restricted cryptocurrency wallet 102 is offline and securely stored), the network-connected device 104 can be instructed, requested, and / or operated to send one or more of the signed transactions to move cryptocurrency funds from one or more higher-level virtual accounts to one or more lower-level virtual accounts.

[0186] In particular, the access-restricted cryptocurrency wallet 102 can configure one or more lower-level virtual accounts as limit-of-value virtual accounts, where the total amount that can be moved into those virtual accounts is restricted to a certain limit. For this purpose, the access-restricted cryptocurrency wallet 102 can generate signed transactions used to move cryptocurrency into one or more limit-of-value virtual accounts such that the cumulative amount does not exceed the limit-of-value amount assigned to each limit-of-value virtual account. The access-restricted cryptocurrency wallet 102 can extend its hierarchical structure to multiple levels and generate multiple signed transactions to move cryptocurrency from one or more higher-level virtual accounts to one or more adjacent lower-level virtual accounts.

[0187] By applying a hierarchical structure to the temporary account, it is possible to support a high degree of flexibility in the total amount of cryptocurrency that can be moved to any receiving account and / or combination of receiving accounts.

[0188] Referring to Figure 6, this is a schematic diagram of an exemplary structure of multiple virtual accounts in a hierarchical structure used in an account-based cryptocurrency service according to some embodiments of the present invention. An access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102, can create a hierarchical structure 600 by creating multiple virtual accounts, such as virtual accounts 312, which are arranged hierarchically in multiple layers, for example, a first layer (LAYER1) and a second layer (LAYER1).

[0189] The access-restricted cryptocurrency wallet 102 can send one or more transactions (TRANS in the diagram) 610 to move the initial total amount of cryptocurrency from an original account such as the original account 310 associated with the access-restricted cryptocurrency wallet 102 to one or more first-tier (higher-level) temporary accounts 312_1. For example, the access-restricted cryptocurrency wallet 102 can send one or more transactions 610A to move the first initial total amount of cryptocurrency to a temporary account 312_1A at a predetermined level, and one or more transactions 610B to move the second initial total amount of cryptocurrency to a temporary account 312_1B at a predetermined level. The first initial amount and the second initial amount may be equal or different.

[0190] The access-restricted cryptocurrency wallet 102 can then generate multiple signed transactions (SIGNED TRANS) 620_1 to move a portion of the total amount of cryptocurrency from one or more first-layer temporary accounts 312_1 to one or more second-layer (lower) temporary accounts 312_2. For example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_1A to move a portion of the first total amount from the first-layer temporary account 312_1A to the first second-layer temporary account 312_2A, and multiple signed transactions 620_1B to move a portion of the first total amount from the first-layer temporary account 312_1A to the second-layer temporary account 312_2B. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_1C to move a portion of the second total amount from the first tier temporary account 312_1B to the third tier second temporary account 312_2C, multiple signed transactions 620_1D to move a portion of the second total amount from the first tier temporary account 312_1B to the fourth tier second temporary account 312_2D, and multiple signed transactions 620_1E to move a portion of the second total amount from the first tier temporary account 312_1B to the fifth tier second temporary account 312_2E.

[0191] Furthermore, the cumulative amount of cryptocurrency contained in multiple signed transactions 620_1 for moving the cryptocurrency portion to each of the second-level temporary accounts 312_2 may be limited to a specific default amount. Thus, the total amount of cryptocurrency stored in each second-level temporary account 312_2 will not exceed the respective default amount set for each of these second-level temporary accounts 312_2. For example, the cumulative amount of the portions of multiple signed transactions 620_1A may be limited by a first default amount set for the second-level temporary account 312_2A. In another example, the cumulative amount of the portions of multiple signed transactions 620_1D may be limited by a second default amount set for the second-level temporary account 312_2D.

[0192] The access-restricted cryptocurrency wallet 102 can further generate multiple signed transactions 620_2 to move a portion of the cryptocurrency from each of the second-tier temporary accounts 312_2 to each receiving account, such as receiving account 314. For example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_2A to move a portion of the cryptocurrency stored in the second-tier temporary account 312_2A to the first receiving account 314A. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_2B to move a portion of the cryptocurrency stored in the second-tier temporary account 312_2B to the second receiving account 314B. In yet another example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_2C to move a portion of the cryptocurrency stored in the second-tier temporary account 312_2C to the third receiving account 314C. In another example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_2D to move a portion of the amount of cryptocurrency stored in the second-tier temporary account 312_2D to the fourth receiving account 314B. In yet another example, the access-restricted cryptocurrency wallet 102 may generate multiple signed transactions 620_2E to move a portion of the amount of cryptocurrency stored in the second-tier temporary account 312_2E to the fifth receiving account 314E.

[0193] The access-restricted cryptocurrency wallet 102 can send multiple signed transactions 620_1 and 620_2 to the network-connected device 104.

[0194] In real time, the network-connected device 104 can be requested, instructed, and / or operated to move cryptocurrency to one or more receiving accounts 314, while the access-restricted cryptocurrency wallet 102 is no longer accessible, for example, while it is stored in a secure location. The network-connected device 104 can therefore send one or more signed 620_2s to move cryptocurrency from each second-tier temporary account 312_2 to each receiving account 314. However, to ensure that the cryptocurrency is present in the second-tier temporary account 312_2B to be moved to the receiving account 314, the network-connected device 104 can first send one or more signed 620_1s to move cryptocurrency from each first-tier temporary account 312_1 to the second-tier temporary account 312_2. For example, suppose the network-connected device 104 is instructed to move a specific amount of cryptocurrency to receiving account 314B. The network-connected device 104 can first move cryptocurrency from the first-tier temporary account 312_1A to the second-tier temporary account 312_2B by sending one or more signed transactions 620_1B that cumulatively contain a portion of the cryptocurrency exceeding a certain amount. The network-connected device 104 can then move cryptocurrency from the second-tier temporary account 312_2B to the receiving account 314B by sending one or more signed transactions 620_2B that cumulatively contain a portion of the cryptocurrency exceeding a certain amount.

[0195] Optionally, the access-restricted cryptocurrency wallet 102 may pre-create multiple virtual accounts in a value-oriented hierarchical structure. This means that the access-restricted cryptocurrency wallet 102 may pre-create virtual accounts such that each level of the structure contains a corresponding virtual account managed to move a corresponding amount of cryptocurrency into multiple receiving accounts associated with multiple recipients. Specifically, the corresponding amount of cryptocurrency allocated to each virtual account is a portion (e.g., a fraction) of the amount allocated to an adjacent, higher-level virtual account.

[0196] For example, suppose an access-restricted cryptocurrency wallet 102 creates a hierarchically structured set of temporary accounts such that each temporary account is configured and set up to move half the amount of cryptocurrency allocated to an adjacent higher-level temporary account. In such a case, the access-restricted cryptocurrency wallet 102 can create a first-level (top-level) temporary account to move a specific amount of cryptocurrency to a receiving account. The access-restricted cryptocurrency wallet 102 can further create a second-level temporary account to move half of a specific amount to a receiving account. The access-restricted cryptocurrency wallet 102 can further create a third-level temporary account to move half of the amount in the second-level temporary account, i.e., a quarter of a specific amount, to a receiving account, and so on, down to a lowest-level temporary account configured to move a minimum amount of cryptocurrency, determined according to a predetermined granularity, to a receiving account.

[0197] After creating multiple hierarchically structured temporary accounts, the access-restricted cryptocurrency wallet 102 can send one or more transactions to move the initial total amount of cryptocurrency from one or more accounts (original accounts) associated with the access-restricted cryptocurrency wallet 102 to each of the temporary accounts. For example, the access-restricted cryptocurrency wallet 102 can move a specific total amount to the first-level temporary account, half of that amount to the second-level temporary account, a quarter of that amount to the third-level temporary account, and so on.

[0198] The access-restricted cryptocurrency wallet 102 can then generate multiple signed transactions to move amounts of cryptocurrency from a hierarchically structured virtual account to multiple receiving accounts. Specifically, the access-restricted cryptocurrency wallet 102 can generate access-signed transactions to move amounts of cryptocurrency from an adjacent, lower-level virtual account that exceed the amount of cryptocurrency allocated to that account, and are less than or equal to the amount allocated to each virtual account. The access-restricted cryptocurrency wallet 102 can construct signed transactions to move such amounts within a predetermined range.

[0199] For example, suppose an access-restricted cryptocurrency wallet 102 allocates half of the cryptocurrency allocated to an adjacent, higher-level virtual account to each virtual account. The access-restricted cryptocurrency wallet 102 can therefore generate signed transactions to move multiple amounts from a first-level virtual account to multiple receiving accounts, within the range of exceeding half of a specific amount and being less than (or less than) a specific amount. However, since these amounts exceed half of a specific amount, the amount of cryptocurrency allocated to the first-level virtual account is sufficient if there is only one such transaction. If there are K receiving accounts, the access-restricted cryptocurrency wallet 102 can generate a total of M*K / 2 signed transactions to move M / 2 amounts of cryptocurrency (i.e., amounts within the range of a specific amount to half of a specific amount) to the K receiving accounts. The access-restricted cryptocurrency wallet 102 can further generate signed transactions to move multiple amounts from a second-level virtual account to multiple receiving accounts, within the range of exceeding one-quarter of a specific amount and being less than (or less than) half of a specific amount. However, since these amounts exceed one-quarter of the specified amount, the amount of cryptocurrency allocated to the second-level temporary account is sufficient if there are only three such transactions. The access-restricted cryptocurrency wallet 102 can therefore generate a total of 3*M*K / 4 signed transactions to move M / 4 units of cryptocurrency (i.e., amounts ranging from half to one-quarter of the specified amount) to K receiving accounts. The access-restricted cryptocurrency wallet 102 can further generate signed transactions to move multiple amounts from the third-level temporary account to multiple receiving accounts that are in the range of exceeding one-eighth of the specified amount and less than (or less than) one-quarter of the specified amount. However, since these amounts exceed one-eighth of the specified amount, the amount of cryptocurrency allocated to the third-level temporary account is sufficient if there are only seven such transactions.The access-restricted cryptocurrency wallet 102 can therefore generate a total of 7*M*K / 8 signed transactions to move M / 8 amounts of cryptocurrency (i.e., amounts ranging from one-quarter to one-eighth of a given amount) to K receiving accounts. The access-restricted cryptocurrency wallet 102 can sequentially generate further signed transactions to be used for further lower-level temporary accounts created in a hierarchical structure, depending on these lower-level temporary accounts. Generalizing the above, for each temporary account at level i, the access-restricted cryptocurrency wallet 102 can generate M / 2. i The amount of cryptocurrency can be allocated. Access-restricted cryptocurrency wallet 102 further allows M / 2 i+1 Exceeding M / 2 i Signed transactions can be generated to move multiple amounts within the range of less than (or less than) a certain amount from an i-level temporary account to multiple receiving accounts. Following the same logic as described for higher-level temporary accounts, the access-restricted cryptocurrency wallet 102 can move 2 of the cryptocurrency to K receiving accounts. i+1 Total number of units to move each unit (2 i+1 )*M*K / (2 i+1 It can generate ) signed transactions.

[0200] By applying a hierarchically structured set of temporary accounts, the number of signed transactions that the access-restricted cryptocurrency wallet 102 needs to generate and send to the network-connected device 104 can be significantly reduced. This is because the signed transactions used for each level of temporary account need to be generated for an amount of cryptocurrency limited to the range applicable to that level. In the above example, where the amount allocated to each level of temporary account is half the amount allocated to the adjacent higher-level temporary account, the total number of signed transactions generated by the access-restricted cryptocurrency wallet 102 may be less than M*K*log(M). Dividing the amount allocated to each level of temporary account by half the amount allocated to the adjacent higher-level temporary account is illustrative, and other division schemes, such as 1 / 2, 1 / 3, 1 / 4, 1 / 5, 1 / 6, etc., may be applied and should not be interpreted as imposing limitations.

[0201] In another example, some cryptocurrencies, such as Bitcoin and Bitcoin Cash, are built and implemented as transaction (UTXO)-based cryptocurrency platforms and services. A transaction in a transaction-based cryptocurrency includes, in its parameters, one or more output amounts of cryptocurrency derived from one or more input amounts of the cryptocurrency included in the transaction, which can be traced back to one or more output amounts of one or more previous transactions. Thus, each input amount may include the ID of each previous transaction that contains the output amount corresponding to that input amount. The transaction ID is determined by the cryptocurrency service being used and usually includes the hash value of each transaction, etc. However, other embodiments may be applied depending on one or more protocols, one or more algorithms and / or provisions of the cryptocurrency service.

[0202] Since each transaction directly depends on one or more preceding transactions, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions in such a way that it maintains a valid trail and trace of the input amounts to the source preceding signed transactions. In particular, the access-restricted cryptocurrency wallet 102 can generate multiple signed transactions in such a way that each signed transaction is derived from a signed transaction in a higher layer and contains a transaction ID (TXID), forming a hierarchical directed acyclic graph (DAG), such as a tree structure or a directed graph. Specifically, each input amount of each signed transaction is related to the TXID of each output amount of each signed transaction in each higher layer. The access-restricted cryptocurrency wallet 102 can construct a hierarchical DAG to distribute a predetermined total amount according to a predetermined granularity.

[0203] Referring to Figures 7A and 7B, these are schematic diagrams of exemplary hierarchical tree configurations of multiple signed cryptocurrency transactions that are pre-generated according to a default tree distribution used in a transaction-based cryptocurrency service according to some embodiments of the present invention.

[0204] As shown in Figure 7A, an exemplary default tree structure 700 created by an access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102 used for one or more temporary accounts, may include a hierarchical distribution of signed split transactions 702 generated to move a default portion of the cryptocurrency back to an account associated with the access-restricted cryptocurrency wallet 102, for example, an original account 310 that initially moved the cryptocurrency to the temporary account. The default portion can be set according to a default granularity, for example, each signed split transaction may contain half the amount of cryptocurrency in the signed split transaction of the layer directly above it (parent).

[0205] In such an exemplary configuration, where each signed split transaction is split into two equivalent parts, each signed split transaction may include an input amount derived from the output amount of an adjacent higher-level signed split transaction. Each signed split transaction may further include at least two output amounts of the same cryptocurrency amount, these two output amounts directed to an account associated with the access-restricted cryptocurrency wallet 102, for example, the original account 310 that initially moved the cryptocurrency to the temporary account.

[0206] The edges connecting the vertices (nodes) of the default tree structure 700 can represent signed partitioned transaction outputs, and the vertices may represent partition points, which are root points used to derive signed transactions, as will be described in detail later.

[0207] For example, suppose the default total amount of cryptocurrency initially moved to each temporary account by the access-restricted cryptocurrency wallet 102 is 16 million units of cryptocurrency, i.e., a transaction (TRANS in the diagram) 702A of 16 million units. In this case, the access-restricted cryptocurrency wallet 102 can generate two second-tier signed split transactions 702B1 and 702B2, each containing half of the 16 million units, i.e., 8 million units, that are directed to the account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can further generate four third-tier signed split transactions 702C1, 702C2, 702C3 and 704C4, each containing half of the 8 million units, i.e., 4 million units, that are directed to the account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can further generate eight fourth-tier signed split transactions 702D1, 702D2, 702D3, 702D4, 702D5, 702D6, 702D7, and 704D8, each containing half of 4M units, i.e., 2M units, which are directed to the account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can further generate 16 fifth-tier signed split transactions 702E1, 702E2, 702E3, 702E4, 702E5, 702E6, 702E7, 702E8, 702E9, 702E10, 702E11, 702E12, 702E13, 702E14, 702E15, and 704E16, each containing half of 2M units, i.e., 1M units, which are directed to the account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can repeat this convergence down to a predetermined minimum fractional amount, for example, 1 unit of cryptocurrency. As described herein, the input amount contained in each signed split transaction is derived from the corresponding output amount contained in each signed split transaction in the higher layer.

[0208] As shown in Figure 7B, which represents segment 704 of the default tree structure 700, the access-restricted cryptocurrency wallet 102 can then generate multiple signed transactions 710, each containing a portion of the funds to move cryptocurrency funds from a temporary account to each receiving account. Because the default tree structure 700 is complex, only segment 704 will be described below for brevity and clarity. However, the same configuration and examples apply to the entire default tree structure 700.

[0209] The access-restricted cryptocurrency wallet 102 can generate multiple signed transactions 710 for each signed split transaction 702. The multiple signed transactions generated for each split transaction 702 are visually represented in a default tree structure 700 as edges extending from each split point vertex (node), with the edges of each parent signed split transaction connected to the split point vertex. The number N of signed transactions 710 generated for each signed split transaction 702 may be equal for at least some of the signed split transactions 702, or it may be a unique number for one or more of the signed split transactions 702. For example, the access-restricted cryptocurrency wallet 102 may generate N1 signed transactions 710B for signed split transaction 702B1, N2 signed transactions 710C for signed split transaction 702C1, N3 signed transactions 710D for signed split transaction 702D1, and N4 signed transactions 710E for signed split transaction 702E1.

[0210] Each signed transaction 710 may include an input amount and two output amounts, the first of which is directed to move a specific portion to a receiving account, and the second amount being the excess (difference) between the input amount and the first output amount, which is directed to move the excess back to an account associated with the access-restricted cryptocurrency wallet 102.

[0211] The input ID (TXID) of each input in each signed transaction 710 is derived from its parent signed split transaction 702. For example, the input amounts for signed transactions 710B1 to 710B (N1) are derived from the output amounts of signed split transaction 702B1. In another example, the input amounts for signed transactions 710C1 to 710C (N2) are derived from the output amounts of signed split transaction 702C1. In yet another example, the input amounts for signed transactions 710D1 to 710D (N3) are derived from the output amounts of signed split transaction 702D1. In yet another example, the input amounts for signed transactions 710E1 to 710E (N4) are derived from the output amounts of signed split transaction 702E1.

[0212] The access-restricted cryptocurrency wallet 102 can move each of the fractional amounts to a receiving account and configure each signed transaction such that the fractional amount is determined according to a predetermined granularity, specifically for each set of signed transactions derived from each signed split transaction. The range of fractional amounts generated by the access-restricted cryptocurrency wallet 102 for each layer of the default tree structure 700 can start from the amount of each signed split transaction and end with the amount of the signed split transaction of the adjacent lower layer. For example, each fractional amount may be set to the first output of each signed transaction 710B1~710B(N1), for example, from 8,000,000 units, 7,999,999 units, 7,999,998 units, etc., up to 4,000,001 units. Complementarily, the second amount of each signed transaction 710B1 to 710B(N1) may include the difference between the input amount and the first output amount, specifically ranging from zero units (no second amount), 1 unit, 2 units, etc., up to 3,999,999 units. In another example, assuming a tier, the first output of each signed transaction 710E1 to 710E(N4) may be set for each partial amount, for example ranging from 1,000,000 units, 999,999 units, 999,998 units, etc., up to 500,001 units. Complementarily, the second amount of each signed transaction 710B1 to 710B(N1) may include the difference between the input amount and the first output amount, specifically ranging from zero units (no second amount), 1 unit, 2 units, etc., up to 499,999 units. However, the range of fractional amounts generated by the access-restricted cryptocurrency wallet 102 for the lowest layer (bottom layer) of the default tree structure 700 can be set to start with the amount of the bottom-level signed split transaction and end with the minimum amount defined for each transfer to a receiving account. For example, suppose the bottom layer has multiple signed split transactions of 100 units each, and the minimum fractional amount defined for each transfer to a receiving account is 1 unit.In such cases, the first output of each signed transaction derived from each lowest-level signed split transaction may be set for each portion amount, for example, from 100 units, 99 units, 98 units, etc., down to 1 unit. Complementarily, the second amount of each signed transaction derived from each lowest-level signed split transaction may include the difference between the input amount and the first output amount, specifically from zero units (no second amount), 1 unit, 2 units, etc., up to 99 units.

[0213] For the sake of brevity, the explanation of the default tree structure 700 does not address the fees that need to be distributed among the computer nodes 204 as a reward for recording each transaction on the blockchain. Fees will be discussed in more detail later.

[0214] As described above in process 110, after generation, the access-restricted cryptocurrency wallet 102 can send multiple signed split transactions and multiple signed transactions to the network-connected device 104. As mentioned above, the signed split transactions and signed transactions are not recorded on the blockchain, but rather stored by the network-connected device 104.

[0215] When requested to send a specific amount of cryptocurrency from a particular temporary account to each receiving account, the network-connected device 104 can select at least one segment of a hierarchical DAG that contains one or more signed transactions, each containing a default fraction, specifically a cumulative fraction that is the sum of one or more fractions greater than or equal to a specific amount. The network-connected device 104 can then send one or more signed transactions contained in the selected segment, marking each signed transaction in the segment that will not be sent as unavailable. The network-connected device 104 can select a segment of the DAG to contain signed transactions that cumulatively contain the minimum amount of cryptocurrency greater than or equal to a specific amount that needs to be moved from the particular temporary account to each receiving account. In other words, the network-connected device 104 can select one or more signed transactions such that the sum of the default fractions of these signed transactions is the minimum amount greater than or equal to a specific amount. However, in order for one or more selected signed transactions to become valid, that is, in order for one or more selected signed transactions to include an input amount that can be traced back to previous transactions, the network-connected device 104 can first send all signed split transactions that lead to (i.e., are in the path to) the selected segment of the signed transaction selected for sending, in order to move a specific amount of cryptocurrency to each receiving account.

[0216] Referring to Figures 8A and 8B, these are schematic diagrams illustrating exemplary uses of an exemplary hierarchical tree structure used to transfer cryptocurrency funds to a receiving account, according to some embodiments of the present invention.

[0217] An exemplary default tree structure, such as a tree structure 700, created by an access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102 used for a specific temporary account created for a transaction-based cryptocurrency, can be used by a network-connected device, such as a network-connected device 104, to send signed transactions to move cryptocurrency funds to their respective receiving accounts.

[0218] When instructed to move a specific amount of cryptocurrency to each receiving account, the network-connected device 104 can select a segment of the tree structure 700 that contains one or more signed transactions, including a cumulative amount (total) of fractional amounts that are greater than or equal to the specified amount.

[0219] For example, suppose network-connected device 104 is instructed to move 1,999,998 units of cryptocurrency from a specific temporary account to each receiving account. In such a case, network-connected device 104 can select segment 802 containing signed transaction 710D3, which includes a first output of 1,999,998 units for each receiving account and a second output of 2 units to be returned to the account associated with the access-restricted cryptocurrency wallet 102. To send signed transaction 710D3, network-connected device 104 can first send signed split transactions on the path leading to signed transaction 710D3, specifically signed split transactions (TRANS in the diagram) 702B1, 702C1, and 702D1, thereby recording signed split transactions 702B1, 702C1, and 702D1 on the blockchain. After the aforementioned signed split transaction is sent and recorded on the blockchain, the network-connected device 104 can send the selected signed transaction 710D3, which can trace back to the previous transaction, specifically to the signed split transaction 702D1, which can then trace back to the signed split transaction 702C1, which can then trace back to the signed split transaction 702B1, which can then trace back to the 16M unit transaction initially sent by the access-restricted cryptocurrency wallet 102 to the temporary account.

[0220] The network-connected device 104 can further mark all other signed transactions in the branch 810 containing the selected segment 802, specifically, signed transactions in the hierarchy contained in segments lower than the selected transaction, as unavailable.

[0221] In another example, let us further assume that the network-connected device 104 has been instructed to move another 1,500,000 units of cryptocurrency from a specific temporary account to each recipient account. Due to the previous move in which signed transaction 710D3 was sent, the cryptocurrency contained in signed transaction 710 has already been moved in signed transaction 710D3, so the entire branch 810 is no longer available. In such a case, the network-connected device 104 can select segment 804 containing signed transaction 710DM_2, which has a first output of 1,500,000 units for each recipient account and a second output of 500,000 units to be returned to the account associated with the access-restricted cryptocurrency wallet 102. In order to send signed transaction 710DM_2, the network-connected device 104 can first send a signed split transaction on the path leading to signed transaction 710DM_2. However, since the signed split transactions 702B1, 702C1, and 702D1 (which are complementary transactions to 702D2, meaning that 702D2 has also been sent) have already been sent to enable the sending of the previous signed transaction 710D3, the network-connected device 104 will not send any additional transactions except for 710DM_2. The network-connected device 104 can then send the selected signed transaction 710DM_2, which can trace back to the previous transaction, specifically to the signed split transaction 702D2, which can then trace back to the signed split transaction 702C1, which can then trace back to the signed split transaction 702B1, which can then trace back to the 16M unit transaction initially sent by the access-restricted cryptocurrency wallet 102 to the temporary account.

[0222] As explained in the example above, the network-connected device 104 can further mark all other signed transactions in the branch containing the selected segment, specifically, signed transactions in the hierarchy contained in segments lower than the selected transaction, as unavailable.

[0223] The cryptocurrency wallet used by each of the one or more recipients is, for example, a network-connected device such as network-connected device 104 used by each recipient as a hot wallet. In such a case, each recipient's network-connected cryptocurrency hot wallet can monitor the blockchain network 206 and identify one or more signed transactions sent by network-connected device 104 to move a portion of the amount to the receiving account associated with each recipient.

[0224] However, the cryptocurrency wallet used by each of the one or more recipients may be another access-restricted cryptocurrency wallet, such as an access-restricted cryptocurrency wallet 102 that does not have network receiving connectivity and is used by each recipient as a cold wallet. In such a case, if the cryptocurrency service used in system 200 is a transaction-based cryptocurrency, and furthermore, a SegWit-based cryptocurrency, it may be necessary to notify the other access-restricted cryptocurrency wallet of the amount of cryptocurrency to be moved to the receiving account associated with that other access-restricted cryptocurrency wallet. In such a case, one or more strings of a limited length can be inserted into the other access-restricted cryptocurrency wallet 102 via a capacity-restricted input interface, such as a capacity-restricted input interface 216 of the other access-restricted cryptocurrency wallet 102. The strings of a limited length may include a very small number (e.g., fewer than 10) of symbols (e.g., codes, digits, etc.) that can be easily inserted via the capacity-restricted input interface 216 of the access-restricted cryptocurrency wallet 102 and can be typed by user 202 using the keyboard of the access-restricted cryptocurrency wallet 102. Furthermore, in SegWit-based cryptocurrencies, a signature is not required to calculate a transaction hash. Therefore, one or more strings of a limited length can contain a predetermined description, for example, the hash value of the first signed transaction among multiple signed transactions sent to a receiving account (associated with) another access-restricted cryptocurrency wallet, the structure of a hierarchical DAG, or the index of one or more last signed transactions among multiple signed transactions sent to a receiving account (associated with) another access-restricted cryptocurrency wallet. The other access-restricted cryptocurrency wallet can parse the inserted one or more strings of a limited length to determine the structure of the hierarchical DAG, and thus derive the amount of cryptocurrency to be moved from a temporary account to a receiving account associated with this access-restricted cryptocurrency wallet.

[0225] The access-restricted cryptocurrency wallet 102 may close one or more of its temporary accounts if one or more conditions are imposed, such as after a predetermined period of time when it is no longer necessary to move the cryptocurrency funds to their respective recipients and therefore the temporary accounts are no longer needed. The access-restricted cryptocurrency wallet 102 may apply one or more methods and / or techniques to close one or more of its temporary accounts.

[0226] For example, if a specific temporary account to be assigned to a specific recipient is created as a Payment Channel 2-2 multi-signature account, the access-restricted cryptocurrency wallet 102 may, as known in the art, send a command to the network-connected device 104 to close the Payment Channel 2-2 multi-signature account in cooperation with the specific recipient.

[0227] In another example applicable to account-based cryptocurrencies that support account closure, such as Ripple, the access-restricted cryptocurrency wallet 102 may send a command to close the temporary account. Optionally, the access-restricted cryptocurrency wallet 102 may send a command to the network-connected device 104 to close the temporary account.

[0228] In another example applicable to account-based cryptocurrencies that do not support explicit account closure, such as Ethereum, an access-restricted cryptocurrency wallet 102 may send one or more (closed) transactions to an account associated with the access-restricted cryptocurrency wallet 102 and recorded on the blockchain. Specifically, the access-restricted cryptocurrency wallet 102 may send one or more closed transactions that include one or more nonces used by one or more signed transactions sent to the network-connected device 104, in particular, one or more nonces of unused signed transactions. Furthermore, one or more closed transactions may include a cryptocurrency amount of zero. Thus, one or more closed transactions utilize one or more nonces of one or more unused signed transactions, so that one or more nonces become unusable, and one or more unused signed transactions also become unusable.

[0229] For some reason, such as the fact that one or more valid signed transactions have never been sent and therefore have never been recorded on the blockchain, the temporary account may contain an excess and / or surplus of cryptocurrency. In such cases, the excess cryptocurrency remaining in the temporary account can be moved back to the account associated with the access-restricted cryptocurrency wallet 102 using one or more methods and / or technologies.

[0230] In one exemplary method, if the access-restricted cryptocurrency wallet 102 has pre-generated multiple signed excess transactions, the network-connected device 104 can send one or more of these signed excess transactions, each containing a portion of the excess cryptocurrency remaining in the temporary account that is cumulatively equal to the amount of excess cryptocurrency left in the temporary account. This technique can be easily applied when the temporary account is created as a new cryptocurrency account. However, if the temporary account is created as a payment channel 2-2 multi-signature account, the network-connected device 104 can, in cooperation with each recipient, sign one or more excess transactions to move the excess cryptocurrency from the temporary account to the account associated with the access-restricted cryptocurrency wallet 102. If the recipient hesitates to sign such excess transactions and the payment channel 2-2 multi-signature account has an expiration date, the excess cryptocurrency can be returned to the account associated with the access-restricted cryptocurrency wallet 102 upon expiration.

[0231] In another example, if a temporary account is created as a new account for an account-based cryptocurrency, the amount of excess cryptocurrency may be reported (notified) to the access-restricted cryptocurrency wallet 102 by inserting the nonce of the most recently sent signed transaction as one or more strings of limited length, for example, inserted via the capacity-restricted input interface 216. The access-restricted cryptocurrency wallet 102 can derive the amount of excess cryptocurrency remaining in the temporary account based on the nonce of the most recently sent signed transaction, and may record on the blockchain and send one or more transactions including the excess cryptocurrency amount to the account associated with the access-restricted cryptocurrency wallet 102.

[0232] In another example, if a temporary account is created as a new account for transaction-based (UTXO) cryptocurrency, the excess cryptocurrency may include all unusable and unused signed transactions identified in the hierarchical DAG structure. The amount of excess cryptocurrency may be reported (notified) to the access-restricted cryptocurrency wallet 102 by inserting, for example, one or more strings of limited length inserted via the capacity-restricted input interface 216, which is used to insert the index (transaction ID) of the unusable or unused signed transactions. The access-restricted cryptocurrency wallet 102 may derive the amount of excess cryptocurrency remaining in the temporary account based on the transaction ID of the most recently sent signed transaction, and may record on the blockchain and send one or more transactions including the excess cryptocurrency amount to the account associated with the access-restricted cryptocurrency wallet 102.

[0233] If the hierarchical DAG structure is divided into many segments due to the sending of a large number of different signed transactions, leaving "holes" in the hierarchical DAG structure, the access-restricted cryptocurrency wallet 102 may be instructed to reconstruct the hierarchical DAG structure. Specifically, the access-restricted cryptocurrency wallet 102 may be instructed to reconstruct the hierarchical DAG structure using the amount of excess cryptocurrency reported to and returned to the access-restricted cryptocurrency wallet 102 via the capacity-restricted input interface 216.

[0234] According to some cryptocurrency blockchain protocols, one or more transactions sent within a blockchain network may include a fee that is distributed to one or more computer nodes 204 as a reward for recording each transaction on the blockchain. However, the amount of the fee may not be fixed, and therefore, the access-restricted cryptocurrency wallet 102 may face the difficulty of having to generate signed transactions without knowing the actual amount of the fee that will apply when the signed transaction actually needs to be sent and recorded on the blockchain in the future.

[0235] To address this restriction, the access-restricted cryptocurrency wallet 102 may apply one or more methods and / or techniques.

[0236] In some cryptocurrencies, the fee for recording each transaction on the blockchain may be allocated within the transaction itself. For example, in transaction-based cryptocurrencies, the fee can typically be represented as the difference between one or more inputs and one or more outputs of the transaction.

[0237] In some exemplary embodiments, the access-restricted cryptocurrency wallet 102 can predict and / or estimate multiple fee amounts that will be applied when signed transactions are actually sent in the future. The access-restricted cryptocurrency wallet 102 can extend each of the multiple signed transactions into a set of signed transactions, where each estimated amount of cryptocurrency is allocated to the fee for each signed transaction in the set. This means that the access-restricted cryptocurrency wallet 102 can generate multiple sets of signed transactions for each of the multiple estimated fee amounts, rather than generating only one signed transaction for each of the multiple predetermined fractions of cryptocurrency to be moved to each receiving account.

[0238] When selecting one or more signed transactions to be sent to transfer the required amount of cryptocurrency to a receiving account, the network-connected device 104 can identify a set of signed transactions that include a portion amount greater than or equal to the amount that needs to be moved, and can select one of the signed transactions in the set according to the fee amount. Specifically, the network-connected device 104 can select signed transactions that include a sufficient fee amount, i.e., a fee greater than or equal to the fee (charge) currently being collected by the computer node 204 to record the transaction on the blockchain.

[0239] In another exemplary embodiment, the access-restricted cryptocurrency wallet 102 can generate one or more dedicated fee distribution transactions for moving fees to a cryptocurrency account associated with the network-connected device 104, and can send one or more fee distribution transactions to the network-connected device 104. One or more fee distribution transactions may include cryptocurrency that can be used by the network-connected device 104 to distribute (pay) fees to one or more computer nodes 204 (minors) that record signed transactions on the blockchain. After sending one or more signed transactions for moving cryptocurrency funds from a temporary account to a receiving account, the network-connected device 104 can, in real time, further send another transaction for moving fees from the cryptocurrency account associated with the network-connected device 104 to a cryptocurrency account associated with a minor computer node 204. In particular, since fee transactions also need to be recorded on the blockchain, a fee transaction sent to move cryptocurrency from the cryptocurrency account associated with the network-connected device 104 to a cryptocurrency account associated with a minor computer node 204 includes fees that record both one or more signed transactions and fee transactions on the blockchain, respectively. This technology can be used with smart miner miner computer nodes 204, which are configured to record one or more first transactions on the blockchain without receiving a fee, and then receive a fee through a second transaction that may include fees for both the first and second transactions. Naturally, network-connected devices 104 can communicate with one or more smart miner computer nodes 204 to notify them that a fee for recording one or more signed transactions on the blockchain will be included in a later transaction.

[0240] In another exemplary embodiment, the access-restricted cryptocurrency wallet 102 may establish an arrangement with one or more partner computer nodes 204 among a plurality of computer nodes 204. In this arrangement, one or more of the partner computer nodes 204 may record each of a plurality of signed transactions sent by the network-connected device 104 to move cryptocurrency from one or more temporary accounts to one or more receiving accounts. The arrangement may further specify a fee to be paid to one or more partner computer nodes 204 periodically or in advance.

[0241] Optionally, the access-restricted cryptocurrency wallet 102 may encrypt the signatures of multiple signed transactions using one or more pieces of secret information, such as a secret value, secret string, secret number, etc. This means that all signed transactions sent from the access-restricted cryptocurrency wallet 102 to the network-connected device 104 will include encrypted signatures.

[0242] Since a signed transaction containing an encrypted signature is not a valid cryptocurrency transaction, the network-connected device 104 must first decrypt the signature of each of the signed transactions before sending one or more signed transactions. Therefore, in order to send one or more signed transactions, the network-connected device 104 must obtain one or more pieces of confidential information that are securely protected or stored and can be provided to the network-connected device 104 under the strict control of user 202, thus adding an additional level of security and safety to the cryptocurrency transaction.

[0243] The access-restricted cryptocurrency wallet 102 can use one or more methods to generate one or more secret pieces of information used to encrypt the signature of a signed transaction. For example, the access-restricted cryptocurrency wallet 102 can use a random number generator and / or one or more pseudo-random algorithms to generate one or more random numbers, secret strings, etc., which function as one or more secret pieces of information.

[0244] The access-restricted cryptocurrency wallet 102 can encrypt the signature of a signed transaction using one or more methods, techniques, and / or algorithms, in particular cryptographic techniques, and one or more pieces of secret information. For example, the access-restricted cryptocurrency wallet 102 can use one or more hash functions to calculate a hash value used to sign each transaction, such as a hash-based message authentication code (HMAC), in combination with the secret information.

[0245] The robustness of confidential information can be derived from its complexity, as is known in this art. However, naturally, the more complex a piece of confidential information becomes, the more difficult it is to preserve, store, and / or manage it, especially when done manually by user 202. For example, using a piece of confidential information of 256 bits or more, such a piece of confidential information can be extremely difficult to break, decipher, and / or obtain by means of a brute-force attack, for example, and thus set a very high level of security. However, simpler confidential information, such as confidential information with slightly more than 40 bits, specifically confidential information using one or more highly complex algorithms, such as one-way cryptographic functions, can be used because the effort and / or time cost of a brute-force attack applied to decipher data encrypted with a highly complex algorithm using relatively short confidential information may exceed the value of the signed transaction, making the effort of this brute-force attack ineffective and uneconomical. Such 40-bit confidential information can be encoded and / or represented by a short string containing a small number of symbols and / or codes (e.g., fewer than 10), and can be easily preserved even manually.

[0246] The access-restricted cryptocurrency wallet 102 may use one piece of secret information to encrypt all signatures of a signed transaction, but to enhance the security of the signed transaction, the access-restricted cryptocurrency wallet 102 may use multiple pieces of secret information to encrypt the signed transaction.

[0247] In particular, multiple secrets can be created such that each secret is used once to decrypt each signed transaction when sending a signed transaction later. For example, the access-restricted cryptocurrency wallet 102 may use corresponding secrets from the multiple secrets to encrypt each of the multiple signed transactions such that each signed transaction is associated with a corresponding (different) secret from the multiple secrets. In another example, the access-restricted cryptocurrency wallet 102 may use each of the multiple secrets to encrypt a different set of alternative signed transactions, and only one signed transaction can be selected and sent from the other set of alternative signed transactions. For example, one secret may be used to encrypt a set of signed transactions, the signed transactions in that set containing the same nonce in a uniform distribution structure such as the uniform distribution 500 which can be generated for account-based cryptocurrencies as described above.

[0248] The access-restricted cryptocurrency wallet 102 may further associate each of several pieces of secret information with the identification data of each signed transaction associated with each piece of secret information, so that when it is necessary to decrypt the encrypted signature of a particular signed transaction, the appropriate secret information related to that particular signed transaction can be used to decrypt the signature of that transaction. The identification data of each signed transaction may include one or more data items that can be extracted from each signed transaction and definitively, finally, and uniquely identify each signed transaction.

[0249] Several methods and / or embodiments can be applied to store and / or retain confidential information used for encrypting and decrypting signed transactions, and, complementaryly, to provide the stored confidential information to the network-connected device 104.

[0250] For example, one or more pieces of confidential information may be held by one or more users, such as user 202, in one or more forms, such as printed material (on paper, etc.), or stored in a storage medium. In such an embodiment, the access-restricted cryptocurrency wallet 102 may present one or more pieces of confidential information to user 202, for example, via the display of the access-restricted cryptocurrency wallet 102. In another example, the access-restricted cryptocurrency wallet 102 may print the confidential information in a particularly secure form, such as a secure barcode, QR code (registered trademark), etc.

[0251] Since the number of confidential information items that user 202 can hold may be extremely limited, such an embodiment can be said to be applicable when the number of signed transactions is small. However, in order to increase the use of confidential information and extend the limit on the number of confidential information items to a large number of signed transactions, multiple signed transactions can share the same confidential information. Specifically, the same confidential information can be shared by a group of alternative signed transactions that form a set of transactions, and ultimately only one of these alternative signed transactions can be sent to each recipient account. For example, the alternative signed transactions may include a set of signed transactions that all have the same portion amount, the same recipient account, etc., but each of the alternative signed transactions may set a different fee. Therefore, ultimately only one of another set of alternative signed transactions can be selected according to the selected fee, and all of these alternative signed transactions may share the same confidential information, that is, they may be encrypted and signed using the same confidential information.

[0252] Furthermore, if one or more pieces of secret information are used to encrypt the signatures of multiple signed transactions, the access-restricted cryptocurrency wallet 102 may display and / or print each of the pieces of secret information associated with the identification data of each signed transaction related to each piece of secret information.

[0253] If the network-connected device 104 is instructed and / or operated to transmit one or more signed transactions with encrypted signatures, the network-connected device 104 may, before transmitting each signed transaction, request user 202 to provide confidential information related to the signed transaction in order to decrypt the signature of that signed transaction. For example, user 202 may type the confidential information through one or more user interfaces of the network-connected device 104, such as a keyboard, touch screen, etc. In another example, the network-connected device 104 may scan printed confidential information, such as a barcode, QR code (registered trademark), etc.

[0254] If multiple pieces of secret information are used to encrypt the signature of a signed transaction, the network-connected device 104 can obtain identification data from each signed transaction and present the obtained identification data to the user 202. The user 202 can select the secret information associated with the presented identification data and provide it to the network-connected device 104 in order to decrypt the signature of each signed transaction.

[0255] In another example, one or more pieces of confidential information may be stored in one or more portable storage devices, such as storage media (e.g., memory sticks), smartphones, or dedicated confidential information storage devices. Generally, portable storage devices may be secure devices that require user authentication, such as passwords, access codes, or biometric authentication, to access them. One or more portable storage devices may be configured to be attached to one or more wired and / or wireless input / output (I / O) interfaces of the access-restricted cryptocurrency wallet 102, such as USB ports, serial ports, RF links, near-field communication (NFC) ports, and / or others.

[0256] Therefore, one or more portable storage devices may be attached to the I / O interface of an access-restricted cryptocurrency wallet 102, which can store one or more pieces of secret information in one or more portable storage devices that are optionally associated with the identification data of the relevant signed transactions when multiple pieces of secret information are used to encrypt the signatures of multiple signed transactions.

[0257] If the network-connected device 104 is instructed and / or operated to send one or more signed transactions having encrypted signatures, one or more portable storage devices are attached to one or more I / O interfaces of the network-connected device 104, and the network-connected device 104 can retrieve secret information stored in one or more portable storage devices. If there are multiple pieces of secret information, the network-connected device 104 may retrieve the secret information appropriate for each signed transaction according to the identification data extracted from each signed transaction, and may select the secret information in one or more portable storage devices that are associated with (linked to) the extracted identification data.

[0258] Optionally, one or more pieces of secret information used by the access-restricted cryptocurrency wallet 102 to encrypt the signature of a signed transaction may be generated by one or more portable storage devices using one or more of the methods described above for the access-restricted cryptocurrency wallet 102, for example, a random number generator, a pseudo-random algorithm, etc. In particular, the portable storage device may have a seed used by the access-restricted cryptocurrency wallet 102 to generate the secret information, and the secret information generated by the access-restricted cryptocurrency wallet 102 may be deterministically calculated by using the seed together with the same methods and / or algorithms applied by the access-restricted cryptocurrency wallet 102.

[0259] In some embodiments, one or more secrets can be divided into multiple secrets shares that can later be used to reconstruct each secret using one or more secret sharing algorithms and / or secret sharing protocols, such as Shamir Secret Sharing (SSS). The access-restricted cryptocurrency wallet 102 can further securely transmit the multiple secrets shares to multiple computer nodes, such as computer node 204, such that each computer node 204 has only the corresponding secrets share among the multiple secrets shares.

[0260] When the network-connected device 104 is instructed and / or operated to send one or more signed transactions having encrypted signatures, multiple computer nodes 204 can participate in one or more MPC sessions to jointly decrypt the signatures of each of the one or more signed transactions. In particular, such an arrangement and / or embodiment can be applied when the network-connected device 104 is utilized by a group of multiple computer nodes 204.

[0261] If the signature of each signed transaction is optionally encrypted, the number of signed transactions may be significantly reduced, especially when multiple pieces of confidential information are used and the confidential information is held by user 202 who has limited ability or skills to preserve, store, manage and / or otherwise control a large number of pieces of confidential information. Several methods can be applied to limit the number of signed transactions.

[0262] For example, suppose a predefined uniform distribution of total amounts is applied to a particular account-based cryptocurrency to generate a set of signed transactions according to a predefined granularity. In such a case, the number of secrets can be reduced, for example, by reducing the granularity of the fractional amounts defined for each signed transaction, thereby reducing the total number of signed transactions in the set. This can be expressed by reducing the number of fractional amounts, i.e., N in the uniform distribution shown in Figure 5. In another example, the number of secrets can be reduced by sharing the same secret in multiple signed transactions. For example, one secret may be used to encrypt the signatures of all signed transactions that share the same nonce, the same receiving account, and the same fractional amount. This can be expressed in the uniform distribution shown in Figure 5 by using the first secret to encrypt all first signed transactions containing the first nonce (nonce 1), using the second secret to encrypt all second transactions containing the second nonce (nonce 2), and similarly using the Mth secret to encrypt all Mth transactions containing the Mth nonce (nonce M).

[0263] In a transaction-based cryptocurrency (UTXO), where each input of each signed transaction is derived from the output of a preceding signed transaction, one or more methods and / or algorithms can be applied to generate multiple signed transactions according to a predetermined granularity, particularly a low-resolution granularity that can result in a reduction in the number of signed transactions.

[0264] For example, an access-restricted cryptocurrency wallet 102 can create a single transaction for a specific amount of cryptocurrency destined for a temporary account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can further define a specific division that divides the specific amount into multiple fractions according to a predetermined low-resolution granularity, the fractions may be equal or unequal. The access-restricted cryptocurrency wallet 102 can then generate multiple signed transactions for each of the one or more temporary accounts, each associated with each receiving account (destination account), with each signed transaction defining the movement of a specific combination of fractions of the specific amount to each receiving account. Each signed transaction for each receiving account can be signed using each secret information.

[0265] When instructed to move a specific amount of cryptocurrency to each receiving account, the network-connected device 104 can select a signed transaction that cumulatively includes the sum of the fractional amounts that are greater than or equal to the specific withdrawal amount.

[0266] For example, if a total of 4 cryptocurrency units is allocated, the access-restricted cryptocurrency wallet 102 can create a transaction for 4 units and send it to a temporary account associated with the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can define a specific division that divides the 4 units into multiple fractional amounts according to a predetermined low-resolution granularity, and can send multiple signed transactions to each of the receiving accounts to move a specific combination of fractional amounts.

[0267] In particular, the access-restricted cryptocurrency wallet 102 can create the following signed transactions for each receiving account: The first signed transaction can determine the movement of the first portion, the second signed transaction can determine the movement of the second portion, the third signed transaction can determine the movement of the third portion, and the fourth signed transaction can determine the movement of the fourth portion. Furthermore, the fifth signed transaction can determine the movement of the sum of the first and second portions, the sixth signed transaction can determine the movement of the sum of the second and third portions, and the seventh signed transaction can determine the movement of the sum of the third and fourth portions. Furthermore, eight signed transactions can determine the movement of the sum of the first, second, and third portions, the ninth signed transaction can determine the movement of the sum of the second, third, and fourth portions, and the tenth signed transaction can determine the movement of all portions, i.e., the sum of the first, second, third, and fourth portions.

[0268] Suppose the first transaction that the network-connected device 104 is instructed to move in real time is a transaction used for an amount of 2 cryptocurrency units. For simplicity, assume that all the initial fractional amounts determined by the division are equal, resulting in four fractional amounts, each used for 1 unit of cryptocurrency. In this case, the network-connected device 104 may select a fifth signed transaction that defines the movement of the sum of the first and second fractional amounts, which together constitute 2 cryptocurrency units. After decrypting the signature of the fifth signed transaction using the respective secret information, the network-connected device 104 can send the fifth signed transaction to the receiving account. Suppose the network-connected device 104 is instructed to move an additional 1 cryptocurrency unit to the receiving account. In this case, the network-connected device 104 may select a third signed transaction that contains a third fractional amount equal to 1 cryptocurrency unit, and after decrypting the signature of the third signed transaction using the respective secret information of the signature, the network-connected device 104 can send the third signed transaction to the receiving account.

[0269] One possibility is that this method could result in excessive fees. In particular, if the total amount of cryptocurrency is large and is divided into multiple portions, multiple signed transactions may be generated for all possible combinations of portions, and it is possible, and can be inferred, that one or more cryptocurrency moves may require the sum of these combinations of signed transactions. Therefore, the initial division may be practically ineffective, and at least some of the multiple signed transactions may ultimately remain unused, so applying a fee to each of these multiple signed transactions would result in excessive fees.

[0270] To address this constraint, an alternative approach can be applied to transaction-based cryptocurrencies (UTXOs). The access-restricted cryptocurrency wallet 102 can first create a hierarchical structure that defines all possible transaction sequences for moving any portion of the total amount and any combination of portions (totals) according to a default low-resolution granularity. Thus, the hierarchical structure can contain multiple branches, each branch defining its own sequence of portion movement. The access-restricted cryptocurrency wallet 102 can then generate multiple transactions for a virtual account associated with the access-restricted cryptocurrency wallet 102 according to the hierarchical structure. Thus, transactions for the virtual account can cover amounts including each portion and combinations of two or more portions, and all possible cryptocurrency amount movement sequences, with the input of each signed transaction derived from the output of the signed transaction preceding it. The access-restricted cryptocurrency wallet 102 can then send the multiple transactions to the virtual account associated with the access-restricted cryptocurrency wallet 102.

[0271] The access-restricted cryptocurrency wallet 102 can further generate multiple signed transactions for one or more receiving accounts, which are duplicates of the transactions sent to the temporary account associated with the access-restricted cryptocurrency wallet 102, and send these to the network-connected device 104. In other words, for each receiving account, the access-restricted cryptocurrency wallet 102 can generate its own signed transaction for each transaction sent to the temporary account. The access-restricted cryptocurrency wallet 102 can encrypt the signature of each signed transaction for each receiving account using its respective secret information, and can send these signed transactions to the network-connected device 104.

[0272] As a result, all signed transactions created for all receiving accounts are derived from each transaction that is moved to a temporary account, so the inputs of each signed transaction are consistently and correctly derived from the output of the preceding signed transaction.

[0273] When instructed and / or operated to send a specific amount of cryptocurrency to a specific receiving account, the network-connected device 104 can, in real time, select an appropriate signed transaction containing a cryptocurrency amount greater than or equal to the specified amount. After decrypting the selected signed transaction using the secret information of each transaction, the network-connected device 104 can send the selected signed transaction to the specific receiving account. In particular, for a first signed transaction, the network-connected device 104 can select a branch of the structure that defines the sequence of signed transactions, the first signed transaction containing a fractional amount greater than or equal to the specified amount. From this point forward, the network-connected device 104 must use the selected branch for all subsequent cryptocurrency transfers. This means that for each cryptocurrency transfer to any receiving account, the network-connected device 104 can select one or more subsequent signed transactions from the selected branch, and each input of a subsequent signed transaction is derived from the output of the signed transaction preceding it.

[0274] In this embodiment, each cryptocurrency transfer to any receiving account involves two signed transactions recorded on the blockchain, which incur fees, thus significantly reducing the total fees paid for sending signed transactions to receiving accounts. The two signed transactions include each transaction sent to a temporary account associated with the access-restricted cryptocurrency wallet 102 and a corresponding signed transaction sent to each receiving account. Since the signed transactions are created according to a hierarchical structure, each transaction sent to a temporary account may contain only one input and two outputs, and each signed transaction sent to one of the receiving accounts may contain one input and one output. In most, if not all, transaction-based cryptocurrencies (UTXOs), fees are based on the size of the transaction. Therefore, by reducing the number of inputs and outputs per signed transaction, the fees for each signed transaction can be significantly reduced compared to the above embodiment where each signed transaction may contain multiple inputs and outputs, and thus the total fees can be significantly reduced.

[0275] Referring to Figure 9, this is a schematic diagram of an exemplary hierarchical structure constructed to move cryptocurrency funds to one or more receiving accounts using a reduced number of signed transactions, according to some embodiments of the present invention.

[0276] To create multiple signed transactions for moving cryptocurrency to one or more receiving accounts, an exemplary hierarchical structure 900 can be created using an access-restricted cryptocurrency wallet, such as the access-restricted cryptocurrency wallet 102. In particular, to support the encryption of signatures in signed transactions, the access-restricted cryptocurrency wallet 102 can create a structure 900 for generating a limited number of signed transactions, typically a small number.

[0277] For simplicity, a structure of 900 with a total value of 5 cryptocurrency units is shown, and the granularity of the fractional amounts is set to 1 cryptocurrency unit.

[0278] As shown, structure 900 may contain five branches, each defining a sequence of partial-amount transfers that cumulatively equal the total amount of five cryptocurrency units. For example, the first branch 902 may contain one transaction of the full amount of five units. In another example, the second branch 904 may contain a first transaction of four units, followed by a second transaction of one unit. In yet another example, the third branch 906 may contain a first transaction of three units, followed by two alternative sequence paths, namely the first and second paths, where the first path contains a second transaction of two units, and the second path contains a second transaction of one unit, followed by another third transaction of one unit. In another example, the fourth branch 908 may contain a first transaction of two units, followed by three alternative sequence paths: the first path, the second path, and the third path. The first path contains a second transaction of three units, the second path contains a second transaction of two units, followed by a third transaction of one unit. The third path contains a second transaction of one unit, followed by two alternative sub-paths: the first sub-path and the second sub-path. The first sub-path has a third transaction of two units, the second sub-path has a third transaction of one unit, followed by another fourth transaction of one unit. In yet another example, the fifth branch 910 follows the logic described for the other branches, but its first transaction defines a transaction of one unit.

[0279] In such a case, the access-restricted cryptocurrency wallet 102 can generate multiple transactions for a temporary account associated with the access-restricted cryptocurrency wallet 102 according to structure 900. This means that each transaction in structure 900 is represented by each transaction sent to the temporary account by the access-restricted cryptocurrency wallet 102. The access-restricted cryptocurrency wallet 102 can further generate multiple signed transactions for each of the receiving accounts, obtained by duplicating the transactions sent to the temporary account. The access-restricted cryptocurrency wallet 102 can then encrypt the signatures of the signed transactions created for one or more receiving accounts and send the signed transactions with the encrypted signatures to a network-connected device such as the network-connected device 104.

[0280] When instructed and / or operated to send a specific amount of cryptocurrency to a specific receiving account, the network-connected device 104 can, in real time, select an appropriate signed transaction containing a cryptocurrency amount greater than or equal to the specified amount. For example, suppose the network-connected device 104 is instructed to create the first transaction, and the first transaction is a transfer of 3 units of cryptocurrency to a first receiving account. In such a case, the network-connected device 104 can select branch 906 of structure 900 and select each signed transaction to be created for the first receiving account, corresponding to the first transaction 920 of branch 906, which is the transaction used for the 3 units. The network-connected device 104 can decrypt the signatures of the selected signed transactions using the secret information of each signature and send the selected signed transactions to the first receiving account.

[0281] Suppose the network-connected device 104 is further instructed to move one unit to a second receiving account following the first transaction. The network-connected device 104 can select subsequent unused signed transactions that represent a fraction of one or more units, in which case the subsequent unused signed transaction is signed transaction 922 corresponding to the second transaction of the second alternative path of branch 906, which is the transaction used for one unit. The network-connected device 104 can decrypt the signatures of the selected signed transactions using the respective secret information of the signatures, and can send the selected signed transactions to the second receiving account.

[0282] It should be noted that if there is only one receiving account (and the fee is fixed), it is possible to avoid duplication of signed transactions and use the original set of signed transactions. In particular, instead of creating a transaction to move a portion of the amount to a temporary account associated with the access-restricted cryptocurrency wallet 102, the access-restricted cryptocurrency wallet 102 can create multiple signed transactions used to move multiple portions and combinations thereof in a single temporary account assigned to a single receiving account.

[0283] Optionally, to support variability in fees for recording signed transactions on the blockchain, the access-restricted cryptocurrency wallet 102 may use one or more of the methods described herein to compensate one or more computer nodes 204 (miners) that record signed transactions on the blockchain. For example, if a smart miner is present, the access-restricted cryptocurrency wallet 102 may generate multiple transactions for a temporary account with a fixed, typically low, fee. One or more smart miners may record a signed transaction to the temporary account even if the fee is insufficient in terms of the likelihood of compensation in future transactions. The access-restricted cryptocurrency wallet 102 may further generate multiple signed transactions for each of the receiving accounts with multiple different fees, duplicate the transaction sent to the temporary account, encrypt the signatures of these transactions, and send these transactions to the network-connected device 104.

[0284] When one or more signed transactions are sent to move cryptocurrency funds from a temporary account to one or more receiving accounts, the network-connected device 104 can, in real time, select a portion of the signed transactions to which an appropriate fee has been assigned. In particular, the amount of the fee for the selected one or more signed transactions can include fees for both the one or more transactions currently being sent to the temporary account and one or more transactions previously sent to the temporary account. Thus, one or more smart miners that record both the one or more signed transactions previously sent to the receiving account and the one or more current transactions for the receiving account can receive an appropriate fee for each of the recorded transactions. In this embodiment, since only one amount of fee is applied to the one or more transactions initially sent to the temporary account, it is possible to significantly reduce the number of signed transactions recorded on the blockchain while incentivizing and encouraging one or more smart miners to record these signed transactions on the blockchain.

[0285] The descriptions of various embodiments of the present invention have been made for illustrative purposes, but this description is not exhaustive and is not intended to be limited to the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used in this disclosure are chosen to best explain the principles of the embodiments, practical applications, or technological improvements over the technologies found in the market, and to enable other skilled artisans to understand the embodiments disclosed in this disclosure.

[0286] During the term of the patents that expire from this application, it is expected that a number of related systems, methods, and computer programs will be developed, and the scope of the terms cryptocurrency service, blockchain, and secure channel is intended to include all such new technologies in advance.

[0287] The term "about" as used in this disclosure refers to ±10%.

[0288] The terms "comprise," "comprising," "include," "including," "have," and their conjugations mean "including but not limited to." This term includes the terms "consisting of" and "consisting essentially of."

[0289] The phrase "consisting essentially of" means that a component or method may include additional elements and / or steps, but only if the additional elements and / or steps do not substantially change the basic and novel features of the claimed component or method.

[0290] The singular forms "a," "an," and "the" as used in this disclosure include the application to a plurality, unless the context clearly indicates otherwise. For example, the term "compound" or "at least one compound" may be a plurality of compounds and may include mixtures thereof.

[0291] The term “exemplary” is used in this disclosure to mean “used as an example, instance, or illustrated example.” Any embodiment described as “exemplary” is not necessarily construed to be preferable or superior to other embodiments, and / or to exclude the incorporation of features of other embodiments.

[0292] The term “optionally” is used in this disclosure to mean “provided in some embodiments but not in other embodiments.” Any particular embodiment of the present invention may include several “optionally” features, as long as these features do not conflict.

[0293] Throughout this application, various embodiments of the present invention may be presented in range form. It is understood that range form is merely for convenience and should not be interpreted as a limitation that excludes flexibility in the scope of the present invention. Therefore, range descriptions are naturally considered to include not only the individual numerical values ​​within the specifically disclosed range, but also all possible subranges. For example, a range description such as 1-6 is naturally considered to include not only the individual numerical values ​​within the specifically disclosed range, such as 1, 2, 3, 4, 5, and 6, but also subranges such as 1-3, 1-4, 1-5, 2-4, 2-6, and 3-6. This applies regardless of the width of the range.

[0294] Whereever a numerical range is indicated in this disclosure, it is intended to include all numbers (decimals or integers) described within that range. The phrases "ranging / ranges between" and "ranging / ranges from" are used interchangeably in this disclosure and are intended to include the first and second described numbers and all decimals and integers between them.

[0295] For clarity, it will be understood that certain features of the present invention described on the premise of separate embodiments may be combined and provided in a single embodiment. Conversely, for brevity, various features of the present invention described on the premise of a single embodiment may be provided separately, arbitrarily and appropriately combined in part, or provided as suitable for other embodiments of the present invention described. Certain features described on the premise of various embodiments should not be considered essential features of the embodiment unless the embodiment would be unable to operate without them.

[0296] Although the present invention has been described with reference to specific embodiments thereof, it will be obvious to those skilled in the art that numerous alternatives, modifications, and variations are apparent. Therefore, it is intended to encompass all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0297] All publications, patents, and patent applications referenced herein are incorporated herein by reference in their entirety, as if each individual publication, patent, or patent application were specifically and individually described herein. In addition, no reference statement or recognition in this application shall be construed as an acknowledgment that such reference is used as prior art in the present invention. To the extent that headings are used, such statement or recognition shall not be construed as necessarily limiting. In addition, any priority document of this application is incorporated herein by reference in its entirety.

Claims

1. An access-restricted cryptocurrency wallet device, At least one processor, Create at least one temporary account that will be assigned to at least one recipient, Send at least one transaction to move a predetermined total amount of cryptocurrency from an account associated with an access-restricted cryptocurrency wallet to the at least one virtual account, and the at least one transaction is recorded on a blockchain managed by a plurality of network-connected computer nodes. Generate multiple signed transactions to move multiple default fractional amounts of cryptocurrency from the at least one temporary account to at least one receiving account associated with the at least one recipient, wherein the sum of the multiple default fractional amounts does not exceed the default total amount. The network-connected device transmits the plurality of signed transactions, and the network-connected device transmits at least one of the plurality of signed transactions to move cryptocurrency from the at least one virtual account to the at least one receiving account without physically engaging with the access-restricted cryptocurrency wallet. A cryptocurrency wallet device configured to have restricted access.

2. The access-restricted cryptocurrency wallet is used by multiple computer nodes that use at least one multi-party computation (MPC) protocol to generate the multiple signed transactions. The access-restricted cryptocurrency wallet device according to claim 1.

3. The access-restricted cryptocurrency wallet device according to claim 1, wherein the plurality of predetermined fractional amounts are valid simultaneously.

4. The network-connected device is implemented by a subset of the plurality of network-connected computer nodes that use at least one multi-party computation (MPC) protocol to send the at least one signed transaction to the at least one receiving account. The access-restricted cryptocurrency wallet device according to claim 1.

5. The at least one processor, Generate multiple signed excess transactions to move cryptocurrency from at least one of the provisional accounts to an account associated with the access-restricted cryptocurrency wallet, The network-connected device transmits at least one of the plurality of signed excess transactions to move cryptocurrency to an account associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

6. The at least one processor, Multiple temporary accounts are created, and each temporary account is assigned to each of the multiple recipients. Send at least one transaction to move a predetermined amount of cryptocurrency from the account associated with the access-restricted cryptocurrency wallet to each of the plurality of temporary accounts, Generate multiple signed transactions of multiple default amounts of cryptocurrency from at least one of the multiple temporary accounts to at least one other of the multiple temporary accounts. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

7. The aforementioned at least one temporary account is created by the access-restricted cryptocurrency wallet as a payment channel 2-2 multi-signature account. In the payment channel 2-2 multi-signature account, each transaction from the at least one temporary account to the at least one receiving account, each transaction recorded on the blockchain, is further signed by the at least one recipient, and the multiple signed transactions are set up to move a predetermined progressively increasing portion of the predetermined total amount. The access-restricted cryptocurrency wallet device according to claim 1.

8. The network-connected device transmits a plurality of signed transactions for moving cryptocurrency from the at least one temporary account to the at least one receiving account, wherein the plurality of signed transactions are not recorded on the blockchain because they are not signed by the at least one recipient. Each of the plurality of signed transactions replaces a preceding signed transaction sent to the at least one receiving account using the transaction identifier (ID) of the transmitted preceding signed transaction. Each of the signed transactions sent includes an amount of cryptocurrency which is the sum of the amount of cryptocurrency moved in that signed transaction and the amount of cryptocurrency moved in the preceding signed transaction. The access-restricted cryptocurrency wallet device according to claim 7.

9. The most recent signed transaction transmitted by the network-connected device to move cryptocurrency from the at least one temporary account to the at least one receiving account is recorded on the blockchain when the at least one recipient signs the most recent signed transaction transmitted. The access-restricted cryptocurrency wallet device according to claim 8.

10. The at least one processor, The aforementioned payment channel 2-2 multi-signature account is a time-limited account associated with a due date, If, within the aforementioned deadline, the at least one recipient fails to sign the most recent signed transaction sent to transfer cryptocurrency from the at least one temporary account to the at least one receiving account, the amount of cryptocurrency held in the payment channel 2-2 multi-signature account will be returned to the account associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 9, further configured as follows.

11. The at least one processor, If the at least one receiving account is associated with each of the at least one recipient's cryptocurrency wallets which is not configured to support the Payment Channel 2-2 Multisig Account, then the Payment Channel 2-2 Multisig Account is configured such that each signed transaction sent to move cryptocurrency from the at least one temporary account to the at least one receiving account and recorded on the blockchain requires a signature from another network-connected device associated with the at least one recipient. The access-restricted cryptocurrency wallet device according to claim 7, further configured as follows.

12. The at least one processor, The access-restricted cryptocurrency wallet closes the at least one temporary account by sending an instruction to the network-connected device to close the payment channel 2-2 multisignature account in cooperation with the at least one recipient. The access-restricted cryptocurrency wallet device according to claim 7, further configured as follows.

13. The aforementioned at least one temporary account is created by the access-restricted cryptocurrency wallet as a new cryptocurrency account associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 1.

14. If the cryptocurrency is an account-based cryptocurrency in which each transaction includes a nonce indicating the number of previous transactions, the access-restricted cryptocurrency wallet generates the plurality of signed transactions such that each of the plurality of signed transactions includes one nonce from a plurality of valid nonces and a corresponding default fractional amount, thereby constituting a uniform distribution of the default total amount according to a default granularity. The access-restricted cryptocurrency wallet device according to claim 13.

15. When transferring a specific amount of cryptocurrency to at least one receiving account, the network-connected device selects at least one of the multiple signed transactions that includes a default portion greater than or equal to the specific amount, and all other signed transactions that include the same nonce and other default portions are discarded. The access-restricted cryptocurrency wallet device according to claim 14.

16. The at least one processor, The plurality of signed transactions for moving each of the predetermined portion amounts to one of the plurality of receiving accounts are generated by configuring each of the plurality of signed transactions to constitute the predetermined total amount, such that each of the plurality of signed transactions includes a nonce from a plurality of valid nonces, a corresponding predetermined portion amount of the predetermined total amount, and a corresponding target receiving account from the plurality of receiving accounts. The access-restricted cryptocurrency wallet device according to claim 14, further configured as follows.

17. The at least one processor, By designating the account associated with the access-restricted cryptocurrency wallet as one of the multiple receiving accounts, the network-connected device transmits at least one of the multiple signed transactions to move cryptocurrency to the account associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 16, further configured as follows.

18. The at least one processor, The access-restricted cryptocurrency wallet closes the at least one of the account-based temporary accounts by sending an instruction to the network-connected device to close the account-based temporary account. The access-restricted cryptocurrency wallet device according to claim 14, further configured as follows.

19. The at least one processor, The access-restricted cryptocurrency wallet closes the at least one temporary account by sending at least one transaction recorded on the blockchain, which includes at least one nonce of the plurality of signed transactions and a cryptocurrency amount of zero, to an account associated with the access-restricted cryptocurrency wallet to move the cryptocurrency to the account associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 14, further configured as follows.

20. If the cryptocurrency is a transaction-based cryptocurrency (UTXO) in which each transaction includes an input amount of at least one cryptocurrency that traces back to each output amount of a previous transaction, the access-restricted cryptocurrency wallet generates the plurality of signed transactions to constitute a hierarchical directed acyclic graph (DAG) containing the plurality of signed transactions, each signed transaction being derived from a higher-level signed transaction and including a transaction ID (TXID), and the hierarchical DAG is configured to distribute the predetermined total amount according to a predetermined granularity. The access-restricted cryptocurrency wallet device according to claim 13.

21. The access-restricted cryptocurrency wallet device according to claim 20, wherein the DAG is configured as a hierarchical tree.

22. When transferring a specific amount of cryptocurrency to the at least one receiving account, the network-connected device selects at least one segment of the hierarchical DAG that includes at least one signed transaction containing a predetermined fraction that is greater than or equal to the specific amount, and each signed transaction in the segment that is not sent is marked as unavailable. The access-restricted cryptocurrency wallet device according to claim 20.

23. The at least one processor, The remaining amount of available cryptocurrency in at least one unavailable transaction is notified to the access-restricted cryptocurrency wallet by inserting at least one limited-length string into the access-restricted cryptocurrency wallet via the capacity-restricted input interface of the access-restricted cryptocurrency wallet, which is configured to accept at least one limited-length string. The access-restricted cryptocurrency wallet device according to claim 22, further configured as follows.

24. The at least one processor, The at least one string includes an index of the at least one unavailable transaction, and the access-restricted cryptocurrency wallet derives the balance from the index known to the access-restricted cryptocurrency wallet that first generated the plurality of signed transactions including the at least one unavailable transaction. The access-restricted cryptocurrency wallet device according to claim 23, further configured as follows.

25. The at least one processor, The access-restricted cryptocurrency wallet sends a transaction to an account associated with the access-restricted cryptocurrency wallet, the transaction is recorded on the blockchain, and includes the cumulative sum of the cryptocurrency portion amounts contained in the at least one unavailable signed transaction. The access-restricted cryptocurrency wallet device according to claim 23, further configured as follows.

26. The at least one processor, If the at least one recipient uses another restricted access cryptocurrency wallet, the amount of cryptocurrency to be transferred to the receiving account associated with the other restricted access cryptocurrency wallet is notified to the other restricted access cryptocurrency wallet by inserting at least one string of limited length into the other restricted access cryptocurrency wallet via the capacity-limited input interface of the other restricted access cryptocurrency wallet. The at least one string includes: a description of the first signed transaction of the plurality of signed transactions sent to the receiving account of the other access-restricted cryptocurrency wallet; the structure of the hierarchical DAG; and the index of the last signed transaction of the plurality of signed transactions sent to move cryptocurrency to the receiving account of the other access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 20, further configured as follows.

27. ​​The at least one processor, If the fee needs to be distributed to at least one of the multiple network-connected computer nodes that record the at least one signed transaction on the blockchain, the access-restricted cryptocurrency wallet extends each of the multiple signed transactions into a set of signed transactions, and allocates an amount of cryptocurrency for each signed transaction in the set to the fee. The network-connected device selects one of the transactions in the set according to the amount of the fee. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

28. The at least one processor, If the fee needs to be distributed to at least one of the multiple network-connected computer nodes that record the at least one signed transaction on the blockchain, the access-restricted cryptocurrency wallet generates at least one fee distribution transaction that includes a dedicated amount of cryptocurrency for the fee. Send the at least one fee distribution transaction to move cryptocurrency to an account associated with the network-connected device, The network-connected device sends at least one fee-sharing transaction to move cryptocurrency to the at least one network-connected computer node that has recorded the at least one signed transaction. The at least one fee distribution transaction includes an amount of cryptocurrency sufficient for the fees for both the at least one signed transaction and the at least one fee distribution transaction. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

29. The at least one processor, If a fee needs to be distributed to at least one of the multiple network-connected computer nodes that record the at least one signed transaction on the blockchain, the access-restricted cryptocurrency wallet establishes an arrangement with at least one partner computer node among the multiple network-connected computer nodes, and in the arrangement, the at least partner computer node records each of the multiple signed transactions transmitted by the network-connected device to move cryptocurrency from the at least one temporary account to the at least one receiving account. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

30. The at least one processor, The signature of each of the aforementioned multiple signed transactions is encrypted using at least one piece of confidential information. The network-connected device decrypts the signature of the at least one signed transaction using the at least one piece of secret information before transmitting the at least one signed transaction. The access-restricted cryptocurrency wallet device according to claim 1, further configured as follows.

31. The at least one piece of secret information used to decrypt the signature of the at least one signed transaction is obtained from a portable storage device associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 30.

32. The at least one confidential piece of information used to decrypt the signature of the at least one signed transaction is provided by at least one user associated with the access-restricted cryptocurrency wallet. The access-restricted cryptocurrency wallet device according to claim 30.

33. The at least one secret information used to decrypt the signature of the at least one signed transaction is reconstructed from multiple secret information shares using at least one secret sharing algorithm. The access-restricted cryptocurrency wallet device according to claim 30.

34. The at least one processor, The signature of each of the multiple signed transactions is encrypted using one of the multiple secrets. The access-restricted cryptocurrency wallet device according to claim 30, further configured as follows.

35. The at least one processor, By presenting the identification data of the at least one signed transaction, it is possible to identify the at least one signed transaction and thus obtain the respective secret information for encrypting the signature of the at least one signed transaction. The access-restricted cryptocurrency wallet device according to claim 33, further configured as follows.

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