Off-chain interaction and on-chain processing using exchange

Abstract

A method is disclosed. The method includes receiving, by a node managing a blockchain, a blockchain transaction request comprising transaction parameters including a master computer digital signature. The method includes verifying, by an entry point smart contract with a second smart contract, at least some of the transaction parameters, and providing to the first smart contract, a signature validation request with the master computer digital signature. The method also includes receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract. The method includes communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request, and calling, by the second smart contract, the first smart contract to request tokens to complete the blockchain transaction. The first smart contract acquires and provides the tokens to an account associated with the second smart contract.

Description

PATENT Attorney Docket No.: 079900-1450600 Client Reference No.: 7756WO01 OFF-CHAIN INTERACTION AND ON-CHAIN PROCESSING USING EXCHANGE CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of the filing date of India Provisional Patent Application No. 202341055317, filed on August 17, 2023, which is herein incorporated by reference. BACKGROUND

[0002] To conduct blockchain transactions, users acquire native blockchain tokens by moving assets from centralized exchanges. In the context of a cryptocurrency, this requires depositing fiat currency into the exchange, purchasing the necessary blockchain tokens, and then transferring them to a personal wallet. However, this approach carries the risk of obtaining too many or too few blockchain tokens. This is problematic, especially in the case where the value of the blockchain tokens (as well as operational fees such as gas fees) regularly fluctuates. Additionally, it can be overwhelming and challenging for individuals who are less technologically saavy and want to engage in blockchain transactions. This process acts as a barrier to entry for those unfamiliar with crypto exchanges and the complexities of buying and bridging tokens. It can be compared to the cumbersome and unfriendly method of exchanging cash for different currencies when traveling to different countries.

[0003] Other problems with processing additional blockchain transactions, which can result in slow overall processing. The account funding approaches (onramp services or transfer via centralized crypto exchange) mentioned above can require blockchain transactions in order to initially transfer funds to a user’s wallet. For example, an Ethereum transaction can take 1-10 minutes to complete depending upon the number of required confirmations, while a Bitcoin transaction can take between 1-1.5 hours to finalize.

[0004] Yet another problem with current blockchain transactions is that they can require that a user use a specific type of application on their communication device. The user also needs to have a communication device with remote communication 1 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 capabilities. This can be a barrier to use, as the methods for using blockchain tokens to conduct interactions may not be familiar to users.

[0005] These and other problems are addressed by embodiments of the invention. BRIEF SUMMARY

[0006] One embodiment includes a method using a node managing a blockchain in a blockchain network, the blockchain comprising an entry point smart contract, a first smart contract, a second smart contract, and a plurality of blocks, the method comprising: receiving, by the node, a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature; verifying, by the entry point smart contract with the second smart contract, at least some of the transaction parameters; providing, by the entry point smart contract to the first smart contract, a signature validation request comprising the master computer digital signature; verifying, by the first smart contract, the master computer digital signature; receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract; communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request; and calling, by the second smart contract, the first smart contract to request tokens to complete the blockchain transaction, wherein the first smart contract acquires and provides the tokens to an account associated with the second smart contract.

[0007] Another embodiment includes a computer node for managing a blockchain comprising an entry point smart contract, a first smart contract, a second smart contract, and a plurality of blocks comprising: a processor; and a non-transitory computer readable medium, the non-transitory computer readable medium comprising code, executable by the processor for performing operations comprising: receiving by the computer node, a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature; verifying, by the entry point smart contract with the second smart contract, at least some of the transaction parameters; 2 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 providing, by the entry point smart contract to the first smart contract, a signature validation request comprising the master computer digital signature; verifying, by the first smart contract, the master computer digital signature; receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract; communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request; and calling, by the second smart contract, the first smart contract to request tokens to complete the blockchain transaction, wherein the first smart contract acquires and provides the tokens to an account associated with the second smart contract.

[0008] Another embodiment of the invention includes A method comprising: transmitting, by a communication device to a master computer, an off-chain transaction request comprising a credential or a token for an off-chain transaction in association with a blockchain transaction, wherein the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer; receiving, by the communication device, an off-chain transaction response from the master computer, the off-chain transaction response comprising a master computer digital signature, the master computer digital signature indicating approval of the authorization request message; and transmitting, by the communication device to a node in a blockchain network managing a blockchain, a blockchain transaction request comprising transaction parameters associated with the blockchain transaction, the transaction parameters including the master computer digital signature, wherein the node verifies the transaction parameters with a second smart contract, and provides a signature validation request comprising the master computer digital signature to a first smart contract using a first smart contract address and receives a signature validation response from the first smart contract, and executes the blockchain transaction by communicating with the second smart contract, wherein second smart contract calls the first smart contract to request funds from first smart contract, which acquires and provides tokens to a second smart contract account.

[0009] Another embodiment of the invention includes a method comprising: transmitting, by a communication device to a master computer, an off-chain transaction request comprising a credential or a token for an off-chain transaction in 3 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 association with a blockchain transaction, wherein the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer; receiving, by the communication device, an off-chain transaction response from the master computer, the off-chain transaction response comprising a master computer digital signature, the master computer digital signature indicating approval of the authorization request message; and transmitting, by the communication device to a node in a blockchain network managing a blockchain, a blockchain transaction request comprising transaction parameters associated with the blockchain transaction, the transaction parameters including the master computer digital signature, wherein the node verifies the transaction parameters with a second smart contract, and provides a signature validation request comprising the master computer digital signature to a first smart contract using a first smart contract address and receives a signature validation response from the first smart contract, and executes the blockchain transaction by communicating with the second smart contract, wherein second smart contract calls the first smart contract to request funds from first smart contract, which acquires and provides tokens to a second smart contract account.

[0010] These and other embodiments are described in further detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG.1 shows a block diagram of a system according to an embodiment.

[0012] FIG.2 illustrates a diagram and process flow illustrating a first interaction method.

[0013] FIG. 3 shows a block diagram of an examplary communcation device acording to embodiments.

[0014] FIG.4 shows a block diagram of an examplary node computer according to embodiments.

[0015] FIG. 5 shows a block diagram of an examplary master computer according to embodiments. 4 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0016] FIG.6 shows a diagram illustrating a portion of a blockchain according to some embodiments. 0008] FIG.7 shows a contract account creation process.

[0008] FIG.8 shows a method and system for issuing a crypto enabled card.

[0017] FIG. 9 illustrates a diagram and process flow illustrating a second interaction method. TERMS

[0018] A “key” may include a piece of information that is used in a cryptographic algorithm to transform input data into another representation. A cryptographic algorithm can be an encryption algorithm that transforms original data into an alternate representation, or a decryption algorithm that transforms encrypted information back to the original data. Examples of cryptographic algorithms may include triple data encryption standard (TDES), data encryption standard (DES), advanced encryption standard (AES), etc.

[0019] A "public key" may include an encryption key that may be shared openly and publicly. The public key may be designed to be shared and may be configured such that any information encrypted with the public key may only be decrypted using a private key associated with the public key (i.e., a public / private key pair).

[0020] A "private key" may include any encryption key that may be protected and secure. A private key may be securely stored at an entity and may be used to decrypt any information that has been encrypted with an associated public key of a public / private key pair associated with the private key.

[0021] A “public / private key pair” may refer to a pair of linked cryptographic keys generated by an entity. The public key may be used for public functions such as encrypting a message to send to the entity or for verifying a digital signature which was supposedly made by the entity. The private key, on the other hand may be used for private functions such as decrypting a received message or applying a digital signature. In some embodiments, the public key may be authorized by a body known as a Certification Authority (CA) which stores the public key in a database and 5 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 distributes it to any other entity which requests it. The private key can typically be kept in a secure storage medium and will usually only be known to the entity. Public and private keys may be in any suitable format, including those based on Rivest-Shamir- Adleman (RSA) or elliptic curve cryptography (ECC).

[0022] An “authorizing entity” may be an entity that authorizes a request. Examples of an authorizing entity may be an issuer, a governmental agency, a document repository, an access administrator, etc. An authorizing entity may operate an authorizing entity computer. An “issuer” may refer to a business entity (e.g., a bank) that issues and optionally maintains an account for a user. An issuer may also issue payment credentials stored on a user device, such as a cellular telephone, smart card, tablet, or laptop to the consumer.

[0023] A “resource provider” may be an entity that can provide a resource such as goods, services, information, and / or access to a location (e.g., a parking space, a transit terminal, etc.). Examples of resource providers include merchants, governmental authorities, secure data providers, etc. A resource provider may operate one or more access devices.

[0024] An “access device” may be any suitable device that provides access to a remote system. An access device may also be used for communicating with a merchant computer, a transaction processing computer, an authentication computer, or any other suitable system. An access device may generally be located in any suitable location, such as at the location of a merchant. An access device may be in any suitable form. Some examples of access devices include POS or point of sale devices (e.g., POS terminals), cellular phones, PDAs, personal computers (PCs), tablet PCs, hand-held specialized readers, set-top boxes, electronic cash registers (ECRs), automated teller machines (ATMs), virtual cash registers (VCRs), kiosks, security systems, access systems, and the like. An access device may use any suitable contact or contactless mode of operation to send or receive data from, or associated with, a mobile communication or payment device. In some embodiments, where an access device may comprise a POS terminal, any suitable POS terminal may be used and may include a reader, a processor, and a computer-readable medium. A reader may include any suitable contact or contactless mode of 6 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 operation. For example, exemplary card readers can include radio frequency (RF) antennas, optical scanners, bar code readers, or magnetic stripe readers to interact with a payment device and / or mobile device. In some embodiments, a cellular phone, tablet, or other dedicated wireless device used as a POS terminal may be referred to as a mobile point of sale or an “mPOS” terminal.

[0025] An "acquirer" may typically be a business entity (e.g., a commercial bank) that has a business relationship with a particular merchant or other entity. Some entities can perform both issuer and acquirer functions. Some embodiments may encompass such single entity issuer-acquirers. An acquirer may operate an acquirer computer, which can also be generically referred to as a “transport computer.”

[0026] A “communication device” may comprise any suitable electronic device capable of remote electronic communication. Examples of remote communication capabilities include using a mobile phone (wireless) network, wireless data network (e.g., 3G, 4G or similar networks), Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), Wi- Max, or any other communication medium that may provide access to a network such as the Internet or a private network. Examples of communication devices include mobile phones (e.g., cellular phones), PDAs, tablet computers, net books, laptop computers, wearable devices (e.g., watches), vehicles such as automobiles and motorcycles, personal music players, hand-held specialized readers, etc.

[0027] A “user” may include an individual. In some embodiments, a user may be associated with one or more personal accounts and / or mobile devices. The user may also be referred to as a cardholder, account holder, or consumer in some embodiments.

[0028] “Credentials” may comprise any evidence of authority, rights, or entitlement to privileges. For example, access credentials may comprise permissions to access certain tangible or intangible assets, such as a building or a file. Examples of credentials may include passwords, passcodes, or secret messages. In another example, payment credentials may include any suitable information associated with and / or identifying an account (e.g., a payment account and / or payment device associated with the account). Such information may be directly related to the account or may be derived from information related to the account. Examples of account 7 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 information may include an “account identifier” such as a PAN (primary account number or “account number”), a token, a subtoken, a gift card number or code, a prepaid card number or code, a user name, an expiration date, a CVV (card verification value), a dCVV (dynamic card verification value), a CVV2 (card verification value 2), a CVC3 card verification value, etc. An example of a PAN is a 16-digit number, such as “4147 0900 0000 1234”. In some embodiments, credentials may be considered sensitive information.

[0029] An “off-chain token” may be a substitute value for a credential. A token may be a string of numbers, letters, or any other suitable characters. Examples of tokens include access tokens such as payment tokens, data that can be used to access secure systems or locations, etc.

[0030] A "off-chain payment token” include an identifier for a payment account that is a substitute for an account identifier, such as a primary account number (PAN) and / or an expiration date. For example, an off-chain token may include a series of alphanumeric characters that may be used as a substitute for an original account identifier. For example, an off-chain token “4900000000000001” may be used in place of a PAN “4147090000001234.” In some embodiments, an off-chain token may be “format preserving” and may have a numeric format that conforms to the account identifiers used in existing transaction processing networks (e.g., ISO 8583 financial transaction message format). In some embodiments, an off-chain token may be used in place of a PAN to initiate, authorize, settle or resolve a payment transaction or represent the original credential in other systems where the original credential would typically be provided. In some embodiments, a token value may be generated such that the recovery of the original PAN or other account identifier from the token value may not be computationally derived. Further, in some embodiments, the token format may be configured to allow the entity receiving the token to identify it as an off-chain token and recognize the entity that issued the off-chain token.

[0031] “Off-chain tokenization” is a process by which sensitive data is replaced with substitute data. For example, a real credential (e.g., a primary account number (PAN)) may be tokenized by replacing the real account identifier with a substitute number that may be associated with the real credential. Further, tokenization can be 8 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 applied to any other information to substitute the underlying information with a token. “Token exchange” or “de-tokenization” can be a process of restoring the data that was substituted during tokenization. For example, a token exchange may include replacing an off-chain payment token with its associated primary account number (PAN). Further, de-tokenization or token exchange may be applied to any other information to retrieve the substituted information from a token. In some embodiments, token exchange can be achieved via a transactional message, such as an ISO message, an application programming interface (API), or another type of web interface (e.g., web request).

[0032] A “blockchain token” may be a representation of an asset or interest that has been tokenized on an existing blockchain. For example, a crypto token is a representation of an asset or interest that has been tokenized on an existing cryptocurrency's blockchain. In some cases, a blockchain token can be referred to as a cryptocurrency or a cryptoasset. In some cases, a blockchain can manage many types of blockchain tokens such as Ethereum, USDC (U.S. digital currency), NFTs, etc.

[0033] A “contract address” may include a digital address that identifies a smart contract. A contract address can identify a smart contract on a blockchain. A contract address could also be a public key of a smart contract.

[0034] An “interaction application” can be an application that can allow for a user to perform an interaction with another entity. One example of an interaction application is a digital wallet or digital wallet application.

[0035] A “digital wallet” may contain electronic information for conducting transactions. A digital wallet may store user profile information, payment credentials, bank account information, cryptocurrency account information, one or more digital wallet identifiers and / or the like and can be used in a variety of transactions, such as but not limited to eCommerce, social networks, money transfer / personal payments, mobile commerce, proximity payments, cryptocurrency transactions, gaming, and / or the like for retail purchases, digital goods purchases, utility payments, purchasing games or gaming credits from gaming websites, transferring funds between users, and / or the like. A digital wallet may be designed to streamline the purchase and 9 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 payment process. A digital wallet may allow the user to load one or more payment cards onto the digital wallet so as to make a payment without having to enter an account number or present a physical card.

[0036] A “cryptocurrency network” may include a one or more computers that participate in maintaining a cryptocurrency ledger. In some cryptocurrency networks, the distributed cryptocurrency ledger may comprise a blockchain.

[0037] A “blockchain” can be a distributed database that maintains a continuously growing list of records secured from tampering and revision. A blockchain can be a non-fungible token blockchain, a cryptocurrency blockchain, or a combination thereof. A blockchain may include a number of blocks of interaction records. Each block in the blockchain can contain also include a timestamp and a link to a previous block. Stated differently, interaction records in a blockchain may be stored as a series of “blocks,” or permanent files that include a record of a number of interactions occurring over a given period of time. Blocks may be appended to a blockchain by an appropriate node after it completes the block and the block is validated. Each block can be associated with a block header. In embodiments of the invention, a blockchain may be distributed, and a copy of the blockchain may be maintained at each full node in a verification network. Any node within the verification network may subsequently use the blockchain to verify interactions. A blockchain can be stored, maintained, and updated in a distributed manner in a peer-to-peer network. A blockchain can be associated with a cryptocurrency application, such as Bitcoin or Ethereum, Ripple, Dash, Litecoin, Dogecoin, zCash, Tether, Bitcoin Cash, Cardano, Stellar, EOS, NEO, NEM, Bitshares, Decred, Augur, Komodo, PIVX, Waves, Steem, Monero, Golem, Stratis, Bytecoin, Ardor, or digital currency exchanges, such as Coinbase, Kraken, CEX.IO, Shapeshift, Poloniex, Bitstamp, Coinmama, Bisq, LocalBitcoins, Gemini and others.

[0038] A “blockchain network” can include a computer network that maintains a blockchain. A blockchain network includes nodes that perform processing to maintain a blockchain.

[0039] A “block header” can be a header including information regarding a block in a blockchain. A block header can be used to identify a particular block on a 10 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 blockchain. A block header can comprise any suitable information, such as a previous hash, a Merkle root, a timestamp, and a nonce. In some embodiments, a block header can also include a difficulty value.

[0040] A “cryptocurrency blockchain” can include a blockchain that stores cryptocurrency. A cryptocurrency blockchain can be utilized to transfer cryptocurrency from one public address to another public address.

[0041] A “cryptocurrency” can include a digital currency. A cryptocurrency can include a digital currency in which transactions are verified and records maintained by a decentralized system using cryptography. A cryptocurrency may not need to be maintained by a centralized authority.

[0042] An “interaction” may include a reciprocal action or influence. An interaction can include a communication, contact, or exchange between parties, devices, and / or entities. Example interactions include a transaction between two parties and a data exchange between two devices. In some embodiments, an interaction can include a user requesting access to secure data, a secure webpage, a secure location, and the like. In other embodiments, an interaction can include a payment transaction in which two devices can interact to facilitate a payment. An interaction can be a transfer of a resource from a first entity to a second entity.

[0043] A “resource” can include digital items and / or physical items. A resource can be an item that is obtainable. A resource can be owned by an entity. A resource can be a physical item such as goods, etc. A resource can be a digital item such as non-fungible tokens, etc.

[0044] A “processing network computer” may include a server computer used for interaction processing. In some embodiments, the network processing computer may be coupled to a database and may include any hardware, software, other logic, or combination of the preceding for servicing the requests from one or more client computers. The network processing computer may comprise one or more computational apparatuses and may use any of a variety of computing structures, arrangements, and compilations for servicing the requests from one or more client computers. In some embodiments, a network processing computer may include data processing subsystems, networks, and operations used to support and deliver 11 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 authorization services, exception file services, and clearing and settlement services. An exemplary network processing computer may include VisaNet™. Networks that include VisaNet™ are able to process credit card transactions, debit card transactions, and other types of commercial transactions. VisaNet™, in particular, includes an integrated payments system (Integrated Payments system) which processes authorization requests and a Base II system, which performs clearing and settlement services. The network processing computer may use any suitable wired or wireless network, including the Internet.

[0045] The processing network computer may process interaction-related messages (e.g., authorization request messages and authorization response messages) and determine the appropriate destination computer (e.g., an issuer computer) for the interaction-related messages. In some embodiments, the network processing computer may authorize interactions on behalf of an issuer. The network processing computer may also manage and / or facilitate the clearing and settlement of interactions. In some cases, the network processing computer can include a token service computer, which can perform tokenization and / or de-tokenization services as described above.

[0046] An “authorization request message” may be an electronic message that requests authorization for an interaction. In some embodiments, it is sent to a transaction processing computer and / or an issuer of a payment card to request authorization for a transaction. An authorization request message according to some embodiments may comply with International Organization for Standardization (ISO) 8583, which is a standard for systems that exchange electronic transaction information associated with a payment made by a user using a payment device or payment account. The authorization request message may include an issuer account identifier that may be associated with a payment device or payment account. An authorization request message may also comprise additional data elements corresponding to “identification information” including, by way of example only: a service code, a CVV (card verification value), a dCVV (dynamic card verification value), a PAN (primary account number or “account number”), a payment token, a username, an expiration date, etc. An authorization request message may also comprise “transaction information,” such as any information associated with a current transaction, such as 12 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 the transaction value, merchant identifier, merchant location, acquirer bank identification number (BIN), card acceptor ID, information identifying items being purchased, etc., as well as any other information that may be utilized in determining whether to identify and / or authorize a transaction.

[0047] An “authorization response message” may be a message that responds to an authorization request. In some cases, it may be an electronic message reply to an authorization request message generated by an issuing financial institution or a transaction processing computer. The authorization response message may include, by way of example only, one or more of the following status indicators: Approval -- transaction was approved; Decline -- transaction was not approved; or Call Center -- response pending more information, merchant must call the toll-free authorization phone number. The authorization response message may also include an authorization code, which may be a code that a credit card issuing bank returns in response to an authorization request message in an electronic message (either directly or through the transaction processing computer) to the merchant's access device (e.g., POS equipment) that indicates approval of the transaction. The code may serve as proof of authorization.

[0048] An “authorizing entity” may be an entity that authorizes a request. Examples of an authorizing entity may be an issuer, a governmental agency, a document repository, an access administrator, etc. An authorizing entity may operate an authorizing entity computer. An “issuer” may refer to a business entity (e.g., a bank) that issues and optionally maintains an account for a user. An issuer may also issue payment credentials stored on a user device, such as a cellular telephone, smart card, tablet, or laptop to the consumer, or in some embodiments, a portable device.

[0049] The term “verification” and its derivatives may include a process that utilizes information to determine whether an underlying subject is valid under a given set of circumstances. Verification may include any comparison of information to ensure some data or information is correct, valid, accurate, legitimate, and / or in good standing.

[0050] A “processor” may include a device that processes something. In some embodiments, a processor can include any suitable data computation device or 13 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 devices. A processor may comprise one or more microprocessors working together to accomplish a desired function. The processor may include a CPU comprising at least one high-speed data processor adequate to execute program components for executing user and / or system-generated requests. The CPU may be a microprocessor such as AMD's Athlon, Duron and / or Opteron; IBM and / or Motorola's PowerPC; IBM's and Sony's Cell processor; Intel's Celeron, Itanium, Pentium, Xeon, and / or XScale; and / or the like processor(s).

[0051] A “memory” may be any suitable device or devices that can store electronic data. A suitable memory may comprise a non-transitory computer readable medium that stores instructions that can be executed by a processor to implement a desired method. Examples of memories may comprise one or more memory chips, disk drives, etc. Such memories may operate using any suitable electrical, optical, and / or magnetic mode of operation.

[0052] A “server computer” may include a powerful computer or cluster of computers. For example, the server computer can be a large mainframe, a minicomputer cluster, or a group of servers functioning as a unit. In one example, the server computer may be a database server coupled to a Web server. The server computer may comprise one or more computational apparatuses and may use any of a variety of computing structures, arrangements, and compilations for servicing the requests from one or more client computers. DETAILED DESCRIPTION

[0053] Embodiments of the invention can use a master computer. In some embodiments, the master computer may be characterized as a paymaster computer. A paymaster is a specialized type of smart contract account that can sponsor fees such as gas fees for user Contract Accounts (think of these as user-centric smart contracts). Embodiments of the invention liberate users from the need to hold native blockchain tokens or constantly engage in bridging tokens merely to cover transaction amounts. From a user’s perspective, this solution is appealing in its simplicity and ease of adoption. 14 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0054] The master computer can abstract away the complexities of the blockchain transaction funding while offering alternative ways for funding. An implementation does this by accepting the user’s payment off-chain from a device such as a payment card or payment card account, covering the equivalent amount on- chain, on behalf of the user. The payment experience on the user's end is as simple as a regular card payment.

[0055] A master computer and a master smart contract offers users an alternative way to pay transaction amounts. The recent ERC-4337 upgrade to the Ethereum network allows users to delegate blockchain transaction payments to a third party through the help of a class of smart contracts. Embodiments of the invention allow users to pay blockchain transaction amounts in fiat currency off-chain using a credit card or other payment device. A master service provider that operates a master service provider computer and accepts the off-chain card payment. The corresponding master smart contract covers the transaction amount on-chain on behalf of the user. Thus, the need for a blockchain user to hold any amount of a native blockchain currency (e.g., Ether for Ethereum) to be able to send transactions is obviated.

[0056] The off-chain payment capability can involve a first smart contract, which can be master smart contract associated with a master computer. The master smart contract can delegate all necessary checks and sourcing of information to an off-chain component such as an off-chain master computer. The on-chain master smart contract can then use the data and approval provided by the off-chain component to authorize and pay for the transaction amount. The way to reliably transfer this information from the off-chain service to the paymaster contract is through public key cryptography. The off-chain web service can utilize a secret key (or private key) to produce a digital signature to send along with the information. The master smart contract can in turn use the corresponding public key to verify the signature and therefore the authenticity of the information.

[0057] Embodiments of the invention have a number of other technical advantages. As blockchain transaction values (e.g., blockchain transaction amounts) are paid using fiat currency, the number of transactions processed by a blockchain network can be reduced, and this improves the overall processing speed of the 15 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 blockchain network because fewer transactions need to be processed. For example, the account funding approaches (onramp services or transfer via centralized crypto exchange) mentioned above in the Background can require blockchain transactions in order to initially transfer funds to a user’s wallet. These transactions do not need to take place in embodiments of the invention. There is no need to continually transfer funds (e.g., ETH) to a user account in advance of a user conducting a blockchain transaction. An Ethereum transaction can take 1-10 minutes to complete depending upon the number of required confirmations, while a Bitcoin transaction can take between 1-1.5 hours to complete. In contrast, performing an off-chain payment card authorization to pay for a transaction can take just a few seconds. Thus, reducing the number of transactions speeding the overall processing of the blockchain network and can save thousands of hours of absolute time and computational time.

[0058] In addition, as explained above, embodiments of the invention are much more convenient for users than paying for blockchain transactions in the currency of the blockchain. Some embodiments allow users to carry a card that resembles a typical credit or debit card. This card can be used to obtain resources using an access device such as a typical POS terminal. The user can conduct purchases using a blockchain token (e.g., a cryptocurrency such as USDC), while using a familiar interaction process that resembles, from the perspective of the user, a conventional credit or debit card transaction.

[0059] FIG. 1 shows a system according to an embodiment. The system 10 shows a user communication device 20 in communication with a blockchain network 40 comprising a plurality of blockchain nodes 40A-40E, and a master computer 50. The master computer 50 can be an off-chain component. The master computer 50 can be in communication with a gateway computer 60, a processing network computer 70, and an authorizing entity computer 80. The communication device 20 can have an interaction application 30, which can manage operation of cryptographic keys associated with an account of a user on a blockchain managed by the blockchain network 40. The master computer 50 can also manage and store a master computer public key and a master computer private key. 16 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0060] For simplicity of illustration, a certain number of components are shown in FIG.1. It is understood, however, that embodiments of the invention may include more than one of each component. In addition, some embodiments of the invention may include fewer than or greater than all of the components shown in FIG.1.

[0061] Messages between the devices included in the system 100 illustrated in FIG.1 can be transmitted using a secure communications protocol such as, but not limited to, File Transfer Protocol (FTP); HyperText Transfer Protocol (HTTP); Secure Hypertext Transfer Protocol (HTTPS), SSL, ISO (e.g., ISO 8583) and / or the like. The communications network may include any one and / or the combination of the following: a direct interconnection; the Internet; a Local Area Network (LAN); a Metropolitan Area Network (MAN); an Operating Missions as Nodes on the Internet (OMNI); a secured custom connection; a Wide Area Network (WAN); a wireless network (e.g., employing protocols such as, but not limited to a Wireless Application Protocol (WAP), I-mode, and / or the like); and / or the like. The communications network can use any suitable communications protocol to generate one or more secure communication channels. A communications channel may, in some instances, comprise a secure communication channel, which may be established in any known manner, such as through the use of mutual authentication and a session key, and establishment of a Secure Socket Layer (SSL) session.

[0062] FIG. 2 shows a system and overlaid method to allow for an off-chain payment for a blockchain transaction. The method of FIG.2 can be used in a “pay per transaction” model, where each transaction is paid for off-chain each time a transaction or event is performed on the blockchain. Stated another way, each transaction initiated by an interaction application 110 such as a cryptowallet may initiate one or more steps in FIG.2. The architecture of the system in FIG.2 can also be thought of as logically containing a “user domain” component, a “blockchain environment” component facilitated by a blockchain network,” and “off-chain environment” component, as illustrated in FIG.2. The blockchain network would have a plurality of nodes such as those shown in FIG.1, where the nodes may have one or more of the specific components shown in the blockchain environment in FIG.2. 17 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0063] Illustrated in FIG.2 is interaction application 110 such as a cryptowallet that can be present in a user communication device in a user domain. An off-chain environment can include a master computer 120 (e.g., a paymaster computer), a gateway computer 130 such as a payment gateway computer (e.g., CyberSource™), a processing network computer 132, and an authorizing entity computer 134.

[0064] The blockchain component can include features or software that would reside in the blockchain network (e.g., blockchain network 40 in FIG. 1). The blockchain component includes a first smart contract 140 (e.g., a paymaster smart contract), a mempool 150, a bundler / node 160, an entry point contract 170, a second smart contract 180 (e.g., a smart contract account of associated with the user), and representative blocks 191, 192, 193 of a blockchain.

[0065] The interaction application 110 can be a cryptowallet that can store public and / or private keys in a user communication device, along with cryptocurrency amounts or other cryptocurrency-based information, to perform cryptocurrency transactions or functions. The interaction application 110 can belong to a user of a communication device that wishes to perform functions with respect to a blockchain.

[0066] Master computer 120 may be a paymaster service computer and can provide a service which can sponsor transaction amounts on behalf of users. In some embodiments, a “paymaster” may be an entity that can sponsor gas fees for transactions on Ethereum-based networks through the use of account abstraction, such as for example, as specified in the ERC-4337 standard.

[0067] The gateway computer 130 can initiate payment transactions with issuers of fiat currency accounts such as credit or debit card accounts. The gateway computer 130 can a merchant processor computer, an acquirer computer, etc.

[0068] The first smart contract 140 can be a paymaster smart contract, which facilitates transactions on a blockchain for a paymaster. The paymaster smart contract can be a smart contract of a particular paymaster or a set of smart contracts, or a smart contract account, which can facilitate transaction sponsorship by allowing third- party designed mechanisms to pay for transactions. In some examples, a paymaster smart contract is a smart contract or computer logic which can allow for the payment 18 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 of a transaction fee on behalf of a user, and executing any logic to decide whether it should forward a transaction in the blockchain.

[0069] Mempool 150 is a memory pool stored in memory in one or more nodes of a blockchain network. In some examples, mempool 150 is a waiting area for transaction that have not yet been executed, are unconfirmed by a blockchain, and have not yet been added to a block. Stated alternatively, mempool 150 can contain transactions which are still being processed by the blockchain.

[0070] Bundler / node 160 can be a software node which facilitates transactions in a blockchain. For example, in the context of Ethereum, a “ software node” can be any instance of Ethereum client software on a computer that is connected to other computers also running Ethereum software, forming a network. A client is an implementation of Ethereum that verifies data against the protocol rules and keeps the network secure. A Bundler can be a software node that obtains one or more requested user operations from a Mempool to create a bundle of transactions that is signed and submitted to the blockchain network as a single transaction.

[0071] Entry point contract 170 can be a singleton contract that acts as a “guard” or “entry point” to account abstraction. The entry point contract 170 can orchestrate the processing of user operations onchain, enabling smart contracts to operate as user wallet accounts on Ethereum according to the ERC-4337 standard. This may allow for additional actions to be performed through user wallet accounts, such as setting up automated payments.

[0072] The second smart contract 180 can be a smart contract account. For instance, a smart contract account can be a smart contract that can be used to interact with other smart contracts on behalf of the owner of the smart contract account. It can enable functionality beyond that which is available through a cryptowallet or other externally owned account alone. The second smart contract 180 can be associated with an account, which is in turn owned by the user of the communication device with the interaction application 110.

[0073] Blocks 191, 192, 193 may be blocks within an exemplary blockchain. For instance, blocks 191, 192, and 193 may be sequential blocks in an Ethereum blockchain, or any other suitable type of blockchain. 19 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0074] As explained with respect to FIG.2, a series of example steps may be undertaken to allow for an external credit account or payment account to be used to pay for blockchain transactions using fiat currency.

[0075] In step 1, a communication device comprising the interaction application 110 can transmit to the master computer 120, an off-chain transaction request comprising a credential or a token for an off-chain transaction in association with a blockchain transaction. For example, a user may initiate a request at the interaction application 110 (e.g., a cryptowallet) on a user communication device in step 1. In this step, a request may be initiated to pay a blockchain transaction amount with a payment card. The interaction application 110 can be programmed to determine the amount of blockchain tokens for the blockchain transaction in fiat currency based on the particular operation requested by the user of the user communication device. At step 1, the card access data (e.g., a credential such as a PAN or a token) associated with the payment card, and payment information, such as the fiat equivalent of the blockchain transaction amount, may be sent to a paymaster service. In some examples, the equivalent may be set based on current fiat to cryptocurrency exchange rates. This information may be sent to the master computer 120 (e.g., a paymaster service computer).

[0076] At step 2, the master computer 120 can initiate an authorization request message with the gateway computer 130 in communication with the authorizing entity computer 134. For example, the master computer 120, after receipt of the information in step 1, may obtain authorization for the blockchain transaction amount payment by communicating with the gateway computer 130. The master computer 120 can initiate (e.g., generate) an authorization request message comprising an amount in fiat currency and can send it to a gateway computer 130. The gateway computer 130 can forward the authorization request message to the processing network computer 132. If the authorization request comprises an off-chain token, then the processing network computer 132 can de-tokenize the off-chain token to obtain the credential (e.g., a PAN or primary account number) associated with the off-chain token. The processing network computer 132 can then transmit the authorization request message with the credential to the authorizing entity computer 134 for authorization. The authorizing entity computer 134 can then send an authorization response message back to the 20 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 gateway computer 130 via the processing network computer 132. The gateway computer 130 can provide an indication of the authorization to the master computer 120.

[0077] At the end of the day or some other period of time, the authorizing entity computer 134 can clear and settle the transaction with the gateway computer, which may manage a fiat currency account associated with the paymaster service operating the master computer 120.

[0078] At step 3, the master computer 120, may receive confirmation of authorization from the gateway computer 130. This information and / or information about the approval of the blockchain transaction amount payment may be sent by the master computer 120 to interaction application 110. For example, the information may include the amount of the blockchain transaction in fiat currency, an address (e.g., a public key) and / or account number of the master computer 120, an authorization code from the authorizing entity computer 134, a date and time, etc. This information and optionally other information about the user’s account may then be digitally signed with a master computer private key stored at the master computer 120 to produce a digital signature. The digital signature may later be verified on-chain by the first smart contract 140 using a corresponding public key corresponding to the master computer private key. The master computer 120 can transmit an off-chain transaction response message comprising (e.g., in addition to the data mentioned above) the digital signature (e.g., the master computer digital signature) indicating approval of the off- chain transaction, a signature validity time window, and an on-chain paymaster contract address (e.g., the address of the first smart contract) to the interaction application 110 on the user communication device.

[0079] At step 4, the communication device comprising the interaction application 110 can transmit to a node (e.g., a computer node) in a blockchain network managing a blockchain, a blockchain transaction request comprising transaction parameters associated with the blockchain transaction. For example, in step 4, a blockchain transaction request for a blockchain transaction may be submitted by a user through his or her cryptowallet to the blockchain network in the blockchain environment. The transaction parameters may include information sufficient to process 21 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 the transaction on the blockchain managed by the blockchain network and the master computer digital signature obtained in step 3. Such information may include the user’s address (e.g., the user’s public key), the recipient’s address (the recipient’s public key), the protocol used to conduct the transaction, and the value to transfer from the user to the recipient, and an address (e.g., a public key) of the first smart contract 140. The value may be a blockchain transaction value in the form of the desired blockchain tokens (e.g., 50 USDC). The transaction information may also include a specific service (e.g., a specific paymaster) which was selected at the time the transaction was submitted. The specific service may be identified with an address (e.g., public key) of the first smart contract and / or the master computer 120. A transaction digital signature of this information (signed by a communication device private key) may also be included in the blockchain request as proof that the user approved of the transaction.

[0080] At step 5, the transaction may be received by mempool 150.

[0081] At step 6, the transaction may be provided from the mempool 150 to bundler / node 160 for processing. Upon processing, the transaction be submitted to entry point contract 170 with other transaction in a bundle.

[0082] The node in the blockchain network also requests verification of the off- chain transaction using the first smart contract 140 associated with the master computer, verifies the transaction parameters with a second smart contract 180, and then executes the blockchain transaction.

[0083] For example, at step 7, the entry point contract can interact with second smart contract 180 to validate the smart contract account and ensure that the requested operation is correct with respect to the selected service (e.g., selected paymaster) and the user’s account. In some examples, second smart contract 180 can be a program corresponding to an account associated with the same user as the interaction application 110. This information can be returned to the entry point contract 170. For example, the second smart contract 180 can determine if the user of the interaction application 110 has sufficient funds to conduct a requested cryptocurrency transaction. The second smart contract 180 and / or the entry point contract 170 can also view the blockchain with the blocks 191, 192, 193 to determine a current state of 22 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 the user’s account. The logic may recognize that a digital signature from the master computer 120 was included in the transaction information.

[0084] At step 8, entry point contract 170 can ensure that the service associated with the first smart contract 140 and the master computer 120 is valid, that the service’s (e.g., paymaster’s) balance of cryptocurrency is sufficient to pay for the blockchain transaction amount, and that the stake of the service is acceptable.

[0085] At step 9, entry point contract 170 can request that the first smart contract 140 validate the digital signature of the off-chain transaction details, which was previously generated by the master computer 120 using the master computer private key. The first smart contract 140 can validate the digital signature produced by the master computer 120 using a public key of the master computer 120. The first smart contract 140 can also check an expiration window for verifying the digital signature.

[0086] At step 10, after receiving confirmation from the first smart contract 140 that the blockchain transaction amount has been paid by the user in fiat currency, the entry point contract 170 can orchestrate the execution of the user function or user transaction requested by interaction application 110 and the second smart contract 180 executes the user function or user transaction.

[0087] In step 11 as part of the transaction execution, the second smart contract 180 optionally requests necessary funds in the form of blockchain tokens (e.g., USDC) from the first smart contract 140 by calling the first smart contract 140.

[0088] In step 12, the first smart contract 140 can contact a (decentralized) token exchange (e.g., Uniswap, Curve Finance, etc. to acquire any blockchain tokens needed for the transaction that it does not currently have. The blockchain tokens, may be, for example, USDC, etc. Such tokens may be obtained and transferred on a blockchain such as the Ethereum blockchain.

[0089] In step 13, the first smart contract provides blockchain tokens needed for the transaction execution and completion to the user’s account associated with the second smart contract 180. 23 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0090] Once the funds are received in the user’s account, the second smart contract 180 can perform operations to execute the remainder of the transaction. For example, the second smart contract 180, could initiate a write operation including the transaction parameters of the blockchain transaction and the transfer of the blockchain tokens to another user (e.g., a receiver of the blockchain tokens) to the blockchain. More specifically, at a final step, the user operation requested can be written by the appropriate nodes in the blockchain network to a next block on the blockchain such as for example, block 193. This can ensure that the operation is provided to the blockchain and recorded.

[0091] In step 14, in another example, the second smart contract 180 could call a third smart contract 181 to complete the transaction. For example, the second smart contract 180 could provide some of the transaction parameters to the third smart contract 181, and it can initiate the transfer of the blockchain tokens obtained from the first smart contract 140 to another user (e.g., a receiver of the blockchain tokens). As an illustration, the third smart contract 181 can be an NFT (non-fungible token) smart contract, which has programmed to initiate a transfer of funds from a sender of funds to a receiver of funds, and to initiate a transfer of an NFT from the receiver of funds to the sender of funds.

[0092] FIG.3 illustrates a diagram of a communication device 300 according to an embodiment. communication device 300 may include device hardware 304 coupled to a system memory 302.

[0093] Device hardware 304 may include a processor 306, a short range antenna 314, a long range antenna 316, input elements 310, a user interface 308, and output elements 312 (which may be part of the user interface 308). Examples of input elements may include microphones, keypads, touchscreens, sensors, etc. Examples of output elements may include speakers, display screens, and tactile devices. The processor 306 can be implemented as one or more integrated circuits (e.g., one or more single core or multicore microprocessors and / or microcontrollers), and is used to control the operation of communication device 300. The processor 306 can execute a variety of programs in response to program code or computer-readable code stored 24 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 in the system memory 302, and can maintain multiple concurrently executing programs or processes.

[0094] The long range antenna 316 may include one or more RF transceivers and / or connectors that can be used by the communication device 300 to communicate with other devices and / or to connect with external networks. The long range antenna 316 may be configured to communicate with a remote base station and a remote cellular or data network, over the air. The short range antenna 309 may be configured to communicate with external entities through a short range communication medium. The short range antenna 309 may comprise a contactless interface that can interact with a contactless interface of another device (e.g., a portable device). Examples of a contactless interface may include one or more radio frequency (RF) transceivers that can send and receive communications using near-field communications (NFC), or other radio frequency or wireless communication protocols. The user interface 308 can include any combination of input and output elements to allow a user to interact with and invoke the functionalities of the communication device 300.

[0095] The system memory 302 can be implemented using any combination of any number of non-volatile memories (e.g., flash memory) and volatile memories (e.g., DRAM, SRAM), or any other non-transitory storage medium, or a combination thereof media. The system memory 302 may store computer code, executable by the processor 306, for performing any of the functions described herein. For example, the system memory 302 may comprise a computer readable medium comprising code, executable by the processor 306, for implementing a method comprising: transmitting, by a communication device to a master computer, an off-chain transaction request comprising a credential or an off-chain token for an off-chain transaction in association with a blockchain transaction, wherein the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer; receiving, by the communication device, an off-chain transaction response from the master computer, the off-chain transaction response comprising a master computer digital signature, the master computer digital signature indicating approval of the authorization request message; and transmitting, by the communication device to a node in a blockchain network managing a blockchain, a blockchain transaction request comprising transaction parameters associated with the blockchain 25 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 transaction, the transaction parameters including the master computer digital signature, wherein the node verifies the transaction parameters with a second smart contract, and provides a signature validation request comprising the master computer digital signature to a first smart contract using a first smart contract address and receives a signature validation response from the first smart contract, and executes the blockchain transaction by communicating with the second smart contract, wherein second smart contract calls the first smart contract to request funds from first smart contract, which acquires and provides blockchain tokens to a second smart contract account.

[0096] The system memory 302 may also store an interaction application 302A, an authentication module 302B, cryptography module 302C, and an operating system 302D. The interaction application 302A may include instructions or code executable by the processor 306 for initiating and conducting an interaction such as those described above.. The authentication module 302B may comprise code, executable by the processor 306, to authenticate a user. This can be performed using user secrets (e.g., passwords) or user biometrics. The cryptography module may comprise cryptographic processing logic such as encryption, decryption, and signing algorithms. It may also store public and private keys associated with the user of the communication device.

[0097] FIG. 4 shows a block diagram of a node computer 400. The node computer 400 may include a processor 402 and a computer readable medium 404, a data storage 406 which can store a blockchain 406A as well as a mempool of transactions, and a network interface 408 coupled to the processor 402.

[0098] The computer readable medium 404 may comprise a communication module 404A, a blockchain processing module 404B, and a smart contract interaction module 404C. The computer readable medium 404 may also comprise code, executable by the processor 402 for performing operations comprising: receiving by the computer node, a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature; verifying, by the entry point smart contract with the second smart contract, at least some of the transaction parameters; 26 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 providing, by the entry point smart contract to the first smart contract, a signature validation request comprising the master computer digital signature; verifying, by the first smart contract, the master computer digital signature; receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract; communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request; and calling, by the second smart contract, the first smart contract to request blockchain tokens to complete the blockchain transaction, wherein the first smart contract acquires and provides the blockchain tokens to an account associated with the second smart contract.

[0099] The communication module 404A can comprise code, executable by the processor 402 to cause the processor 402 to communicate with external entities such as the previously described master computer and communication device.

[0100] The blockchain processing module 404B may comprise code that causes the processor 402 to interaction and process transactions for including on a blockchain as described above.

[0101] The smart contract interaction module 404C may comprise code that causes the processor 306 to perform smart contract interactions such as those described above.

[0102] FIG.5 shows a block diagram of a master computer 500 according to an embodiment. The master computer 500 comprises a processor 502 and a computer readable medium 504, a data storage 506, and a network interface 508 coupled to the processor 306.

[0103] The computer readable medium 504 may comprise a communication module 504A, which may have similar functions as communication module 404A above, a cryptography module 504B which may have similar functions as cryptography module 302C above, and an authorization processing module 504C. The authorization processing module 504C may comprise code, executable by the processor 502 to initiate (e.g., generate) authorization request messages, transmit authorization request messages, receive authorization response messages, etc. 27 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0104] The computer readable medium 504 may comprise code executable by the processor 502 for performing operations comprising: receiving, by the master computer from a communication device, an off-chain transaction request comprising a credential or a token for an off-chain transaction in association with a blockchain transaction; initiating, by the master computer, an authorization request message with a gateway computer in communication with an authorizing entity computer; receiving, by the master computer, an authorization response message from the authorizing entity computer; and transmitting, by the master computer, an off-chain transaction response to the communication device, wherein the communication device transmits, to a node in a blockchain network managing a blockchain, a blockchain transaction request comprising transaction parameters associated with the blockchain transaction, wherein node requests verification the off-chain transaction using a first smart contract and verifies the transaction parameters with a second smart contract, and then executes the blockchain transaction. In other embodiments, the master computer can transmit the blockchain transaction request to the node in the blockchain network.

[0105] FIG.6 shows a diagram of a blockchain according to embodiments of the present invention. FIG.6 includes a blockchain 600 comprising a first block 610 and a second block 640. The blockchain 600 can include any suitable number of blocks (e.g., 10, 500, 2000, 500000, etc.).

[0106] Current blockchain technologies, such as Bitcoin and Ethereum, maintain an append-only ledger in a network. The ledger includes a list of blocks of transaction data, the blocks are cryptographically chained together. A block is created by a computationally intensive process called proof-of-work in which valid blocks need to demonstrate a sufficient “difficulty" (i.e., sufficient computation power to create on average). If there are more than one available chains of blocks, then network participants (i.e., nodes) can download all blocks in all chains and follow the chain which has the highest total difficulty. This mechanism guarantees that, eventually, the network will agree on a single and valid chain, see [Garay et al, The Bitcoin backbone protocol: Analysis and applications. In Advances in Cryptology - EUROCRYPT 2015, pages 281–310, 2015], [Bitcoin Website. bitcoin.org], and [Rafael Pass, Lior Seeman, and Abhi Shelat. Analysis of the blockchain protocol in asynchronous networks. In 28 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 Jean-Sébastien Coron and Jesper Buus Nielsen, editors, Advances in Cryptology – EUROCRYPT 2017, pages 643–673, Cham, 2017. Springer International Publishing.], which are all incorporated herein by reference for all purposes.

[0107] The blockchain 600 can create a history of data deposits, messages, or entries in a series of blocks where each block contains a mathematical summary, called a hash, of the previous block. This creates a chain where any changes made to a block will change that block's hash, which must be recomputed and stored in the next block. This changes the hash of the next block, which must also be recomputed and so on until the end of the chain.

[0108] Although the hash can be simple to compute, rules may be imposed, which require the value of the hash to be below a certain threshold value (i.e., a difficulty value). In addition, the hash is based on a type of mathematical function that is not reversible. One cannot predict what input can be used to produce the desired output. A valid hash is found by repeatedly adjusting a changeable value in the block, and recalculating the hash until it meets the validity requirements. The freely changeable value can be a nonce. The unpredictable nature of the hash considerably increases the difficulty of finding a nonce that produces a valid hash of the block.

[0109] As an example, the first block 610 can include a block header 620 and block entries 630. The block header 620 of the first block 610 can comprise a previous hash 612, a timestamp 614, a Merkle root 616, and a nonce 618.

[0110] The previous hash 612 can be a hash of the previous block’s header. The previous hash 612 can be the result of a non-reversible mathematical computation using data from the previous block as the input. According to some embodiments, the computation used can include a SHA256 hash function. One of ordinary skill in the art would recognize that any suitable hash function could be used without departing from the spirit and scope of the present invention. The hash function can be designed so that any change to the data in the previous block results in an unpredictable change in the hash of that block. The previous hash 612 can be a link between blocks, chaining them together to form the blockchain 600.

[0111] When calculating the previous hash 612 for the previous block, a node can determine if the previous hash 612 can meet certain criteria defined by a difficulty 29 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 value. In some embodiments, the difficulty value may include a number that the calculated hash must be less than. However, because the output of the hashing function is unpredictable, the output cannot be determined what input will result in an output that is less than the difficulty value before the hash is calculated. The nonce 618 can be used to vary the data content of the block, allowing for a large number of different outputs to be produced by the hash function in pursuit of an output that meets the difficulty value. This makes can make it computationally expensive to produce a valid block with a nonce 618 that produces a hash value meeting the criteria of the difficulty value.

[0112] The hash algorithms used for the previous hash 612 can include MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA-512 / 224, SHA-512 / 256, SHA- 3 or any suitable hash function. There is also no requirement that a hash be computed only once. The results of a hash function may be reused as inputs into another or the same hash function again multiple times in order to produce a final result. One of ordinary skill in the art would recognize that any hash function could be used to compute the required hashing without departing from the spirit and scope of the present invention.

[0113] The Merkle root 616 can be a root of a Merkle tree, which can include a tree in which every leaf node is labelled with the hash of a data block, for example an entry. Each leaf of the Merkle tree can represent one of the entries. Each entry can be hashed together with a sibling node (i.e., entry) in the Merkle tree. Successively hashing sibling nodes in the Merkle tree can result in the Merkle root 616.

[0114] The block entries 630 can include interaction data and / or smart contracts. The block entries 630 can include any suitable number of entries. Example entries can include the data described above, such as witnesses, signed witnesses, digital signatures, interaction messages, unconditional payment data, proof of inclusions, other data related to the processing of an offline interaction between two user devices, etc. In some embodiments, an entry may be a null value, for example, in the case of the Merkle tree being a sparse Merkle tree.

[0115] In some embodiments, the number of entries in the block entries 630 may be limited by the overall size of the block (e.g., the first block 610). For example, 30 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 the blocks on the blockchain may be limited by a certain amount of data (e.g., 1 / 2 MB, 1 MB, 2 MB, 5 MB, 10 MB, etc.). In other embodiments, the number of entries in the block entries 630 may be a predetermined number of entries. For example, the nodes in the verification network can determine that 1, 10, 150, 500, 1000, etc. entries can be included in the block entries 630. The entries can be transactions, user operations, smart contracts, etc.

[0116] The timestamp 614 can include a time that the block was created within a certain range of error. According to some embodiments of the present invention, the full nodes of the verification network can check the timestamp 614 against their own known time and can reject any block that seems to have an erroneous timestamp 614.

[0117] The nonce 618 can be a value adjusted by a full node while performing a proof-of-work process, as described herein. A nonce can be input into a hash function along with block data to determine the output hash value. A correct nonce (also referred to as a golden nonce) yields an output hash value that satisfies a predetermined criteria, such as being less than a difficulty value.

[0118] The second block 640 can be similar to the first block 610. For example, the second block 640 can include a block header 650 and block entries 660. The block header 650 of the second block 640 can comprise a previous hash 652, a timestamp 654, a Merkle root 656, and a nonce 658. The block entries 660 can include image data, interaction data, smart contracts, etc., and can be similar to the block entries 630.

[0119] FIG.7 shows a diagram illustrating an contract account creation process according to embodiments.

[0120] In step 1, the user utilizes an application on a communication device 62 and a trusted execution environment (TEE) to generate a keypair for their master account contract. The keypair can include a secret key (sk) (or private key) and a public key (pk). The secret key (sk) can be stored on the communication device 62.

[0121] In step 2, the public key is sent to an intermediary entity such as an authorizing entity computer 134 operated by an authorizing entity (e.g., a bank), to 31 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 conduct a KYC (know your customer) process and other processes required for compliance.

[0122] In step 3, the authorizing entity computer 134 forwards the public key as part of the account creation request to a service node comprising the master computer 120 (e.g., a Visa Crypto Service node).

[0123] In step 4, the service node deploys a main account contract such as the previously described second smart contract 180 on the blockchain. The second smart contract 180 is associated with an account of the user, and it can use the public key for signature verification.

[0124] FIG. 8 shows a system and method for issuing a crypto enabled user device such as a crypto enabled access card (e.g., payment card).

[0125] In step 1, a user uses a smart card application on their communication device 62 (e.g., the user’s phone) communicate with an authorizing entity (e.g., ain issuer bank) operating the authorizing entity computer 134 to request the issuance of a crypto-enabled card 63. The user causes the smart card application on the communication device 62 to sign the request to produce a digital signature. The digital signature is produced using the private key (sk) created in the method described with respect to FIG.7.

[0126] In step 2, authorizing entity computer 134 receives the card request and signature. The authorizing entity conducts a KYC (know your customer) process and / or other processes required for compliance. The card-issuing authority forwards the request to the service node comprising the master computer 120 (e.g., the Visa Crypto Service node).

[0127] In step 3, the master computer 120 provides the request to a coordination platform 152 using an API call to request a new card.

[0128] In step 4, the coordination platform 152 makes a request to a card manufacturer 58 to issue the crypto-enabled card, and provides the relevant information to the card manufacturer. 32 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01

[0129] In step 5, the card manufacturer 58 creates a new crypto-enabled card with a new public-private key pair (e.g., a user device public key such as a card public key, and a user device private key such as a card private key), which is securely stored on the card. The card manufacturer 58 can be associated with the authorizing entity operating the authorizing entity computer 134 in FIG.7.

[0130] In step 6, the card manufacturer 58 sends the new public key to the coordination platform 152, which relays it to the master computer 120.

[0131] In step 7, the card manufacturer 58 sends the physical card 63 with the new public key and a new private key corresponding to the new public key to the user.

[0132] In step 8, the master computer 120 can send a transanction request to a main account smart contract on the blockchain to deploy a sub-account smart contract on the blockchain. The main account smart contract can be a smart contract managed by the authorizing entity operating the authorizing entity computer 134. The sub-account smart contract can correspond to the previously described second smart contract and can be specifically associated with the user. The transaction request also includes a public key of the new card, a digital signature of the user (created by using the communication device private key or secret key), and an optional master computer digital signature to cover blockchain transaction amounts.

[0133] In step 9, a main account smart contract 170 on the blockchain receives the transaction request, and sends the master computer signature to the first smart contract 140, which verifies the signature and covers the blockchain transaction amounts of the transaction.

[0134] In step 10, the main account contract deploys a sub-account smart contract (second smart contract 180), and provides the public key that will be used for signature verification / authorization to it.

[0135] FIG. 9 shows a block diagram of a system and an overlaid method according to embodiments. FIG.9 repeats many of the steps described above with respect to FIG.2. Steps that are new and / or different include steps 1A, 1B, and 4’.

[0136] The method in FIG. 9 uses a card 111 such as the one issued in the process described above in FIG.8. The card 111 may be an example of a user device. 33 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 In some embodiments, the user device does not have direct remote communication capabilities. For example, in some embodiments, the user device, may not have hardware to directly connect to a cellular network or the Internet. The user device may interact with an access device 113, which may be a terminal such as a POS (point of sale) terminal. This is different than the embodiment in FIG.2, where the user uses a communication device with in interaction application to interact directly with the blockchain network comprising the blockchain nodes and the blockchain using a cellular communications network or the Internet.

[0137] The use of a user device such as a card to perform blockchain transaction is particularly advantageous. For example, the user is able to perform blockchain transactions by having a simple card. The user can use the card at any access device that may be operated by a resource provider to obtain access to a resource, such as a good, service, or secure location.

[0138] With reference to FIG.9, the user of the card 111 may wish to conduct a transaction such as a payment card transaction with a resource provider (e.g., a merchant) that operates the access device 113. The user may wish to conduct a transaction with the resource provider. The user may intend to provide a value of 100 USDC to the resource provider in exchange for access to a good, a service, or a secure location. The access device 113 may display the amount of the current transaction, and this and other access device information may be passed to the card 111. The card 111 can receive this transaction parameter along with other along with transaction parameter information (e.g., a public key associated with the resource provider and the public key associated with the card 111) and sign it with the private key on the card 111 to form a digital signature. The card 111 can do this by interacting with the access device 113 using a contact or contactless (e.g., NFC or near field communication) mode of operation. The card 111 can then send digital signature, the transaction information, and the credential or the off-chain token to the access device 113.

[0139] In step 1B, the access device 113 may then transmit a transaction request message to the master computer 120. In step 2, the master computer performs an authorization process for an off-chain value (e.g., off-chain fiat currency such as 34 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 U.S. dollars) as in the process of FIG. 2. The access device 113 can communicate with the master computer 120 using any suitable protocol including ISO 8583 and / or TCP IP. The transaction request message may be an authorization request message in some embodiments.

[0140] In step 4’, after receiving the authorization response message from the authorizing entity computer 134, the master computer provides a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature. The remaining steps in FIG.9 can correspond to the steps in FIG.2, and descriptions thereof are incorporated herein. Step 4’ is different than step 4 in FIG.2, since in step 4 in FIG. the blockchain transaction request is provided by the communication device instead of the master computer 120.

[0141] Any of the software components or functions described in this application may be implemented as software code to be executed by a processor using any suitable computer language such as, for example, Java, C, C++, C#, Objective-C, Swift, or scripting language such as Perl or Python using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer readable medium for storage and / or transmission, suitable media include random access memory (RAM), a read only memory (ROM), a magnetic medium such as a hard-drive or a floppy disk, or an optical medium such as a compact disk (CD) or DVD (digital versatile disk), flash memory, and the like. The computer readable medium may be any combination of such storage or transmission devices.

[0142] Such programs may also be encoded and transmitted using carrier signals adapted for transmission via wired, optical, and / or wireless networks conforming to a variety of protocols, including the Internet. As such, a computer readable medium according to an embodiment of the present invention may be created using a data signal encoded with such programs. Computer readable media encoded with the program code may be packaged with a compatible device or provided separately from other devices (e.g., via Internet download). Any such computer readable medium may reside on or within a single computer product (e.g., a 35 78741514V.1PATENT Attorney Docket No.079900-1450600 Client Ref. No.7756WO01 hard drive, a CD, or an entire computer system), and may be present on or within different computer products within a system or network. A computer system may include a monitor, printer, or other suitable display for providing any of the results mentioned herein to a user.

[0143] The above description is illustrative and is not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of the disclosure. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the pending claims along with their full scope or equivalents.

[0144] One or more features from any embodiment may be combined with one or more features of any other embodiment without departing from the scope of the invention.

[0145] As used herein, the use of "a," "an," or "the" is intended to mean "at least one," unless specifically indicated to the contrary. 36 78741514V.1

Claims

WHAT IS CLAIMED IS:

1. A method using a node managing a blockchain in a blockchain network, the blockchain comprising an entry point smart contract, a first smart contract, a second smart contract, and a plurality of blocks, the method comprising: receiving, by the node, a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature; verifying, by the entry point smart contract with the second smart contract, at least some of the transaction parameters; providing, by the entry point smart contract to the first smart contract, a signature validation request comprising the master computer digital signature; verifying, by the first smart contract, the master computer digital signature; receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract; communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request; and calling, by the second smart contract, the first smart contract to request blockchain tokens to complete the blockchain transaction, wherein the first smart contract acquires and provides the blockchain tokens to an account associated with the second smart contract.

2. The method of claim 1, wherein the first smart contract acquires the blockchain tokens via a token exchange.

3. The method of claim 1, wherein the blockchain transaction transfers an amount of the blockchain tokens from a first user associated with the second smart contract to a second user, wherein the method further comprises: transmitting, by the second smart contract to a third smart contract, which completes the blockchain transaction.37 78741514V.

14. The method of claim 1, wherein the master computer digital signature is received from a master computer that generated the master computer digital signature.

5. The method of claim 4, wherein the master computer stores a master computer private key of a master computer public-private key pair, and produces the master computer digital signature with the master computer private key.

6. The method of claim 1, wherein the master computer digital signature is generated by a master computer, after the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer.

7. The method of claim 6, wherein the authorization request message has an off-chain value.

8. The method of claim 1, wherein the blockchain transaction request is received from an interaction application on a communication device.

9. The method of claim 8, wherein the transaction parameters are generated using the communication device.

10. The method of claim 9, wherein the communication device is a mobile phone.

11. The method of claim 1, wherein the blockchain transaction request is received from a master computer, wherein the master computer generates the master computer digital signature after the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer.

12. The method of claim 11, The method of claim 12, wherein before initiating the authorization request message, the master computer receives an off-38 78741514V.1chain transaction request comprising the transaction parameters and a credential or credential from an access device that interacts with a user device comprising a user device private key, wherein the user device does not have remote communication capabilities.

13. The method of claim 12, and wherein the user device is in the form of a card.

14. The method of claim 13, wherein the user device signs at least some of the transaction parameters using the user device private key to produce a transaction digital signature, which is provided to the node via the access device.

15. The method of claim 1, wherein the transaction parameters comprise a public key associated with a communication device, an address of a sender associated with the communication device, an address of a receiver of a blockchain transaction value associated with the blockchain transaction request, the blockchain transaction value being in the blockchain tokens, and a first smart contract address associated with the first smart contract.

16. The method of claim 1, wherein after the account associated with the second smart contract receives the blockchain tokens, the node initiates a write operation including the transaction parameters of the blockchain transaction to the blockchain.

17. The method of claim 11, wherein the transaction parameters further comprise a third smart contract address associated with a third smart contract, the third smart contract, wherein after the account associated with the second smart contract receives the blockchain tokens, the second smart contract calls the third smart contract to complete the blockchain transaction.

18. A computer node for managing a blockchain comprising an entry point smart contract, a first smart contract, a second smart contract, and a plurality of blocks comprising:39 78741514V.1a processor; and a non-transitory computer readable medium, the non-transitory computer readable medium comprising code, executable by the processor for performing operations comprising: receiving by the computer node, a blockchain transaction request comprising transaction parameters associated with a blockchain transaction, the transaction parameters including a master computer digital signature; verifying, by the entry point smart contract with the second smart contract, at least some of the transaction parameters; providing, by the entry point smart contract to the first smart contract, a signature validation request comprising the master computer digital signature; verifying, by the first smart contract, the master computer digital signature; receiving, by the entry point smart contract from the first smart contract, a signature validation response from the first smart contract; communicating, by the entry point smart contract with the second smart contract to execute the blockchain transaction request; and calling, by the second smart contract, the first smart contract to request blockchain tokens to complete the blockchain transaction, wherein the first smart contract acquires and provides the blockchain tokens to an account associated with the second smart contract.

19. A method comprising: transmitting, by a communication device to a master computer, an off- chain transaction request comprising a credential or an off-chain token for an off-chain transaction in association with a blockchain transaction, wherein the master computer initiates an authorization request message with a gateway computer in communication with an authorizing entity computer; receiving, by the communication device, an off-chain transaction response from the master computer, the off-chain transaction response comprising a master computer digital signature, the master computer digital signature indicating approval of the authorization request message; and transmitting, by the communication device to a node in a blockchain network managing a blockchain, a blockchain transaction request comprising40 78741514V.1transaction parameters associated with the blockchain transaction, the transaction parameters including the master computer digital signature, wherein the node verifies the transaction parameters with a second smart contract, and provides a signature validation request comprising the master computer digital signature to a first smart contract using a first smart contract address and receives a signature validation response from the first smart contract, and executes the blockchain transaction by communicating with the second smart contract, wherein second smart contract calls the first smart contract to request funds from first smart contract, which acquires and provides blockchain tokens to a second smart contract account.

20. The method of claim 19, wherein the communication device is a mobile phone.41 78741514V.1

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