Device for cryptocurrency transaction between a buyer and a merchant of a physical store

Abstract

The apparatus for cryptocurrency transaction between a buyer and a merchant of a physical store comprises a blockchain formed by a computer network of nodes for managing a register containing cryptocurrency transactions, a cryptocurrency exchange, a buyer's electronic currency payment device, a FIAT currency wallet associated with the buyer's payment device, a merchant's payment acceptance terminal for FIAT currency, a merchant's cryptocurrency electronic wallet present in the blockchain and associated with the merchant terminal, and a buyer's cryptocurrency electronic wallet present in the blockchain and associated with the buyer's device, the payment acceptance terminal being configured to: communicate with the cryptocurrency exchange and convert an amount in FIAT currency of the transaction into an equivalent cryptocurrency value of the transaction; derive from a communication with the buyer's device an asymmetric cryptographic key pair of the buyer so obtaining the identity of the buyer's cryptocurrency electronic wallet associated with it; command a temporary block in the buyer's FIAT currency wallet of an amount in FIAT currency equal to the equivalent cryptocurrency value of the transaction; check the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet and, in case of an available amount less than the equivalent cryptocurrency value of the transaction, activate a timer and, if at the expiration of a predetermined time limit the available cryptocurrency amount in the buyer's cryptocurrency electronic wallet is still less than the equivalent cryptocurrency value of the transaction, command the withdrawal from the buyer's FIAT currency wallet of the blocked amount in FIAT currency, command the conversion of the withdrawn amount in FIAT currency into an amount in cryptocurrency equal to the equivalent cryptocurrency value of the transaction, command the transfer to the merchant's cryptocurrency electronic wallet of the amount in cryptocurrency of the transaction, and command the registration of the cryptocurrency transaction in the blockchain.

Description

[0001] DEVICE FOR CRYPTOCURRENCY TRANSACTION BETWEEN A BUYER AND A

[0002] MERCHANT OF A PHYSICAL STORE

[0003] DESCRIPTION

[0004] The present invention relates to an apparatus for cryptocurrency transactions between a buyer and a merchant of a physical store. In the current economic scenario, cryptocurrencies are assets primarily used as investment and speculation tools, thus deviating from their original conception as a means of payment for goods and services. This departure from their nature as a means of payment is likely caused by the lack of user-friendly tools for cryptocurrency exchange between two or more parties or by the complexity of understanding the infrastructure by the average user and merchants. This, in fact, represents a critical aspect in the adoption of a new payment system, considering that it has also occurred in traditional banking systems and these mechanisms are often unknown to end users, yet widely used.

[0005] Another point that has hindered the adoption of cryptocurrencies for paying goods and services is the issue related to time. Indeed, for a transaction between parties to be confirmed, it is necessary to wait for a confirmation time, which in contrast to traditional systems is significantly higher. It should be noted that the problem of exchange delay, namely the time between sending the payment and the "secure" receipt by the receiver, is not a technological problem but rather a security layer typical in the world of cryptocurrencies that will always exist, and there is no intention to reduce it in favour of usability convenience.

[0006] Currently, exchanges and payments for goods and services on which the global economy relies are made using FIAT currencies, both for online payments and physical stores. Until now, the use of FIAT currencies has been much more convenient than cryptocurrencies and is currently the most widespread and commonly accepted exchange tool. Additionally, the economic infrastructures that allow the exchange of FIAT currencies guarantee immediate and simple consumption without the need for advanced technical knowledge of the tools that enable such exchanges. To better understand the state of the art globally, the following examples of cryptocurrency payment operations in physical stores have been identified:

[0007] First example: The merchant enters the amount to be paid on a POS (Point of Sale) terminal. The buyer can choose to pay with a card (traditional FIAT currency only), with a QR code, with other systems like WeChat, or with a cryptocurrency wallet. If paying with a card, the process involves the typical card swipe or tap on the POS terminal. If paying with a QR code, the buyer clicks the "QR code" icon on the POS terminal, a QR code is generated, and the buyer scans it with their payment app. If cryptocurrency payment is chosen, the buyer selects the cryptocurrency payment option on the POS terminal, a QR code is generated, and the buyer scans it with their smartphone app. The POS terminal automatically receives the payment and prints the receipt.

[0008] Second example: The merchant enters the price of the product / service on the POS terminal. The buyer selects their cryptocurrency payment wallet. The POS terminal generates a QR code. The merchant uses their chosen payment app to scan the QR code. The buyer confirms the payment, and the POS terminal prints the receipt. The POS terminal generates a QR code with instructions for the smart contract. The customer scans the QR code with their compatible cryptocurrency wallet and approves the transaction. The funds are then deducted from the customer's cryptocurrency wallet and routed to the merchant's account.

[0009] In contrast to FIAT currencies, cryptocurrencies, while widely used as investment assets, have deviated from their nature as peer-to-peer (P2P) intermediary-free exchange mediums between two or more parties. This is because the existing economic infrastructure is not readily set up to accept cryptocurrency exchanges. Additionally, for a secure exchange to occur, a significant waiting time is required compared to traditional banking systems.

[0010] In banking systems, users are not concerned with the technical workings of the infrastructure facilitating the exchange (such as SEPA); they simply need to know they can spend their money in FIAT currency. In the context of cryptocurrencies, users often understand blockchain technology and thus need to know how it works. However, the tools used so far have been difficult to use and understand, decipherable only by a few, such as professionals and experts in the field.

[0011] Another aspect that hinders the competitiveness of cryptocurrencies in a system where exchange times often exceed 10 minutes is their exchange confirmation time between two parties. For example, in the Bitcoin (BTC) blockchain, the average wait time for transaction confirmation is 10 minutes for liquidity transfer confirmation and at least 60 minutes to prevent "double spending" attacks that would temporarily make the transaction happen, but after a few tens of minutes it might not be accepted by the blockchain network, and therefore it would be canceled as if it had never happened.

[0012] We talk about average time because the time for a transaction can vary based on the flow of transactions generated in that time window.

[0013] Very long waiting times do not provide guarantees to merchants: if the transaction is not successful for various reasons, the buyer could be far from the store and therefore untraceable, thus increasing the possibility of fraud and double spending, a problem known within the world of cryptocurrencies and blockchain technology.

[0014] Double spending exploits the confirmation time to spend the same asset for multiple purchases, and when the real transaction confirmation occurs, only one succeeds while the others are rejected, yet goods and services have already been sold.

[0015] The purpose of this invention is to address the inconveniences identified in the described technique. One technical task that this invention aims to solve is how to execute a cryptocurrency transaction at a physical store quickly, efficiently, simply, and securely.

[0016] This and other technical tasks are solved according to the invention by an apparatus for cryptocurrency transaction between a buyer and a merchant of a physical store, characterized by comprising a blockchain formed by a computer network of nodes for managing a register containing cryptocurrency transactions, a cryptocurrency exchange, a buyer payment device for paying with digital FIAT currency, a FIAT currency wallet associated with said buyer's payment device, a merchant's payment terminal for accepting payment with digital FIAT currency, a merchant's cryptocurrency electronic wallet present in said blockchain and associated with said merchant terminal, and a buyer's cryptocurrency electronic wallet present in said blockchain and associated with said buyer device, said payment acceptance terminal being configured to:

[0017] • communicate with said cryptocurrency exchange which converts an amount in FIAT currency of the transaction into an equivalent cryptocurrency value of the transaction;

[0018] • derive from a communication with said buyer device an asymmetric cryptographic key pair of the buyer so obtaining the identity of the buyer's cryptocurrency electronic wallet associated with it;* command a temporary block in the buyer's FIAT currency wallet of an amount in FIAT currency equal to the equivalent cryptocurrency value of the transaction;

[0019] • check the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet and, in case of an available amount less than the equivalent cryptocurrency value of the transaction, activate a timer and, if at the expiration of a predetermined time limit said available cryptocurrency amount in said buyer's cryptocurrency electronic wallet is still less than the equivalent cryptocurrency value of the transaction, command the withdrawal from said buyer's FIAT currency wallet of said blocked amount in FIAT currency, command the conversion of said withdrawn amount in FIAT currency into an amount in cryptocurrency equal to said equivalent cryptocurrency value of the transaction, command the transfer to the merchant's cryptocurrency electronic wallet of said amount in cryptocurrency of the transaction, and command the registration of the cryptocurrency transaction in said blockchain.

[0020] The apparatus according to the invention is particularly useful when an unstable type of cryptocurrency is selected for the transaction.

[0021] Preferably, said buyer's electronic fiat currency payment device consists of a credit card. It should be noted that various algorithms exist for generating pairs of asymmetric keys (public and private) used in different blockchain technologies. For instance, Bitcoin and its derivatives utilize secp256kl, while Ethereum employs ECDSA. However, in a broader context, the creation of a key pair begins with an input chosen randomly by a user, typically a very large number or the hash of a secret phrase transformed into a numerical value. From this input, the asymmetric key pair for any curve can be derived using appropriate algorithms.

[0022] Furthermore, the funds' address is typically obtained through deterministic algorithmic derivation of the public key.

[0023] The above can be formalized with a set of generic functions: f(x, CurveAlg) = PrivateKey fl (PrivateKey, Curve Alg) = PublicKey f2(PublicKey, CurveAlg) = WalletAdress

[0024] Here, "x" is a big integer, and " Curve A Ig" is a known and standard algorithm dependent on the asymmetric key technology used in the respective blockchain. This algorithm allows for deterministic private key derivation, from which a public key and subsequently an address can be derived.

[0025] By extracting unique information from the credit card, it is possible to obtain a private key and, consequently, the public key and the associated address based on the blockchain technology in which one intends to operate.

[0026] Using this information as a seed for generating a pair of asymmetric keys certainly makes it possible to satisfy the algorithmic requirements and therefore the application would be able to obtain the same pair of keys for each card every time: x = f PAN, ExpirationDate]) f(x, ECDSA) = PrivateKey where f3represents a function that accepts a mixed array of strings and numerical values as input, converts them into bytes, and applies hashing algorithms to combine them, ensuring a deterministic outcome.

[0027] However, there are security criteria that cannot be ignored, such as the attempt to generate keys from a dictionary that contains all possible card numbers, which make this step highly insecure. A "salt" must therefore be introduced, that is to say a series of numbers which, added or combined to the card data, make the dictionary attack impossible; in this case the function would be: x = f3[PAN, ExpirationDate, SALT]) f(x,ECDSA)

[0028] = PrivateKey

[0029] The technique used to obtain PAN, ExpirationDate and SALT uses a series of steps in order to obtain information that uniquely identifies the credit card, i.e. by subjecting the credit card to the cycle of steps several times, the result obtained must be the same. To obtain PAN and ExpirationDate, standard APDU commands or sequences of commands provided by the card manufacturer are used. The creation of the SALT is much more complex since this information does not exist within the credit card and based on the type of credit card a different technique is used, in particular the algorithm has an ordered list of strategies to obtain the SALT, not all of them the techniques are good for all credit cards so they are tried in sequence until one responds in order to confirm that the strategy was successful, in which case the SALT is obtained from the first strategy that gave a positive result.

[0030] The sequence of strategies is as follows:

[0031] 1 - Reading the credit card's public key: some credit cards have this information written into a record and it is unique to the credit card

[0032] 2 - Starting a secure session challenge: most credit cards have a private key written inside which however is impossible to read due to the security layer of the credit card itself; in this case one tries to start a session secure communication between merchant’s payment device and credit card, in particular, through specific APDU commands depending on the type of manufacturer, a random number signed by the device is passed to the credit card and the credit card signs that data again to negotiate a secure communication key, this secure key can be used like SALT as long as one always starts the secure session with the same number, and by using the PAN as the initial number one can obtain a unique secure session key for each credit card.

[0033] 3 - EMV cards contain a series of certificates internally, enabling verification to determine if the data within the card has been altered due to tampering. The card data is signed by a set of authoritative certificates, including the PAN among these data. Therefore, the certified information, if validated as authentic, is also a unique datum that can be used as a SALT.

[0034] 4 - Credit card PIN: in some cases it is possible to check against the credit card whether a PIN is valid or not (Pin Offline), there is no field readable by the merchant’s payment device in which the PIN is written in plain text, but it is possible to ask the credit card if a certain PIN is valid or not. In this case the process requires the collaboration of the buyer who will have to enter the PIN of his credit card, the merchant’s payment device verifies it and in case of positive outcome the PIN is used as SALT together with a secret SALT, known at the algorithm level and not public.

[0035] 5 - Reading specific and unique tags inside the credit card: some manufacturers have encoded the unique identification of the credit card as a serial code and the manufacturer with its own identification number, other manufacturers allow you to read the “9F2D” tag which identifies “Integrated Circuit Card (ICC) PIN Encipherment Public Key Certificate” and other unique tags: if this information is readable or obtainable, it is used as SALT

[0036] 6 - Secret SALT: As a last resort, in case all attempts fail, a default SALT securely encoded in the device library is used. However, it should also be considered that some credit cards have integrated tokenization technology, in this case it is possible to request the public key using specific APDU commands and have the credit card itself to sign the transaction since the signature technology is present inside the credit card; in this case there is no need to obtain the SALT since the credit card already has all the secure signature technologies within it and it is therefore the credit card that uses its own security devices, such as FingerPrint, PIN, interaction with its own app or other biometric systems to directly produce the signature to move funds in the blockchain chain.

[0037] Preferably, said payment acceptance terminal includes a POS (Point Of Sale) programmed for interaction with said blockchain and said buyer's electronic FIAT currency payment device.

[0038] Preferably, said payment acceptance terminal includes a display.

[0039] Preferably, said payment acceptance terminal is programmed to display the transaction amount in FIAT currency and the cryptocurrency value of the transaction.

[0040] Preferably, said payment acceptance terminal is programmed to accept the selection of payment with a cryptocurrency from a plurality of selectable cryptocurrencies.

[0041] Preferably, said payment acceptance terminal is programmed to also support a real-time transaction in stable cryptocurrency.

[0042] Preferably, said payment acceptance terminal is programmed to also support a transaction in FIAT currency.

[0043] Through the technical solution provided by the invention, a guarantee is thus provided on a transaction on a payment and collection circuit (e.g., SEPA circuit for Euro payments) by the buyer. In case the cryptocurrency units are not received within the predetermined time, the guarantee is collected by the merchant as alternative compensation. This allows the exchange to occur in a few seconds, without waiting for confirmation on the reference blockchain.

[0044] The procedure followed by the buyer on the merchant's terminal guides the buyer to carry out the transaction on the blockchain and proposes to accept to guarantee a total amount in FIAT currency that can cover the cryptocurrency units expected by the merchant.

[0045] The buyer is guaranteed that if their cryptocurrencies are delayed in reaching the merchant, but the merchant has already collected the guarantee on the payment and collection circuit (e.g., SEPA circuit), their cryptocurrencies will return to the originating cryptocurrency wallet. The apparatus according to the invention prevents "double spending" because in case of an attempted attack, when the promised cryptocurrencies do not reach the merchant, the merchant is protected by the FIAT currency units guaranteed by the buyer.

[0046] An example of an apparatus for a cryptocurrency transaction between a buyer and a physical store merchant is described below, by way of example but not limitation.

[0047] The apparatus works both in the case of selecting payment with a stable cryptocurrency, where the collection can occur essentially in real-time, and in the case of selecting payment with an unstable cryptocurrency, which may instead result in a temporal delay of the collection.

[0048] The blockchain consists of a series of traditional computers connected to the internet, called nodes, capable of recognizing each other and connecting within the network, creating a network of secure connections where transactions are transferred.

[0049] Transactions are effectively signed documents containing digitally signed commands.

[0050] The blockchain supports various universally recognized signature protocols, including ECDSA signatures on p-384 elliptic curve.

[0051] This particular signature does not require a central system to assign a public cryptographic key to each user, as anyone can independently create a pair of cryptographic keys by generating a very large random number on their own electronic device (PC, Tablet, Smartphone), which is used as the "seed" for generating the two related cryptographic keys, a public key, and a private key.

[0052] In the blockchain, each public key identifies a cryptocurrency wallet capable of containing data and cryptocurrencies.

[0053] The public key effectively acts as a user's IBAN so that knowing someone's public key, money can be sent by indicating their public key as the recipient.

[0054] To move money from one public cryptographic key to another, the sender's private cryptographic key must be known. Only the sender is able to know their private cryptographic key and is thus the only one who can, using both cryptographic keys, sign a transaction that, among the many possible things, can also transfer money to any other public cryptographic key.

[0055] It should be noted that knowledge of the private cryptographic key allows, through known algorithms, to derive the associated public cryptographic key, while the reverse operation is practically impossible.

[0056] For precision and technical efficiency, the destination address of the funds is not exactly the public cryptographic key but a compressed version that can be easily obtained by applying a mathematical formula of MultiHash to the public cryptographic key; this makes the destination address shorter (compressed) without changing the transfer logic.

[0057] There is also an advantageous alternative method, compared to random seed generation, for creating the pair of cryptographic keys: it consists of using a secret information, known only to the user (a password, a phrase, a code, etc.) as the seed for the creation of the cryptographic key pair. Thus, the cryptographic key pair can also be obtained from secret information.

[0058] In the blockchain, however, both the buyer's cryptocurrency electronic wallet and the merchant's cryptocurrency electronic wallet are identified by a respective public cryptographic key.

[0059] Within the blockchain, a principle of determination is provided so that every cryptocurrency electronic wallet within the blockchain exists anyway: if a cryptocurrency electronic wallet has funds, it exists truly and has a cryptocurrency balance based on ownership (e.g., #BTC: 100, #EURS: 50, etc.); if it does not exist truly, it still exists virtually but has a balance of 0 for each cryptocurrency present.

[0060] With that said, the beginning of the payment process through the merchant's terminal coincides with the need for a merchant to receive a cryptocurrency payment from a buyer to market a product or service. The merchant's terminal can be a hardware product identified by a classic POS device that has installed within it software that connects the FIAT ecosystem with blockchain technology.

[0061] The merchant's terminal can thus be a traditional POS comprising a smartphone with a CPU, an NFC reader for credit card reading, wireless and WIFI communication modules, a user interface display such as a touch screen, and a printer.

[0062] Through the display of the merchant's terminal, the transaction amount in FIAT currency can be entered, and the cryptocurrency to be used for payment can be selected.

[0063] The merchant's terminal connects to the exchange to calculate in real-time the conversion of the transaction amount in FIAT currency into an equivalent value in the selected cryptocurrency.

[0064] The buyer allows data exchange between their payment device in FIAT electronic currency and the merchant's terminal.

[0065] For example, the buyer places their credit card (Visa, MasterCard, American Express, etc.) on the NFC reader of the merchant's terminal.

[0066] The credit card is of the conventional type, as it does not need to be pre-configured to handle cryptocurrencies in any way.

[0067] The merchant's terminal reads the credit card data using NFC technology, which also allows encrypted and secret information written inside the credit card to be retrieved.

[0068] Once the credit card data is acquired, through authorized providers, the merchant's terminal requests a temporary block in the buyer's FIAT currency wallet for an amount equal to the equivalent value of the transaction in the selected cryptocurrency, as a guarantee that the subsequent payment in the selected cryptocurrency will proceed smoothly.

[0069] If the request for a temporary block is unsuccessful, the payment process is cancelled, and the merchant can create a new payment. The merchant's terminal combines the credit card data and the encrypted information contained within the credit card itself to derive the public cryptographic key of the account that identifies the buyer's cryptocurrency electronic wallet on the blockchain.

[0070] Advantageously, the invention utilizes the encryption inherent in traditional payment systems, such as conventional credit cards, as an asymmetric signature component of the transaction executed by the account identifying the buyer's cryptocurrency electronic wallet on the blockchain. The merchant's terminal, with reference to the cryptocurrency selected for payment, checks the amount of that cryptocurrency available in the buyer's cryptocurrency electronic wallet on the blockchain.

[0071] As mentioned earlier, the first time the merchant's terminal interacts with a credit card with which there have been no previous interactions, it is already associated with a cryptocurrency electronic wallet on the blockchain with a balance of 0 for each type of cryptocurrency.

[0072] The merchant's terminal constructs and signs the payment transaction from the buyer's cryptocurrency electronic wallet on the blockchain to the merchant's cryptocurrency electronic wallet on the blockchain using the blockchain account of the merchant.

[0073] If the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet on the blockchain is not less than the equivalent cryptocurrency value of the transaction, regardless of whether the selected cryptocurrency is stable or unstable, the transaction is completed and recorded on the blockchain.

[0074] If instead the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet on the blockchain is less than the equivalent cryptocurrency value of the transaction and the cryptocurrency selected for the transaction is stable, the merchant's terminal concludes and records the transaction in real-time using the locked FIAT currency amount.

[0075] If instead the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet on the blockchain is less than the equivalent cryptocurrency value of the transaction and the cryptocurrency selected for the transaction is unstable, the merchant's terminal signs but does not record the transaction on the blockchain.

[0076] In this case, the merchant's terminal activates a temporary counter, and if, upon reaching a time limit, the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet on the blockchain is still less than the equivalent cryptocurrency value of the transaction , it commands the withdrawal from the buyer's FIAT currency wallet of the locked fiat currency amount, commands the conversion of the withdrawn fiat currency amount into an amount of cryptocurrency equal to the equivalent cryptocurrency value of the transaction, commands the transfer to the merchant's cryptocurrency electronic wallet of the cryptocurrency amount of the transaction, and commands the recording of the transaction in cryptocurrency on the blockchain. When activating the temporary counter, the merchant's terminal displays an indication for the transfer of cryptocurrency to the buyer's cryptocurrency electronic wallet on the blockchain.

[0077] In particular, a qrCode is generated on the display of the merchant's terminal that can be captured by a buyer's electronic device, such as a buyer's smartphone, to execute the transfer of cryptocurrency funds, for example, from a buyer's cryptocurrency Wallet Manager to the buyer's cryptocurrency electronic wallet on the blockchain.

[0078] In particular, in the qrCode both the cryptocurrency to be exchanged and the destination electronic wallet of the buyer on the blockchain are coded in addition to the amount to be transferred.

[0079] Common Wallet Manager systems (both those with mobile apps and common exchanges) once the qrCode is read, allow the buyer to complete the cryptocurrency transfer following the instructions on the qrCode itself.

[0080] The qrCode thus indicates the currency chosen by the merchant during collection, the amount, and the destination address will be the public cryptographic key of the buyer on the blockchain. From this point onwards, it is not possible to determine with certainty whether the buyer has indeed made the cryptocurrency transfer due to all the issues related to exchange technology (long processing times, double spending, etc.).

[0081] However, the merchant can still conclude the sales process, for example, by clicking on the button provided by the graphical interface of their payment acceptance terminal, even if they have not received any confirmation of the actual receipt of the cryptocurrency, allowing the buyer to leave the commercial premises without waiting for real-time collection times (which in some cases could even be several days).

[0082] An automatism of the merchant's terminal remains active until the time limit (configurable by the merchant), waiting for the funds indicated in the transaction to arrive in the buyer's cryptocurrency electronic wallet on the blockchain.

[0083] In case the funds arrive in the buyer's cryptocurrency electronic wallet on the blockchain within the predetermined time limit, the merchant's terminal retrieves and concludes the transaction, which is recorded on the blockchain, also cancelling the temporary block of FIAT currency in the buyer's FIAT currency wallet.

[0084] If, however, the funds do not arrive in the buyer's cryptocurrency electronic wallet on the blockchain within the predetermined time limit, the locked FIAT currency amount is used to conclude the transaction as described above.

[0085] If the buyer intends to carry out fraudulent operations to cancel the cryptocurrency transaction, the merchant has still collected the FIAT currency amount converted into cryptocurrency as described above.

[0086] If the buyer delays the transfer of cryptocurrencies to their cryptocurrency electronic wallet on the blockchain and the locked FIAT amount has been collected by the merchant, their cryptocurrency electronic wallet on the blockchain still receives the cryptocurrencies, which are no longer transferred to the merchant and remain available to the buyer for future payments. Below is only an example configuration of the merchant's terminal.

[0087] The apparatus for cryptocurrency transactions between a buyer and a merchant in a physical store revealed by the present invention allows the buyer to pay safely, and the merchant guarantees confidence in receiving payment, both with cryptocurrencies and with FIAT currency. At the time of purchase, the procedure is as simple as it is secure, as the merchant enters the price of the item / service, the buyer approaches the credit card or any payment device and selects the payment method chosen between cryptocurrency and FIAT currency.

[0088] If the buyer chooses to pay in FIAT currency, the transaction is finalized thanks to the credit card alone, and the merchant receives the predetermined quantity of cryptocurrency as the FIAT currency is converted into cryptocurrency.

[0089] If the buyer chooses to pay in cryptocurrency, the user activates their cryptocurrency payment app on their smartphone (e.g., Binance, BlueWallet, etc.), scans the qrCode displayed on the merchant's terminal, and the transaction is finalized.

[0090] The selected cryptocurrency quantity arrives at the merchant (in their wallet on the blockchain).

[0091] If, for any reason, the cryptocurrencies do not arrive at the merchant, the credit card used to initialize the payment serves as security: the FIAT currency amount corresponding to the chosen cryptocurrency quantity is charged to the credit card used.

[0092] In this way, the merchant still receives the amount of money due for the sale of the product / service, and the same amount of cryptocurrency is sent, preferably in the form of stable cryptocurrency, to the merchant's wallet on the blockchain.

[0093] In summary, the credit card is used to initialize the payment and allow the buyer to spend their cryptocurrencies, held in various exchanges (Binance, Coinbase, etc.) or on the public blockchain, directly in physical and virtual stores, guaranteeing that the merchant's non-receipt due to issues strictly related to blockchain problems (double spending, long collection times, etc.) is nevertheless covered by the credit card provided as security during the process. The system provides a collection guarantee to the merchant without the risk of cryptocurrency double spending: cryptocurrency double spending cannot occur because if a buyer attempts it, the already spent cryptocurrency is no longer available, and therefore that amount is deducted from the credit card provided as security, and the money is sent in stable currency to the merchant's wallet on the blockchain.

Claims

CLAIMS1. Apparatus for cryptocurrency transaction between a buyer and a merchant of a physical store, characterized by comprising a blockchain formed by a computer network of nodes for managing a register containing cryptocurrency transactions, a cryptocurrency exchange, a buyer payment device for paying with digital FIAT currency, a FIAT currency wallet associated with said buyer's payment device, a merchant's payment acceptance terminal for accepting payment with digital FIAT currency, a merchant's cryptocurrency electronic wallet present in said blockchain and associated with said merchant terminal, and a buyer's cryptocurrency electronic wallet present in said blockchain and associated with said buyer payment device, said payment acceptance terminal being configured to:• communicate with said cryptocurrency exchange which converts an amount in FIAT currency of the transaction into an equivalent cryptocurrency value of the transaction;• derive from a communication with said buyer payment device an asymmetric cryptographic key pair of the buyer so obtaining the identity of the buyer's cryptocurrency electronic wallet associated with it;• command a temporary block in the buyer's FIAT currency wallet of an amount in FIAT currency equal to the equivalent cryptocurrency value of the transaction;• check the amount of cryptocurrency available in the buyer's cryptocurrency electronic wallet and, in case of an available amount less than the equivalent cryptocurrency value of the transaction, activate a timer and, if at the expiration of a predetermined time limit said available cryptocurrency amount in said buyer's cryptocurrency electronic wallet is still less than the equivalent cryptocurrency value of the transaction, command the withdrawal from said buyer's FIAT currency wallet of said blocked amount in FIAT currency, command the conversion of said withdrawn amount in FIAT currency into an amount in cryptocurrency equal to said equivalent cryptocurrency value of the transaction, command the transfer to the merchant's cryptocurrencyelectronic wallet of said amount in cryptocurrency of the transaction, and command the registration of the cryptocurrency transaction in said blockchain.

2. Apparatus for cryptocurrency transaction according to claim 1, characterized in that said cryptocurrency is of the unstable type.

3. Apparatus for cryptocurrency transaction according to any preceding claim, characterized in that said buyer's electronic payment device consists of a credit card.

4. Apparatus for cryptocurrency transaction according to any preceding claim, characterized in that said payment acceptance terminal comprises a POS (Point Of Sale) programmed for interaction with said blockchain and said with buyer's electronic payment device.

5. Apparatus for cryptocurrency transaction according to the preceding claim, characterized in that said payment acceptance terminal comprises a display.

6. Apparatus for cryptocurrency transaction according to the preceding claim, characterized in that said payment acceptance terminal is programmed to display the amount in FIAT currency of the transaction and the equivalent value in cryptocurrency.

7. Apparatus for cryptocurrency transaction according to any preceding claim, characterized in that said payment acceptance terminal is programmed to accept the selection of payment with a cryptocurrency among a plurality of selectable cryptocurrencies.

8. Apparatus for cryptocurrency transaction according to any preceding claim, characterized in that said payment acceptance terminal is also programmed to support a real-time transaction in stable cryptocurrency.

9. Apparatus for cryptocurrency transaction according to any preceding claim, characterized in that said payment acceptance terminal is also programmed to support a transaction in FIAT currency.

10. Apparatus for cryptocurrency transaction according to any preceding claim, characterized by using the encryption inherent in said credit card as a component of asymmetric signature of the transaction.

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