A method for pairing a first device, called an initiator device, with a second device, called an acceptor device, initiator device and acceptor device.

Description

1 / 17 “METHOD OF PAIRING A FIRST APPARATUS CALLED AN INITIATOR APPARATUS WITH A SECOND APPARATUS, CALLED AN ACCEPTANCE APPARATUS, INITIATOR APPARATUS AND ACCEPTANCE APPARATUS” 1. FIELD OF THE INVENTION

[001] The invention relates to the field of authentication. The invention relates, more particularly, to the authentication of hardware devices with each other. 2. STATE OF THE ART

[002] There are numerous well-known protocols in the state of the art that allow two devices to be authenticated before transmitting or exchanging confidential information. This is the case, for example, of a wireless communication terminal, which seeks to authenticate itself with a user's local network, for example, a wireless Wi-Fi network. To this end, before exchanging any data, the terminal must first authenticate itself with the communication network. This authentication is usually done by entering a key, for example, a WEP (Wired Equivalent Privacy) key, a WPA (Wi-Fi Protected Access) key, a PSK (pre-shared key), or similar. One of the problems with this type of key is its length. The WEP key consists of 13 characters, while a WPA-PSK key is usually a passphrase that can be time-consuming to type.

[003] Other fields require authentication between wireless devices. This is the case, for example, for devices that communicate using Bluetooth® technology. Bluetooth is a wireless technology for creating wireless personal area networks that operate in the 2.4 GHz frequency range, which does not require authorization, with a range of about 10 meters. The networks are generally formed by nomadic peripherals, such as cell phones, Petition 870260041530, dated 04 / 05 / 2026, page 12 / 58 2 / 17 personal digital assistants and laptops. By default, Bluetooth communication is not authenticated, and any peripheral can exchange data with any other peripheral.

[004] A Bluetooth peripheral (e.g., a mobile phone) may choose to require authentication in order to provide a specific service. Bluetooth authentication is usually done with PIN codes. A Bluetooth PIN code is a sequence of ASCII characters with a maximum length of 16 characters. By default, the user must enter the same PIN code on both peripherals. Once the user has entered the PIN code, the two peripherals generate a binding key. This binding key can then be stored either on the peripherals themselves or on an external storage medium. During the next exchange, both peripherals will use the previously generated binding key. This procedure is called pairing. When the binding key is lost by one of the peripherals, the pairing operation must be repeated so that a new key can be generated.

[005] When the data that has to be exchanged between the two Bluetooth terminals is sensitive (bank data, for example), the exchanges that follow the pairing step are encrypted, for example, using the E0 algorithm. E0 is the stream encryption algorithm used to protect the confidentiality of data exchanged in the Bluetooth system.

[006] The problem, however, is the same as with WEP or WPA keys: before any encrypted exchange, the user must first enter a PIN code on the terminal, the length of this PIN code varying from 4 to 16 characters, given that for the most secure applications, a 16-character PIN code is preferred.

[007] Regardless of the technology, Wi-Fi or Bluetooth, entering an excessively long PIN code or key leads to at least Petition 870260041530, dated 04 / 05 / 2026, page 13 / 58 3 / 17 minus two problems:

[008] - on the one hand, there is a high risk of error during input. In fact, it is almost certain that the input will consist of at least one error. This is especially true when the input is made with masked characters (the typed characters are not displayed, but instead a sequence of asterisks is displayed);

[009] - on the other hand, since the entry is done manually, there is no guarantee that a malicious person might not snoop on the entry operation in order to appropriate the PIN code or key for fraudulent use.

[010] Security solutions have been proposed, mainly in order to run a wireless connection. They consist of the near-simultaneous activation of two devices to be connected together. One of these approaches is known as “Wi-Fi Protected Setup (WPS)”, and is a local wireless network standard that is simple and secure. This solution, however, would not solve all problems, since one of the WPS variants involves the introduction of a PIN code.

[011] In other words, it is necessary to provide a connection solution that is both simple and discreet, in order to, on the one hand, avoid input errors and, on the other hand, guarantee the confidentiality of the data necessary for the connection or pairing. 3. SUMMARY OF THE INVENTION

[012] The invention does not have these disadvantages of the prior art. The invention relates to a method of pairing a first apparatus, called an initiator apparatus, with a second apparatus, called an acceptor apparatus, the said initiator apparatus being intended to transmit and receive data to and from the said acceptor apparatus. Petition 870260041530, dated 04 / 05 / 2026, p. 14 / 58 4 / 17

[013] According to the invention, the said method comprises:

[014] - a step in generating a pairing code;

[015] - a processing step, in the form of a first symbol, of the said pairing code, by the said acceptance device;

[016] - a stage of receiving the said first symbol by the said initiating device;

[017] - a decoding step of the aforementioned first received symbol, which provides the aforementioned pairing code.

[018] According to the invention, the pairing code is random and volatile. It is not stored and cannot be retrieved later.

[019] According to a particular feature, the aforementioned pairing method also includes:

[020] - a step in obtaining, by the said acceptance device, at least one useful piece of data;

[021] - a processing step, in the form of a second symbol, of the aforementioned at least one useful piece of data.

[022] According to a particular feature, the aforementioned pairing method also includes:

[023] - a step in receiving the said second symbol by the said initiating device;

[024] - a decoding step of the aforementioned second symbol, which provides the aforementioned useful data.

[025] According to a particular feature, the first symbol mentioned and the second symbol mentioned form the same symbol.

[026] According to a particular embodiment, a symbol belongs to a type of symbol, and that type of symbol belongs to the group comprising: Petition 870260041530, dated 04 / 05 / 2026, p. 15 / 58 5 / 17

[027] - a one-dimensional barcode;

[028] - a two-dimensional barcode;

[029] - an image with a watermark;

[030] - a modulated sound sequence.

[031] According to a particular feature, the initiating device in question is a PDA and the accepting device in question is a payment terminal.

[032] According to a particular feature, the said processing step of the said pairing code in the form of a first symbol comprises a step for printing the said first symbol on a printer of the said acceptance device.

[033] According to a particular embodiment, the said stage of receiving the said first symbol, by means of the said initiating device, comprises a stage of receiving an image that represents the said first symbol.

[034] The invention also relates to an initiator device intended to transmit and receive data to and from an acceptor device.

[035] According to the invention, this device comprises:

[036] - means of receiving a first symbol, which represents a pairing code, which allows the pairing of said accepting device and said initiating device, said first symbol being processed by an accepting device;

[037] - means of decoding the aforementioned first received symbol, which provides the aforementioned pairing code.

[038] The invention also relates to an acceptance device intended to transmit and receive data to and from an initiating device. According to the invention, this device comprises:

[039] - means of generating a pairing code that Petition 870260041530, dated 04 / 05 / 2026, p. 16 / 58 6 / 17 allows the pairing of the aforementioned acceptance device and the aforementioned initiator device;

[040] - means of processing the said pairing code in the form of a first symbol.

[041] The invention also aims to provide information support that is readable by a data processor and that comprises instructions of a program, as mentioned above.

[042] The information carrier can be any entity or device that is capable of storing the program. For example, the carrier can include a storage device, such as a ROM, for example, a CD-ROM or a microelectronic ROM circuit, or even a magnetic recording device, such as a floppy disk or a hard disk.

[043] Furthermore, the information carrier may be a transmission carrier, such as an electrical or optical signal, which may be transmitted via an electrical or optical cable, by radio or by other means. The program, according to the invention, may be specially uploaded to an Internet-type network.

[044] Alternatively, the information carrier may be an integrated circuit in which the program is embedded, the circuit being adapted for execution or being used in the execution of the method in question.

[045] According to one embodiment, the invention is implemented by means of software and / or hardware components. In this respect, the term “module” may correspond, in this document, equally to a software component as to a hardware component, or to a set of hardware and software components.

[046] A software component corresponds to one or more Petition 870260041530, dated 04 / 05 / 2026, page 17 / 58 7 / 17 computer programs, one or more subprograms of a program, or, more generally, any element of a program or software capable of performing a function or a set of functions, as described above for the module in question. Such a software component is executed by a data processor of a physical entity (terminal, server, etc.) and is capable of accessing the hardware resources of that physical entity (memories, recording media, communication bus, input / output electronic boards, user interfaces, etc.).

[047] Similarly, a hardware component corresponds to any element of a hardware unit capable of performing a function or a set of functions, as described above for the module in question. It can be a programmable hardware component or a component with an integrated processor, for the execution of programs, for example, an integrated circuit, a smart card, a memory card, an electronic board for the execution of firmware, etc. 4. FIGURES

[048] Other features and advantages of the invention will become clearer from the following description of a preferred embodiment, given by means of a simple illustrative and non-exhaustive example, and from the accompanying drawings, of which:

[049] - Figure 1 describes the general principle of the invention;

[050] - Figure 2 describes the steps required to pair a PDA with a payment terminal;

[051] - Figure 3 represents an acceptance apparatus, according to the invention;

[052] - Figure 4 represents an initiating apparatus, according to the invention. 5. DESCRIPTION OF AN IMPLEMENTATION Petition 870260041530, dated 04 / 05 / 2026, page 18 / 58 8 / 17 5.1. Reminder of the principle of the invention

[053] As explained above, the invention offers an innovative method for entering a pairing code (e.g., a PIN code) for pairing two devices. The invention can also be applied specifically to Bluetooth pairing technology, but it is also possible to apply it to other protocols that involve user input of a PIN code or a password or “password” (a secret phrase used for better security than that provided by a simple password).

[054] In a particular embodiment, which will be described here below, the invention solution implements two Bluetooth devices, one that initiates the pairing process and another that accepts it.

[055] Hereafter, the terms “initiating device” and “receiving device” will be used to designate these two devices, respectively.

[056] The method of the invention is described with reference to figure 1. Within the scope of the invention, the initiating device EInit has an electronic image sensor (such as a code reader, a barcode reader, a peripheral that allows the reading and decoding of images, such as cameras embedded in smartphones or other electronic devices) and the accepting device EAcc has a printer or a screen, and must be able to print or display the symbols (the accepting device, more generally, has a means of visual or sound processing).

[057] The term “symbol” used herein is understood to mean any type of representation of digital or alphanumeric data, in the form of a graphic or audio symbol (examples are: one-dimensional, two-dimensional or three-dimensional barcodes, sound pulses, etc.). According to the invention, the symbol comprises a set Petition 870260041530, dated 04 / 05 / 2026, p. 19 / 58 9 / 17 of the data that can be processed by the receiving device and received by the initiating device. According to the invention, the symbol cannot be interpreted by a human being (it is not directly legible and understandable, or audible and understandable). In a specific embodiment of the invention, the symbol is superimposed on an image, according to a watermark method (i.e., a watermark image). In this embodiment, the initiating device receives the image and deciphers the mark hidden in the received image. From this mark, it recreates the symbol and decodes it to obtain the PIN code. There is, therefore, a double encoding of the PIN code. This is advantageous from several points of view. On the one hand, the fact that the symbol is hidden in a watermark image prevents a fraudster from realizing that the displayed image contains a code.On the other hand, to obtain the hidden mark, it is necessary to execute a method of discovering (decoding) the symbol, and this constitutes, in fact, a double encoding, increasing security. Advantageously, the image used to insert the symbol is, for example, the logo of the store, bank, or entity using the terminals. Thus, it becomes even more difficult for anyone to discover that a symbol has been sent. In the case of a sound sequence, the advantages are similar. Firstly, this is because the sequence is produced on the initiative of the first terminal, and therefore a fraudster does not know when it is produced. Secondly, as in the case of the watermark image, the sound sequence again represents an encoding of the symbol, and therefore a double decoding is necessary to obtain the information.Third, the modulated sound sequence can be sent at frequencies imperceptible to a fraudster, so that he is not allowed to know when the code is sent. Depending on the achievements, a. Petition 870260041530, dated 04 / 05 / 2026, p. 20 / 58 A 10 / 17 modulated sound sequence can be, for example, a DTMF sequence. Thus, in the context of the invention, there are several types of symbols that can be used. As will be presented below, the different types of symbols can be used together or successively.

[058] According to the invention, the pairing process is generally done in two steps by the user:

[059] - the Eacc acceptance device processes 10 (prints or displays or sends as sound) the SYMB symbols of the PIN code. In addition, other parameters can also be processed (address of the acceptance device, for example, this aspect being described in detail below);

[060] - the Einit initiator device receives the PIN code (through reading, scanning or audio recognition) via the symbol reader. When other parameters are used (the address of the accepting device, for example), this address is also received.

[061] Thus, there is no manual input on the part of the user, and this simplifies the process and avoids errors.

[062] The standard pairing mechanism with authentication is therefore initiated 30, and the two devices are connected in a few seconds (depending on the radio environment).

[063] The PIN code is generated 10-1 randomly on the accepting device, and consists of as many characters as possible, thus ensuring a high level of security for the connection between the two devices. In the case of an application that uses Bluetooth technology, for example, the PIN code consists of 16 characters.

[064] Furthermore, the PIN code is generated asynchronously, before or after the 10-0 pairing decision of the initiator device EInit with the accepting device Eacc and, therefore, is not Petition 870260041530, dated 04 / 05 / 2026, page 21 / 58 11 / 17 is stored in non-volatile memory on the Eacc accepting device. The 10-0 decision is made by a user who decides to pair the two devices. The PIN code is random and volatile.

[065] When two devices are already paired, it is also possible to create a new pairing with a new random PIN code. This allows the encryption key to be changed periodically and therefore further increases the security of this connection.

[066] As explained earlier, the EInit initiator device can be provided not only with the PIN, but also with other useful data that can be considered to increase the security level of the proposed method. Depending on the settings, this useful data may be required for validating the pairing process.

[067] One example of such other useful data sets that may be mentioned is the address (e.g., the Bluetooth address) of the Eacc accepting device. Depending on the embodiments of the invention, the provision of one of these useful data sets may be done in a different manner.

[068] In a first embodiment, the provision of useful data is separated from the provision of the PIN code. This means that, subsequent to the receipt of the symbol representing the PIN code by the EInit initiator device, a second receipt step occurs. This separation into two steps ensures compliance with the procedure and therefore offers additional security. Naturally, these sets of useful data are also presented in the form of a symbol that may be of a different type from the first symbol. Thus, for example, the first symbol may be a one-dimensional barcode, while the second symbol may be in the form of a two-dimensional barcode. Petition 870260041530, dated 04 / 05 / 2026, page 22 / 58 12 / 17

[069] In a second embodiment, the useful data can be provided together with the PIN code, in the form of a symbol. This provision of data and the PIN code together can consist of the same single symbol, for example, a one-dimensional or two-dimensional barcode, or through the use of two different types of symbols (the first symbol can be a one-dimensional barcode, while the second symbol can be in the form of a two-dimensional barcode). The difference between this second embodiment and the first embodiment is perceived when receiving the symbols. The presentation of the useful data together with the PIN code, but with a symbol distinct from the PIN code symbol, makes profitable use of the ability of new scanners to read multiple barcodes simultaneously. 5.2. Description of a special achievement

[070] This embodiment provides a description of the implementation of the invention, for pairing two devices using Bluetooth technology: a PDA and a payment terminal are paired. In this embodiment, the PDA is the initiating device and the payment terminal is the accepting device.

[071] In comparison with the difficulties and problems mentioned above, pairing a payment terminal has other difficulties, including the obligation to guarantee a level of absolute confidentiality of the data transmitted to the terminal.

[072] Indeed, one of the functions that forms the basis for pairing a payment terminal with a PDA is the payment function. This function is briefly described with reference to Figure 2. Once the payment terminal and the PDA have been paired (using the method that is the subject of the invention), i.e., after step 30 of Figure 1, these two entities will exchange encrypted data, for example, according to the following process: Petition 870260041530, dated 04 / 05 / 2026, p. 23 / 58 13 / 17

[073] A customer C makes purchases in a store using a PDA. The customer can use the PDA for this purpose, as can the salesperson who owns the PDA. The PDA is used to identify 40 items purchased by the customer. For this purpose, the PDA uses an application known as a "commercial" application, which runs on the PDA. This identification phase must be understood in its broadest sense. It can be a barcode scan, or a verification done with an optical sensor of a camera, or a selection from a list of products presented on the PDA screen. This "identification" phase is repeated 40-1 as many times as the customer wishes to purchase products or services.

[074] Once the customer has completed their purchases, the PDA's "commercial" application requests payment for the customer's purchases C through the TP payment terminal. This request Rq is transmitted 50 by the PDA to the TP payment terminal via the Bluetooth connection, which has been previously configured by the method that is the object of the invention. This encrypted request Rq mainly comprises the transaction value (among other parameters). This value is retrieved by the TP payment terminal, which uses it to initiate a transaction. Generally, this operation is performed with a user's CP payment card. When the transaction 60 is initiated, the payment terminal takes control: this means that the commercial application, which is started on the PDA, is placed in "pending" mode. The TP payment terminal alone controls the progress of the payment operation. Thus, customers make payments through a TP payment terminal.When the payment is validated by the TP payment terminal (or when the transaction fails), the TP payment terminal sends the RES result of the transaction to the PDA (i.e., either a payment confirmation or a transaction failure notification), and to the application. Petition 870260041530, dated 04 / 05 / 2026, page 24 / 58 The 14 / 17 commercial application installed on the PDA resumes control to finalize the purchase. This checkout operation, depending on the commercial application, may consist of crediting loyalty points to a customer's account, or checking stock levels, etc.

[075] From the description just given, it is easily understood that the threats to data exchange between the PDA and the terminal must be controlled as efficiently as possible. It is therefore essential to ensure a high level of security in the pairing process between the PDA and the payment terminal. Indeed, it can be understood that if a hacker manages to obtain the PIN code transmitted from the payment terminal to the PDA from the outset, the subsequent security of exchanges between these two devices will be severely compromised.

[076] In this embodiment, the inventors had the ingenious idea of ​​using the functions that are integrated into both the payment terminal and the PDA. More particularly, in this embodiment, the payment terminal has a printer and the PDA has an optical barcode reader. Thus, instead of requesting the merchant to enter a PIN code, the inventors proposed, in this embodiment, to randomly generate a PIN code on the payment terminal and then print the symbol representing the PIN code in the form of a barcode using the payment terminal's printer. Once printed, this symbol, in the form of a barcode, is then identified by the PDA, through the appropriate reading application, and is interpreted by the PDA. The result of this interpretation (which is the PIN code generated by the payment terminal) is then provided to the PDA's Bluetooth module so that it can complete the pairing procedure.

[077] In this realization, once again, a second symbol is Petition 870260041530, dated 04 / 05 / 2026, p. 25 / 58 15 / 17 printed in the form of a barcode. It corresponds to the Bluetooth address of the payment terminal. This second barcode is also verified by the PDA in the second stage, and the Bluetooth address of the payment terminal is obtained. This allows for unique authentication of the terminal with which the PDA must be paired.

[078] Thus, the present method of the invention solves both of the problems mentioned above, namely, on the one hand, the problem related to errors in inserting very long character sequences and, on the other hand, the problem related to the necessary confidentiality that the entered PIN code must involve.

[079] The invention has been described in a particular embodiment. It is, of course, evident that the invention is by no means limited to this embodiment. The invention also relates to apparatus that allows pairing, as described above. More particularly, the invention relates to an acceptance apparatus. The acceptance apparatus comprises, according to the invention: means for generating a synchronization code in response to this pairing decision, means for processing the synchronization code in the form of a symbol. These processing means, as indicated, may consist of a printer, a screen, or a sound processing means.

[080] All these means are controlled by a computer program that is specifically adapted according to an initial pairing protocol, to generate a pairing code, converting it into a symbol and processing that symbol. The computer program also includes a pairing suspension phase provided that the pairing procedure has not been completed on the initiating equipment. Petition 870260041530, dated 04 / 05 / 2026, page 26 / 58 16 / 17

[081] The invention also relates to an initiating apparatus. The initiating apparatus comprises, according to the invention, means of obtaining a symbol from a pairing code, in response to this pairing decision, means of decoding the received symbol, which provides a pairing code or other useful data as a function of the symbol and its type. These means of obtaining can, as already indicated, consist of an optical sensor, a camera, a microphone.

[082] All these means are controlled by a computer program specifically adapted, according to an initial pairing protocol, to obtain one or more symbols, decoding it into a pairing code and executing the subsequent pairing. The computer program also includes a pairing suspension phase, provided that the pairing procedure has not been completed in the accepting device.

[083] Referring to figure 3, we present an embodiment of an acceptance apparatus, according to the invention.

[084] This acceptance apparatus comprises a memory 31, consisting of a temporary storage memory, a processing unit 32 equipped, for example, with a microprocessor P, and controlled by a computer program 33 that executes the modification method, according to the invention.

[085] At initialization, the instruction code of the computer program 33 is, for example, loaded into RAM and then executed by the processor of the processing unit 32. The processing unit 32 inserts at least one piece of information I, such as a pairing decision. The microprocessor of processing unit 32 executes the steps of the pairing method previously described here, according to the program instructions. Petition 870260041530, dated 04 / 05 / 2026, page 27 / 58 17 / 17 of computer 33, to provide processed information T, such as the symbol or symbols necessary for pairing the equipment. For this purpose, the device comprises, in addition to the temporary storage memory 31, the means described above. The means are controlled by the microprocessor of the processing unit 32.

[086] Referring to figure 4, we present an embodiment of an initiating apparatus, according to the invention.

[087] This device comprises a memory 41 consisting of a temporary storage memory, a processing unit 42 equipped, for example, with a microprocessor P, and controlled by a computer program 43 that executes the pairing method, according to the invention.

[088] At initialization, the instruction code of the computer program 43 is loaded, for example, into RAM, and then executed by the processor of the processing unit 42. The processing unit 42 inserts at least one piece of information I, such as a symbol from an acceptance device. The microprocessor of the processing unit 42 executes the steps of the modification method described above, according to the instructions of the computer program 43, to offer a processed piece of information T, such as the pairing code. For this purpose, the device comprises, in addition to the temporary storage memory 41, the means described above. The means are controlled by the microprocessor of the processing unit 42.

[089] As has been perfectly understood, the pairing method, as described above, actually comprises a first submethod for pairing, which is executed on the initiating terminal, and a second submethod for pairing, which is executed on the accepting terminal. Petition 870260041530, dated 04 / 05 / 2026, page 28 / 58

Claims

1 / 3 CLAIMS 1. A method for pairing a first device called an initiator device (Einit) with a second device called an acceptor device (Eacc), said initiator device (Einit) intending to transmit and receive data to and from said acceptor device (EAcc), said method comprising: - a step (10-1) of generating an asynchronous pairing code, comprising a random PIN code by said acceptor device (EAcc); - a step (10) of rendering, in the form of a first symbol (SYMB) superimposed on a watermarked image, said pairing code by said acceptor device (Eacc); - a step (20) of acquiring said first symbol (SYMB) by said initiator device (Einit);- a step of decoding the aforementioned first symbol (SYMB) acquired, providing the aforementioned pairing code, characterized in that the aforementioned method further comprises: - a step of obtaining, by the aforementioned acceptance device (EAcc), at least one useful data point; - a step of rendering, in the form of a second symbol (SYMB), the aforementioned at least one useful data point; - a step of acquiring the aforementioned second symbol (SYMB) by the aforementioned initiating device (Einit); and - a step of decoding the aforementioned second symbol (SYMB), delivering useful data by the aforementioned initiating device (Einit).

2. Matching method, according to claim 1, characterized in that said second symbol (SYMB) Petition 870260041530, dated 04 / 05 / 2026, p. 29 / 58 2 / 3 belongs to a type of symbol and said type of symbol belongs to the group comprising: - a one-dimensional barcode; - a two-dimensional barcode; - a watermarked image; - a modulated sound sequence.

3. A method for pairing, according to any one of claims 1 or 2, characterized in that said initiating device (Einit) is a PDA.

4. A method for pairing, according to any one of claims 1 to 3, characterized in that said acceptance device (EAcc) is a payment terminal.

5. A method according to any one of claims 1 to 4, characterized in that said step for rendering said pairing code in the form of a first symbol (SYMB) superimposed on a watermarked image comprises a step for printing said first symbol (SYMB) on a printer of said acceptance apparatus (EAcc).

6. Method, according to any one of claims 1 to 5, characterized in that said step for acquiring said first symbol (SYMB) superimposed on a watermarked image by means of said initiator apparatus (Einit) comprises a step for acquiring an image representing said watermarked image.

7. Initiating device (Einit) intended to transmit and receive data to and from an accepting device (EAcc), comprising: - means for acquiring a first symbol (SYMB) superimposed on a watermarked image representing an asynchronous pairing code comprising a random PIN code, allowing the pairing of said accepting device (Eacc) and said initiating device (Einit), said first symbol (SYMB) being reproduced by an accepting device (Eacc); - means for decoding said first symbol (SYMB) acquired which provides said pairing code, characterized by further comprising - means for acquiring a second symbol (SYMB) representing useful data; and - means for decoding said second symbol (SYMB) which provides said useful data.

8. An acceptance device (Eacc) intended to transmit and receive data to and from an initiator device (Einit), comprising: - means for generating an asynchronous pairing code comprising a random PIN code, enabling the pairing of said acceptance device (Eacc) and said initiator device (Einit); - means for rendering said pairing code in the form of a first symbol (SYMB) superimposed on a watermarked image, further characterized by comprising - means for obtaining at least one useful data point; - means for rendering said at least one useful data point in the form of a second symbol (SYMB).

9. A matching method according to claim 4, characterized in that the said watermarked image is a watermarked logo of an entity that uses said payment terminal. Petition 870260041530, dated 04 / 05 / 2026, p. 31 / 58

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