Patent Publication Number: US-2023137390-A1

Title: Method for managing a biometric smart card

Description:
FIELD OF THE INVENTION 
     The present invention relates to methods for managing a biometric smart card. It relates particularly to methods of managing biometric features of a smart card which embeds at least one biometric sensor. 
     BACKGROUND OF THE INVENTION 
     Smart cards are portable small devices comprising a memory, a microprocessor and an operating system for computing treatments. They may comprise services applications like payment applications. Such secure elements may comprise a plurality of memories of different types, like non-volatile memory and volatile memory. They are considered as tamper-resistant (or “secure”) because they are able to control the access to the data they contain and to authorize or not the use of data by other machines. A smartcard may also provide computation services based on cryptographic components. In general, smartcards have limited computing resources and limited memory resources and they are intended to connect a host machine which provides them with electric power either in contact mode or contactless mode. 
     A smart card may contain a biometric sensor like a fingerprint sensor which can contribute to the authentication of the user of the smartcard. A biometric smart card may embed a biometric reference data corresponding to the user of the smart card. Such a biometric reference data is recorded during an enrollment phase. The biometric smartcard embeds a biometric algorithm designed to compare a data captured by the biometric sensor with the biometric reference data in order to authenticate the cardholder. 
     When a biometric smart card is stolen, lost or has a validity date which has expired, the genuine user of the biometric smart card may want that biometric features of the smart card are no more reachable for security and privacy reasons. 
     There is need to enhance the management of biometric features of a smart card. 
     SUMMARY OF THE INVENTION 
     The invention aims at solving the above mentioned technical problem. 
     An object of the present invention is a method for managing a biometric smart card associated to a user. The biometric smart card comprises a reference biometric data which has been previously enrolled by the user, a biometric sensor which is configured to collect a captured biometric data from a person and a secure element able to communicate with the biometric sensor through a communication channel. The method comprises the steps of:
         receiving, by the biometric smart card, a specific data;   checking, by the biometric smart card, the specific data by using a control data pre-stored in the biometric smart card; and   only if said checking is successful, executing by the biometric smart card both an erasing command for removing said reference biometric data from the biometric smart card and a disabling command for permanently deactivating said communication channel.       

     Advantageously, the biometric smart card may receive the specific data from a hardware machine which is coupled to the biometric smart card, the specific data may be a cryptographic data and the control data may be a key. 
     Advantageously, the biometric smart card may receive the erasing command, the disabling command and the specific data from a hardware machine coupled to the biometric smart card and the specific data may be a PIN code entered by said user. 
     Advantageously, the biometric smart card may receive said erasing command and disabling command from a hardware machine coupled to the biometric smart card, the biometric smart card may receive said specific data directly from the user, the specific data may be a biometric data and the control data may be the reference biometric data. 
     Advantageously, the biometric smart card may receive said specific data from a hardware machine coupled to the biometric smart card, said specific data may be a current date, said control data may be a validity date pre-stored in the biometric smart card and said erasing command and disabling command may be pre-stored in the biometric smart card. 
     Advantageously, the biometric smart card may get power from a hardware machine coupled to the biometric smart card, the biometric smart card may receive said specific data directly from the user, the specific data may be a biometric data, the control data may be said reference biometric data and said erasing command and disabling command may be pre-stored in the biometric smart card. 
     Advantageously, the biometric smart card may be configured to work at least in an enrolment mode and in a erasing mode, the activation of the erasing mode may be triggered by a predefined sequence of actions of the user and the biometric smart card may comprise a LED which may be gradually turned on to guide the user when performing the predefined sequence of actions. 
     Advantageously, the disabling command may permanently deactivate said communication channel by updating a digital value or by physically destroying a hardware component into the biometric smart card. 
     Another object of the present invention is a biometric smart card allocated to a user and comprising a reference biometric data previously enrolled by said user, a biometric sensor configured to collect a captured biometric data from a person and a secure element able to communicate with the biometric sensor through a communication channel. The biometric smart card comprises at least a processing unit and instructions which cause said biometric smart card to:
         receive a specific data,   check the specific data by using a control data pre-stored in the biometric smart card, and   only if said checking is successful, execute both an erasing command for removing said reference biometric data from the biometric smart card and a disabling command for permanently deactivating said communication channel.       

     Advantageously, the biometric smart card may be configured to receive said erasing command, said disabling command and said specific data from a hardware machine coupled to the biometric smart card and the specific data may be a PIN code entered by said user. 
     Advantageously, the biometric smart card may be configured to receive said erasing command and disabling command from a hardware machine coupled to the biometric smart card, the biometric smart card may be configured to receive said specific data directly from the user, the specific data may be a biometric data and the control data may be the reference biometric data. 
     Advantageously, the biometric smart card may be configured to receive said specific data from a hardware machine coupled to the biometric smart card, said specific data may be a current date, the control data may be a validity date which has been pre-stored in the biometric smart card and said erasing command and disabling command may be pre-stored in the biometric smart card. 
     Advantageously, the biometric smart card may get power from a hardware machine coupled to the biometric smart card, the biometric smart card may be configured to receive said specific data directly from the user, the specific data may be a biometric data, the control data may be said reference biometric data and said erasing command and disabling command may be pre-stored in the biometric smart card. 
     Advantageously, the biometric smart card may be configured to work at least in an enrolment mode and in a erasing mode, the activation of the erasing mode may be triggered by a predefined sequence of actions of the user, the biometric smart card may comprise a LED and the biometric smart card may gradually turn on said LED to guide the user when performing the predefined sequence of actions. 
     Advantageously, the disabling command may permanently deactivate said communication channel by updating a digital value or by physically destroying a hardware component into the biometric smart card. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the present invention will emerge more clearly from a reading of the following description of a number of preferred embodiments of the invention with reference to the corresponding accompanying drawings in which: 
         FIG.  1    shows a first exemplary flow diagram for managing biometric features of a smart card according to an example of the invention, 
         FIGS.  2 - 6    show several exemplary embodiments of a smart card coupled to a hardware machine according to a plurality of embodiments of invention, and 
         FIG.  7    shows a diagram of a smart card according to an example of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention may apply to any type of biometric smart card associated to a user and intended to provide a service. The biometric smart card may be a bank smart card or an identity badge for instance. 
       FIG.  1    shows a first exemplary flow diagram for managing biometric features of a smart card according to an example of the invention. 
     In this example, the biometric smart card is a banking card intended to be used by its associated user (i.e. bank customer) for payment or cash withdrawal. 
     The bank smart card  10  embeds a biometric sensor  40  designed to capture fingerprint data. The bank smart card embeds a secure element  20  comprising a hardware processing unit, memory and an operating system designed to contribute to bank services. The secure element is configured to establish a communication channel with the biometric sensor in order to get access to data captured by the sensor. The communication channel may be established either directly between the secure element and the sensor or through a controller of the sensor. The bank smart card comprises a reference biometric data which has been enrolled by the user (i.e. bank customer). 
     At an optional first step S 10 , the user (e.g. bank customer) may declare to her/his bank that the biometric smart card  10  has been lost or stolen. This information is provided to a server computer  90  of the bank. 
     At an optional second step S 20 , a person who found the smart card  10  is supposed to start an online transaction at a hardware machine coupled to the biometric smart card. For instance, the transaction may be a payment to be carried out between the smart card and a distant server through a terminal located at a point of sales. 
     At step S 30 , the smart card receives a specific data  55 . In this example, the specific data may be provided to the smart card by the distant server  90  through the local terminal. 
     At step S 40 , the biometric smart card checks the specific data  55  by using a control data  25  which has been pre-stored in the biometric smart card. For example, the control data  25  may be a key which has been stored in the smart card before its issuance (E.g. at manufacturing stage) and the specific data may be a signature whose authenticity can be checked using the key  25 . 
     Only if the checking of step S 40  is successful, at step S 50 , the biometric smart card executes both an erasing command for permanently removing the reference biometric data from the biometric smart card and a disabling command for permanently deactivating the communication channel that allows the secure element  20  to communicate with the biometric sensor  40  into the biometric smart card. It is important to note that the deactivation of the communication channel (and the ability to establish the communication channel) is not temporary, but definitive. 
     In one variant, the disabling command may permanently deactivate the communication channel (between the secure element and the biometric sensor) by updating a digital value. For instance, the disabling command may permanently erase or disable a key in the secure element. For instance, the disabling command may permanently block the GPIO (General Purpose Input/Output) of the secure element which are used to communicate with the biometric sensor. 
     In one variant, the disabling command may permanently deactivate the communication channel by physically destroying a hardware component into the biometric smart card. For instance, the disabling command may blow a fuse required to physically access the sensor. 
     It is to be noted that the erasing command and disabling command may be received by the smart card with the specific data  55  via a script for instance or the smart card may receive a triggering data that triggers the execution of the erasing command and disabling command which may be pre-stored in the smart card. 
     In on embodiment, steps S 10  and S 20  may be replaced by a step in which the cardholder (I.e. the genuine user of the smart card) requests the bank to deactivate the biometric feature of the smart card. Such a request may be performed through the user interface of an ATM (Automated Teller Machine) for example. It is to be noted that such a request may be performed before the smart card validity expires. 
     In on embodiment, steps S 10  and S 20  may be replaced by a step in which the cardholder inserts the smart card into a hardware machine (like a portable card reader) which is not connected to the bank server and requests deactivation of the biometric features of the smart card through the user interface of the hardware machine. 
     In on embodiment, steps S 10  and S 20  may be replaced by a step in which the cardholder inserts the smart card into a hardware machine (like a portable card reader) which is not connected to the bank server and requests deactivation of the biometric features of the smart card by following a specific sequence using the biometric sensor of the smart card. 
     In on embodiment, steps S 10  is not executed. The sequence may start at step S 20  and the smart card may receive the current date as specific data  55  and automatically compare the received date to its own pre-stored validity date (as control data) at step S 40 . 
       FIG.  2    shows a first exemplary embodiment of the smart card coupled to a hardware machine according to an example of invention. 
     In the example of  FIG.  2   , a bank server  90  comprises a first script processing key  91  and is able to use the key  91  to generate scripts whose integrity and authenticity can be checked by the smartcard  10 . A hardware machine  80  is connected to the bank server  90  using conventional networks and protocols. The hardware machine may be an ATM or Point of Sale (POS) terminal. The biometric smart card  10  comprises a reference biometric data  21  (previously stored during enrolment of the cardholder) and a second script processing key  25  which is paired with the first script processing key  91 . The biometric smart card  10  also comprises a secure element and a biometric sensor (not shown). 
     Assuming that the bank server  90  knows that the genuine user (e.g. bank customer) declared that the biometric smart card  10  has been lost or stolen, a person who got the smartcard  10  may try to unduly use the smartcard. This person may start an online transaction with the hardware machine  80 . The bank server  90  may generate a script  70  comprising an erasing command  71 , a disabling command  72  and a cryptographic data  55  computed by using the first script processing key  91 . Preferably, the cryptographic data may be a MAC (message authentication code). 
     Then the script  70  may be forwarded to the smart card  10  through the hardware machine  80 . In other words, the smart card may receive from the hardware machine  80  a specific data  55  which is a cryptographic data. 
     Then the biometric smart card may check the MAC  55  (i.e. the specific data) by using the second script processing key  25  (as control data). 
     Only if the MAC has been successfully checked (i.e. the script  70  has been authenticated), the biometric smart card may make the decision to execute both the erasing command  71  for removing the reference biometric data  21  from the biometric smart card and the disabling command  72  for permanently deactivating the communication channel that allows the secure element to communicate with the biometric sensor into the biometric smart card. 
     It is to be noted that the receipt of the script  70  by the card may occur even if the cardholder has not been authenticated by the smart card. Naturally, the online transaction initially requested is not completed. 
     The script  70  may be handled by using the convention script processing mechanism as defined by EMV© specifications. 
     In another embodiment, the genuine user (e.g. bank customer) may have requested to the bank the deactivation of the biometric features before the end of life of the smart card. The genuine user may start an online transaction with the smart card in order to initiate the sending of a script similar to the one described above. In such a case, the cardholder may be authenticated (through a PIN or a fingerprint for instance) or not, depending on a preset bank policy and/or the desire to correctly complete the online transaction. 
       FIG.  3    shows a second exemplary embodiment of the smart card coupled to a hardware machine according to an example of invention. 
     In the example of  FIG.  3   , a biometric smart card  10  is inserted in a hardware machine  81  like an ATM, a POS terminal or a portable card reader. The biometric smart card  10  comprises a secure element, a biometric sensor, a reference biometric data  21  and a control data  25  which is intended to control the authenticity of a PIN code value associated to the genuine user  50 . The hardware machine  81  stores the erasing command  71  and the disabling command  72 . The hardware machine  81  includes a user interface which may comprise a display and a keyboard. 
     The genuine user  50  may insert the smart card  10  into the hardware machine  81 , enter her/his PIN code  51  and request deactivation of the biometric features of the smart card  10  through the user interface of the hardware machine  81 . 
     The hardware machine  81  may send the entered PIN code  51  to the smart card  10 . The hardware machine  80  may send the erasing command  71  and the disabling command  72  to the smart card  10 . In other words, the biometric smart card receives the erasing command, the disabling command and the specific data from the hardware machine  81  coupled to the biometric smart card and the specific data is a PIN code  51  entered by the user  50 . 
     The biometric smart card may check the received PIN code  51  (which is the specific data) by using the previously stored control data  25 . 
     Only if the received PIN code  51  has been successfully checked (i.e. the PIN code  51  entered by the cardholder is valid), the biometric smart card  10  may execute both the erasing command  71  for removing the reference biometric data  21  from the biometric smart card and the disabling command  72  for permanently deactivating the communication channel that allows the secure element to communicate with the biometric sensor into the biometric smart card. 
     Preferably, the user may be informed of the successful completion of the deactivation operation by a message displayed via the user interface of the hardware machine  81 . 
       FIG.  4    shows a third exemplary embodiment of the smart card coupled to a hardware machine according to an example of invention. 
     In the example of  FIG.  4   , a biometric smart card  10  is inserted in a hardware machine  82  like an ATM, a POS terminal or a portable card reader. The biometric smart card  10  comprises a secure element, a biometric sensor, a reference biometric data  21 . The control data  25  is the reference biometric data  21 . The hardware machine  82  comprises the erasing command  71  and the disabling command  72 . The hardware machine  82  includes a user interface which may comprise a display and a keyboard. 
     The genuine user  50  may insert the smart card  10  into the hardware machine  82 , present her/his finger to the sensor so that the smart card gets the fingerprint  52  of the user  50  and request deactivation of the biometric features of the smart card  10  through the user interface of the hardware machine  82 . 
     The hardware machine  82  may send the erasing command  71  and the disabling command  72  to the smartcard  10 . In other words, the biometric smartcard may receive the erasing command and the disabling command from the hardware machine  82  coupled to the biometric smart card and may receive the specific data (biometric data in this example) directly from the user  50 . 
     The biometric smart card may check the captured fingerprint  52  (which is the specific data) by using the previously stored reference biometric data  21  (which is the control data  25  in this example). It is to be noted that the captured biometric data  52  may be treated before the comparison with the reference biometric data  21 . For instance an anti-spoofing algorithm may be applied to the captured data  52 . 
     Only if the captured biometric data  52  has been successfully checked (i.e. the fingerprint of the cardholder has been successfully recognized), the biometric smart card  10  may execute both the erasing command  71  for removing the reference biometric data  21  from the biometric smart card and the disabling command  72  for permanently deactivating the communication channel that allows the secure element to communicate with the biometric sensor into the biometric smart card. 
     Preferably, the user may be informed of the successful completion of the deactivation operation by a message displayed via the user interface of the hardware machine  82 . 
       FIG.  5    shows a fourth exemplary embodiment of the smart card coupled to a hardware machine according to an example of invention. 
     In the example of  FIG.  5   , a biometric smart card  10  is inserted in a hardware machine  83  like an ATM or a POS terminal. The biometric smart card  10  comprises a secure element, a biometric sensor, a reference biometric data  21  and a control data  25 . The control data  25  is the expiration date  24  (i.e. validity date) of the banking application of the smart card  10 . The biometric smart card  10  already comprises the erasing command  71  and the disabling command  72 . The hardware machine  83  may include a user interface which may comprise a display and a keyboard. 
     The user (which may be either the genuine user or another one) may insert the smart card  10  into the hardware machine  83  and start a transaction with the hardware machine  83 . 
     The hardware machine  83  may automatically send the current date  53  to the smart card  10 . 
     The biometric smart card may automatically check the received date  53  (which is the specific data) by using the previously stored expiration date  24  (which is the control data  25  in this example). 
     Only if the received date  53  has been successfully checked (i.e. the validity of banking services of the smart card  10  has expired compared to the received date  53 ), the biometric smart card  10  may execute both the erasing command  71  for removing the reference biometric data  21  from the biometric smart card and the disabling command  72  for permanently deactivating the communication channel that allows the secure element to communicate with the biometric sensor into the biometric smart card. 
     In other words, the biometric smart card may receive the specific data from a hardware machine  83  coupled to the biometric smart card, the specific data may be the current date  53  which is used as control data and both the erasing command and disabling command may be pre-stored in the biometric smart card. 
     According to the example of  FIG.  5   , the smart card may automatically make the decision to deactivate its own biometric features. 
     The transaction initially requested is not completed. 
     It is to be noted that the authentication of the cardholder may be optional for the example of  FIG.  5   . 
     Preferably, the user may be informed of the successful completion of the deactivation operation by a message displayed via the user interface of the hardware machine  83 . 
       FIG.  6    shows a fifth exemplary embodiment of the smart card coupled to a hardware machine according to an example of invention. 
     In the example of  FIG.  6   , a biometric smart card  10  is inserted in a hardware machine  84  like a portable card reader that powers the smart card. Alternatively, the card  10  may be coupled to a NFC mobile phone which may power the smart card thanks to its generated electromagnetic field. The biometric smart card  10  comprises a secure element, a biometric sensor, a reference biometric data  21 . In this example, the control data  25  is the reference biometric data  21 . The biometric smart card  10  already comprises the erasing command  71  and the disabling command  72 . The biometric smart card  10  comprises an agent  27  configured to trigger the deactivation of the biometric features as soon as the user  50  has been successfully authenticated via the biometric sensor. 
     The hardware machine  84  may be devoid of user interface. 
     The genuine user  50  may couple the smart card  10  to the hardware machine  84  and present her/his finger to the sensor so that the smart card may get the fingerprint  52  of the user  50 . 
     The biometric smart card may check the captured fingerprint  52  (which is the specific data) or sequence of captured fingerprints by using the previously stored reference biometric data  21  (which is the control data  25  in this example). 
     Only if the captured biometric data  52  (or sequence of captured fingerprints) has been successfully checked, the biometric smart card  10  may execute both the erasing command  71  for removing the reference biometric data  21  from the biometric smart card and the disabling command  72  for permanently deactivating the communication channel that allows the secure element to communicate with the biometric sensor into the biometric smart card. 
     In one embodiment, the biometric smart card may be configured to work at least in an enrolment mode and in an erasing mode. The activation of the erasing mode may be triggered by a predefined sequence of actions of the user. 
     In order to request deactivation of the biometric features of the smart card  10 , the user  50  may present a sequence of fingerprints. The sequence of fingerprints may be a series of fingerprints coming from different fingers and/or an order series of enrolled and not-enrolled fingers. For instance a triggering series may be the following sequence (ordered or in any order): thumb, index, middle and little finger. For instance a triggering series may be the following ordered sequence: a fingerprint leading to a successful matching, fingerprint leading to an unsuccessful matching and fingerprint leading to a successful matching. 
     Advantageously, the biometric smart card may comprise at least one LED which is gradually turned on to guide the user when performing the predefined sequence of actions. 
       FIG.  7    shows a diagram of a smart card according to an example of the invention. 
     In this example, the biometric smart card  10  is a banking smart card. 
     The smart card  10  comprises a secure chip  20  (also called secure element), a biometric sensor  40  and a controller  30  of the sensor. The controller  30  may be a processing unit (also named processor unit) like a microcontroller unit (MCU). The biometric sensor may be a conventional biometric sensor like a fingerprint sensor. 
     The controller  30  is coupled to the biometric sensor  40 . In particular, the processing unit  30  is the only entity that can directly access the sensor. The controller  30  is configured to retrieve biometric data  60  (also named raw biometric data) from the sensor  40 . 
     The controller  30  comprises a first local key  33  intended to be used to establish a secure communication channel with the secure element  20 . The controller  30  may comprise a biometric algorithm  31  aiming at detecting spoofing attacks on the sensor  40 . 
     Optionally, the controller  30  may comprise an analyzer engine  32  for extracting remarkable items from the biometric data collected by the sensor  40 . 
     The controller  30  comprises a processor and a non-volatile memory (not shown). In one embodiment, the non-volatile memory stores software instructions which are executed by the processor to perform the functions described above. In one embodiment, the functions of the controller  30  may be implemented as pure hardware solution or a combination of hardware and firmware. 
     In the example of  FIG.  7   , the secure element  20  is a conventional smart card chip with additional features. The secure element  20  is able to contribute to a banking transaction with an external machine. For instance, the transaction may be a payment transaction or cash withdrawal. The secure element  20  comprises a reference biometric data  21  previously enrolled by the user  50 . The secure element  20  comprises an extracting engine  22  for extracting remarkable items  52  from the biometric data collected by the sensor  40 . The secure element  20  comprises a biometric algorithm  26  aiming at comparing the reference biometric data  21  with remarkable items  52  extracted from the biometric data  60  collected by the sensor  40 . The secure element  20  comprises an operating system (not shown). 
     The secure element  20  comprises the expiration date  24  of the Banking features of the smart card  10 . It is to be noted that the card may remain functional for services or commands other than the banking aspect beyond the validity date. 
     In one embodiment, the secure element  20  may comprise a control data  25  which is different from the reference biometric data  21  and from the expiration date  24 . 
     In one embodiment, the secure element  20  may comprise a second local key  23  intended to be used to establish a secure communication channel with the controller  30 . The first and second local keys are paired. 
     In the example of  FIG.  7   , the secure element  20  can access the sensor  40  through the controller  30  only. In other words, the secure element can communicate with the biometric sensor through a communication channel that goes through the controller  30 . Thus, by permanently removing the (logical or physical) link between the secure element  20  and the controller  30 , the communication channel between the secure element and the biometric sensor can be permanently deactivated. 
     In one embodiment, the secure element  20  may comprise an agent  27  configured to trigger the deactivation of the biometric features as soon as the user  50  has been successfully authenticated via the biometric sensor. 
     The secure element  20  comprises a processor and a non-volatile memory (not shown). In one embodiment, the non-volatile memory stores software instructions which are executed by the processor to perform the functions of the secure element. In one embodiment, the functions of the secure element  20  may be implemented as pure hardware solution or a combination of firmware and hardware. 
     In one embodiment, the smart card  10  may comprise one or several LEDs ( 11 ,  12 ) allowing to provide information to the user and physically coupled to the secure element. For example one or several LEDs can be used to guide the user when performing a predefined sequence of actions for triggered activation of the erasing mode in the smart card. For example one or several LEDs may be lit to indicate the end of the operation of deactivation of the biometric feature of the smart card. 
     In one embodiment, the secure element  20  may comprise pre-stored erasing command  71  and disabling command  72 . (Not shown at  FIG.  7   ) 
     In a one embodiment, the secure element  20  may comply with Specifications from EMV® Contactless Specifications for Payment Systems Version 2.6 or Version 3.0. 
     In a one embodiment, the secure element  20  may comply with Visa® Integrated Circuit Card Specification (VIS) Version 1.6 or Version 2.2. 
     In a one embodiment, the secure element  20  may comply with M/Chip Advance Card Application Specification Version 1.2.2 or Version 1.2.3. 
     The controller  30  and the secure element  20  may communicate through ISO-7816 protocol, through SWP (Single Wire Protocol) or any relevant protocol. 
     Although the controller  30  and the secure element  20  have been described has separated components in the above-presented examples, they also may be merged in a single hardware component, like a secure microcontroller. For instance, the secure element  20  may include the features of the controller  30 . In such an embodiment, the secure element  20  may directly access the sensor  40  through a direct communication channel which may be permanently deactivated by updating a digital value in a specific field (or a register) or by destroying a hardware component needed to handle the communication channel. 
     Thanks to the invention, it is possible to permanently deactivate the biometric features of a smart card. 
     The invention allows to enhance the monitoring of risk of fraud for lost and stolen biometric cards. 
     The invention allows to enhance the management of the end of life of biometric data and features embedded in a smartcard in order to meet cardholder expectations regarding the management of data deemed sensitive. 
     The invention is not limited to the described embodiments or examples. In particular, the described examples and embodiments may be combined. 
     The invention is not limited to Banking smart cards and applies to any biometric smart cards allocated to a user. 
     The biometric smart card may embeds several biometric sensors (of same or different types) and the invention may allow to deactivate access to all embedded biometric sensors. 
     Although examples of the invention has been provided in the banking domain, the invention also applies to other domains. For example, the online transaction may be an access request to a physical building, room or area. 
     In another example, the online transaction may be the user&#39;s identity authentication by an external machine. 
     Although examples of the invention has been provided for a fingerprint sensor, it may apply to devices embedding any biometric sensor targeting various types of data: iris, voice, face, blood or palm print for examples. 
     It is to be noted that the invention applies to any biometric smart cards or similar devices able to be coupled to a hardware machine in contact or contactless mode.