Patent Publication Number: US-2021173912-A1

Title: Method for securing access to a watch

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to European Patent Application No. 19214102.6 filed Dec. 6, 2019, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a method for securing access to a watch and a system implementing such a method. 
     The invention also relates to a watch comprising such a system as well as a computer program. 
     PRIOR ART 
     A watch comprises a set of functions which can be used by the wearer. Such functions can relate in addition to setting the time or date, to use of confidential or private data specific to the wearer and useful for accessing customised services. These data are for example keys, certificates, authentication codes, passwords and PINs which are used to connect the watch securely to a private corporate network, authentication with respect to secure servers such as a bank server, or a secure messaging system for sending and receiving signed and/or encrypted emails. As such, it is understood that it is important to be able to secure access to the use of the functions of such a watch. 
     For this purpose, in the prior art, methods are known envisaging securing access to a watch and in particular to the functions of this watch, by reinforcing the authentication criteria authorising this access for example by implementing additional authentication steps. 
     However, one of the major drawbacks of such methods is linked with the fact that, once the wearer of the watch is authenticated, it is then possible for any individual to obtain access to the functions of the watch particularly in the event of the latter being stolen. 
     It is understood that there is a need to find an alternative solution, particularly which does not have the drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     An aim of the present invention is consequently that of proposing a method for securing access to a watch which is reliable and robust. 
     Such a method has the advantage of ensuring the identity of the wearer of the watch automatically, transparently and non-intrusively for the wearer. 
     In this aim, the invention relates to a method for securing access to a watch including the following steps:
         authentication of the wearer of the watch with a view to authorising access to the functions of this watch based on an interaction between the wearer of the watch and a graphic representation comprised in said watch, and   periodic checking of the identity of the wearer of the watch through a verification of the validity of a digital data item determined based on at least one biometric data item of the wearer of said watch with a view to retaining/removing the authorisation for access to said functions.       

     In further embodiments:
         the authentication step comprises a presentation sub-step of a graphic representation on a visual data broadcasting interface of said watch;   the authentication step comprises a selection sub-step within a limited time interval of a sequence of at least two identification portions comprised in said graphic representation aiming to identify said wearer, said sequence corresponding to an identification code of the wearer;   the authentication step comprises a validation sub-step of the selected sequence;   the checking step comprises an acquisition sub-step by at least one multispectral biometric skin sensor comprised in the watch, of a plurality of images of a portion of the wearer&#39;s skin adjacent to said sensor, said images comprising said at least one biometric data item comprised in this skin portion;   the checking step comprises a sub-step of generating a digital identification item based on said at least one biometric data item;   the checking step comprises a sub-step of validating a digital identification item generated in anticipation of the wearer identity check;   the validation sub-step comprises a comparison phase including a sub-phase of retaining the authorisation to access said functions of the watch if the digital identification item is substantially similar or similar to a reference digital identification item;   the acquisition sub-step comprises an illumination phase of the skin portion along different wavelengths;   the acquisition sub-step comprises a capture phase of images of the skin portion illuminated at different wavelengths;   the generation sub-step comprises a characterisation phase of said at least one biometric data item comprised in the acquired images relative to said skin portion;   the generation sub-step comprises a design phase of the digital identification item based on the characterisation of said biometric data item;   the biometric data item relates to a vascular network or to a texture of this skin.       

     The invention also relates to a system for securing access to a watch implementing this method, the system comprising the following interconnected elements: a processing unit, a biometric sensor, an input interface and a visual data broadcasting interface. 
     Advantageously, the biometric sensor is a multispectral biometric skin sensor. 
     The invention also relates to a watch, particularly a connected mechanical watch, including such a system. 
     The invention also relates to a computer program comprising program code instructions for executing the steps of the method when said program is executed by a processing unit. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Further specificities and advantages will emerge clearly from the description given hereinafter, which is by way of indication and in no way limiting, with reference to the appended figures, wherein: 
         FIG. 1  is a schematic representation of a watch comprising a system for securing access to a watch, according to an embodiment of the invention, and 
         FIG. 2  is a logic diagram relating to a method for securing access to a watch, according to the embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a watch  100  comprising a system for securing access to a watch  100  and in particular to the use of functions of this watch  100 . Such a system  1  is comprised in the watch  100  which is preferably a hybrid-display connected mechanical watch  100 . In this context, this electronic device  100  comprises a body such as the watch case, and an attachment element such as a bracelet making it possible for this body to be fastened for example to the wearers wrist. This system  1  more specifically comprises in a non-limiting and/or non-exhaustive manner:
         a processing unit  2  including hardware and software resources in particular at least one processor cooperating with memory elements  6 ;   a visual data broadcasting interface  3  such as a hybrid display dial provided with a first analogue display component and a second digital and/or alphanumeric display component;   an audio data broadcasting interface  4  such as a speaker;   a wireless communication interface  5  (for example cellular, WLAN Bluetooth, etc.);   an input interface  34  such as a keypad or indeed a touch-sensitive interface comprised for example in the visual data broadcasting interface  3 , and   a biometric sensor  35  particularly in this embodiment a multispectral skin sensor, said sensor  35  comprising at least one photographic sensor  36 , at least one multispectral light source  37  and at least one thermal image sensor  38 , the light source  37  being capable of emitting luminous radiation in wavelengths between 300 and 1100 nm, furthermore, this light source  37  can be of the laser type.       

     In this system  1 , the processing unit  2  is connected inter alia to the visual and audio data broadcasting interfaces  3 ,  4 , to the input interface  34  as well as to the wireless communication interface  5  and to the biometric sensor  35 . It will be noted additionally that the biometric sensor  35  is arranged in the body of the electronic device  100  and/or in the attachment element. 
     This system  1  implemented in the electronic device  100  is capable of checking the identity of the authenticated wearer of the watch discreetly without direct intervention/interaction of the wearer with this watch  100 , so that they can use the functions of the watch  100  all the time that they are wearing it, without having to undergo authentication again. The wearer is then identified transparently and discreetly, based on at least one biometric data item. Within the scope of the present embodiment, the biometric data item is comprised in a portion of the wearer&#39;s skin and can be a vascular network of the skin or indeed a texture of this skin. This skin of the wearer covering their body has a specificity, less obvious for those skilled in the art to envisage as not naturally seen by the human eye, linked with the absorption and reflection characteristics at different wavelengths (spectrum) of the components of the skin, located at different depths. In a simplified model, the skin consists of a semi-transparent layer known as the “epidermis” located on the surface then, below the epidermis, a layer known as the “dermis” and comprising, inter alia, the blood vessels (or vascular network) wherein haemoglobin is highly reflective at high wavelengths near red being comprised for example between 760 and 930 nm which makes it possible herein to reveal or detect the vascular network of the wearer&#39;s skin. In other words, the light absorption spectrum of the components of the epidermis and the dermis forming the skin not being uniform along electromagnetic wavelengths, the appearance and colour of the skin are the result of a complex combination of these phenomena. Thus, when it is necessary to detect or reveal a biometric data item such as the skin texture of this wearer, a texture essentially formed of cracks and cavities, the skin can then be illuminated by a light source restricted to the wavelengths around red which tends to make the shadow phenomenon at the bottom of cracks disappear. Indeed, a retroprojection effect occurs by reflecting these near-red wavelengths onto the dermis and through the epidermis, whereas illuminating the skin by a source of a colorimetric spectrum at a distance from red, typically the band of wavelengths located between violet (400 nm) and up to orangey yellow (600 nm), makes it possible on the other hand to contrast these skin cracks significantly through the appearance of shadows at the bottom of these cracks. It will be noted that the identification of a biometric data item comprised in the skin can be enhanced using the thermal image sensor  38  preferably without illumination. By way of example, for the detection of the skin texture particularly when the portion of this wearer&#39;s skin concerned is endowed with hairs, the use of the thermal image sensor  38  makes it possible to reveal the cracks of this skin texture which are generally warmer than the surrounding skin and the hairs colder than this surrounding skin. Thus, in this configuration, the hairs can be distinguished thermally from the cracks of the skin texture due to this difference between the respective temperature thereof. 
     It will be noted that the thermal images can be captured under illumination in a given wavelength according to the biometric data item to be detected or revealed. 
     It is therefore understood, according to the principle of the invention, that the periodic identification of the wearer is carried out based on at least one biometric data item comprised in images of a portion of this wearers skin which can be illuminated where applicable along different wavelengths in order to capture the images comprising the biometric data item sought. Thus, this biometric data item, comprised in these images, can be detected by the illumination performed in different wavelengths or without illumination for example when capturing thermal images is involved. 
     In this system  1 , the memory elements  6  of the processing unit  2  comprise data relating to a previously defined/generated reference digital identification item. These memory elements  6  also include digital image processing algorithms  39  making it possible to characterise at least one biometric data item relating to the wearers skin and which is comprised in the images relative to the portion of the wearers skin. These memory elements  6  also include generation algorithms  40  of the reference digital identification item but also of the digital identification item which is generated periodically within the scope of the wearer&#39;s identity check. 
     These memory elements  6  of the processing unit  2  also comprise at least one graphic representation  41  envisaged to take part in the authentication process of the wearer so that the latter has access to the functions of the watch  100 . This graphic representation  41  can for example be an image comprising at least one object. By way of example, this image defines a scene comprising a plurality of objects such as houses, vehicles and/or a celestial body such as the moon, etc. It is obviously understood that this image can define further types of scene including at least one object. These memory elements  6  also include data relating to a reference sequence  42  comprising reference identification portions of this graphic representation  41 , said portions having been previously selected by the wearer of the watch during the configuration of an authentication process. 
     Such a system  1  of the watch  100  is capable of implementing a method for securing access to the watch  100  and in particular to the use of functions of this watch  100 , represented in  FIG. 2 . Such a method aims to check the identify of an authenticated user discreetly, i.e. non-intrusively and automatically, so that they can use the functions of the watch  100  all the time that they are wearing it, without having to undergo authentication again. The functions of the watch  100  can relate to setting the time, date, or indeed using a timer, a navigation system, a pedometer, an activity logger, a messaging system, access to confidential or private data specific to the wearer and useful for accessing customised services, etc. 
     This method comprises an authentication step  10  of the wearer of the watch  100  with a view to authorising access to the functions of this watch  100  based on an interaction between the wearer of the watch and a graphic representation comprised in said watch  100  more specifically a graphic representation displayed on/in the visual data broadcasting interface  3  of said watch  100 . This step  10  enables the wearer to prove their identity. More specifically, this step  10  comprises a sub-step  11  of presenting a graphic representation  41  on the visual data broadcasting interface  3  of said watch  100 . This sub-step  11  includes a display generation phase  12 , on/in the visual data broadcasting interface  3 , of the graphic representation  41  envisaged for the implementation of this authentication. This phase  12  can comprise a selection sub-phase by the user from a sample of at least two graphic representations  41  displayed on the visual data broadcasting interface  3 , of the graphic representation  41  envisaged for the implementation of this authentication. it will be noted that the wearer is the only one to know the graphic representations  41  that they selected during the configuration of the authentication process for access to the functions of the watch  100 . 
     This presentation sub-step  11  then comprises a countdown activation phase  13  once the generation phase  12  is carried out. In other words, the preconfigurable countdown is activated once the graphic representation  41  is presented on the broadcasting interface  3 . Such a phase  13  helps from a limited time interval defined by this countdown, to count down the estimated time required for the input of the sequence of identification portions of the graphic representation  41  displayed on/in the broadcasting interface  3 . 
     Subsequently, the authentication step  10  comprises a selection sub-step  14  within a limited time interval of a sequence of at least two identification portions of said graphic representation  41  aiming to identify said wearer, said sequence corresponding to an identification code of the wearer. Such identification portions are not directly visible in the graphic representation  41  presented on/in the broadcasting interface  3 . Under these conditions, the selection sub-step  14  comprises a visualisation phase  15  of at least one of said identification portions of the sequence in said graphic representation  41 . This visualisation phase  15  comprises a selection sub-phase of at least one zone of interest of the graphic representation  41  suitable for comprising said at least one identification portion. During this sub-phase, the wearer selects for example a first zone of interest or a second zone of interest by making an enlargement of this first zone or this second zone using the input interface  35 . Once this first or second zone of interest has been selected, the identification portions then become visible. In this configuration, each identification portion usable for creating/forming the sequence can be selected using the input interface  35 . 
     It should be noted that the sequence comprises an ordered number of identification portions and that the zone of interest selected can comprise for example three identification portions of which merely two are ordered successively one after the other in the sequence. In this context, the remaining identification portion requires to be part of the sequence, the selection of an identification portion comprised in a further zone of interest of the graphic representation  41 . 
     Then, the authentication step  10  comprises a validation sub-step  16  of the selected sequence. This validation sub-step  16  comprises a checking phase  17  that the selection of the sequence of identification portions has been carried out within the time interval defined by the countdown. Insofar as this selection has been carried out within this limited time interval, the validation sub-step  16  then comprises a comparison step  18 , implemented by the processing unit  2 , between said selected sequence and the reference sequence  42 . This comparison phase  18  comprises a sub-phase of prohibiting access to the functions of the watch  100  if said sequence is substantially different or different from the reference sequence  42 . Conversely, this comparison phase  18  comprises a sub-phase of authorising access to the functions of the watch  100  if said sequence is substantially similar or similar to the reference sequence  42 . 
     Insofar as this selection has not been carried out within this limited time interval, the validation sub-step  16  comprises a repeating step  19  of the presentation  11  and selection  14  sub-steps. If, subsequently, the selection of the sequence has once again not been carried out within the limited time interval, the validation sub-step  11  then envisages a sub-step of blocking/locking access to the functions of the watch  100 . In this context, a specific unlocking/unblocking procedure is then required to restore access to said watch. 
     This method then comprises a periodic checking step  20  of the identity of the wearer of the watch through a verification of the validity of a digital data item determined based on at least one biometric data item of the wearer of said watch with a view to retaining/removing the authorisation for access to said functions. Such a step is also known as periodic discreet checking step. Within the scope of the present embodiment, the biometric data item is comprised in a portion of the wearer&#39;s skin. During this step  20 , the period associated with the checking is regular or irregular and can be configured automatically by the processing unit  2  or defined by the wearer. By way of example, this period can be a few seconds or a few minutes. Such a checking step  20  makes it possible to verify following each period that the wearer of the watch is always the same by checking their “biometric” identity based on a digital identification item established according to at least one biometric data item comprised in this wearer&#39;s skin. 
     This checking step  20  then comprises an acquisition sub-step  21  by the sensor  35  of a plurality of images of a portion of the wearers skin, said skin being arranged adjacently to said sensor, said images comprising at least one biometric data item comprised in this skin portion. This sub-step  21  comprises an illumination phase  22  of the skin portion along different wavelengths. More specifically, during this phase  22 , the processing unit  2  controls the multispectral biometric sensor  35  and in particular the light source  37  such that the latter emits luminous radiation towards the skin portion along a specific wavelength adapted to detecting or revealing said at least one specific biometric information item of the skin, herein sought within the scope of the wearer identity check, and which is comprised in this portion of the wearers skin. Once the illumination has been configured, the acquisition sub-step  21  comprises a capture phase  23  of images of this skin portion illuminated at at least one wavelength suitable for detecting or revealing said at least one biometric data item. During this phase  23 , the processing unit  2  controls the multispectral biometric skin sensor  35  and in particular the photographic sensor  36  synchronously with the activation/deactivation of the light source  37 , in order to carry out the capture of at least one image relative to the illuminated skin portion for at least one wavelength. 
     This acquisition sub-step  21  can also comprise a capture phase  24  of at least one thermal image of the skin portion. Such a phase  24  is carried out preferably without illumination but in further alternatives an illumination of the portion can be performed in at least one given wavelength, this being dependent obviously on the biometric data item to be detected or revealed. This phase  24  can be carried out before or after the illumination  22  and image capture  23  phases. 
     The checking step  20  then comprises a generation sub-step  25  of the digital identification item based on said at least one biometric data item comprised in the acquired images of the skin portion. Such a sub-step  25  comprises a characterisation phase  26  of said at least one biometric data item comprised in the images relative to said skin portion. During this phase  26 , the processing unit  2  implements processing algorithms  39  of the images acquired aiming to identify/detect in each thereof said at least one biometric data item comprised therein. As mentioned above, this can involve data items relating for example to the texture of the skin or to the vascular network comprised in this portion of the wearer&#39;s skin. The implementation of these algorithms  39 ,  40  by the processing unit  2  can for example envisage a segmentation process of these images. It is understood herein that each image acquired gives an overview of the portion of the wearer&#39;s skin, and then includes variable relevance zones for the identification of said at least one biometric data item. Such a segmentation process helps extract the segments to be processed and remove the parts not to be processed in these images. These algorithms  39  can then envisage an indexing of these image segments comprising characteristics relating to said at least one specific biometric data item to be identified, by location zones in the skin portion, in order to be able to assign to each zone the suitable processing with respect to the morphological typology of the characteristic of this geographic zone of the portion. In this context, these algorithms  39  process each segment of these images by detecting the data carried by the pixels of each of these images by carrying out processing, transformation and detection type image analysis operations. Subsequently, these algorithms  39  perform characteristic filtering and extraction or vectorisation operations, in order to convert the image data relating to said at least one identified and extracted biometric data item, into parametric data, typically relative numerical values expressed for example as an index or percentage. 
     It is understood herein that the acquisition of several images representing the same skin portion helps enhance the precision and efficacy of this characterisation phase  26 . 
     Subsequently, the generation sub-step  25  comprises a design phase  27  of the digital identification item based on the characterisation of said at least one biometric data item. During this phase  27 , the processing unit  2  implements generation algorithms  40  of such a digital identification item specifically envisaged for processing the parametric data obtained during the characterisation phase  26 , said parametric data relating to the biometric data item. 
     Then, the checking step  20  comprises a validation sub-step  20  of the digital identification item generated in anticipation of the wearer identity check. This validation sub-step  28  comprises a comparison phase  29 , implemented by the processing unit  2 , between the digital identification item generated and the reference digital identification item. In this method, the reference digital identification item can be created, once the wearer has been duly authenticated and their identity is assured, during a definition step  11  of this reference digital identification item envisaging sub-steps similar to the acquisition  21  and generation  25  sub-steps implemented during the checking step  20 . In this method, once the wearer of the watch  100  is authenticated, the processing unit  2  implements this definition step  11  and then archives the reference digital identification item obtained in the memory elements  6  of the processing unit  2 . This reference digital identification item can therefore be determined automatically by the processing unit  2  or configured by the wearer during a setting process intended to guide the wearer in the definition of this reference digital identification element. 
     This comparison phase  29  comprises an access authorisation removal sub-phase  30  to said functions of the watch  100  if the digital identification item generated is substantially different or different from the reference digital identification item. In this scenario, the access to the functions of the watch  100  is then removed as the wearer and owner of the watch  100  may no longer be in possession thereof. As such in this context to use the functions of the watch  100  again, it is necessary to undergo authentication. 
     The comparison phase  29  also comprises an access authorisation retention sub-phase  31  to said functions of the watch  100  if the digital identification item generated is substantially similar or similar to the reference digital identification item. In this case, the checking unit  2  once again executes, according to the determined period, the sub-steps of acquisition  21  and generation  25  of the checking step  20  in order to carry out the comparison phase  29  once again. 
     Thus, the invention makes it possible to continuously automatically and non-intrusively check the identity of the wearer of the watch particularly once they are authenticated. 
     The invention also relates to a computer program comprising program code instructions for executing steps  10  to  31  of this method when said program is executed by the processing unit  2  of the watch  100 .