Abstract:
An electronic payment terminal is disclosed including a display screen including first and second terminals for receiving display data, a first processor connected to the first terminal and adapted for supplying display data to the first terminal at a first rate, and a second processor connected to the second terminal and adapted for supplying display data to the second terminal at a second rate lower than the first rate and adapted for supplying to the display screen a signal for the selection of the display data received at one of the first and second terminals. The second processor is further connected to the first processor and is adapted to send to the first processor a signal for authorizing or forbidding the transmission of display data to the display screen.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to electronic payment units, and in particular electronic payment units provided with a display screen. 
       Discussion of the Related Art 
       [0002]    An electronic payment unit generally comprises a housing containing a printed circuit to which are connected various components, including a keyboard, a chip card reader, a magnetic card reader, a display screen, a liquid crystal display or LCD, etc. 
         [0003]    A processor, attached to the printed circuit, enables to perform an electronic payment operation. It especially controls the data exchange with the chip of a chip card introduced into the card reader, the data display on the display screen, etc. Due to the security constraints imposed by banks for electronic payment operations, the processor generally implements ciphering algorithms in the data exchange with the chip card. Such a processor is generally called a security processor or cryptoprocessor. 
         [0004]    Due to its operation, the security processor is not capable of transmitting data at a high rate to the display. Thereby, the images displayed on the display screen of an electronic payment unit are generally limited to prompts for example corresponding to sequences of alphanumeric characters. As an example, during a payment operation, the security processor may send an order to display the amount of the financial transaction, then to display a prompt such as “input code” or “code?”. The user then inputs a confidential code via the electronic payment unit keyboard, the confidential code being stored in a memory of the security processor. Most of the time, the display screen of the electronic payment unit remains unused or is only used to display a fixed image. 
         [0005]    The design of the security processor is a complex operation given the multiple security constraints imposed for the electronic payment operations that the security processor must perform. It can thus, in practice, uneasily be envisaged to modify the security processor to have it transmits data to the display at a higher rate. 
       SUMMARY 
       [0006]    The present invention aims at obtaining an electronic payment unit enabling to display images at a high rate on a display while remaining compatible with the security constraints specific to the field of electronic payment operations. 
         [0007]    According to another object, the display of the electronic payment unit may be a conventional display. 
         [0008]    To achieve all or part of these objects, as well as others, an embodiment of the present invention provides an electronic payment unit comprising a display comprising first and second terminals for receiving display data; a first processor connected to the first terminal and capable of providing display data to the first terminal at a first rate; and a second processor connected to the second terminal and capable of providing display data to the second terminal at a second rate lower than the first rate and capable of providing the display with a signal of selection of the display data received on one of the first or second terminals. The second processor is further connected to the first processor and is capable of providing the first processor with a signal for allowing or forbidding the transmission of display data to the display. 
         [0009]    According to an embodiment of the present invention, the display comprises a third terminal and the second processor is connected to the third terminal and is capable of providing the selection signal to the third terminal. 
         [0010]    According to an embodiment of the present invention, the display is a liquid crystal display. 
         [0011]    According to an embodiment of the present invention, the first processor is connected to the first terminal by a parallel link. 
         [0012]    According to an embodiment of the present invention, the second processor is connected to the second terminal by a serial link. 
         [0013]    According to an embodiment of the present invention, the second processor is connected to a chip card and/or magnetic card reader. 
         [0014]    According to an embodiment of the present invention, the second processor is connected to a device for detecting an unauthorized access to the unit. 
         [0015]    An embodiment of the present invention also provides a method for displaying display data on a display of an electronic payment unit, said display comprising first and second terminals for receiving display data, the payment unit further comprising a first processor connected to the first terminal and capable of providing display data to the first terminal at a first rate and a second processor connected to the second terminal and capable of providing display data to the second terminal at a second rate lower than the first rate. The method comprises having the second processor provide the display with a signal for selecting display data received on one of the first or second terminals and providing the first processor with a signal for allowing or forbidding the transmission of display data to the display. 
         [0016]    According to an embodiment of the present invention, when the second processor provides the display with a signal for selecting the display data received on the first terminal, the second processor transmits a signal to the first processor allowing it to provide display data to the display. When the second processor transmits to the display a signal for selecting the display data received on the second terminal, the second processor provides the first processor with a signal notifying it not to transmit display data to the display. 
         [0017]    According to an embodiment of the present invention, the display comprises a control unit and a display panel, the control unit being capable of displaying on the display panel images obtained based on the display data. Before the second processor provides the display with the signal for selecting the display data received on the first terminal, the second processor provides configuration data to the display. The control unit is capable of displaying images obtained from the display data received on the first terminal on a portion only of the display panel which depends on the configuration data. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The foregoing objects, features, and advantages of the present invention will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings, among which: 
           [0019]      FIG. 1  shows, in the form of a block diagram, certain components of an electronic payment unit according to an embodiment of the present invention; and 
           [0020]      FIG. 2  illustrates steps of a method for using, according to an embodiment of the present invention, the electronic payment unit of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    For clarity, the same elements have been designated with the same reference numerals in the different drawings. In the following description, data transmitted to a display and which enable to display one or several images are called display data. Data transmitted to a display and which enable to define the operating parameters of the display for the subsequent display of images (number of colors, portion of the display used to display the images, etc.) are called configuration data. 
         [0022]    An embodiment of the present invention is based on the fact that most displays currently available for sale comprise several access terminals enabling to receive data (display and configuration data), generally at different rates. Conventionally, only one of the access terminals is used in practice, according to the features of the processor connected to the display. In an electronic payment unit, only the access terminal enabling to receive data at low rate is used and connected to the security processor. An embodiment of the present invention provides using, in addition to the security processor, another processor which does not perform operations submitted to the security constraints specific to electronic payment operations and which is capable of providing display data to a display over a high-rate link to enable to display high-rate images on the display. To remain compatible with the security constraints specific to electronic payment operations, only the security processor can determine the display data to be taken into account by the display at a given time. 
         [0023]      FIG. 1  shows in the form of a block diagram an electronic payment unit  10  according to an embodiment of the present invention. Only those elements which are useful to the understanding of the present invention will be described. The elements taking part in the usual operation of the electronic payment unit without being directly involved in the context of the present invention will not be described. 
         [0024]    Electronic payment unit  10  comprises a housing  11  containing the following elements: 
         [0025]    a display  12 ; 
         [0026]    a first processor  13 , called security processor, and a second processor  14  (application processor), separate from first processor  13 ; 
         [0027]    a chip card and/or magnetic card reader  15 ; 
         [0028]    a keyboard  16 ; and 
         [0029]    at least one protection device  17  capable of detecting whether an unauthorized access to housing  11  has occurred. 
         [0030]    These different elements may be connected to a printed circuit, not shown, contained in housing  11  and which ensures the electric connections between these elements. Housing  11  comprises openings, not shown, enabling a user to see the images displayed on screen  12 , to manipulate keyboard  16 , and to introduce a card into reader  15 . 
         [0031]    Display  12  for example corresponds to an LCD such as the LCD sold by Wintek under reference DF3224XM-6FLW. As an example, display  12  comprises a display panel  18  (LCD). This panel is, for example, formed of pixels that may be selected via display electrodes. Display  12  comprises a display unit  19  (LCD driver) which controls the electrodes of display panel  18 . Display  12  further comprises a control unit  20  (LCD controller) capable of exchanging data with display unit  19  and with a volatile memory  21  (RAM). Display  12  comprises two access terminals  22 ,  24  for the reception of data, especially display data. As an example, access terminal  24  is capable of receiving high-rate data and access terminal  22  is capable of receive low-rate data. Screen  12  further comprises a selection terminal  26  capable of receiving a selection signal. According to the selection signal received on terminal  26 , control unit  20  uses the display data received on access terminal  22  or on access terminal  24 . The received display data may be stored in memory  21 . Control unit  20  is further capable of converting the display data stored in memory  21  and/or directly received on access terminal  22  or at access terminal  24  into signals adapted to display unit  19 . 
         [0032]    Conventionally, security processor  13  is capable of controlling the operation of payment unit  10  when a payment operation is performed. An example of operation of a security processor or cryptoprocessor is described in French patent application 07/55148 filed by Sagem Monetel. Security processor  13  is connected to display  12 , to keyboard  16 , to reader  15 , and to protection device  17 . In particular, security processor  13  enables to exchange data in encrypted form with a bank card placed in reader  15  and enables to securely store confidential data. Protection device  17  for example corresponds to dummy keys and/or to a flexible printed circuit comprising mesh tracks as described in French patent applications 06/50617 and 06/54845 filed by Sagem Monetel. Protection device  17  transmits to security processor  13  an alert signal upon detection of an unauthorized access to unit  10 . Security processor  30  can then control the stopping of unit  10  and the deleting of any confidential data stored in the memory. Security processor  13  is capable of providing display and configuration data to display  12  via a low-rate link  34 , for example, a serial link, connected to access terminal  22 . Processor  14  is capable of providing display data to display  12  via a high-rate link  36 , for example, a link of parallel or RGB type, connected to access terminal  24 . Processor  14  is not capable of providing configuration data to display  12 . 
         [0033]    Security processor  13  is capable of providing a selection signal to display  12  via a dedicated link  38  connected to selection terminal  26 . Security processor  13  is connected to processor  14  by a data exchange link  39 . 
         [0034]    Link  34  allows a low-rate data transfer between security processor  13  and control unit  20 , for example, on the order of 10 Mbits/s. This mainly only enables to display fixed images on panel  18 , for example, prompts corresponding to sequences of alphanumeric characters. Link  36  enables to transfer data between processor  14  and control unit  20  at a high rate, for example, on the order of 100 Mbits/s. This enables to display videos on display panel  18 . This for example applies to commercial or advertising videos. 
         [0035]      FIG. 2  shows an operating mode of unit  10  of  FIG. 1  according to an embodiment of the present invention. The method starts at step  40  at which security processor  13  transmits a selection signal to control unit  20  via link  38  through which it controls unit  20  so that it only takes into account the data (display data and/or configuration data) received on access terminal  22 . Thereby, control unit  20  does not take into account the display data which would be received on access terminal  24 . The method carries on at step  42 . 
         [0036]    At step  42 , if messages are to be displayed on display  12  by security processor  13 , security processor  13  transmits display data to control unit  20  via link  34 . These data, that may be stored in memory  21 , are converted into signals adapted to display unit  20  which accordingly controls display panel  18 . Since security processor  13  is designed to respect the different security constraints specific to electronic payment operations, the display data provided to display  12  are data which comply with such security rules. When the step at which data are displayed by security processor  13  is over and security processor  13  has no new data to display, the method carries on at step  44 . 
         [0037]    At step  44 , security processor  13  determines whether it has received a display request transmitted by processor  14  over link  39 . If not, the method carries on at step  42  at which security processor  13  can again transmit data to display  12 . If, at step  44 , security processor  13  receives a display request transmitted by processor  14 , the method carries on at step  46 . 
         [0038]    At step  46 , security processor  13  transmits a selection signal to control unit  20  via link  38  through which it controls unit  20  so that said unit only takes into account the data received on access terminal  24 . Thereby, control unit  20  does not take into account the display data which would be received on access terminal  22 . Further, security processor  13  transmits a signal to processor  14  over link  39  to allow it to provide display data to control unit  20 . The method carries on at step  48 . 
         [0039]    At step  48 , processor  14  provides control unit  20  with display data over link  36 . Display data, that may be stored in memory  21 , are converted by control unit  20  to provide signals adapted to display unit  19  which controls the display of these data on display panel  18 . 
         [0040]    At step  48 , as long as security processor  13  does not need to display data, processor  14  can keep on transmitting display data to display  12 . As soon as security processor  13  needs to transmit data (display or configuration data) to display  12 , it transmits a message to processor  14  over link  39 , notifying it to interrupt the transmission of display data to display  12 . Processor  14  then stops transmitting display data over link  36 . The method then carries on at step  40  at which security processor  13 , as described previously, transmits a selection signal to control unit  20  over link  38  through which it control unit  20  so that it only takes into account the data received on access terminal  22 . 
         [0041]    According to another embodiment, at step  48 , display panel  18  is not entirely assigned to processor  14 , a portion of display panel  18  remaining permanently assigned to security processor  13 . In this case, at step  46 , before security processor  13  transmits to control unit  20  a selection signal with which it controls unit  20  so that said unit only takes into account the display data received on access terminal  24 , processor  13  transmits to control unit  20 , via terminal  22 , configuration data which define the portion of display panel  18  in which the display data provided by processor  14  will be displayed at step  48 . Processor  13  may further transmit display data to control unit  20  to display, in the portion of display panel  18  which is not assigned to processor  14 , a message indicating that the data which will be displayed on the rest of panel  18  at step  48  will not be displayed in the context of a secure payment operation. This message then remains displayed on display  12  all along step  48  during which microprocessor  14  transmits to control unit  20 , through terminal  24 , display data which result in the displaying of images in the portion of panel  18  assigned to processor  14 . 
         [0042]    The present embodiment of the present invention enables to take advantage of all the display possibilities offered by display  12 . Indeed, security processor  13  being dedicated to electronic payment operations, it only allows to display prompts on display  18 . Since the design of processor  14  is not submitted to the security constraints specific to electronic payment operations, it may control in a simple way the displaying of images or videos by taking advantage of the possibilities offered by display  12 . The present embodiment of the present invention thus enables to optimize the use of display  12  while decreasing as much as possible the modifications to be brought to security processor  13 . Further, the present embodiment enables to optimize the use of display  12  of electronic payment unit  10  since, when display  12  is not used by security processor  13 , it may be used for other purposes by processor  14 . Moreover, since the selection of data to be displayed is performed exclusively by security processor  13 , via the selection signal transmitted to control unit  20 , the security of the operation of the electronic payment unit is not altered. 
         [0043]    Specific embodiments of the present invention have been described. Various alterations and modifications will occur to those skilled in the art. In particular, display  12  may have a structure different from that described previously.