Abstract:
The master secure element comprises a processor, a memory and a logic unit and at least controls the user input of the handset in order to secure the user authentication based on PIN entry. The PIN code is entered directly into the secure element with no possibility for the host processor to intercept the code or for a malware program to inject the code into the master secure element.

Description:
[0001]    Related application “Validating a Transaction with a Secure Input and a Non-Secure Output”, Attorney Docket No. 81524742US01 filed on the same day and assigned to the same assignee is incorporated by reference herein in its entirety. 
         [0002]    Related application “Validating a Transaction with a Secure Input without Requiring PIN Code Entry”, Attorney Docket No. 81526126US01 filed on the same day and assigned to the same assignee is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0003]    Mobile platforms or connected devices such as smart phones, personal computers, tablet PCs and smart meters are integrating a secure element to authenticate the platform, to protect user credentials or to secure transactions. The secure element is typically a highly tamper resistant device that provides a secure execution environment isolated from the host processor. The secure element may be integrated into various form factors such as, for example, SIM cards, SD cards, or small outline packages attached directly on the printed circuit board (embedded secure element). 
         [0004]    The activation of the functionalities of a device or validation of an operation involving the device typically requires authentication of the user by the secure element. Typically, the user enters a PIN directly on a touch screen or a keypad of the device. The entered PIN is communicated to the secure element via the host processor which resides in an open, nonsecure environment. Because user&#39;s devices are typically connected to one or more network, the devices can be infected by malware capable of intercepting the user&#39;s PIN. 
         [0005]    The secure element is integrated into, for example, a mobile handset or PC that is controlled by the host processor. The secure element is typically a slave device that cannot distinguish between a PIN entered by the user or by malware. In both instances, the secure element receives the same command from the host processor. In the typical mobile handset architecture, the PIN is entered either on a physical keypad or on a virtual keypad of a touch screen. The user input is always under the control of the host processor which creates security vulnerabilities. Typical solutions to the vulnerabilities are software solutions, that may or may not be enforced by hardware features that attempt to isolate the PIN entry process, including the keypad and or display drivers, from other processes that run on the host processor. The various techniques of process isolation or virtualization create a secure environment that is typically not tamper resistant and also typically increases the complexity of the required software architecture. One implementation of such a technique is the TEE proposed by GlobalPlatform TEE White Paper, February 2011 and incorporated herein by reference in its entirety which states in part:
       The TEE is a separate execution environment that runs alongside the Rich OS and provides security services to that rich environment. The TEE offers an execution space that provides a higher level of security than a Rich OS; though not as secure as a Secure Element (SE), the security offered by the TEE is sufficient for most applications. In this way, the TEE delivers a balance allowing for greater security than a Rich OS environment with considerably lower cost than an SE.       
 
         [0007]    Prior art connected device architecture  100  (e.g. mobile handset architecture) is shown in  FIG. 1 . Display  110  and keypad  120  (keypad  120  may be a physical or virtual keypad) are connected to host processor  130  along with Secure Element (SE)  150  and Subscriber Identity Module (SIM)  140 . SIM  140  is a secure element that typically contains the international mobile subscriber identity (IMSI) and the related key used to authenticate subscribers on mobile networks. SE  150  and SIM  140  securely store applications such as a mobile wallet application. SE  150  and SIM  140  activation is protected with two passwords: a personal identification number (PIN) for ordinary use and a personal unblocking code (PUK) for PIN unlocking. When the PIN is requested by SE  150  or SIM  140 , host processor  130  can inform the user that it is running in secure mode by displaying a security indicator that, for example, was preselected by the user such as mother&#39;s maiden name or a selected photo thumbnail. While the security indicator provides a valuable indication to the user, it does not guarantee that the PIN received by SE  150  has been entered by the user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a prior art connected device architecture. 
           [0009]      FIG. 2   a  shows an embodiment in accordance with the invention. 
           [0010]      FIG. 2   b  shows an embodiment in accordance with the invention. 
           [0011]      FIG. 3  shows an embodiment in accordance with the invention. 
           [0012]      FIG. 4  shows a prior art alphanumeric keypad. 
           [0013]      FIG. 5   a  shows an embodiment in accordance with the invention. 
           [0014]      FIG. 5   b  shows an embodiment in accordance with the invention. 
           [0015]      FIG. 6  shows an embodiment in accordance with the invention. 
           [0016]      FIG. 7  shows an embodiment in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    In accordance with the invention, connected device architecture  100  shown in  FIG. 1  is modified. In an embodiment in accordance with the invention as shown in  FIG. 2   a , the connected device architecture  200  gives control of keypad  220  to master secure element (MSE)  250  when a secure input such as a user PIN is requested. When MSE  250  requests a PIN input from the user, keypad  220  is fully controlled by MSE  250 . For all non-secure input operations, keypad  220  remains under control of host processor  230 . The PIN received by MSE  250  cannot be intercepted by host processor  230 . In accordance with the invention, the user is authenticated because only the user knows the PIN and only the user can enter the PIN or other secure input such as a password. The user is typically alerted to the operational state of connected device architecture  200  by security indicator  215  which is directly controlled by MSE  250  to prevent entry of, for example, a PIN in non-secure mode. Security indicator  215  may, for example, be a light emitting diode; or a polarized mask layer or a color filter integrated into display  210 , that is activated to inform the user that connected device architecture  200  is operating in secure mode and that keypad  220  is under control of MSE  250  and not host processor  230 . 
         [0018]    In an embodiment in accordance with the invention as shown in  FIG. 2   a , the connected device architecture  200  in an embodiment in accordance with the invention can also secure the PIN entry for another secure element, such as SIM card  240 . An application running on SIM card  240  only accepts the PIN entry from MSE  250  through the single wire protocol (SWP). MSE  250  becomes a trusted or secure extension of host processor  230  that provides tamper resistant security to all operations related to PIN entry for connected device architecture  200 . 
         [0019]    In an embodiment in accordance with the invention as shown in as shown in  FIG. 2   b , connected device architecture  205  gives control of touch screen  220  to master secure element (MSE)  250  when a secure input such as a user PIN is requested. When MSE  250  requests a PIN input from the user, touch screen  218  is fully controlled by MSE  250 . For all non-secure input operations, touch screen  218  remains under control of host processor  230 . The PIN received by MSE  250  cannot be intercepted by host processor  230 . In accordance with the invention, the user is authenticated because only the user knows the PIN and only the user can enter the PIN or other secure input such as a password. The user is typically alerted to the operational state of connected device architecture  205  by security indicator  215  which is directly controlled by MSE  250  to prevent entry of, for example, a PIN in non-secure mode. Security indicator  215  may, for example, be a light emitting diode; or a polarized mask layer or a color filter integrated into display  210 , that is activated to inform the user that connected device architecture  205  is operating in secure mode and that touch screen  218  is under control of MSE  250  and not host processor  230 . 
         [0020]    With reference to  FIG. 2   b , the connected device architecture  205  in an embodiment in accordance with the invention can also secure the PIN entry for another secure element, such as SIM card  240 . An application running on SIM card  240  only accepts the PIN entry from MSE  250  through the single wire protocol (SWP). MSE  250  becomes a trusted or secure extension of host processor  230  that provides tamper resistant security to all operations related to PIN entry for connected device architecture  205 . 
         [0021]    Additionally, connected device architecture  205  in  FIG. 2   b  provides communication capability such as, for example, Near Field Communication capability between MSE  250  and external Secure Element (SE)  255 . Typically SE  255  may be a contactless smart card with NFC capability or part of another mobile device equipped with NFC capability. MSE  250  provides secure entry via NFC of the PIN into SE  255  and becomes a secure hub for user credentials transferred by external secure elements. 
         [0022]    In accordance with the invention, MSE  250  allows embedded secure applications to at least control the user input and the communications interfaces to other secure elements (e.g. SIM card  240 ). MSE  250  provides a universal secure environment that supports the dematerialization of the security services on mobile devices such as bank cards, mobile wallets, mobile points of sale, virtual SIM, authentication tokens, digital rights management, automatic fare collection etc. Because a PIN code intercepted by malware cannot be introduced into MSE  250 , host processor  230  does not need to integrate security features such as process isolation, virtualization, security indicators and the like to protect the PIN entry process. MSE  250  assures that the PIN entered by the user can only originate from keypad  220  or touch screen  218 . 
         [0023]      FIG. 3  shows the secure PIN entry process for an embodiment in accordance with the invention. In step  310 , MSE  250  asks host processor  230  to request the user to provide a PIN. In step  320 , host processor  230  activates display  210  to display the PIN entry field to the user. In step  330 , the user verifies that security indicator  215  is activated and enters the PIN* using touch screen  218  (or keypad  220 ) which are directly connected to MSE  250 . In step  340 , MSE  250  compares the PIN securely stored in MSE  250  with the PIN* that was input by the user using keypad  220  or touch screen  218 . If PIN is equal to PIN*, the user is authenticated. Note that only the user and MSE  250  have access to the correct PIN. If the PIN* entered by the user and the PIN stored in MSE  250  differ, the user is not authenticated and the transaction is aborted. Note that a numerical PIN may be easily replaced by a password if keypad  220  or touch screen  218  supports letters. Keypad  420  shown in  FIG. 4  is an example of a keypad that supports both numbers and letters. 
         [0024]    In an embodiment in accordance with the invention, MSE  500  shown in  FIG. 5   a  includes processor (CPU)  510  electrically coupled to memory  520 , host interface  570  and SIM interface  560 . Host keypad interface  550 , keypad interface  530  are electrically coupled to multiplexer (MUX)  540  which is electrically coupled to CPU  510 . MUX  540  and security indicator  215  (via security indicator interface  555 ) are controlled by application  525  running in MSE  250  and stored in memory  520  (see  FIGS. 2 and 5 ). By controlling MUX  540 , application  525  stored in memory  520  and running on CPU  510  appropriately redirects user input from keypad interface  530  back to keypad interface to host  550  or to CPU  510  as required. 
         [0025]    The master secure element such as MSE  250  may integrate either a full driver for a multi-touch and gesture input or a reduced driver that only supports a single touch input for PIN or password entry operation. 
         [0026]    In addition to PIN or password entry, connected device architecture  205  in accordance with the invention shown in  FIG. 5   b  is equipped with touch screen  218  (e.g. such as used in smart phones) instead of keypad  220  to offer the option of using biometric methods to authenticate the user based on finger gestures or a stylus signature, for example. Note that touch screen  218  can function as a virtual keypad and allows PIN and password entry as well. 
         [0027]    MSE  505  in an embodiment in accordance with the invention is shown in  FIG. 5   b  and includes processor (CPU)  510  electrically coupled to memory  520 , host interface  570  and SIM interface  560 . Host touch screen interface  551  and touch screen interface  531  are electrically coupled to multiplexer (MUX)  540  which is electrically coupled to CPU  510 . MUX  540  and security indicator  215  (via security indicator interface  555 ) are controlled by application  525  running in MSE  250  and stored in memory  520  (see  FIGS. 2   a - b  and  5   a - b ). By controlling MUX  540 , application  525  stored in memory  520  and running on CPU  510  appropriately redirects user input from touch screen interface  531  back to touch screen interface to host  551  or to CPU  510  as required. Additionally, NFC interface  590 , typically an RF Frontend, is directly connected to CPU  510  of MSE  505 . MSE  505  functions as a secure NFC controller. 
         [0028]    A fingerprint sensor or other suitable biometric sensor may optionally be embedded in connected device architectures  200  and  205  to authenticate the user. The biometric template provided by the sensor is directly verified within MSE  600  (see  FIG. 6 ). 
         [0029]    In an embodiment in accordance with the invention shown in  FIG. 6 , MSE  600  incorporates touch screen interface  630  which is electrically connected to MUX  640 . Additionally, touch screen interface to host  650  is electrically connected to MUX  640  which is electrically connected to CPU  610 . CPU  610  is also electrically connected to memory  620 , host interface  670 , NFC interface  615 , SIM interface  660  security indicator interface  655  and optional fingerprint sensor interface  605 . By controlling MUX  640 , application  625  stored in memory  620  and running on CPU  610  appropriately redirects user input from touch screen interface  630  back to touch screen interface to host  650  or to CPU  610  as required. Application  625  also controls security indicator  215  via security indicator interface  655 . 
         [0030]    Typically, a more powerful CPU  610  is required to handle stylus signatures, finger gestures or fingerprint templates for verification purposes. These inputs as well as a PIN input may be handled in real time by MSE  600  or MSE  500  or encrypted by MSE  600  or MSE  500  and sent to backend server  710  (see  FIG. 7 ) for processing, respectively. These inputs as well as a PIN input may be sent to backend server  710  in real time or stored in memory  620  or memory  520 , respectively for later verification by backend server  710 , if for example, a data connection to backend  710  is temporarily unavailable. 
         [0031]      FIG. 7  shows connected architecture  700  with backend server  710  in an embodiment in accordance with the invention. The arrows  1 ,  2  and  3  represent secure connections. Application  525  is running on MSE  750  which is securely connected to touch screen  218 , to backend server  710  and via an NFC connection to secure element  255  such as a smart card or another mobile platform. All security features are handled by MSE  750 . Note communication between MSE  750  and backend server  710  is encrypted to provide a secure end to end connection. 
         [0032]    While the invention has been described in conjunction with specific embodiments, it is evident to those skilled in the art that many alternatives, modifications, and variations will be apparent in light of the foregoing description. Accordingly, the invention is intended to embrace all other such alternatives, modifications, and variations that fall within the spirit and scope of the appended claims.