Abstract:
A method for operating a host device includes inserting a plug-in adapter, having a subscriber identity module (SIM) component disposed thereon, into a host receptacle of the host device. A memory card is inserted into a memory receptacle on the plug-in adapter. After inserting the plug-in adapter and the memory card, communications are conveyed between the host device and the SIM component via the adapter and the memory card.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application 60/937,631, filed Jun. 27, 2007, which is incorporated herein by reference. This application is related to a U.S. patent application entitled “Memory Interface Card with SIM Functions,” filed on even date. 
    
    
     FIELD OF THE DISCLOSURE 
     The present invention relates generally to computing and communication devices, and specifically to device authentication. 
     BACKGROUND OF THE DISCLOSURE 
     Electronic memory cards are commonly used for non-volatile storage of digital data in many electronic computing and communication devices. A variety of different card formats are available from various suppliers, such as SanDisk Corporation (Sunnyvale, Calif.). SanDisk, for example, offers Secure Digital (SD™) cards, as well as smaller microSD™ cards, which are designed to be plugged into a compatible receptacle in a host device. Such cards contain flash memory and an embedded processor, which communicates with the host processor using a predefined bus protocol (such as the SD protocol). 
     A subscriber identity module (SIM) is a type of smart card that is used for authentication of a host device in which the SIM is installed, based on a unique identifier that is stored securely in the SIM. The SIM may also include a memory (such as flash memory or other non-volatile memory) for storing data. The term “SIM card” originally came into use in the specific context of authenticating mobile telephones in Global System for Mobile (GSM) telephone networks, but has now come to refer to any smart card or other electronic component that securely stores a unique identifier for purposes of authentication. In the context of the present patent application, the term “SIM component” is used in this broad sense. For purposes of authentication, SIM components commonly communicate with the host processor using a predefined SIM protocol, such as the ISO 7816 protocol defined by the International Organization for Standardization. 
     SUMMARY OF THE DISCLOSURE 
     In some embodiments, a plug-in adapter includes a first contact for connection to a host device, at least two second contacts for connection to a memory card, a third contact for connection to a subscriber identity module (SIM) component, and circuitry that connects at least one of the second contacts to the third contact and connects at least another of the second contacts to the first contact so as to create a communication path between the host device and the SIM component via the memory card. 
     The adapter may include a connector containing the first contact and configured to mate with a host receptacle in the host device, wherein the connector may be compatible with an SD card standard. Typically, the connector is configured to permit the adapter to be removed from the host device. Additionally or alternatively, the adapter may include a memory receptacle, which contains the second contacts, for receiving the memory card, wherein the memory receptacle may be compatible with a microSD card standard. 
     In one embodiment, the circuitry is configured to enable the host device to communicate with the SIM component via the memory card in accordance with an ISO 7816 standard. 
     Additionally or alternatively, the at least one of the second contacts is configured to communicate with an antenna connection of the memory card. 
     The third contact may be fixedly connected to the SIM component. Alternatively, the adapter may include a SIM receptacle containing the third contact and configured to removably receive the SIM component. 
     Another embodiment provides computing apparatus, including a host device including a host receptacle compliant with a first memory card standard, a memory card compliant with a second memory card standard, and a plug-in adapter. The adapter includes a connector configured to mate with the host receptacle and containing a first contact for connection to the host device and a memory receptacle configured to receive the memory card and containing at least two second contacts for connection to the memory card, as well as a third contact for connection to a subscriber identity module (SIM) component. Circuitry in the adapter connects at least one of the second contacts to the third contact and connects at least another of the second contacts to the first contact so as to create a communication path between the host device and the SIM component via the memory card. 
     The circuitry and memory card may be configured to enable the host device to communicate with the SIM component by exchanging messages via the memory card in accordance with an ISO 7816 standard, wherein the messages are encapsulated for transmission between the host device and the memory card in accordance with the first card standard, and wherein the memory card comprises a processor, which is configured to parse and convey the messages to and from the SIM component in accordance with the ISO 7816 standard. 
     A further embodiment provides a method for operating a host device, including inserting a plug-in adapter, having a subscriber identity module (SIM) component disposed thereon, into a host receptacle of the host device and inserting a memory card into a memory receptacle on the plug-in adapter. After inserting the plug-in adapter and the memory card, communications are conveyed via the adapter and the memory card between the host device and the SIM component. 
     In yet another embodiment, a method for operating a host device includes receiving at a memory card, via a plug-in adapter in which the memory card is inserted, a message from the host device that is directed to a SIM component on the plug-in adapter, and conveying the message from the memory card to the SIM component on the plug-in adapter. The message may be transmitted from the host device in accordance with a first protocol, and conveying the message may include parsing and conveying the message from the memory card to the SIM component in accordance with a second protocol. In a disclosed embodiment the first protocol is an SD protocol, while the second protocol is an ISO 7816 protocol. 
     The present disclosure will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, pictorial illustration of a mobile computing device; 
         FIG. 2  is a block diagram showing components of a computing device; 
         FIG. 3  is a block diagram that schematically illustrates communication flow among elements of a computing device; 
         FIG. 4  is a block diagram that schematically illustrates a plug-in adapter and memory card; and 
         FIG. 5  is a block diagram that schematically illustrates a plug-in adapter and memory card in an alternative configuration. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a schematic, pictorial illustration of a mobile computing device  20 , having multimedia capabilities for receiving and playing digital content, such as video programs and music. For this purpose, device  20  contains a novel arrangement of digital memory and authentication components, as described with reference to the figures that follow. The device has an output interface, such as a video display  22  and audio speaker (not shown), as well as user controls  24  for selecting programs and performing other user control functions. The device also has a communication interface, represented by an antenna  26 , for communicating with a network  30 , such as a cellular or other mobile network or a satellite network. Alternatively or additionally, device  20  may communicate with a fixed network, such as a wired telephone, cable, or packet network. 
     Device  20  may be capable of playing content from different sources, including both content stored internally in the device memory and content transmitted over network  30  from a content provider  28 . The content provider may charge a subscription fee or pay-per-view charge for each program that the user of device  20  chooses to view. To ensure that only authorized devices are capable of playing these programs, the content provider may use a conditional access system (CAS), which requires that device  20  contain a SIM component authorized by the content provider in order to authenticate the end user and enable it to decode the programs. (As noted above, the “SIM component” may be any sort of smart card or other suitable electronic device that contains a unique identifier.) 
     This sort of SIM-based authentication requirement can be problematic for some types of mobile devices. For example, assuming device  20  to be a mobile telephone, the device will typically contain a SIM component provided by the operator of network  30  and will not have an additional SIM receptacle available for the CAS of the content provider. Although it would be possible, in principle, to use the same SIM component for both purposes, this solution requires close cooperation between the mobile network operator and the content provider, which is not always practical. The user could switch the mobile network SIM and CAS SIM components back and forth for communication and media playing, but this solution is also impractical. In other cases, assuming device  20  to be a portable media player without telephony capabilities, for example, the device may not have a SIM receptacle at all. 
     On the other hand, current mobile devices do generally have a memory receptacle available, such as an SD card slot. In the embodiments described hereinbelow, a novel adapter is inserted into this memory receptacle, in a way that makes it possible for the receptacle to be used for both device memory and SIM authentication. Specifically, the adapter contains a SIM component (which may be embedded or removable) and a receptacle for a memory card (such as a microSD card). Circuitry in the adapter creates a communication path between the host device and the memory card and between the memory card and the SIM component. Thus, the host device can carry out both memory operations and SIM authentication operations via the adapter and the embedded processor of the memory card. Device  20  can be used in this manner both for receiving and playing programs on line from content provider  28 , using a suitable CAS SIM in the adapter for authentication, and playing prerecorded programs that are stored in the memory. 
       FIG. 2  is a block diagram that schematically shows internal details and components of device  20 , in accordance with one possible embodiment. Operations of the device are controlled by a host central processing unit (CPU)  40 , with input/output (I/O) interfaces  42  for communicating with network  30  and for interacting with display  22  and controls  24  ( FIG. 1 ). As noted above, device  20  may comprise a SIM card (not shown) provided by the operator of network  30  for authentication of the device on the network. 
     Device  20  comprises a host receptacle  48 , which is designed to receive a standard memory card. In the present embodiment, the receptacle is assumed to be SD-compatible, but the principles of the present disclosure may similarly be applied using other memory card standards. An adapter  44  comprises a substrate with a connector  45 , which plugs into receptacle  48 . The connector contains contacts  46  that connect the adapter via the receptacle to the host device. The term “contacts,” in the context of the present patent application and in the claims, refers to physical connection points, which may comprise, for example (without limitation), pins, pads or sockets. 
     Adapter  44  contains a memory receptacle  50  for receiving a memory card  52 , such as a microSD card in the present example. Receptacle  50  comprises contacts  54 ,  56  which connect to a suitable connector on the memory card. Memory card  52  comprises an embedded processor  58  and a memory  60 , such as a flash memory array. Memory  60  is typically used for storing both data (such as video recordings) for the host device and firmware to be run by the embedded processor. 
     Adapter  44  also holds a SIM component  62 , which connects to contacts  64  on the adapter. Typically, the SIM component is configured to communicate in accordance with a predetermined standard, such as ISO 7816. The SIM component may be embedded in the adapter and fixedly connected to contacts  64 . Alternatively, adapter  44  may comprise a SIM receptacle  65  containing contacts  64 , into which the SIM component may be inserted and removed as desired. 
     Circuitry  66  on adapter  44  interconnects contacts  46 ,  54 ,  56  and  64  so as to enable host CPU  40  to communicate with SIM component  62 . The flow of communications is described hereinbelow with reference to  FIG. 3 , while different possible configurations of circuitry  66  are shown in  FIGS. 4 and 5 . Generally speaking, circuitry  66  may simply comprise conductive paths between the appropriate contacts, with little or no added switching or other logic. In the embodiments that are described herein, there is no need for an embedded processor in adapter  44  to parse and execute messages from host CPU  40 , since these functions are carried out by processor  58  in memory card  52 . 
     Memory card  52  may be a standard product, comprising off-shelf hardware, with firmware modified as necessary to carry out the novel functions that are described herein. In one embodiment (described below in greater detail with reference to  FIG. 4 ), memory card  52  has input/output pins for communicating with a Near Field Communication (NFC) antenna. These pins connect to contacts  56  in receptacle  50 , while contacts  54  are used for the data connections between the memory card and the host device. Instead of connecting to an antenna, however, contacts  56  are used in this embodiment to connect processor  58  to SIM component  62 , and the firmware run by the processor is modified in order to use the antenna pins for sending and receiving SIM messages. 
       FIG. 3  is a block diagram that schematically illustrates communication flow among elements of device  20  in an embodiment relating to receiving and playing content from content provider  28 . This content is subject to the CAS of the content provider and is accessed by device  20  using a CAS application program  70  running on host CPU  40 . To authenticate device  20  and decode the content, CAS application  70  accesses SIM component  62  via a communication path that passes through adapter  44  to memory card  52 , and from the memory card back through the adapter to the SIM component, as shown in the figure. The term “path,” in the context of the present patent application and the claims, may refer to any sort of physical or logical connection between endpoints (or a combination of physical and logical connections). Such a path typically terminates on and/or passes through the types of contacts that are defined above. 
     Host CPU  40  communicates with processor  58  on memory card  52  using a standard memory bus protocol, such as the SD protocol. For this purpose, an SD driver program  72  generates the appropriate memory commands and parses responses returned from the memory card. These commands and responses are passed through transparently by adapter  44 . An SD host control program  74  is responsible for link control between the host device and memory card. 
     SIM component  62 , however, communicates using a SIM protocol, such as ISO 7816, not the memory bus protocol that is used between the host device and memory card  52 . To support communication with the SIM component, the host CPU uses a SIM-to-SD driver program  76 . This program encapsulates outgoing SIM messages from CAS application  70  in commands that are compatible with the SD protocol and parses responses from the memory card in order to extract and interpret the incoming SIM messages from the SIM component, which it then passes to the CAS application. This encapsulation enables the CAS application to communicate with the SIM component without exporting a SIM protocol interface. In memory card  52 , processor  58  performs similar encapsulation and parsing functions in order to convey the SIM messages to and from SIM component  62 . 
     To this end, device  20  may utilize existing methods for encapsulating SIM messages in a memory bus protocol. Such methods are described, for example, in U.S. Patent Application Publication 2004/0064612 and in U.S. Pat. No. 7,305,535, whose disclosures are incorporated herein by reference, and may be adapted for use in the present embodiment. Although the present embodiment relates specifically to encapsulation of ISO 7816 messages in the SD protocol, similar principles may be used in transmitting other types of SIM protocol messages, as well as in encapsulating SIM messages in other memory bus protocols. 
       FIGS. 4 and 5  are block diagrams schematically show two different possible implementations of circuitry  66  in device  20 . 
     In the embodiment of  FIG. 4 , in accordance with the SD protocol, memory card  52  exchanges four-bit data with the host device via adapter  44  using SD data lines that are labeled DATA  0  . . . DATA  3 . The SD standard provides only these four data lines. Therefore, to communicate with SIM component  62 , the processor in memory card  52  is programmed to use two additional pins, labeled ANTENNA  0  and ANTENNA  1 , which are conventionally used for communicating with a NFC antenna, as explained above. 
     In accordance with ISO 7816, SIM component  62  has pins for VCC (power), clock, data and reset, as shown in  FIG. 4 . VCC is provided directly from the host device via adapter  44 . Memory card  52  normally provides the standard clock and data signals to the SIM component via ANTENNA  0  and ANTENNA  1 . When it is necessary to reset the SIM component, the memory card provides a reset command in the form of a special sequence of pulses over the clock and data lines. A simple logic circuit  82  in circuitry  66  detects this sequence and asserts the reset input to the SIM component. Logic circuit  82  may comprise, for example, a state machine, a microprocessor, or a programmable or hard-wired controller, which is configured to activate the reset of SIM component  62  in response to the command from the memory card. Thus, the requirements of the standard ISO 7816 interface to the SIM component are satisfied. 
       FIG. 5  is a block diagram that schematically shows details of circuitry  66 , in accordance with an alternative embodiment. This embodiment takes advantage of an optional one-bit data mode provided by the SD standard. In this case, only the DATA  0  line is needed to convey data between the host device and memory card  52 . The remaining SD data lines—DATA  1 , DATA  2  and DATA  3 —are available to convey the clock, data and reset signals between the memory card and SIM component  62 . Thus, in this embodiment, circuitry  66  need comprise no more than suitable conductive traces on the substrate of adapter  44 , and there is no need for logic circuit  82 . 
     It will be appreciated that the embodiments described above are cited by way of example, and that the present disclosure is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.