U.S. patent application number 11/557591 was filed with the patent office on 2008-05-08 for method and apparatus for enabling content to be shared among multiple devices in a secure environment.
This patent application is currently assigned to GENERAL INSTRUMENT CORPORATION. Invention is credited to Michael D. Kotzin.
Application Number | 20080109656 11/557591 |
Document ID | / |
Family ID | 39361033 |
Filed Date | 2008-05-08 |
United States Patent
Application |
20080109656 |
Kind Code |
A1 |
Kotzin; Michael D. |
May 8, 2008 |
Method and Apparatus for Enabling Content to be Shared Among
Multiple Devices in a Secure Environment
Abstract
A Master device (e.g., a SIM card) is configured with
information regarding one or more Slave devices (e.g., SIM cards)
that are associated with the Master device. The Master device is
installed in a user device that receives content files and access
and usage rights from a content provider. The Master device
identifies one or more Slave devices that are associated with the
Master device and transmits content files and the rights data to
the Slave devices. A user device in which a Slave device is
installed receives the content files and rights data sent by the
Master device. The Slave device extracts a key from the rights data
and provides the key to a decryption component of the user device,
which uses the key to decrypt the content file.
Inventors: |
Kotzin; Michael D.; (Buffalo
Grove, IL) |
Correspondence
Address: |
Motorola, Inc.;Law Department
1303 East Algonquin Road, 3rd Floor
Schaumburg
IL
60196
US
|
Assignee: |
GENERAL INSTRUMENT
CORPORATION
Horsham
PA
|
Family ID: |
39361033 |
Appl. No.: |
11/557591 |
Filed: |
November 8, 2006 |
Current U.S.
Class: |
713/165 ;
726/30 |
Current CPC
Class: |
H04L 2463/101 20130101;
H04W 12/04 20130101; G06F 21/6218 20130101; H04W 12/08 20130101;
H04L 63/0853 20130101; G06Q 20/1235 20130101; H04W 12/43 20210101;
G06F 2221/2141 20130101 |
Class at
Publication: |
713/165 ;
726/30 |
International
Class: |
H04L 9/32 20060101
H04L009/32; G06F 21/24 20060101 G06F021/24 |
Claims
1. An apparatus for enabling content files to be shared among
multiple user devices, the apparatus comprising: a Master device
configured to be installed in a user device, the Master device
comprising: an input/output (I/O) device configured to receive and
send data; and a digital rights management (DRM) processor
configured to perform a DRM algorithm, wherein the DRM processor
identifies at least one Slave device associated with the Master
device and sends rights data associated with a content file to a
Slave device identified by the Master device as being associated
with the Master device, the rights data enabling a user device in
which the Slave device is installed to gain access to a content
file associated with the rights data.
2. The apparatus of claim 1, wherein the DRM processor sends the
rights data and the content file associated with the rights data to
the Slave device.
3. The apparatus of claim 2, wherein the rights data includes
access and usage rights data.
4. The apparatus of claim 1, wherein the Master device is an
integrated circuit (IC) of a System Identification Module (SIM),
and wherein the Slave device is an IC of a System Identification
Module (SIM).
5. The apparatus of claim 1, wherein the Master device further
comprises: a memory element configured to store the rights
data.
6. The apparatus of claim 1, wherein prior to the DRM processor
sending the rights data to the Slave device, the DRM processor
identifies any Slave devices that are associated with the Master
device.
7. The apparatus of claim 6, wherein prior to the DRM processor
sending the rights data to the Slave device, the DRM processor
analyzes an identity of the Slave device and only sends the rights
data to the Slave device if the DRM processor determines that the
Slave device is associated with the Master device.
8. The apparatus of claim 1, wherein the rights data includes a
digital decrypting key that is used by the user device in which the
Slave device is installed to decrypt the content file.
9. An apparatus for enabling content files to be shared among
multiple user devices, the apparatus comprising: a Slave device
configured to be installed in a user device, the Slave device
comprising: an input/output (I/O) device configured to receive and
send data; and a digital rights management (DRM) processor
configured to perform a DRM algorithm, the DRM processor receiving
rights data via the I/O device from a Master device associated with
the Slave device, the DRM processor extracting a key from the
rights data and providing the key to one or more components of the
user device, said one or more components of the user device using
the key to gain access to a content file associated with the rights
data.
10. The apparatus of claim 9, wherein when the DRM processor
receives rights data and the content file associated with the
rights data from the Master device.
11. The apparatus of claim 9, wherein the rights data includes
access and usage rights data.
12. The apparatus of claim 9, wherein the Slave device is an
integrated circuit (IC) of a System Identification Module (SIM),
and wherein the Master device is an IC of a System Identification
Module (SIM).
13. The apparatus of claim 9, wherein the Slave device further
comprises: a memory element configured to store the rights data
received in the Slave device from the Master device.
14. An apparatus for enabling content files to be shared among
multiple user devices, the apparatus comprising: at least first and
second System Identification Module (SIM) cards electrically
interface with one another, each of the SIM cards having one or
more electrical contacts thereon that are in electrical contact
with one or more electrical contacts on another of the SIM cards to
enable each of the SIM cards to communicate with at least one other
of the SIM cards, wherein each SIM card includes a digital rights
management (DRM) processor configured to perform a DRM
algorithm.
15. A method for enabling content files to be shared among multiple
user devices, the method comprising: in a Master device,
identifying one or more Slave devices that are associated with the
Master device; and in the Master device, causing rights data
associated with a content file to be sent to a Slave device
identified by the Master device as being associated with the Master
device, wherein a user device in which the Slave device is
installed uses the rights data to gain access to the content file
associated with the rights data.
16. The method of claim 15, further comprising: in the Master
device, causing the content file associated with the rights data to
be sent the Slave device.
17. The method of claim 15, wherein the rights data includes access
and usage rights data.
18. The method of claim 15, wherein the Master device is an
integrated circuit (IC) of a System Identification Module (SIM),
and wherein the Slave device is an IC of a System Identification
Module (SIM).
19. The method of claim 15, further comprising: storing the rights
data in a memory element of the Master device.
20. The method of claim 15, wherein the rights data includes a
digital decrypting key that is used by the user device in which the
Slave device is installed to decrypt the content file.
21. A method for enabling content files to be shared among multiple
user devices, the method comprising: in a Slave device, receiving
rights data associated with a content file, the rights data being
sent to the Slave device by a Master device associated with the
Slave device; and in the Slave device, extracting a key from the
rights data and providing the key to one or more components of a
user device in which the Slave device is installed to enable the
user device to gain access to the content file.
22. The method of claim 21, further comprising: in the Slave
device, receiving the content file associated with the rights data,
the content file being sent the Slave device from the Master
device.
23. The method of claim 21, wherein the rights data includes access
and usage rights data.
24. The method of claim 21, wherein the Master device is an
integrated circuit (IC) of a System Identification Module (SIM),
and wherein the Slave device is an IC of a System Identification
Module (SIM).
25. The method of claim 21, further comprising: storing the rights
data in a memory element of the Slave device.
26. The method of claim 21, wherein the rights data includes a
digital decrypting key that is used by the user device in which the
Slave device is installed to decrypt the content file.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The invention relates to a method and an apparatus for
enabling content to be shared among multiple devices in a secure
environment in which access and usage rights are controlled.
BACKGROUND OF THE INVENTION
[0002] The term "content" is used in the broadcast and
communications industries to denote digital files, such as, for
example, video files (e.g., movies), audio files (e.g., music),
image files, and text files. Content is distributed by a content
provider to end users over wired and wireless networks to devices
that have content renderers that render the content, e.g., display
the content on a display device and/or playback the content on an
audio playback device. For example, a cable television provider or
multiple service operator (MSO) may allow a paying customer to
download a movie that the user then watches on a laptop computer, a
television set, a mobile telephone, etc.
[0003] Content providers manage the distribution of content (e.g.,
downloading, streaming, etc.) by using one or more of a variety of
digital rights management (DRM) techniques. DRM techniques are used
to prevent unauthorized users from gaining access to content while
allowing authorized users to access the content. This is typically
accomplished by encrypting the content when it is distributed to
the authorized user, and providing the user with a key that allows
the user's device to decrypt the content so that it can be
rendered. DRM, however, encompasses more than securing content from
unauthorized access. It also encompasses describing, identifying,
trading, monitoring, and tracking of all forms of rights usages
over both tangible and intangible assets. The term "tangible
assets" refers to physical content, whereas the term "intangible
assets" generally refers to copyrights in the content held by
copyrights holders.
[0004] Recently, consumer demand has been increasing for ways to
allow end users of content to use, or share, the content in
multiple devices, e.g., the television, a personal computer (PC), a
laptop computer, a mobile telephone, etc. Content providers are
interested in providing end users with this capability, but need to
be able to ensure that the provided content is fully secured and
that control over access and usage rights are controlled. Various
DRM techniques have been proposed to address these goals.
[0005] One known DRM technique that is directed toward achieving
these goals is implemented in iTunes products offered by Apple
Computers, Inc. The DRM technique implemented in these products
allows a user to share the same downloaded content among a fixed
number of devices. The devices that share the content are managed
by a master device, such as a PC, that checks the devices in and
out to ensure that no more than an allowed number of devices are
sharing the content at a given time. This DRM technique, however,
is implemented in software, which is prone to subversion. In fact,
this particular DRM technique has already been compromised by
someone who was able to convert protected content into unprotected
content.
[0006] DRM techniques have also been implemented in hardware. DRM
hardware solutions generally are more secure or less easily
compromised than DRM software solutions. Nevertheless, to date, no
suitable hardware implementations have been developed that achieve
the goals of allowing users to simultaneously share the same
content among multiple devices while ensuring that the content
remains secure, i.e., cannot be accessed by unauthorized or
unintended users.
[0007] Accordingly, a need exists for a secure way of allowing
content to be shared among multiple devices.
SUMMARY OF THE INVENTION
[0008] The invention provides an apparatus and a method for
enabling content files to be shared among multiple user devices. In
accordance with one aspect of the invention, the apparatus
comprises a Master device that has an input/output (I/O) device
configured to receive and send data, and a digital rights
management (DRM) processor configured to perform a DRM algorithm.
The DRM processor identifies at least one Slave device associated
with the Master device and sends rights data associated with a
content file to the Slave device identified as being associated
with the Master device. The rights data enables a user device in
which the Slave device is installed to gain access to the content
file associated with the rights data.
[0009] In accordance with another aspect of the invention, the
apparatus comprises a Slave device that has an I/O device
configured to receive and send data, and a DRM processor configured
to perform a DRM algorithm. The DRM processor receives rights data
via the I/O device from a Master device associated with the Slave
device. The DRM processor extracts a key from the rights data and
provides the key to the user device, which uses the key to gain
access to a content file associated with the rights data.
[0010] In accordance with another aspect of the invention, the
method performed by the Master device comprises identifying one or
more Slave devices that are associated with the Master device, and
causing rights data associated with a content file to be sent to a
Slave device identified by the Master device as being associated
with the Master device. A user device in which the Slave device is
installed uses the rights data to gain access to the content file
associated with the rights data.
[0011] In accordance with one aspect of the invention, the method
comprises receiving rights data in a Slave device from a Master
device associated with the Slave device, and extracting a key from
the rights data and providing it to one or more components of the
user device to enable the user device to gain access to a content
file associated with the rights data.
[0012] In accordance with another aspect of the invention, the
apparatus comprises at least first and second System Identification
Module (SIM) cards electrically interfaced with one another. Each
of the SIM cards has one or more electrical contacts thereon that
are in electrical contact with one or more electrical contacts on
another of the SIM cards to enable each of the SIM cards to
communicate with at least one other of the SIM cards. Each SIM card
includes a DRM processor configured to perform a DRM algorithm.
[0013] These and other features and advantages of the invention
will become apparent from the following description, drawings and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a pictorial network diagram that
demonstrates an example of the manner in which the invention allows
multiple devices to share content.
[0015] FIG. 2 illustrates a block diagram of the portion of the
Master SIM shown in FIG. 1, and portions of a user device in which
the Master SIM is installed.
[0016] FIG. 3 illustrates a block diagram of the portion of one of
the Slave SIMs shown in FIG. 1, and portions of a user device in
which the Slave SIM is installed.
[0017] FIG. 4 illustrates a flowchart that represents the method of
the invention performed by the Master SIM shown in FIG. 2 in
accordance with an exemplary embodiment.
[0018] FIG. 5 illustrates a flowchart that represents the method of
the invention performed by the Slave SIM shown in FIG. 3 in
accordance with an exemplary embodiment.
[0019] FIG. 6 illustrates a flowchart that represents another
exemplary embodiment of the method performed by the Slave SIM shown
in FIG. 3.
[0020] FIG. 7 illustrates a pictorial diagram of a cavity formed in
a user device and configured to accommodate multiple SIMs to allow
content and access and usage rights to be shared among the
SIMs.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] In accordance with the invention, a method and apparatus are
provided that allow content to be shared among multiple devices in
a secure manner that prevents or reduces the likelihood that
unintended users will gain access to the content or remove the DRM
content protection. Thus, the invention provides a DRM solution
that allows an end user to share content among multiple devices in
a secure environment in which access and usage rights associated
with the content are controlled.
[0022] The method and apparatus of the invention preferably are
implemented in the form of a DRM hardware solution, such as a
System Identification Module (SIM) card, for example. As is known
in the art, a SIM card has an integrated circuit (IC) on it that
provides a secure platform due to the fact that it is very
difficult if not impossible to determine the configuration of the
IC through inspection. Thus, a SIM card is an example of a hardware
device that is suitable for use with the invention. However, the
invention is not limited to using SIM cards for this purpose. Other
hardware devices may instead be used. The invention is being
described with reference to SIM cards in order to demonstrate an
example of one possible implementation of the invention.
[0023] In accordance with the invention, a plurality of SIM cards
are associated with one another in a way that allows them to
communicate content amongst themselves and/or to communicate access
and usage rights amongst themselves. The associated SIM cards are
distributed to an authorized user who then installs one of the
cards in each of the user's devices that are to share content. One
of the SIMs functions as the Master SIM and the other SIMs function
as Slave SIMs. After the Master SIM has received content and access
and usage rights from a content provider, the Master SIM provides
the Slave SIMs with the content and with access and usage rights to
that content. The Master SIM may transmit the content to the Slave
SIMs, or the slave SIMs may download the content from the content
provider site using rights that the Master SIM has provided to
them.
[0024] FIG. 1 illustrates a pictorial network diagram that
demonstrates an example of the manner in which the invention allows
multiple devices to share content. In accordance with this
exemplary embodiment, one Master SIM 1 is associated with four
Slave SIMs 10, 20, 30 and 40. The Master SIM 1 is manufactured or
one-time programmed with secret information about each of the Slave
SIMs 10-40. Likewise, the Slave SIMs 10-40 are manufactured or
one-time programmed with secret information about the associated
Master SIM 1. The Slave SIMs 10-40 may be manufactured or one-time
programmed with secret information about the each other.
[0025] A content provider 2 transmits content and access and usage
rights associated with the content to the Master SIM 1. The content
and rights may be transmitted wirelessly or over a wired link to
the Master SIM 1. The manner in which content and the rights
associated with the content are distributed is well known. For
example, the way in which this is typically accomplished today is
by sending the content file to the user device as an encrypted
file. Subsequent to sending the encrypted content file to the user
device, a decryption key is sent to the user device. The user
device then uses the key to decrypt the content file to enable the
content to be rendered on the user device.
[0026] The Master SIM 1 performs operations similar to those
performed by the content provider 2 in that the Master SIM 1
transmits encrypted content files, access rights and usage rights
to the associated Slave SIMs 10-40 over wired or wireless links.
The access rights and usage rights are typically contained in
digital keys. The term "rights data" is used herein to denote any
type of data that is needed to be able to access and use content,
including digital keys. The Master SIM 1 may transmit only rights
data to the Slave SIMs 10-40 rather than transmitting rights data
and content to the Slave SIMs 10-40. In this case, the Slave SIMs
10-40 will communicate directly with the content provider 2, which
will then transmit the encrypted content associated with the access
and usage rights to the Slave SIMs 10-40.
[0027] FIG. 2 illustrates a block diagram of the portion of the
Master SIM 1 that performs the DRM tasks of the invention, and
portions of a user device 50 in which the Master SIM 1 is located.
In this example, the user device 50 is a set-top box (STB) located
at a subscriber premises, although the user device 50 may be any
one of a variety of devices including, for example, a PC, a mobile
telephone, a personal digital assistant (PDA), etc. The Master SIM
1 includes an input/output (I/O) device 60, a DRM processor 70 and
a memory element 80. The STB 50 includes an I/O device 91, a
processor 90 and a decryption component 92. Encrypted content files
and keys are transmitted to the STB 50 from the content provider 2.
The transmission of the encrypted content files and keys may be
performed in the known manner described above with reference to
FIG. 1. The invention is not limited with respect to the manner in
which the content files and keys are delivered to the STB 50.
[0028] The encrypted content files and keys are received by the I/O
device 91 of the STB 50 and delivered to the processor 90 of the
STB 50. The processor 90 sends the keys over a SIM interface 93 to
the I/O device 60 of the Master SIM 1, which delivers the keys to
the DRM processor 70 of the Master SIM 1. The DRM processor 70
stores the keys in the memory element 80. When the STB 50 executes
a rendering application program to render the content, the
processor 90 of the STB 50 obtains the associated key from the
Master SIM 1 via the SIM interface 93 and delivers the key to the
decryption component 92, which then uses the key to decrypt the
content file to allow the rendering application program to render
the content on a rendering device (not shown), such as a television
(not shown).
[0029] The DRM processor 90 performs one or more algorithms
directed to authorizing the access and usage of content files
received by the Master SIM 1 by one or more associated Slave SIMs
10-40. As stated above, the Master SIM 1 is manufactured or
one-time programmed with information regarding the associated Slave
SIMs 10-40, as well as with information regarding the access and
usage rights that are to be provided by the Master SIM 1 to the
Slave SIMs 10-40. The Slave SIMs 10-40 may or may not be provided
with the same access and usage rights as are provided by the
content provider 2 to the Master SIM 1. For example, the Master SIM
1 may be programmed or configured to execute rights rules that
dictate the access and/or usage rights that are to be provided to
the Slave SIMs 10-40.
[0030] The Master SIM 1 transmits the encrypted content files and
data regarding the access and usage rights being provided to the
Slave SIMs 10-40. This rights data includes the keys needed to
decrypt the associated content files. The transmission of the
encrypted content files and rights data to the Slave SIMs 10-40 may
be over a wired or wireless link. Typically, the transmission of
the encrypted content files and rights data to the Slave SIMs 10-40
will be via a wired interface. For example, if the Slave SIM 10 is
used in a mobile telephone, the telephone user removes the card
containing the Slave SIM 10 from the telephone and inserts it into
a SIM card slot in the STB 50. The encrypted content and rights
data are then transferred from Master SIM 1 to the Slave SIM
10.
[0031] FIG. 3 illustrates a block diagram of the portion of one of
the Slave SIMs 10 that performs the DRM tasks of the invention, and
portions of a user device 110 in which the Slave SIM 10 is located.
The Slave SIM 10 includes an I/O device 130, a DRM processor 140
and a memory element 150. The user device 110 in which the Slave
SIM 10 is installed includes an I/O device 111, a processor 120 and
a decryption component 112. Encrypted content files and rights data
(e.g., keys) are transmitted to the user device 110 from the Master
SIM 1. The encrypted content files and rights data are received by
the I/O device 111 and delivered to the processor 120. The
processor 120 sends the rights data over a SIM interface 123 to the
I/O device 130 of the Slave SIM 10, which delivers the data to the
DRM processor 140 of the Slave SIM 10. The DRM processor 140 stores
the rights data in the memory element 150.
[0032] When the user device 110 executes a rendering application
program to render the content, the processor 120 of the user device
110 obtains the associated key from the Slave SIM 10 via the SIM
interface 123 and delivers the key to the decryption component 112,
which then uses the key to decrypt the content file to allow the
rendering application program to render the content on a rendering
device (not shown), such as a television (not shown).
[0033] The DRM processor 140 of the Slave SIM 10 is manufactured or
one-time programmed with information regarding the associated
Master SIM 1. This information may also include information about
the other Slave SIMs 20-40 associated with the Master SIM 1. In
addition, the DRM processor 140 may be programmed or manufactured
to execute a time-out routine that causes the DRM processor 140 to
become disabled after a preset time period such that the content
received from the Master SIM 1 cannot be used by the user device
110 after the expiration of the preset time period. This can be
accomplished in a variety of ways. For example, the Slave SIM 10
may include an on-board clock that the DRM processor 140 uses to
determine when the time-out time period has expired. In this case,
the DRM processor 140 counts clock cycles and determines when the
number of clock cycles counted exceeds a threshold value. Rather
than the Slave SIM 10 executing the time-out routine, the Master
SIM 1 may execute an algorithm that causes a disabling signal to be
transmitted to the Slave SIM 10 after the expiration of a preset
time period.
[0034] Regardless of how the DRM processor 140 of the Slave SIM 10
is disabled from using the content after a preset time period, once
the DRM processor 140 has become disabled, the Slave SIM 10 will
need to be "refreshed" in order for the DRM processor 140 to again
become enabled. The Slave SIM 10 may be refreshed in a number of
ways. For example, the Slave SIM 10 may be refreshed by inserting
the card on which the Slave SIM 10 is located into a slot (not
shown) in the user device 50 in which the Master SIM 1 is
installed. The Master SIM 1 then transfers access and/or usage
rights data to the Slave SIM 10. Another way of refreshing the
Slave SIM 10 is to place very tight time constraints on the
refreshing process such that if the refreshing process is not
performed within a relatively short preset time period, the refresh
process fails. For example, if the refresh process is performed by
directly connecting a Universal Serial Bus (USB) port of the Master
SIM 1 to a USB port of the Slave SIM 1, and communicating the
enabling signals between the ports, the refreshing process will be
accomplished very quickly due to the high rate of data transfer
provided by the USB communications protocol. Consequently, the
refreshing process will be successful. On the other hand, if an
attempt is made to perform the refreshing process over an Internet
link, the round trip delay incurred in communicating data between
the Master SIM 1 and the Slave SIM 10 will be too great to allow
the refreshing process to be successfully completed within the
corresponding time constraints. The time-out/refresh feature of the
invention is useful in that it prevents a thief or otherwise
unauthorized user of the Slave SIM 10 from being able to use
content supplied by the Master SIM 1.
[0035] FIG. 4 illustrates a flowchart that represents the method of
the invention performed by the Master SIM in accordance with an
exemplary embodiment. After the Master SIM receives content and
rights data from a content provider, the Master SIM performs a DRM
algorithm to identify one or more associated Slave SIMs, as
indicated by block 161. The Master SIM may execute the DRM
algorithm automatically to identify an associated Slave SIMs. For
example, the Master SIM may execute the DRM algorithm and identify
any associated Slave SIMs when the Master SIM is first installed in
the user device and supplied power. Alternatively, the Master SIM
may execute the DRM algorithm only upon receiving a protected
content file from the content provider. Alternatively, the Master
SIM may only execute the DRM algorithm when a Slave SIM requests a
content file from the Master SIM. After the Master SIM has
identified one or more associated Slave SIMs, the Master SIM sends
content and rights data to the Slave SIMs, as indicated by block
162.
[0036] FIG. 5 illustrates a flowchart that represents the method of
the invention performed by the Slave SIM in accordance with an
exemplary embodiment. The Slave SIM receives a content file and
rights data from a Master SIM, as indicated by block 171. The Slave
SIM typically stores the rights data (e.g., decryption keys) in
memory in the Slave SIM. The Slave SIM extracts the key from the
rights data and provides it to the processor of the user device, as
indicated by block 173. As described above, a decryption component
of the user device uses the keys to decrypt the content.
[0037] FIG. 6 illustrates a flowchart that represents another
exemplary embodiment of the method performed by the Slave SIM. In
accordance with this embodiment, the DRM algorithm performed by the
Slave SIM includes the time-out routine described above with
reference to FIG. 3. Whenever the processor 120 of the user device
110 executes an application program to render the content, the
processor 120 sends a request for the content key over the SIM
interface 123 to the Slave SIM 10. The DRM processor 140 receives
the request, as indicated by block 181. The DRM processor 140 then
determines whether the time-out period has expired, as indicated by
block 182. If the DRM processor 140 determines that the time-out
period has not expired, the DRM processor 140 sends the key to the
processor 120 of the user device, as indicated by block 183. If the
DRM processor 140 determines that the time-out period has expired,
the DRM processor 140 disables itself, as indicated by block 184.
Instead of disabling itself, the DRM processor 140 may simply not
send the key to the processor 120 of the user device. The DRM
processor 140 may send a message to the processor 120 to inform the
user that the Slave SIM 10 has become disabled and needs to be
refreshed by the Master SIM 1. The DRM processor 140 may also send
a message to the processor 120 when the time-out period is close to
expiring so that the user can refresh the Slave SIM 10 before it
becomes disabled to avoid interruption of content rendering.
[0038] The DRM processors 70 and 140 used in the Master and Slave
SIMs 1 and 10 may be any type of computational devices that are
suitable for performing the functions described above with
reference to FIGS. 1-6, including, for example, a microprocessor, a
microcontroller, an application specific integrated circuit (ASIC),
a programmable gate array, etc. The processor may be implemented
solely in hardware or in a combination of hardware and software or
firmware. In the case where the processors are implemented in a
combination of hardware and software or firmware, the software
programs executed by the processor will be stored in the memory
elements 80 and 150. The memory elements 80 and 150 are typically
solid-state devices integrated with the DRM processors 70 and 140,
respectively, on the same IC. The memory elements 80 and 150 may be
any type of computer-readable mediums such as, for example, random
access memory (RAM), dynamic RAM (DRAM), flash memory, read only
memory (ROM), compact disk ROM (CD-ROM), digital video disks
(DVDs), magnetic disks, magnetic tapes, etc. The invention also
encompasses electrical signals modulated on wired and wireless
carriers (e.g., electrical conductors, wireless carrier waves,
etc.) in packets and in non-packet formats.
[0039] In order to provide a user with the ability to share content
with multiple other users, the user device may have multiple SIM
card slots in it for installing Master and/or Slave SIM cards in
the user device. Alternatively, the user device may have a cavity
in it configured to hold multiple SIM cards. The SIM cards have
modified physical and electrical designs that allow them to
interface with each other and function as a single system. FIG. 7
illustrates a pictorial diagram of a cavity 210 formed in a user
device (not shown) and configured to accommodate multiple SIM cards
220, 230 and 240. The SIM cards 220, 230 and 240 are stacked one on
top of another (or side by side) and electrically connected to one
another to allow them to communicate with each other. The
electrical connections between the SIM cards 220, 230 and 240 may
be made by metal bumps 211 that are formed on at least some of the
contacts 212 of the SIM cards 220, 230 and 240. The cavity 210 may
be, for example, a spring-loaded holder of the user device for
enabling the SIM cards to be easily loaded into and unloaded from
the user device.
[0040] The invention has been described with reference to certain
embodiments for the purpose of demonstrating the principles and
concepts of the invention. It should be noted, however, that the
invention is not limited to the embodiments described herein. As
will be understood by those skilled in the art, many modifications
can be made to the embodiments described herein, and all such
modifications are within the scope of the invention.
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