U.S. patent application number 16/681465 was filed with the patent office on 2020-05-14 for signaling system switching and key derivation.
This patent application is currently assigned to VERIMATRIX. The applicant listed for this patent is VERIMATRIX. Invention is credited to Jacob T. Carson, Ronald P. Cocchi, Michael A. Gorman.
Application Number | 20200153840 16/681465 |
Document ID | / |
Family ID | 62148015 |
Filed Date | 2020-05-14 |
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United States Patent
Application |
20200153840 |
Kind Code |
A1 |
Carson; Jacob T. ; et
al. |
May 14, 2020 |
SIGNALING SYSTEM SWITCHING AND KEY DERIVATION
Abstract
A method and apparatus for controlling a group of the client
devices to switch at least one client device of the group of client
devices from a first conditional access system to a second
conditional access system is disclosed. In one embodiment, the
method comprises generating a group identifier identifying the
group of the client devices, transmitting a first client device
signaling message having the group identifier only to each client
device of the identified group of the client devices, and
transmitting a second client device signaling message to the
plurality of client devices, the second client device signaling
message comprising the group identifier and signaling each client
device having the group identifier stored in the non-volatile
memory to switch from the first system client to the second system
client.
Inventors: |
Carson; Jacob T.; (Long
Beach, CA) ; Gorman; Michael A.; (Cypress, CA)
; Cocchi; Ronald P.; (Seal Beach, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VERIMATRIX |
Meyreuil |
|
FR |
|
|
Assignee: |
VERIMATRIX
Meyreuil
FR
|
Family ID: |
62148015 |
Appl. No.: |
16/681465 |
Filed: |
November 12, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15791260 |
Oct 23, 2017 |
10476883 |
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16681465 |
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14382539 |
Sep 2, 2014 |
9800405 |
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PCT/US2013/028761 |
Mar 1, 2013 |
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15791260 |
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62446196 |
Jan 13, 2017 |
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61606260 |
Mar 2, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 9/0822 20130101;
H04L 9/3297 20130101; H04N 21/4623 20130101; H04N 21/23895
20130101; H04N 21/4627 20130101; H04L 63/104 20130101; H04L 63/068
20130101; H04L 9/3247 20130101; H04L 9/0861 20130101; H04N 21/44
20130101; H04L 63/062 20130101; H04N 21/43853 20130101 |
International
Class: |
H04L 29/06 20060101
H04L029/06; H04N 21/4623 20060101 H04N021/4623; H04N 21/2389
20060101 H04N021/2389; H04N 21/4385 20060101 H04N021/4385; H04L
9/08 20060101 H04L009/08; H04L 9/32 20060101 H04L009/32 |
Claims
1. In a system of a plurality of client devices for receiving data
from a provider, each of the client devices having a securely
executing system client and a middleware module communicating with
the system client, a method of controlling a group of the client
devices to switch at least one client device of the group of the
client devices from a first system client to a second system client
via a plurality of client device signaling messages, the method
comprising: generating a group identifier identifying the group of
the client devices; transmitting a first client device signaling
message having the group identifier only to each client device of
the identified group of the client devices, the first client device
signaling message signaling an action to assign the client device
receiving the message to the identified group of the client
devices, the group identifier for storage in each client device of
the identified group of the client devices in non-volatile memory;
and transmitting a second client device signaling message to the
plurality of client devices, the second client device signaling
message comprising the group identifier and signaling each client
device having the group identifier stored in the non-volatile
memory to switch from the first system client to the second system
client; wherein the first client device signaling message and the
second device signaling message are transmitted on a switching
message channel monitored by the middleware module of each of the
plurality of client devices, the switching message channel
identified by an identifier transmitted to each of the plurality of
client devices as application specific data.
2. The method of claim 1, wherein: the first client device
signaling message comprises: a first action code of a plurality of
action codes and payload data; the first action code signaling the
action to assign the client device receiving the message to the
identified group of the client devices; and the payload data
including the group identifier of the identified group of the
client devices; the second client device signaling message
comprises: a second action code of the plurality of action codes
and second payload data; the second action code signaling each
client device having the group identifier stored in the
non-volatile memory to switch from the first system client to the
second system client; and the second payload data identifies the
second system client.
3. The method of claim 2, wherein the second client device
signaling message comprises a time at which the switch to the
second system client is to be made by the client device.
4. The method of claim 2, wherein the first client device signaling
message and the second client device signaling message are
transmitted as private data of a digital video broadcasting (DVB)
standard.
5. The method of claim 4, wherein: the method further comprises
transmitting the identifier of the switching message channel to the
plurality of client devices in a access table.
6. The method of claim 5, wherein the plurality of action codes
further comprises: a first action code addressing all of the client
devices; and a second action code addressing only single client
devices.
7. The method of claim 6, further comprising: monitoring, by the
middleware module of at least one of the identified group of the
client devices, the channel identified by the identifier of the
switching message channel; receiving, in the middleware module of
the at least one of the identified group of the client devices, the
first client device signaling message; and storing the group
identifier in non volatile storage of the at least one of the
identified group of the client devices.
8. The method of claim 7, further comprising: receiving, in the
middleware module of the at least one of the identified group of
the client devices, the second client device signaling message;
determining if the second client device signaling message comprises
the group identifier; and if the second client device signaling
message comprises the group identifier, switching the at least one
client device to the second system client.
9. The method of claim 8, wherein the first client device signaling
message and the second client device signaling message each further
comprise: a sequence number action code and associated sequence
number; and a timestamp action code and associated timestamp;
wherein the group identifier is stored in non-volatile memory only
if the sequence number of the sequence number action code is
compares favorably with a sequence number of a sequence number
action code of a third client device signaling message is
numerically previous to the first client device signaling message;
and the at least one of the identified group of the client devices
is switched to the second system client only if the timestamp of
the associated timestamp action code is temporally ahead of a
current system time.
10. The method of claim 9, further comprising: initializing the
second system client; providing security data to the second system
client to derive keys for decrypting the data; determining a
management message channel identifier from the access table;
receiving a management message on the management message channel
identified by the management message channel identifier; receiving
a map table associated with the data; determining a control message
channel identifier corresponding to the second system client from
the map table; receiving control messages on a control message
channel identified by the control message channel identifier; and
decrypting the data using the second system client according to the
derived keys and the control message.
11. In a system of a plurality of client devices for receiving data
from a provider, each of the client devices having a securely
executing system client and a middleware module communicating with
the system client, an apparatus for controlling a group of the
plurality of client devices to switch at least one client device of
the group of the client devices from a first system client to a
second system client via a plurality of client device signaling
messages, comprising: a private data generator, comprising: a
processor; a memory, the memory storing processor instructions
comprising instructions for: generating a group identifier
identifying the group of the client devices; a transmitter,
communicatively coupled to the private data generator, the
transmitter for: transmitting a first client device signaling
message having the group identifier only to each client device of
the identified group of the client devices, the first client device
signaling message signaling an action to assign the client device
receiving the message to the identified group of the client
devices, the group identifier for storage in each client device of
the group of the client devices in non-volatile memory; and
transmitting a second client device signaling message to the
plurality of client devices, the second client device signaling
message comprising the group identifier and signaling each client
device having the group identifier stored in the non-volatile
memory to switch from the first system client to the second system
client; wherein the first client device signaling message and the
second device signaling message are transmitted on a switching
message channel monitored by the middleware module of each of the
plurality of client devices, the switching message channel
identified by an identifier transmitted to each of the plurality of
client devices as application specific data.
12. The apparatus of claim 11, wherein: the first client device
signaling message comprises: a first action code of a plurality of
action codes and payload data; the first action code signaling the
action to assign the client device receiving the message to the
group of the client devices; and the payload data including the
group identifier of the group of the client devices; the second
client device signaling message comprises: a second action code of
the plurality of action codes and second payload data; the second
action code signaling each client device having the group
identifier stored in the non-volatile memory to switch from the
first system client to the second system client; and the second
payload data identifies the second system client.
13. The apparatus of claim 12, wherein the second client device
signaling message comprises a time at which the switch to the
second system client is to be made by the client device.
14. The apparatus of claim 12, wherein the first client device
signaling message and the second client device signaling message
are transmitted as private data of a digital video broadcasting
(DVB) standard.
15. The apparatus of claim 14, wherein: each of the plurality of
client devices comprises: a client device processor; a client
device memory, storing client device processor instructions
implementing the middleware module, the instructions including
instructions for: monitoring a conditional access switching message
channel for the first client device message and the second client
device messages; and the transmitter further transmits the
identifier of the conditional access switching message channel to
the plurality of client devices in an access table.
16. The apparatus of claim 15, wherein the plurality of action
codes further comprises: a first action code addressing all of the
client devices; and a second action code addressing only single
client devices.
17. The apparatus of claim 16, wherein: the client device processor
instructions implementing the middleware module further comprise
instructions for: monitoring the channel identified by the
identifier of the switching message channel; receiving the first
client device signaling message; and the client device processor
instructions further comprise instructions for storing the group
identifier in non volatile storage of the at least one of the group
of the client devices.
18. The apparatus of claim 17, wherein: the client device processor
instructions implementing the middleware module further comprise
instructions for: receiving, the second client device signaling
message; determining if the second client device signaling message
comprises the group identifier; and the client device processor
instructions further comprise instructions for switching the at
least one client device to the second system client if the second
client device signaling message comprises the group identifier.
19. The apparatus of claim 18, wherein the first client device
signaling message and the second client device signaling message
each further comprise: a sequence number action code and associated
sequence number; and a timestamp action code and associated
timestamp; wherein the group identifier is stored in non-volatile
memory only if the sequence number of the sequence number action
code is compares favorably with a sequence number of a sequence
number action code of a third client device signaling message is
numerically previous to the first client device signaling message;
and the at least one of the group of the client devices is switched
to the second system client only if the timestamp of the associated
timestamp action code is temporally ahead of a current system
time.
20. The apparatus of claim 19, wherein: the client device processor
instructions implementing the middleware module further comprise
instructions for: initializing the second system client; providing
security data to the second system client to derive keys for
decrypting the data; receiving a management message channel
identifier determined by a system client from the received access
table; receiving a management message on the management message
channel identified by the management message channel identifier;
receiving a map table associated with the data; determining a
control message channel identifier corresponding to the second
system client from the program map table; and receiving control
messages on a control message channel identified by the control
message channel identifier; the client device further comprises a
security processor communicatively coupled to a security processor
memory, the security processor memory comprising security processor
instructions for: decrypting the data using the second system
client according to the derived keys and the control message.
21. In a system of a plurality of client devices for receiving data
from a provider, each of the client devices having a securely
executing system client and a middleware module communicating with
the system client, an apparatus for controlling a group of the
plurality of client devices to switch from a first system client to
a second system client via a plurality of client device signaling
messages, comprising: a private data generator, comprising: a
processor; a memory, the memory storing processor instructions
comprising instructions for: generating a group identifier
identifying the group of the client devices; a transmitter,
communicatively coupled to the private data generator, the
transmitter for: transmitting a first client device signaling
message having the group identifier only to each client device of
the identified group of the client devices, the first client device
signaling messages signaling an action to assign the client device
receiving the message to the identified group of the client
devices, the group identifier for storage in each client device of
the group of the client devices in non-volatile memory; and
transmitting a second client device signaling message to plurality
of client devices, the second client device signaling message
comprising the group identifier and signaling each of the group of
client device having the group identifier stored in the
non-volatile memory to switch from the first system client to the
second system client; wherein: the first client device signaling
message and the second device signaling message are transmitted on
a conditional access switching message channel monitored by the
middleware module of each of the plurality of client devices, the
conditional access switching message channel identified by an
identifier transmitted to each of the plurality of client devices
as application specific data. each of the plurality of client
devices comprises: a client device processor; a client device
memory, storing client device processor instructions implementing
the middleware module, the instructions including instructions for
monitoring the conditional access switching message channel for the
first client device signaling message and the second client device
switching message; and the transmitter further transmits the
identifier of the conditional access switching message channel to
the plurality of client devices as application specific data.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/791,260, entitled "SIGNALING CONDITIONAL
ACCESS SYSTEM SWITCHING AND KEY DERIVATION," by Jacob T. Carson,
Michael A. Gorman, and Ronald P. Cocchi, filed Oct. 23, 2017, now
U.S. Pat. No. 10,476,883, which application:
[0002] claims benefit of U.S. Provisional Patent Application Ser.
No. 62/446,196, entitled "SIGNALING METHOD FOR CAS SWITCHING AND
KEY DERIVATION," by Jacob T. Carson, Michael A. Gorman, and Ronald
P. Cocchi, filed Jan. 13, 2017;
[0003] is a continuation-in-part of U.S. patent application Ser.
No. 14/382,539, entitled "BLACKBOX SECURITY PROVIDER PROGRAMMING
SYSTEM PERMITTING MULTIPLE CUSTOMER USE AND IN FIELD CONDITIONAL
ACCESS SWITCHING," by Ronald P. Cocchi et al., filed Sep. 2, 2014,
which application is a National Stage Entry of international patent
application PCT/US13/28761, entitled "BLACKBOX SECURITY PROVIDER
PROGRAMMING SYSTEM PERMITTING MULTIPLE CUSTOMER USE AND IN FIELD
CONDITIONAL ACCESS SWITCHING," by Ronald P. Cocchi et al., filed
Mar. 1, 2013, now issued as U.S. Pat. No. 9,800,405, and which
application claims benefit of U.S. Provisional Patent Application
Ser. No. 61/606,260, entitled "BLACKBOX SECURITY PROVIDER
PROGRAMMING SYSTEM PERMITTING MULTIPLE CUSTOMER USE AND FIELD
CONDITIONAL ACCESS SWITCHING," by Ronald P. Cocchi et al., filed
Mar. 2, 2012;
[0004] all of which applications are hereby incorporated by
reference herein.
[0005] This application is also related to U.S. patent application
Ser. No. 15/652,082, entitled "METHOD AND APPARATUS FOR SUPPORTING
MULTIPLE BROADCASTERS INDEPENDENTLY USING A SINGLE CONDITIONAL
ACCESS SYSTEM," by Ronald P. Cocchi et al., filed Jul. 17, 2017,
which also claims benefit of U.S. Provisional Patent Application
Ser. No. 62/446,196, entitled "SIGNALING METHOD FOR CAS SWITCHING
AND KEY DERIVATION," by Jacob T. Carson, Michael A. Gorman, and
Ronald P. Cocchi, filed Jan. 13, 2017, all of which applications
are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0006] The present invention relates to systems and methods for
securely providing media programs and other information to
subscribers via a black box Security Provider Programming system,
and in particular to a system and method for securely providing
data for use by a hardware device of a receiver for conditional
access.
2. Description of the Related Art
[0007] The provision of information such as media programs to
remote consumers is well known in the art. Such provision may be
accomplished via terrestrial or satellite broadcast, cable, closed
circuit, or Internet transmission to consumer electronics (CE)
devices at the consumer's home or office.
[0008] A common problem associated with such transmission is
assuring that the reception of such information is limited to
authorized end-users. This problem can be solved via the use of
encryption and decryption operations performed by devices with
appropriate security functionality. For example, it is well known
to encrypt media programs before transmission to CE devices with
electronics and processing that permits the encrypted media
programs to be decrypted and presented to only authorized
users.
[0009] To implement this functionality, the CE products typically
include keys, software, and other data. Since such data is of value
to unauthorized users as well, CE companies need a way to protect
this valuable information.
[0010] Typically, this has required the production of CE devices
with special integrated circuits (or chips) with security features
enabled and information needed to perform the security functions
loaded into chip memory. Such chips can include System on Chips
(SOC), which comprise the primary Central Processing Unit (CPU) of
the CE device (which may also include secondary processors,
security processors, custom Application Specific Integrated
Circuits (ASICSs), etc.) or other chip devices that perform the
processing of commands within a CE device. Conditional Access
providers provide content protection schemes to secure broadcast
content is paid for when viewed by subscribers. Problems arise when
the content protect schemes are either compromised or implemented
in a man which security holes or flaws can be exploited by
attacker. The cost to design, manufacturer and distribute these CE
devices is extremely expensive. Significant savings can be achieved
if a service provider or broadcaster can re-purpose existing CE
devices by replacing the conditional access (CA) system used with
CE devices that are in the field (distributed to or in use by
customers). As an alternative to switching CA systems, the CE
device can be provisioned to support separate and cryptographically
isolate CA systems during manufacture. This permits the security
provided by another CA vendor 108B to be used in the event the
security provided by another one of the CA vendors 108B and
co-existing on the chip 114, is compromised.
[0011] What is needed is a system and method for providing a
security infrastructure that permits the programming of unique
security functions in standardized chip designs and enables
switching among different and existing CA systems deployed in CE
devices. The present invention satisfies that need.
SUMMARY OF THE INVENTION
[0012] To address the requirements described above, the present
invention discloses a method of controlling a group of the client
devices to switch at least one client device of the group of client
devices from a first conditional access system to a second
conditional access system via a plurality of client device
signaling messages, each comprising at least one of a plurality of
action codes and payload data. In one embodiment, the method, which
can be applied to a system of a plurality of client devices for
receiving media programs from a service providers, comprises
generating a group identifier identifying the group of the client
devices, transmitting a first client device signaling message
having the group identifier only to each client device of the
identified group of client devices, the group identifier for
storage in each client device of the identified group of client
devices in non-volatile memory, and transmitting a second client
device signaling message to plurality of client devices, the second
client device message comprising the group identifier and signaling
a switch of each of the identified group of client devices from the
first conditional access system to the second conditional access
system.
[0013] Hence, disclosed herein is a system and method that service
provider 102 or broadcaster to utilize high security chip device
features to enable in-field switching of CA vendors and/or
co-existence of CA vendors for fielded CE Devices. This is possible
in part, due to a set of base security features that can be
integrated into commercially available integrated circuitry for use
in CE products, yet customizable for many different applications.
Use of black box programmed secure silicon features enables service
providers or broadcasters to switch CA vendors or for different CA
systems from multiple vendors to co-exist in CE devices by
cryptographically isolating key sets allocated to and used by
independent CA vendors.
[0014] This enables strong and unique encryption of sensitive data
(such as HDCP and/or CI+keys) that can be logically associated with
data in individual chip devices, and allows CE device manufacturers
to prevent unauthorized code being run on the CE devices and
protects provisioned data from both independent partners (i.e. CA
providers) and attackers. Importantly, techniques and systems
described herein also allow chip device manufacturers to design and
build chips that can be used by any one of a plurality of
customers, service provider, or CA vendors.
[0015] The system described herein also permits programming of
unique secrets into the chip device at the chip manufacturing site
and permits later allocation of these chip devices to any one of a
number of potential CE device manufacturers and/or CA vendors. Chip
device programming can also occur at the packaging or product
manufacturing facility by execution of an in-field programming
sequence on the chip device.
[0016] A method for unlocking a hardware device is also disclosed.
In one embodiment, the method comprises the steps of transmitting a
product provisioning key (PPK) encrypted according to a secret
value (SV) (E.sub.SV[PPK]) from a first entity to a second entity
for secure storage in a hardware device; receiving a customer
validation code (CVC) from the second entity, the (CVC) computed in
the hardware device from the encrypted product provisioning key
E.sub.SV[PPK]; receiving an unlock request comprising the customer
validation code (CVC) and a hardware unique identifier (PID) in the
first entity from the second entity; computing an expected customer
validation code (CVC) in the first entity from the secret value
(SV) and the product provisioning key (PPK); and transmitting data
unlocking the hardware device if the expected customer validation
code (CVC) computed by the first entity matches the received
customer validation code from the second entity.
[0017] The keys and programming infrastructure summarized above as
provided by an independent security provider enables fielded CE
devices to change conditional access vendors giving the service
provider or broadcaster more flexibility in managing their
business. Enabling the ability to change conditional access vendors
in fielded CE devices can result in saving the service provider a
significant capital investment. The savings are realized by using
the provided vendor independent security architecture and
downloading a new software image containing an alternate
conditional access vendor application without having to replace
fielded CE devices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Referring now to the drawings in which like reference
numbers represent corresponding parts throughout:
[0019] FIG. 1A is a diagram of selected architectural entities
described in this disclosure;
[0020] FIG. 1B is a diagram of an exemplary chip;
[0021] FIG. 2 illustrates the customer product differentiator field
and signed hash block used to verify third party customer input
data for fielded SOCs;
[0022] FIG. 3 illustrates the Boot ROM signature check over the
code section enabling insertion of a CA vendor Public RSA key in a
fielded SOC;
[0023] FIG. 4A illustrates use of a Secret Value stored in hardware
to protect a given CA vendor customer's common block of data or
key;
[0024] FIG. 4B illustrates use of a Secret Value and Product
Provisioning Key both stored in hardware to protect a CA vendor's
common block of data or key;
[0025] FIG. 5A is a diagram presenting illustrative method steps
that can be used to enable encryption of sensitive code or data and
provide it to an independent CA vendors or untrusted consumer
electronics (CE) device manufacturer for provisioning;
[0026] FIG. 5B is a diagram illustrating use of a product
provisioning key and secret value stored in hardware to protect a
CA vendors' common block of data or key enabling in-field insertion
of a secret value post SOC manufacturing;
[0027] FIG. 6 is a diagram of one embodiment of the product
identifier (PID) described above;
[0028] FIG. 7 illustrates the boot process, image signing and RSA
public key authentication for over the air updates;
[0029] FIG. 8A is a diagram illustrating exemplary method steps
that can be used to deliver the unlocking data;
[0030] FIG. 8B illustrates a more specific example of the
calculation and distribution of customer validation data by the CE
source 108 after the chip 114 is manufactured;
[0031] FIG. 9 is a diagram illustrating exemplary method steps for
controlling a group of client devices to switch from a first CAS to
a second CAS via a plurality of client device signaling
messages;
[0032] FIG. 10 is a diagram illustrating exemplary operations
performed by the client devices in receiving and handling the first
client device message and the second client device message;
[0033] FIGS. 11-12 illustrate the operations presented in FIGS.
9-10 in greater detail; and
[0034] FIG. 13 illustrates an exemplary computer system that could
be used to implement the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0035] In the following description, reference is made to the
accompanying drawings which form a part hereof, and which is shown,
by way of illustration, several embodiments of the present
invention. It is understood that other embodiments may be utilized
and structural changes may be made without departing from the scope
of the present invention.
[0036] This disclosure describes a system and method that allows
third parties to provide set top boxes with advanced security
features that (1) allow the signing of a customer's public key, (2)
allow programming of chips with secret keys at chip manufacturing
facility and (3) provide service providers a method to
independently allocate those secret keys to security vendors when
the CE device is in the field.
Architectural Entities
[0037] FIG. 1A is a diagram of selected architectural entities
described in this disclosure. They include a service provider 102,
a chip manufacturer 104, a security provider 106, a third party
vendor(s) 108 and subscriber(s) 110. The service provider 102
transmits media programs and information to consumer electronics
(CE) device(s) 112 that are deployed to subscribers 110. The CE
device 112 presents the media programs to the subscribers 110. The
CE device 112 can include devices such as set-top boxes (STBs)
integrated receiver/decoders (IRDs) portable CE devices such as
cellphones or personal data assistants (PDAs), laptop computers,
tablet computers, and desktop computers. Any device with the
required processing and memory capacity having the proper
programming or hardware can be used as a CE device. An exemplary
IRD is disclosed in U.S. Pat. No. 6,701,528, which is hereby
incorporated by reference herein.
[0038] To assure that only authorized subscribers 110 receive the
media programs and information, the CE devices 112 perform security
functions that are implemented at least in part using hardware
processing/memory devices 114 (hereinafter alternatively referred
to as chips) that are produced by chip manufacturer 104. For
example, the transport module of the IRD disclosed in U.S. Pat. No.
6,701,528, is typically implemented by a chip.
[0039] FIG. 1B is a diagram of an exemplary chip 114. The chip 114
comprises memory 152 communicatively coupled to a processor or CPU
150. The memory 152 stores instructions and/or data such as keys
that are used to implement the conditional access functionality of
the CE device 112. The memory 152 may include read only memory
(ROM) 152A, one-time-programmable memory (OTP) 152B, and flash
memory 152C. The chip 114 may also comprise a configuration portion
154, which may include a series of fuses 156A-156C and/or flags
158A-156B. The flags 158 may also be reflected by values in the
memory 152. The fuses 156 are irreversibly activated by the chip
manufacturer 104 to implement particular chip 114 functionality.
For example, activation of fuse 156A may activate a triple data
encryption standard (DES) functional capability of the chip 114,
while fuse 156B may activate an RSA encryption functionality.
[0040] The CE devices 112 are manufactured by a CE source 108. In
one embodiment, the CE source 108 is defined to include a
particular CE manufacturer 108A that is responsible for the
manufacture of a CE device 112 having hardware and software capable
of implementing the CA functions allocated to the CE device 112 by
a particular CA vendor 108B, which provides the instructions and
data (for example, software and keys) that are used by the CE
device 112 hardware to implement the CA functions required for the
CA system used by the service provider 102. A particular CE source
108 is identified by a particular CE manufacturer's 108A product
used with a particular CA system from CA vendor 108B used with the
CE device 112. For purposes of the discussion below, when the same
CE device 112 is used with the instructions and data (or smart card
implementing some or all of the instructions and data) from two
different CA vendors 108B, this represents two distinct CA sources
108
[0041] In one embodiment, the CE device 112 hardware is capable of
performing the CA functions allocated to the CE device 112 for
multiple CA vendors 108B at the same time. For example, a first CA
vendor 108B1 (CA vendor 1) may define a CA system that allocates a
first set of CA functions to the CE device 112, and a second CA
vendor 108B2 (CA vendor 2) may define a second CA system that
allocates a second set of CA functions at least partially different
than the first set of functions to the CE device 112. The CE device
112 may support both CA systems by storing instructions and data
that allow the CE device hardware to perform the CA functions
allocated to the CE device 112 in both the first CA system and the
second CA system. Thus, using the CA functionality provided by both
the first CA vendor 108B1 and the second CA vendor 108B2, the
fielded CE device 112 may be capable of performing the CA functions
needed to receive and decrypt media programs and data transmitted
by two different service providers 102 (for example, DIRECTV AND
ECHOSTAR).
[0042] The CE device 112 hardware may also support the replacement
or substitution of one set of allocated CA functions for another
set of allocated functions. For example, rather than support both
the first set and the second set of allocated CA functions, the CE
device 112 hardware may be configured such that a first set of
allocated CA functions is automatically disabled when the second
set of allocated CA functions are enabled. This would allow, for
example, a receiver initially configured to receive media programs
from a first service provider 102 to be de-configured from
receiving such programs, and to instead receive media programs from
a second service provider 102. Or, the first service provider 102
could desire a change its content protection services from its
initial CA vendor 108B1 to those provided by a second CA vendor
108B2.
[0043] In another embodiment, the CE device source 108 may also
include one or more CA vendors 108B that are architectural entities
separate from the CE manufacturer 108A. For example, the CE device
112 may employ a smart card 114' (for example, as shown by the
access card of FIG. 2 of U.S. Pat. No. 6,701,528) or other
removable security device having security functions defined by the
CA vendor 108B. The CA vendor 108B may manufacture and provide this
security device 114' to the CE manufacturer 108A for ultimate
provision to the subscriber(s) 110 with the CE device 112.
[0044] The CE source 108 may accept chips 114 from the chip
manufacturer 104 and install them into the CE device 112. As
described below, the present invention allows the chips 114 to be a
standard design, yet uniquely and remotely programmable so as to be
useful for CE devices 112 from different CE manufacturers 108A, and
that can perform the allocated CA functionality for multiple CA
systems enabled by different CA vendors 108B and used by different
service providers 102.
[0045] In one embodiment, the chips 114 are programmed via use of a
black box 116 provided by a third party security provider 106. The
black box 116, as the name implies, is a device that performs a
transformation of data such as code or keys, without revealing how
the transformation is performed or disclosing the data. The use of
the black box 116 in this instance, allows the security provider
106 to program instructions and/or data into the chip 114 at the
chip manufacturer's facility and under the control of the chip
manufacturer 104 without exposing that information and/or data
itself to the chip manufacturer 104.
[0046] Data from the security provider 106 or the service provider
102 may also be programmed into the chip 114 at the CE source 108
or the subscriber 110 location using the techniques described
below.
Customer Product Differentiator Field
[0047] A customer product differentiator, somewhat analogous to a
customer number, is used by the security provider 106 and/or the
chip manufacturer 104 to identify a customer specific configuration
of a specific chip 114 for the functions to be performed by the CE
Device 112 from a particular CE Source 108. The customer product
differentiator (CPD 202) may be assigned to a particular CE Source
108 or service provider 102, for example, PANASONIC, DIRECTV or
ECHOSTAR. Further, a single service provider 102 or CE source 108
may have different CPDs for products that are used in different
markets if those products require chips that implement different
security functions. In one embodiment, the customer product
differentiator comprises a bit customer product differentiator (CPD
202) represented by a 32 bit field.
[0048] FIG. 2 is a diagram illustrating the use of the CPD 202. A
customer product differentiator or CPD field 202 is generated and
used with a signed hash block 210 to verify CE source 108 input
data before that data is used in fielded chips 114 (i.e. deployed
in fielded CE devices 112 installed at subscriber 110 locations).
The security provider 106 uses the CPD 202 field as part of an
input to fix chip 114 security data received from the CE source 108
(such as a specific flash-based CE source 108 public RSA key) to a
given value. Optionally to further increase security, the address
location for a flash-based third-party public RSA key and/or the
CPD 202 can also be used fix input data for a given CE source 108
and incorporated into the signed hash block 210.
[0049] This process can be implemented as follows. In block 200,
the public RSA key of the security provider 106 is stored in ROM
152A at the mask level or OTP 152B using the black box 116.
Customer-specific data 208 is generated by combining the CPD 202
with a public key 201 of the CE source 108 and optional chip
configuration information, as shown in block 206.
[0050] Chip configuration information may vary according to the CA
functions to be implemented by the chip 114 in the CE device 112.
For example, a particular chip 114 may have the ability to
implement a plurality of encryption/decryption schemes, depending
on the setting of internal flags of the activation of internal
fuses 156. The chip 114 configuration information may describe the
enabled functionality of the chip 114 by indicating, for example,
which flags are set and/or which fuses 156 are activated.
[0051] Typically, the above combination operation 206 is performed
by the security provider 106. In one embodiment, the CPD field 202
is assigned by the security provider 106 and the combining
operation of block 206 is a hash operation. The result is CE source
108 data 208 that is unique and specific to that CE source 108 and
customer product. This data may be stored in a map which controls
the activation of fuses 156.
[0052] In block 210, the customer-specific data 208 generated above
is signed with a private key of the security provider 106
Kpr.sub.SP. In blocks 212 and 214, this signed combination and the
customer product differentiator or CPD 202 is provided to the CE
source 108. The CE source 108 writes the signed customer data 208
and the customer product differentiator or CPD 202 to a memory 152
of the chip 114. The customer data 208 signed with the security
provider's 106 private RSA key is also securely stored at the CE
source 108 site for use in the generation of future customer
operations.
[0053] In blocks 216-218, the CE source 108 writes their CE source
public key (Kpu.sub.CE) into a memory 152 of the chip 114 and also
writes an image of the CE device 112 boot code signed by the
private key of the CE source 108 into memory 152c of the chip 114.
Boot code comprises coded instructions that are verified and
executed automatically when a CE device 112 is powered up.
[0054] The chip 114 is thereafter installed into the customer
device 112 by the CE manufacturer 108A, and provided to the
subscriber 110 for use. When the customer device 112 and chip 114
are powered up, a boot code 314 is verified, then executed by the
chip 114, as further described with reference to FIG. 3.
[0055] Continuing with the operations illustrated in FIG. 2, the
security provider 106 generates the signed hash block 208 over the
customer-specific data using the chip 114 configuration (provided
in block 201), the CE source's public RSA key, and the CPD field
202. The CE source 108 can store the signed hash CPD field 202 in
one time programmable (OTP) memory 152B location of the chip 114 as
shown in block 214, however, the CPD 202 could reside in flash
memory for example in cases where there is not enough OTP or the
chip 114 does not support OTP. If the CE source 108 or other entity
were to alter the CPD field 202 or the CE source's public RSA key,
then the RSA signature validation described below and illustrated
in blocks 310 and 312 using the security provider's 106 signed hash
block 308 would fail and the chip 114 will not completely execute
the boot code instructions, and will chip 114 and CE device 112
will be otherwise unusable. This is further described below.
[0056] The security provider's public RSA key is embedded in Read
Only Memory (ROM) 152A or One Time Programmable memory (OTP) 152B
within the chip 114 as described below with reference to FIG. 3.
This serves as the hardware root of trust in the chip 114.
Boot ROM Signature Check
[0057] U.S. Patent Publication 2007/0180464, entitled "Method and
System for Restricting use of Data in a Circuit," (hereby
incorporated by reference herein) discloses a method for checking
the signature of boot code stored in ROM. These techniques can be
extended to support code protection as discussed herein.
[0058] The security provider 106 supplies a 2048 bit RSA public key
that is stored in a ROM 152A of the chip 114 or an OTP bank 152B
within the chip 114, as shown in block 200.
[0059] An Elliptical Curve Cryptography (ECC) key could also be
used to perform asymmetric cryptographic operations in a similar
manner to which is described below using RSA. Public key storage in
a ROM 152A of the chip 114 is preferred and is the most secure
location because it cannot be changed in the field, however,
storage as data in the OTP 152B still provides a hardware root of
trust. This can be implemented by programming the chip 114 using
the black box 116 provided by the security provider 106 during chip
114 manufacturing.
[0060] The chip 114 may also include boot code that is used upon
power up to boot or start the chip 114. In one embodiment, this
boot code is signed by the CE source's private key, before storage
in the chip 114 so as to permit later validation before further
processing as described below.
[0061] FIG. 3 is a diagram presenting an exemplary embodiment of
how the boot code image can be verified before it is executed by
the chip 114. When the CE device 112 is powered up, a boot sequence
is initiated by the chip 114, as shown in blocks 302 and 304. Next,
the public key of the second entity (in this case, the CE source
108) is verified.
[0062] Recall that the signed hash (which was generated with the CE
source's public RSA key and the CPD) was stored in block 214 and
the CE Source's public key was stored in the chip 114 in block 216.
That hash can be recomputed in the chip 114 using the CPD 202 that
was stored in the chip 114 in block 214, the CE Source public RSA
key stored in the chip in block 216, and the chip configuration
data. Further, the signature over the hash, i.e. the signed hash,
stored in block 214 can be verified using the security provider's
106 public key which is retrieved from the ROM 152A or OTP 152B of
the chip 114. The hash will only be equivalent to the recomputed
hash if the CE source's public RSA key written in block 216 is
equivalent to the CE source's public RSA key used to generate the
hash in block 206 are equivalent.
[0063] If the comparison indicates that the CE source's public key
is not valid, processing stops and the chip 114 will fail to exit
the reset mode. If the comparison indicates that the CE source's
public key is valid, processing is passed to block 314 where the
boot sequence is verified using the verified CE source's public
key.
[0064] If the boot sequence is verified, the boot code image is
verified as shown in blocks 314-318 and the boot code is executed.
If the boot sequence is not verified, chip 114 will again fail to
exit the reset mode and will be non-operational.
[0065] In the above operations, a hardware security co-processor
built into the chip 114 can read the CE source's public RSA key
(which was stored in block 216) from memory such as a flash
location in the chip 114 and use it to verify the stored signature
for the customer application code that has been calculated over the
entire section of customer application code to be downloaded for
execution. The chip 114 memory location from which the security
provider's 106 public RSA key is read may be fuse 156 locked to a
specific ROM 152A or OTP 152B key by the chip manufacturer 104,
that is, at electronic wafer sort or when sensitive immutable data
is stored in the chip 114 by the black box 116 provided to the chip
manufacturer 104 by the security provider 106. In one embodiment,
once the location of the security provider's 106 public RSA key 200
has been selected, it cannot be changed in the field. This security
provider 106 public RSA key is used as the chip's hardware root of
trust in code signing, thereby, enabling use of at CE source 108 or
CA vendor 108B public RSA key.
[0066] The main processor or central processing unit (CPU) 150 of
the chip 114 incorporated into the CE device 112 may be held in a
reset mode until the boot code check of blocks 314-318 is
completed, thereby, eliminating the possibility of executing
unknown user or malicious boot code.
[0067] Typically, the chip 114 must support the ability to extend
the public ROM/OTP keys held by the security provider 106 to CE
source 108--defined RSA keys by checking a signed hash stored in
the chip 114. This enables a first entity, such as the security
provider 106, to sign the public RSA keys of the second entity
(such as the CE source 108--defined public RSA keys) and allows
validation of the CE source's 108 public RSA key based on the
security of the root of trust in the security provider's public RSA
key stored in ROM/OTP 152A/152B. Preferably, this hardware-based
validation process occurs in a secure manner that is not modifiable
or accessible by other elements in the CE device 112 such as a
general-purpose processor 904A or general purpose processor 904B.
This process is typically controlled by a hardware state machine or
performed on a separate embedded security co-processor executing
from a private secure memory location.
[0068] The signed hash 210 used to validate the CE source's public
RSA key incorporate the CPD 202 field assigned by the first entity
(the security provider 106) to properly bind the CE Source's public
RSA key to a specific party, that is, the CE Source 108 to which
the CPD 202 was assigned. Incorporating additional information such
as the address of the memory 152 location of where the CPD 202
value and/or CE source's public RSA are stored further limits
potential attacks by fixing values to particular areas in a map of
the memory 152 of the chip 114.
[0069] Having either the CPD field 202 or CPD address field
incorporated into the signed hash 210 also enables the CE source
108 to assign an alternate CPD field 202 and/or CPD address, either
of which enables switching from a first CA vendor 108B1 to a second
CA vendor 108B2 as discussed below.
[0070] Incorporating either the CPD field 202 or CPD address field
into the signed hash enables the CE Source 108 to revoke a
previously assigned CE source 108 public RSA key by changing the
value of the CPD 202 itself, assigning a new CE source public RSA
key for a new CE source 108 and sending a new software image as is
also discussed below. The previously signed CE source public RSA
key will no longer be successfully validated by the security
provider's signed hash 210 since the signed hash incorporates the
old CPD value 202, which will no longer pass the verification
process of blocks 310 and 312 of FIG. 3 since the CPD value 202 has
changed, thereby, revoking the signed hash 210 and previous CE
source public RSA key. The previous CE source public RSA key could
be used once again if the security provider 106 provides another
signed hash 210 using the old CE source public RSA key, an old CPD
value 202 with a newi CPD address because the new address could
used to store the previously old CPD value.
[0071] The generation of the signed hash 210 is typically
accomplished using the security providers' private RSA key and the
chip manufacturer's supplied tool chain at the security provider's
106 trusted facility. The security provider 106 may generate the
signed hash 210 through use of publicly available tools such as
OpenSSL or custom tools developed by the security provider 106. The
signed hash 210 validation in the chip 114 occurs using the
security provider's public RSA key stored in the ROM/OTP of the
chip 114.
[0072] As an alternative to switching CA systems, a broadcaster or
service provider 102 may decide to enable the CA functionality of
multiple CA systems provided by multiple distinct CA vendors 108B
(e.g. CA vendor 108B1 and CA vendor 108B2) to be implemented in a
single CE device 112. In this case, the broadcaster or service
provider 102 may assign a single CPD 202 and CE Source public RSA
key 201 to verify a CE device 112 boot image that combines the
security functionality of both CA vendors 108B1 and 108B2. In this
case, the boot code may combine and integrate two distinct
portions, a first portion for the first CA vendor 108B1, and a
second portion for the second CA vendor 108B2. Since current chip
114 designs cannot independently verify the signed hashes for two
distinct boot code regions with two different public keys, a common
CE source public RSA key 201 can used to verify the combined boot
code portion containing the boot sequence for both CA vendors 108B1
and 108B2. In future chip 114 designs that can do so, a separate CA
vendor public RSA key 201 can be used for each boot code
portion.
[0073] The signed hash 210 may be incorporated in the boot flash
image 152C by the CE source 108 as shown in 316 using tools
provided by the chip manufacturer 104 once the CE Source 108 has
finalized it own boot code. The signed hash 210 is validated in the
chip 114 each time the chip 114 is powered up and before the chip
114 exits the reset mode. The precise boot process may be chip
114--specific as defined by the chip manufacturer 104.
[0074] The chip 114 may support several security provider RSA
public keys, however, the number of production ROM locations
available in the chip 114 is typically limited due to physical
storage sizing and timing for the availability of the data (i.e.
the security provider's public RSA key placed in ROM must be
available at the time of the initial chip design). As described
above, one of the unique features of the present invention is the
ability for a standard chip 114 to be used with a multiplicity of
different CE sources 108, service providers 120 and/or CA vendors
108B, with the security features customized for each CE source 108
and/or application. Typically, there are not enough ROM hardware
slots in the chip 114 for all of the possible CE sources 108 to
have their security data embedded in the ROM for the production
chip 114. Also, since all CE sources 108 are typically not known
during the development phase of the chip 114, the security data of
every CE source 108 cannot be incorporated into the more secure
production ROM during the development stage. The techniques
discussed below extend the public RSA key of the security provider
106 as the hardware root of trust to multiple CE sources 108,
service providers 102 and/or CA vendors 108B to enable in-field
switching and or augmentation of CA functions implemented in the
chip 114 and without the use of a black box 116. Instead, this
programming system takes a generically manufactured chip 114 and
binds a specific flash memory-based CE source 108--provided public
RSA key 201 to a particular customer such as the CE Source 108 or
service provider 102 utilizing the security provider's
ROM/OTP-based public RSA key 200 as the hardware root of trust.
Secret OTP Value (SV) Use to Protect Sensitive Data
[0075] A secret value (SV) 451 programmed by the security provider
106 can be stored in the chip 114 OTP memory 152B, and that SV 451
can be used to indirectly modify or manipulate sensitive data that
is externally supplied to the chip 114. Such sensitive data can be
supplied from the service provider 102 via a broadcast, a third
party CA vendor 108B, a USB port, Internet server, DVD or similar
means.
[0076] FIG. 4A and FIG. 4B are diagrams illustrating how data (D)
can be securely received from one or more CA vendors 108B and can
be provided for use by the chip 114 in a CE device 112. The data is
protected from access by unauthorized CA vendors 108B and potential
attackers. Such data (D) may be a key for decrypting media programs
transmitted by the service provider 102 using the CE device 112, a
common code block of data 408 including instructions for execution
by the CE device 112, or similar data.
[0077] A customer global key (CGK) 402 is generated or assigned by
a first entity such as the security provider 106 and transmitted to
a second entity such as the CE source 108 or a first CA vendor
108B1. The data (D) 408 of interest is encrypted according to the
customer global key 402 provided by the security provider 106 to
produce encrypted data E.sub.CGK[D] as shown in block 410. In a
third party black box programming architecture performed by the
security provider 106, this encryption may be performed, for
example, by the second entity or CE source 108 or CA vendor 108B.
The security provider 106 may select the CGK uniquely for each CE
source 108 or CA vendor 108B. Since the CGK is unique to each CA
Source 108A/CA Vendor 108B, sensitive intellectual property such as
code or data can cryptographically isolated and protected from
successive CA vendors 108B in case switching of CA systems or
vendors is desired. Such CA systems from CA vendors 108B can
concurrently be implemented in the CE device 112.
[0078] In block 404, the customer global key (CGK) 402 is also
encrypted according to a secret value (SV) key by the security
provider 106 (or CE source 108) to produce an encrypted customer
global key E.sub.SV[CGK] 406. In one embodiment, each chip 114 has
a unique SV key 451, and the security provider 106 or CE source 108
encrypts the CGK uniquely for each chip 114 using that chip's
unique SV key 451.
[0079] The encrypted customer global key E.sub.SV[CGK] 406 and the
encrypted data E.sub.CGK[Data] 412 are then transmitted or
distributed to the CE device 112 and the chip 114, where it is
received and processed, as shown in blocks 414 and 416.
Transmission can be by physical transfer of a storage medium or
using wired or wireless data transmission. The encrypted customer
global key E.sub.SV[CGK] 406 is then decrypted according to the SV
key 451 stored in the chip 114 to reproduce the customer global key
403 and the encrypted data E.sub.CGK[Data] is decrypted with the
reproduced customer global key CGK to reproduce the data (D), as
shown in blocks 418 and 420. Either or both of these operations can
be performed by a third entity (for example, the user's fielded CE
device 112 using the chip 114). In one embodiment, these decryption
operations are hardware controlled and not accessible or modifiable
by the CE device 112. It is important to note that the CGK is not
shared between potential CA vendors 108B and that this
cryptographic isolation is maintained in the chip 114 by encrypting
the CGK with the SV key that is unique to each chip 114.
[0080] When needed, the CGK may again be decrypted using the SV key
within the key ladder (a secure processing engine that handles
security keys in the chip 114 without exposing such secrets to the
main CPU or exporting key material for access by software) with the
results of this decryption unavailable to the software of the main
CPU, thereby supporting both CA switching and CA co-existence in
the CE device 112.
[0081] In block 420, the decrypted CGK 402 is used to decrypt the
E.sub.CGK[Data] 412, resulting in the Data 408, which is used by
the chip 114 to perform security related functions such as
decrypting the media program. The decrypted Data 408 can also be a
key used to further decrypt the broadcast content or a common block
of code/data, as shown in block 422. If the operations of blocks
418 or 420 fail, processing stops, as shown in FIG. 4A. The
foregoing operations can be used to transmit data from a second CA
Vendor 108B2 as well.
[0082] FIG. 4B shows another embodiment of how to securely
distribute data from the service provider 102 or CA vendor 108B. In
this embodiment, the CGK 402 remains unique to each CA vendor 108B
and cryptographic isolation is maintained in the chip 114 by use of
a product provisioning key (PPK) 453 that is not shared with any
other CA vendor 108B or third party. When needed, the CGK 402 is
decrypted with the PPK 453 within the chip's 114 secure key
processing engine that handles content protection keys, the key
ladder, whose results are not available to software of the main
processor of the chip 114, thereby supporting switching between CA
systems (which may be supplied by different CA vendors 108B)
co-existing in the CE device 112. Support for CA switching and CA
co-existence is discussed in detail in the sections below.
[0083] The security provider 106 generates a secret value (SV) 451
that is unique to each chip 114 and a product provisioning key
(PPK) 453 that is unique to a particular chip 114 design or model,
but not unique to a particular chip 114. The PPK 453 could be
changed for a given number of chips 114 programmed by the black box
116 or manufactured for a specific period of time. The SV 451 is
programmed into the chip, as shown. Further, the PPK 453 encrypted
by the SV 451 is also generated and programmed into the chip 114.
These programming operations are performed by the chip manufacturer
104 using the black box 116 provided to the chip manufacturer 104
by the security provider 106. New keys are periodically loaded into
the black box 116 which resides at the chip manufacturer 104 by
encrypted DVDs or USB drive images created by the security provider
106 at their secure facility.
[0084] A customer global key (CGK) 402 is generated by a first
entity such as the security provider 106 and transmitted to a
second entity such as the CE source 108 or CA vendor 108B. The data
(D) 408 is encrypted according to the customer global key 402 to
produce encrypted data E.sub.CGK[D] as shown in block 460. The
encryption of the data (D) may be performed, for example, by the
second entity such as the CE source 108 or CA vendor 108B.
[0085] As shown in block 457, the customer global key (CGK) 402
assigned by the security provider 106 is also encrypted according
to a product provisioning key (PPK) 453 by the security provider
106, as shown in block 457 to produce an encrypted customer global
key E.sub.PPK[CGK] 459. The security provider 106 selects the CGK
402 uniquely for each CE source 108/CA vendor 108B combination,
thus enabling the security provider 106 to support many third party
CA Vendors 108B and/or CE Sources 108 using chips 114 from multiple
chip manufacturers 104 while cryptographically isolating the CGK
402 intended for use by one CA Vendor 108B1 from that used by
another CA Vendor 108B2 and potential attackers by use of the PPK
453.
[0086] The encrypted customer global key E.sub.PPK[CGK] 459 and the
encrypted data E.sub.CGK[Data] 462 are then transmitted or
distributed to the CE device 112 and hence, the chip 114, where it
is received and processed, as shown in blocks 464 and 465. This can
be accomplished by physical transmission of media storing the
encrypted customer global key E.sub.PPK[CGK] 459 and the encrypted
data E.sub.CGK[Data] 462 or by electronic transmission of the data,
by wireless or wired means since the sensitive data is encrypted.
Also, the security provider 106 may transmit the encrypted customer
global key E.sub.PPK[CGK] 459 to the CE source 108, and the CE
source 108 may transmit both the encrypted customer global key
E.sub.PPK[CGK] 459 and the encrypted data E.sub.CGK[Data] 462 to
the CE device 112.
[0087] The encrypted PPK 453 is recovered by decrypting
E.sub.SV[PPK] that was programmed into the chip 114 using the SV
programmed into the chip. This is shown in block 467. The encrypted
customer global key E.sub.PPK[CGK] 459 is decrypted according to
the recovered PPK 453 to reproduce the customer global key CGK 402
as shown in block 469 and the encrypted data E.sub.CGK[Data] is
decrypted with the reproduced customer global key CGK 402 to
reproduce the data 408, as shown in blocks 470 and 472. Either or
both of these operations can be performed by a third entity (for
example, the user's fielded CE device 112 using the chip 114). In
one embodiment, these decryption operations are hardware controlled
and not accessible or modifiable by the chip's main processor or
any other processor associated with the CE device 112.
[0088] If the operations in blocks 469 or 470 fail, processing
stops, as shown in FIG. 4B.
[0089] The decrypted data 408 is typically data that is used by the
chip 114 to perform security related functions. For example, the
decrypted data 408 can include a key used to decrypt the broadcast
content or can be a common block of code/data for performing
security related functions. The data may also comprise a media
program decryption key also known as the control word (CW) and/or a
pairing key (PK) that cryptographically binds the CE device 112
with an external device such as a smart card.
[0090] Secure Product Code-Data Provisioning by Arbitrary Third
Party Customers
[0091] FIG. 5A is a diagram presenting illustrative method steps
that can be used for the encryption of sensitive code or data to
enable cryptographic separation of code and data for different CA
vendors 108B and CA co-existence. The encrypted block can be
provided to an untrusted consumer electronics (CE) device
manufacturer 108A for provisioning.
[0092] The hardware device such as a chip 114 is received from a
first entity such as the security provider 106, wherein the
hardware device has a securely stored SV key 451 and a product
provisioning key (PPK) 453 encrypted by the SV key (E.sub.SV[PPK]),
as shown in block 502. A CGK 402 and the CGK encrypted according to
the PPK 453 (E.sub.PPK[CGK] 459) is received from the first entity,
as shown in block 506. The Data is 408 encrypted according to the
customer global key to produce encrypted data (E.sub.CGK[Data]
462), and the encrypted data E.sub.CGK[Data] 462 and hardware
device are transmitted to a third party, as shown in blocks 508 and
510. In one embodiment, the SV key and the encrypted product
provisioning key E.sub.SV[PPK] 455 are securely stored in the
hardware device 114 via a black box 116 the first entity.
[0093] The encrypted data E.sub.CGK[D] 462, the encrypted customer
global key E.sub.PPK[CGK] 459, and the hardware device 114 are
received by the third party such as a CE Source or CA vendor 108B,
as shown in block 512, and installed into the CE device 112.
[0094] The encrypted product provisioning key E.sub.SV[PPK] 455 is
then decrypted according to the SV key 451 stored in the chip 114,
as shown in block 514. The encrypted customer global key
E.sub.PPK[CGK] 459 is then decrypted according to the decrypted PPK
453 to produce the customer global key CGK 402, as shown in block
516. Finally, the encrypted data E.sub.CGK[Data] 462 is decrypted
according to the customer global key, as shown in block 520. The
data is then available for use.
[0095] FIG. 5B is a diagram showing a specific example of the
operations presented in FIG. 5A. The security provider 106 defines
a PPK 453 and a SV 451, and programs the PPK 453 encrypted by the
SV key 451 into the chip 114, as shown in blocks 552-554. This is
accomplished via the security provider's black box 114 disposed at
the chip manufacturer 114. Typically, the PPK 453 is held secret
and not exported to software in the CE device 112, which would
leave it vulnerable to unauthorized attack.
[0096] The security provider 106 then provides each CE source 108
(i.e. CE manufacturer 108A/CA vendor 108B combination) with a
different customer global key, CGK 402 (in one embodiment, a 128
bit value) and the CGK 402 encrypted with the PPK 453, referred to
as the E.sub.PPK[CGK], as shown in block 556.
[0097] The CE source 108 encrypts their sensitive code/data (D) 408
with the CGK 402, as shown in block 558, and provides the encrypted
code/data to the CE manufacturer 108A during CE device
manufacturing for the initial load, as shown in block 560. The chip
114 decrypts E.sub.SV[PPK] to obtain the PPK, and decrypts the
E.sub.PPK[CGK] using the obtained PPK 453 to produce the CGK 402,
which is thereafter usable by the third party software application
such as CE device 112 or a Set Top Box (STB) User Interface (UI)
code executing in the chip 114, as shown in blocks 562-566. This
allows the CGK 402 to be unique to each CE Source 108 (CE
manufacturer 108A/CA Vendor 108B) combination without revealing the
PPK external to the security provider 106 and assures that the CGK
402 is known only to the CE Source 108 combination it is assigned
to and no other party, excepting the security provider 106, which
assigned the CGK 402. This enables the PPK 453, CGK 402, and SV 451
from distinct CA vendors 108B to be used independently without
exposing these keys or other data to other CA vendors 108B or third
parties. As a consequence, different key sets (E.sub.PPK[CGK] 459
and CGK 402) can be allocated to each CA vendor 108B. This permits
a plurality of CA vendors 108B to implement CA functionality on a
single chip 114.
[0098] Using this process, the CA vendor-specific CGK 402, the
protected code/data segment 408 and the global PPK 453 are not
exposed outside the hardware controlled key ladder of the chip 114,
which is the secure key processing engine that handles content
protection keys. Again, the PPK 453 is held secret by the security
provider 106 and not given to the chip manufacturer 104 or any
third party and the CGK 402 is never given a third party outside
the CE source 108 or CA vendor 108B.
[0099] Among the advantages of this scheme include: [0100] (1) The
global chip 114 secret, PPK 453, is not given to the chip
manufacturer 114 or any third party. It is held secure by only the
security provider 106; [0101] (2) Each CE source 108 or CE
manufacturer 108A/CA vendor 108B combination receives their own
provisioning key, CGK 402; and [0102] (3) A hardware chip
114--unique secret (SV 451) is used as the root of trust, and each
CA vendor 108B can be provided a different SV key when several chip
unique SVs are provisioned in the chip 114 during black box 116
manufacturing.
[0103] In one embodiment, the security provider's programming is
tied to a particular chip 114 identified by a public value referred
to as a Product Identifier (PID) 600. The chip 114 is uniquely
programmed and provisioned by the security provider's black box 116
and tracked by the chip manufacturing process. The programming
methodology taught in this disclosure enables the placement of
secondary provisioning/activation server at third party CE product
manufacturing facilities 108A to track actual CE devices 112
produced and tested as opposed to chips 114 manufactured by the SOC
chip manufacturer 104. This secondary provisioning/activation
server can be located in the CE Source Operations of FIGS. 4A and
4B. The programming methodology taught in this disclosure can
automate reporting (at chip 114 fabrication and CE device 112
manufacturing) and less is hands-on for authorized third parties to
track production of CE devices 112 for accounting purposes such as
determining royalty payments for software licensing. This solves a
major problem for CE manufacturers 108A who may not be receiving
accurate reports from suppliers or distributors for royalty payment
purposes for licensed software or hardware that the CE manufacturer
108A is due.
[0104] The other significant advantage with this architecture is
that security is enforced purely in hardware, which is
significantly harder to defeat than software based implementations.
Hardware based storage, which cannot be modified by a third party
customer or an attacker, can be used for the security provider's
Public RSA or security provider's ECC key, CPD field 202, first
secret value (SV) 451, one or more additional secret values (SV2,
SV3, SV4, etc.), product identifier (PID) 600, JTAG unlock and
E.sub.SV[PPK] 455 (the PPK encrypted with the SV).
Product Identifier (PID) Assigned to Arbitrary Customers
[0105] FIG. 6 is a diagram of one embodiment of the product
identifier (PID) 114 described above. The PID 600 identifies the
specific chip 114 (not just the chip 114 configuration), and may be
provided to the CE source 108 after the chip 114 is manufactured.
In one embodiment, the PID is a 64 bit Public CE Device ID that is
generated by the security provider 106 and programmed in the chip
114 by the black box 116.
[0106] The security provider 106 ensures that the PIDs 600 are
globally unique across all supported products, that is, across
multiple chip manufacturers 104 and multiple CE device
manufacturers 108A. A system-wide unique value is needed to ensure
that any manufactured chip 114 can be allocated to any
customer.
[0107] In one embodiment, the PID 600 consists of a chip
manufacturer identifier 602, a model number 604 that specifies the
type of chip 114 produced by that chip manufacturer 104, a reserve
field 606 for future use and a monotonically increasing serial
identifier 608 to uniquely identify the chip 114 within the product
family and manufacturer.
Conditional Access System Swap with Different Key Sets
[0108] The infrastructure provided by the security provider 106 in
chips 114 programmed by the black box 116 allows for a broadcaster
or service provider 102 to change Conditional Access Systems (CAS)
at its discretion.
[0109] In traditional systems for large CA Vendors 108B, the
Conditional Access provider held the root RSA key used to sign the
boot loading code. The boot loader code, which is used by the Set
Top Box (STB) or CE device 112 internal software to validate and
authenticate a software download it has received, performs this
critical verification step. This is to ensure an authorized party
provides the code. If the boot loader cannot successfully validate
the code, the code received in the download message will be
rejected.
[0110] The public portion of an RSA key root key is either part of
the ROM mask set of the chip 114 or it is programmed into a secure
portion of One Time Programmable (OTP) memory as part of the chip
manufacturer's foundry process. This key can be used by the
security infrastructure of the chip 114 to authenticate the
download, which has been signed with the corresponding private key
section of the programmed RSA key. If the signed hash 210 cannot be
validated as shown in FIG. 3, then the public RSA key verified in
310 is not correct or does not match with the public portion of the
RSA key (either 200 or 201), the chip 114 will not come out of
reset or will not continue with its operations, depending on the
security rules of the chip 114.
[0111] In the past, this RSA key signing and authentication process
was held by the Conditional Access (CA) vendor 108B, which could
block the broadcaster or service provider 102 from performing
downloads to the fielded CE device 112 simply by not signing the
code. If a broadcaster or service provider 102 wanted to change CA
vendors 108B and did not get the ability to sign the code from the
originating CA vendor 108B, then the only option available to the
broadcaster or service provider 102 would be to change out the in
field CE device 112 with one that it did have the proper download
capability. This is a prohibitively expensive proposition for most
broadcaster or service provider 102, which prevents them from
running their system as they wish.
[0112] In this proposed infrastructure, the root public RSA key is
extended by storing the CA vendor public RSA key in flash as shown
in 216. In this case the CA vendor public RSA key 201 is either
held by the broadcaster/service provider 102, or by a trusted third
party that acts as an escrow entity. This allows the broadcaster or
service provider 102 wide latitude in operating its system if it
wishes to either change out CAS vendors 108B providers or to use
multiple CAS systems in the field.
[0113] This infield CA vendor 108B replacement scheme enabled by
the security provider 106 for its third party customers (i.e.
service providers 102, CE source 108, and/or CA vendors 108B)
utilizes a combination of the security provider 106 black box 116
programmed data and the security provider 106 assigned keys given
to the third party customer. Keys and programmed values that enable
switching CA vendors include the security provider 106 ROM RSA key,
Product Provisioning Key (PPK) 453, the Customer Global Key (CGK)
402, third party customer RSA key 201 signed by the security
provider's 106 private RSA key 210, the Customer Product
Differentiator (CPD) 202, and one or more Secret Value (SV) keys
451.
[0114] Each chip 114 contains a unique public identifier (the PID)
600 and a private symmetric provisioning key (the Product
Provisioning Key (PPK) 453). The PID 600 can be freely shared with
any third party while the PPK 453 is kept private by the security
provider 106 and is never released to any third party and/or
Consumer Electronic (CE) Source 108. The JTAG password unlocks
access to debug information and is only provided if the CE device
112 experiences an in field failure.
[0115] The security provider 106 black box 116 programs a series of
Secret Values (SVs) 451 that are allocated to the individual CE
source 108 and/or CA vendors 108B as the CE source 108 or CA vendor
108B requires as a part of its conditional access system to secure
content distribution. If multiple SVs 451 are programmed by the
service provider 102 via the security provider 106 black box 116
and distributed to the field, the service provider may later elect
to provide one or more of these SVs to an individual CA vendor 108B
when the CE device 112 is first used in the field or the service
provider 102 can chose to save one or more SVs 451 for a subsequent
CA vendor 108B switch for the fielded CE device at a later
time.
[0116] These SV values 451 can both be provided by the security
provider 106, i.e. 2 or more keys, and held in escrow or given to
the broadcaster or service provider 102 to hold. Another option
open to the broadcaster or service provider 102 is for one of the
SV values 451 to be provided by the security provider 106 and the
others provided by an external key source or some other CA vendor
108B.
[0117] This allows for the broadcaster or service provider 102 to
have multiple CA vendors 108B operating in the field at the same
time using one STB. This can be done so that the broadcaster or
service provider 102 can segregate their markets by broadcast
methodology (i.e. Cable, Satellite distribution, IPTV, etc.),
region (i.e. different areas of a particular City or Country, or
Geographic Location such as the Asia-Pacific market), or content
package (High Definition Programming, Sports or Premium content) or
any other market segmentation as market forces dictate.
[0118] For each CA vendor 108B, there is typically some type of
code resident in the CE device 112, such as a Security Kernel,
which is used to pass keys, perform certain housekeeping functions,
etc. as deemed necessary by that vendor. Given that the broadcaster
or service provider 102 has control over the in field download via
the public RSA root key 201, it is a simple matter to update these
Security Kernels in the field.
[0119] If the broadcaster or service provider 102 knows in advance
that one or more CA vendors 108B may be operating on their network,
the Security Kernels could be integrated into the "Golden Image" of
the CE device 112 code at the manufacturing line, thus eliminating
the need to do an in field download.
[0120] The broadcaster or service provider 102 would then be able
to use the appropriate CAS infrastructure by utilizing the specific
SV 451 and other associated keys for that vendor. Again, this type
of flexibility is unprecedented in the Pay TV industry and is only
possible utilizing the security provider 106 black box 116
programmed data and the security provider 106 assigned keys given
to the third party customer, (i.e. service providers 102, CE source
108, and/or CA vendors 108B).
Switching CA Vendors for Fielded CE Devices
[0121] The keys and programming infrastructure found in the chip
114 as provided by an independent security provider 106 enables the
fielded Consumer Electronic (CE) device 112 to change conditional
access (CA) vendors 108B (hereinafter alternatively referred to as
conditional access system (CAS) vendors), thus giving the service
provider 102 or broadcaster more flexibility in managing their
business. This can result in saving the service provider 102 a
significant capital investment by using the provided security
architecture (including the chip 114 and CE device 112) and
downloading a new software containing an alternate CA vendor 108B
application without having to replace fielded CE devices 112.
[0122] A service provider 102 or broadcaster can switch CA vendors
108B in a legacy conditional access system without swapping fielded
CE devices 112 using the method specified herein. This in-field CA
vendor 108B replacement scheme enabled by the security provider 106
for its third party customers utilizes a combination of black box
116 programmed data and security provider 106 assigned keys given
to the third party customer (i.e. service providers 102, CE source
108, and/or CA vendors 108B). Keys and programmed values that
enable switching CA vendors 108B include the security provider 106
ROM RSA key, PPK 543, CGK 402, third party customer RSA key 201
signed by the security provider's private RSA key Kpr.sub.SP (item
210), CPD 202, and one or more SV keys 451.
[0123] The foregoing description of describes a system boot code
can be securely installed, verified, and executed in the CE device
112 and wherein data (D) used for conditional access can be
securely provided to the CE device 112 for use in the conditional
access system. The same procedures can be used to either provide
additional conditional access functionality (e.g. to support a
conditional access system provided by another CA vendor 108B) or to
revoke the conditional access functionality of a CA vendor 108B and
substitute that of another CA vendor 108B. Adding additional
functionality to support another CA vendor 108B can be accomplished
by the storage of additional security values, while revoking
conditional access functionality of one CA vendor 108B to
substitute another can be accomplished by replacing previously
installed security values with the security values for the new CA
vendor 108B.
[0124] For example, a generic bootloader 706 and/or SOC security
driver can be installed in the flash memory of the System On a Chip
(SOC) 114 using the procedures shown in FIG. 2 and FIG. 3 instead
of the CE source 108 specific or secondary boot loader 710. This
generic bootloader 706 and/or SOC security driver is capable of
accepting a new customer flash application image for the CE device
112 and can authenticate a third party public RSA key 201
associated with the new CA vendor 108B stored in the new CE device
112 flash image as shown in blocks 302-312 of FIG. 3.
[0125] The new CE device 112 application flash image includes:
[0126] A new third party RSA key (different from the previous third
party RSA key 201 of FIG. 2), a new CPD 202 and a new
E.sub.PPK[CGK] 459; [0127] New customer flash conditional access
application code 316 from the same or a new CA vendor 108B with its
own content protection scheme; [0128] An optional new CE device 112
application that potentially uses new conditional access
application code to implement the conditional access system; and
[0129] The security provider 106 defined code download and
verification module will be included in the deployed software
image.
[0130] When the CE device 112 reboots after the successful
download, the new CE device application flash image is
authenticated as shown in FIG. 3 with the new signed third party
RSA key as shown in 310, new CPD 202, and new CA vendor 108B
application, thereby, enabling the new CA vendor 108B application
to take control of the CE device 112 and provide content protection
services for the service provider 102.
[0131] FIG. 7 shows a bootloader cascade beginning with the generic
bootloader 706 authorizing the secondary bootloader 710 supplied by
a CAS provider that in turn authorizes a STB application. The
generic bootloader 706 is generally not replaced in the field. This
bootloader 706 verifies Customer RSA key 201, i.e. Cust1 as shown
in 708. The generic bootloader 706 does not contain the CAS
vendor's 108B public RSA key 201. The generic bootloader 706 needs
to be able to point to a new Over-the-Air (OTA) image 716 provided
by the CAS vendor and load this image if the new image passes RSA
Signature verification from FIG. 3. Subsequent STB reboots will
load the new CAS OTA image 716, which may contain a revised
secondary bootloader 710.
[0132] A download verification module resident in the STB
Application monitors and guides the download process shown in 714.
The code needed to download and authenticate the new CE Device 112
image is controlled by the security provider 106 and the
broadcaster/service provider 102. The download verification module
shown in 714 must be incorporated into the STB code image 716 to
accept updates, validate updated image and re-launch the STB
application. The download verification module shown in 714
assembles data segments of the encrypted image for the OTA update
716, verifies data integrity and assists generic bootloader 706 in
validating the signature. Following validation of the signature,
the image 716 is decrypted and made ready for re-launching the
updated CE Device 112 image.
[0133] Table I lists the data used by the CE Source 108 and/or CA
vendor 108B in their typical operation in providing a secure
content distribution system for their service provider 102.
TABLE-US-00001 TABLE I Typical keys and data fields used in
providing a secure content distribution system Key and/or Security
Field Name Resident in Who programs SP Public RSA ROM/OTP key
ROM/OTP SP 102 or (from 210) Chip Mfg. 104 Customer Public RSA key
(Cust Flash CE Source 106 in Pub RSA Key) 201 field Customer
Product Differentiator OTP CE Source 106 in (CPD) 202 field Hash of
Customer Public RSA & Flash CE Source 108 in CPD (Hash) field
Signed Hash of Customer RSA Flash CE Source 108 in key and Customer
Product field Differentiator (Signed Hash) 210 Customer signature
over signed Flash CE Source 108 in code (Cust Sig) 218 field One or
more Secret Value (SV) OTP SP 102 by black Key(s) 451 box 116 or
via SV insertion Encrypted Product Provisioning Key OTP SP 102 by
black (E.sub.SV[PPK]) 455 box 116 Encrypted Customer Global Key
Flash CE Source 108 in (E.sub.PPK[CGK]) 459 field Secret Value 2
(SV2) Key 451 OTP CE Source 108 in field Product ID (PID) 600 OTP
SP 102 by black box 116 JTAG unlock key OTP SP 102 by black box
116
[0134] Table II shows what keys and data fields in a particular CE
device 112 are fixed (do not change) after a new software image
containing an alternate conditional access vendor application has
been downloaded and authenticated by the chip 114.
TABLE-US-00002 TABLE II Fixed key and data fields when accepting a
new software image for an alternate conditional access vendor
application Fixed Keys/Security Fields for all downloaded images
used in the CE Device 112 SP Public RSA key (stored in ROM or OTP)
(block 200) SV, SV.sub.CA2, SV.sub.CA3, SV.sub.CA4, . . .
(programmed by black box) 451 E.sub.SV[PPK] 455 PID 600 JTAG
[0135] The PID 600 is a public identifier and can be freely shared
with any third party. The PPK 453 is kept private to the security
provider 106 and is never released to any third party and/or CE
Source 108 (an encrypted version of the E.sub.SV[PPK] 455 is stored
in the chip 114, via the black box 116 as is the secret value (SV)
451 needed to decrypt the E.sub.SV[PPK] 455). The JTAG value is
only provided if the CE device 112 experiences an in field failure.
Table II also shows different values of the SV key 451. The first
value SV 451 is the value programmed by the security provider 106
via the black box 116 and is allocated to the individual CE source
108 and/or CA vendors 108B as the CE source 108 or CA vendor 108B
requires as a part of its conditional access system to secure
content distribution. SV.sub.CA2 is distinguished from SV2 451,
which can be optionally programmed by the black box 116). Hence, if
multiple SVs 451 are programmed by the service provider 102 via the
black box 116 and distributed to the field, the service provider
102 may later elect to provide one or more of these SVs 451 (e.g.
SV) to an individual CA vendor 108B when the CE device 112 is first
used in the field or the service provider 102 can chose to save one
or more SVs 451 (SV.sub.CA2, SV.sub.CA3, SV.sub.CA4 . . . ) for a
subsequent CA vendor 108B switch for the fielded CE device 112 at a
later time.
[0136] The downloaded STB image contains the switchable keys from
Table III, i.e. the initial image loaded in the STB flash contains
CA Vendor key set 0 as defined below: [0137] Cust Pub RSA Key0
[0138] Hash0 [0139] Signed Hash0 [0140] Cust Sig0 [0141]
E.sub.PPK[CGK0]
[0142] CA switch means that the new STB flash for the new STB
application contains an image that has values for CA Vendor key set
1. The Code Signing verification routine needs to reference these
fields from the STB flash image.
[0143] Table III shows the new key and data fields that utilized
when a new CE device image implements a switch from one CA vendor
108B to another CA vendor 108B.
TABLE-US-00003 TABLE III New Key and Data Fields Utilized in a CE
Device After a Switch to a Different CA Vendor 108B or Different
Conditional Access System Keys/Security Downloadable Downloadable
Downloadable Fields Keys/Security Keys/Security Keys/Security
contained in Fields modified Fields modified Fields modified the
initial in first CA in second CA in third CA image loaded provider
switch provider switch provider switch into the CE image delivered
image delivered image delivered Device at to the fielded CE to the
fielded CE to the fielded CE Manufacturing Device Device Device SV1
SV2 SV3 SV4 Cust Pub RSA Cust Pub RSA Cust Pub RSA Cust Pub RSA
Key0 Key1 Key2 Key3 (201) (201) (201) (201) CPD0 CPD1 CPD2 CPD3
(202) (202) (202) (202) Hash0 Hash1 Hash2 Hash3 Signed Hash0 Signed
Hash1 Signed Hash2 Signed Hash3 (210) (210) (210) (210) Cust Sig0
Cust Sig1 Cust Sig2 Cust Sig3 (218) (218) (218) (218)
E.sub.PPK[CGK0] E.sub.PPK[CGK1] E.sub.PPK[CGK2] E.sub.PPK[CGK3]
(459) (459) (459) (459)
[0144] Each CA vendor 108B switch results in the installation and
use of a new Customer Public RSA key 201 (i.e. Cust Pub RSA Key1,
Cust Pub RSA Key2, Cust Pub RSA Key3 in the Table III). The
security provider 106 assigns each new CA vendor 108B a unique CPD
202 (i.e. CPD1, CPD2, CPD3 in Table III). The security provider 106
hashes the Customer Public RSA key 201 and CPD 202 producing unique
hash values and signs each new hash with the security providers 106
own Private key as requested by the service provider 102. (i.e.
Signed Hash1, Signed Hash2, Signed Hash3 in Table III). To
optionally further increase security, the address location for the
flash-based third-party public RSA key 201 and/or the CPD 202 can
also be used fix input data for a given CE source 108 and
incorporated into the signed hash block 210. The secret values
(SVs) 451 programmed by the black box 116 during SOC manufacturing
are allocated as determined by the service provider/broadcaster 102
or CE device 112 owner. In Table III a different SV value 451 is
allocated to the CA vendor 108B after a switch is performed.
[0145] The security provider 106 also assigns a new CGK 456 and
generates the E.sub.PPK[CGK]459 for each switch to a new CA vendor
108B or different conditional access system. Upon a successful
download and a CE device 112 reboot, the new CE device 112
application flash image 716 is authenticated with the new signed
Third Party RSA key 210, new CPD (202), and new CA vendor 108B
application 716 as shown in FIG. 3. This enables the new CA vendor
108B application to take control of the CE device 112 and provide
content protection services for the service provider 102 with the
conditional access system new CA vendor 108B.
[0146] An existing CE vendor's 108B conditional access data can
also be revoked. This is made possible by incorporating the CPD 202
into the signed hash 210 to enable the CE source 108 to revoke a
previously assigned CE source 108 public RSA key 201. In this
embodiment, the CE Source 108 provides a new public RSA key 201 to
the security provider 106. The security provider 106 assigns a new
CPD 202 to be used with the new public RSA key 201, with the new
CPD 202 to be stored at the same address as the CPD 202 currently
stored and used with the existing public RSA key 201. If the
replaced CPD 202 was stored in OTP, then a few bits of the new CPD
202 may be changed so that the physical address of the CPD 202 does
not change. The security provider 106 returns a new signed hash 210
for the new CE source public RSA key 201 and new CPD 202. The CE
source 108 transmits a new software image 716 to the CE device 112
(for example, by wireless means). The previously signed CE source
public RSA 201 key will no longer be successfully validated by the
security provider's signed hash 210 since the signed hash uses old
CPD 202 value, which will no longer pass the verification process
in blocks 304-312 of FIG. 3 since the CPD 202 value has changed,
thereby, revoking the signed hash and previous CE source public RSA
key 201 in the CE Device 112. The previous CE source public RSA key
201 could be used once again if the security provider source
provides another signed hash 210 using the old CE source public RSA
key, old CPD value 202 with a new CPD address since the CPD value
202 at the old CPD address location has been changed.
TABLE-US-00004 TABLE IV Provisioning for CA Co-Existence
Keys/Security Fields Keys/Security Fields allocated to CA Vendor 1
allocated to CA Vendor 2 loaded into the CE Device at loaded into
the CE Device at Manufacturing Manufacturing Cust Pub RSA Key0 201
Cust Pub RSA Key0 201 CPD0 202 CPD0 202 Hash0 Hash0 Signed Hash0
210 Signed Hash0 210 Cust Sig0 218 Cust Sig0 218 SV1 451 SV2 451
E.sub.PPK[CGK1] 459 E.sub.PPK[CGK2] 459
[0147] Table IV shows a provisioning example where two CA vendors
108B can coexist in the same CE device. A common Customer private
RSA key signs the final CE Device binary image containing the
production code 716. The CE Device 112 would verify the signature
using the Cust Pub RSA Key0 shown in 708 contained in the image 716
loaded during CE Device manufacturing or sent over the air. In this
case the Customer who holds/generated the code signing RSA key 201
would be the CE Device 112 owner who is responsible for the overall
operation of the STB or CE Device and the Co-existence of both CA
vendors 108B in the field. The CE device 112 owner would be
responsible for receiving the final binary images from the two CA
vendors 108B and making sure that the applications 716 perform
properly together. Each CA vendor 108B maintains its own Secret
Value key 451 (SV1 and SV2 respectively) programmed by the black
box 116 during SOC manufacturing that protects content related
items such as Control Words and subscription entitlements. Each CA
vendor 108B also is provided with its own Customer Global Key 202
(CGK1 and CGK2 respectively) that is used to protect sensitive code
and CE Device data contained in the application code image 716. CA
Co-Existence works in a single CE Device 112 because each CA
vendor's 108B content protection mechanism is cryptographically
protected and isolated against the other through the allocation of
independent key sets (SV1/E.sub.PPK[CGK1] and SV2/E.sub.PPK[CGK2]
respectively) programmed by the black box 116. The CA vendor 108B
designs their unique content protection and distribution
architecture based on these root keys resident in the CE device
112. Since the root key sets shown in Table IV are unique and
separate for each CA vendor 108B, encrypted subscription
entitlements and control words can be delivered uniquely to the CE
Device 112 without fear of them being manipulated or falsely
created by the other CA vendor 108B.
Chip Ownership Validation Code for JTAG Unlock Value
[0148] In one embodiment, service provider 102 uses a key to
protect a Joint Test Action Group (JTAG) port on the chip that is
used to obtain access to higher security areas of the chip 114
(e.g. the chip's internal states). The value for this key can be
programmed by the black box 116 during chip 114 manufacturing. In
one embodiment, the key is a 128-bit JTAG key. The JTAG key should
be a 128-bit value. Smaller values JTAG key lengths are acceptable
if there is a delay function between successive password unlock
attempts. For adequate security, the key length should be at least
64 bits in length. Access to the JTAG port is gained when the
password is supplied. This key cannot be exported to software.
[0149] FIG. 8A is a diagram presenting exemplary method steps that
can be used as a method for a first entity (service provider 106)
to deliver JTAG data to unlock the hardware device or chip 114 to a
second entity (CE source 108). The chip 114 ownership by the second
entity can be verified by the first entity if the second entity
delivers an authentication value produced uniquely for each chip
114 as recoded during the manufacturing process. There are numerous
methods that can be employed several of which are identified
here.
[0150] FIG. 8A is a diagram illustrating exemplary method steps
that can be used to deliver the unlocking data. As shown in block
802, a product provisioning key that has been encrypted with the
chip 114 unique secret value SV 451 is transmitted from the first
entity (the service provider 102) to the second entity (CE source
108) for secure storage in the chip 114. In one embodiment, this is
accomplished via the Black box 116. A chip 114 PID 600 is also
stored in the chip 114. The chip is provided to the CE Source,
which installs the chip 114 in a CE device 112, and provides the CE
device 112 with the chip 114 to third parties, such as end users,
as shown in block 804. When the CE device wishes to unlock the
hardware chip using JTAG or similar data, the CE source 108 and
transmits, and the service provider 102 receives an unlock request,
as shown in block 806. The unlock request comprises a customer
validation code CVC 862 that is computed by the chip 114 and
reproducible in the service provider 106 as well as chip 114
identifying information such as the PID 600. In one embodiment, the
CVC 862 computed in the hardware device from the encrypted product
provisioning key E.sub.SV[PPK] alone or with an additional seed. In
other embodiments, the CVC 862 is also computed using the CE source
108 unique customer product differentiator (CPD 202), the chip 114
unique PID 600. The service provider 102 receives the unlock
request having the CVC 862 and PID 600, and computes an expected
CVC 862 from the secret value SV 451, and CPD/PID/PPK as required,
as shown in block 808. The resulting expected CVC 862 is compared
to the CVC 862 received from the CE source 108 in the unlock
request, and if the two values match, the service provider 102
transmits the requested JTAG data to the CE Source 108. The CE
Source can then use that data to unlock the chip 114 as
desired.
[0151] FIG. 8B illustrates a more specific example of the
calculation and distribution of customer validation data by the CE
source 108 after the chip 114 is manufactured. The service provider
102 can implement a chip 114 ownership validation scheme that the
CE source 108 or subscriber 110 can use to prove ownership of the
CE device 112 before the service provider 102 releases a JTAG key
to a requesting party. The CE source 108 participates in the
generation of validation codes when the chip 114 is produced.
[0152] First, the consumer validation code (CVC 862) must be
determined. This can be accomplished in a number of ways.
[0153] First, since the E.sub.SV[PPK] 455 itself us unique, it can
be used as the consumer validation code CVC 862, as shown in block
852.
[0154] Alternatively, the CVC 862 may be computed inside the chip
114 from different combinations of E.sub.SV[PPK], the chip PID 600,
the unique customer product differentiator CPD 202, and a seed
provided by the service provider 102. For example, the CVC 862 can
be computed as an XOR of the PID 600 and E.sub.SV[PPK] 455, as
shown in block 856, as an XOR of the PID 600, the E.sub.SV[PPK]
455, and the CPD 202, as shown in block 858, or an XOR of the CPD
202 and the E.sub.SV[PPK] 455, as shown in block 860. All of these
CVC 862 calculations are unique to the chip 114, SV 451 and
globally unique PID 600, which could only be have been produced by
a single chip 114 of the entire population of fielded chips 114.
The CVC 862 (alternatively referred to hereinafter as the hash
validation code) and optionally the PID 600 are recorded as shown
in block 864 for later use in validating chip 114 or CE device 112
ownership.
[0155] The service provider 102 needs to be able to validate third
party owner of the CE device before the JTAG unlock key can be
release to a third party customer (e.g. CE source 108). The third
party customer such as the CE source 108 transmits a JTAG unlock
request 866 to the service provider 102. The request includes the
CVC 862 862 and PID 600 for the chip 114 for which they require a
JTAG unlock key. The service provider 102 looks up the SV 451 of
the chip 114 using the PID 600 supplied by the third party
customer. The service provider 102 uses the SV 451 and the PID/CPD
to calculate the expected CVC 862, as shown in blocks 872 and 874.
The service provider 102 verifies that the customer supplied CVC
862 matches the calculated expected CVC 862 to determine if they
are the legitimate third party owner of the chip 114. If so, the
JTAG data needed to unlock the chip 114 is transmitted to the third
party customer, as shown in block 878.
Signaling for CAS Switching and Key Derivation
[0156] It is desirable for service providers to have the capability
to segment a population of CE devices 112 (hereinafter
alternatively referred to as client devices 112) into a number of
different groups based on CAS switching requirements. For example,
a service provider may want client devices 112 of a particular
generation to switch to a second CA system based upon a discovered
vulnerability discovered in that particular generation of client
device 112. It is especially desirable that this capability include
fielded devices that are already deployed in consumer locations.
This fluid ability to define and redefine groups of fielded devices
allows different CAS switching paradigms to be defined, including
CAS switching that occurs slowly throughout the fielded client
device 112 population.
[0157] Described below is a CAS switching paradigm and a method for
signaling such switching that permits groups of fielded client
devices 112 to be defined and redefined as necessary, and provides
a technique for signaling when and how such CAS switching should
take place. In the embodiment described below, the client device
112 has previously received an appropriate application image
containing a current CAS application that will be switched out and
a new CAS application that will be switched in to replace the
current CAS application. In this process, the CAS switching process
is guided by the vendor of the middleware executing on the client
device 112 (for example, the CA vendor 108B), and no direct support
is required from the CAS application itself. Typically, the CAS
client runs in the client device 112 on a security processor
separate and peripheral from the primary CPU of the client device
112 or a trusted execution environment (TEE), while the middleware
typically executes on the same CPU used for the primary CAS
application.
[0158] In one embodiment, the CAS signaling and switching is
performed on a client device 112 compliant with the digital video
broadcasting (DVB) specifications, including "Digital Video
Broadcasting (DVB): Implementation Guidelines of the DVB Simulcrypt
Standard, ETSI TR 102 035, Version 1.1.1, published 2002 by the
European Telecommunications Standards Institute; "Digital Video
Broadcasting (DVB): Head-end implementation of DVB SimulCrypt,"
ESTI TS 103 197, Version 1.5.1, published 2008 by the European
Telecommunications Standards Institute; and "Common Interface
Specification for Conditional Access and Other Digital Video
Broadcasting Decoder Applications," EN 50221, published February
1977 by the Technical Committee CENELEC TC 206, all of which are
hereby incorporated by reference herein. In this instance, the CAS
switching process involves the Application Specific Data (ASD),
which is defined in the Digital Video Broadcasting (DVB)
specifications as Private Data (PD). CAS switching data is inserted
by the service provider 102 (hereinafter alternatively referred to
as the headend 102) into the content delivery network (CDN) for
delivery to the selected client devices 112. This data is received
and processed by the middleware in the client device 112 to use the
appropriate CAS application as directed by the signaling mechanism
described herein.
[0159] This process allows the operator of a service provider or
headend 102 (COMCAST, DIRECTV, DISHTV, or ECHOSTAR, for example) to
set up groups in the client device 112 population as they see fit
at the time they intend to perform a switch away from the existing
CAS vendor 108B to a new CAS vendor 108B whose application resides
in the device. A CAS switch may be desirable in the event the
exiting CAS system has been hacked, due to an expiring business
relationship with the existing CAS, or more favorable business
terms and/or features are available in a new CAS.
[0160] The CAS data is passed to each defined group of client
devices 112 through the middleware based on the ASD. The new CAS is
signaled to the middleware by a message sent from the headend 102
indicating that the middleware should begin using the new CAS. The
individual SoC 114 in each client device 112 may require a reboot
if required or needed to properly configure the data and key
handling resources in the SoC 114. Specific SoCs 114 may be
utilizing a derived key mechanism (defined below), which means that
the key ladder responsible for calculating the control words used
to decrypt encrypted video packets must be properly configured in
the SoC 114 for a given CAS client.
[0161] The Private Data Generator (PDG) described in the DVB
standard closely resembles an entitlement management message (EMM)
generator, receives and processed the ASD. This implementation is
independent of the CA vendor 108B of the CAS, so it is not
necessary to discuss details of the CAS switching implementation or
process with individual CAS vendors 108B. The CAS switch is
independent of the CAS client itself as it is guided by state in
the middleware implemented in the client device 112. After a
switch, entitlements are delivered to the new CAS client (i.e. CAS
application for the new operational CAS in the client device) for
it to properly provide the subscriber with access to their
paid/subscribed programming.
[0162] Typically, a CAS switch is performed during off peak viewing
hours to minimize disruption in the subscriber/viewing population.
However, since the switch command is a part of the same signal that
delivers the content itself, a switch from one CAS to another will
not occur if the client device 112 is not receiving the content
delivery signal at the time a CAS switch is requested by the
headend 102. Consequently, a second or third attempt to complete
the CAS switch may be required before the switch actually takes
place. Messages to the middleware could be repeated in a carousel
fashion (similar to how electronic program guides (EPGs) are
currently distributed), and contain a date/time to perform the
actual switch/reboot. That increases the likelihood that all client
devices 112 in the group perform the switch command at the same
time, irrespective of when each client device 112 may have been
tuned to the receive the content delivery signal.
DVB Definitions
[0163] The DVB standard defines a program association table (PAT)
and a conditional access table (CAT). Both the PAT and the CAT are
associated with DVB program identifiers (PIDs) that identify each
program in a data stream that may comprise multiple programs. The
data stream may also comprise multiple independent program map
table (PMT) sections. Each PMT section is given a unique
user-defined PID and maps a program number to the metadata
describing the program and the program streams.
[0164] The PIDs associated with each PMT section are defined in the
PAT, and are the only PIDs defined there. The streams themselves
are contained in packetized elementary stream (PES) packets with
user-defined PIDs specified in the PMT. The PMT is comprised of
sections for each program number represented in a transport stream,
each section of which contains the packet identifier and
characteristics of each elementary stream in the program service.
The CAT is used for conditional access management of the cypher
keys used for decryption of restricted streams. The CAT table
contains privately defined descriptors of the system used and the
PID of the EMM associated with that system. It is used by a network
provider to maintain regular key updates.
[0165] FIG. 9 is a diagram illustrating exemplary method steps for
controlling a group of client devices 112 to switch from a first
CAS to a second CAS via a plurality of client device signaling
messages. As described below, the client device signaling messages
each comprise at least one of a plurality of action codes and
payload data.
[0166] In block 902, a group identifier that identifies the group
of client devices 112 is generated. In block 904, a first client
device signaling message is transmitted to only each client of the
identified group of client devices 112 (the first client device
signaling message is not transmitted to client devices 112 that are
not in the identified group). The first client device signaling
message includes the group identifier. The group identifier is for
storage in a non-volatile memory of each client device 112 of the
group of client devices 112.
[0167] In block 906, a second client device signaling message is
transmitted to the plurality of client devices 112 (which may
include client devices 112 that are not in the identified group).
The second client device signaling message includes the group
identifier and signals a switch of each of the group of client
devices 112 from the first conditional access system to the second
conditional access system.
[0168] In one embodiment, each of the plurality of devices
comprises a middleware module, and the first client device message
and the second client device message are transmitted on a
conditional access switching message channel monitored by the
middleware module of each of the plurality of devices. In this
case, an identifier of the conditional access switching message
channel (e.g. a switching message PID) is transmitted to each of
the plurality of devices, for example, in a conditional access
table.
[0169] FIG. 10 is a diagram illustrating exemplary operations
performed by the client devices 112 in receiving and handling the
first client device message and the second client device message.
In block 1002, a middleware module of at least one client device
112 of the group of client devices 112 monitors a channel
identified by the identifier of the conditional access switching
message channel. In block 1004, the middleware module of the at
least one of the client devices 112 receives the first client
device message transmitted in block 904 (which includes the group
identifier). In block 1006, the group identifier is stored in
non-volatile memory of the at least one of the client devices 112.
The middleware of the client devices 112 continue to monitor the
conditional access switching message channel, and in block 1008,
the middleware module of the at least one of the group of client
devices 112 receives the second client device message. Block 1010
determines whether the second client device signaling message
comprises the group identifier received and stored in blocks 1004
and 1006. If so, the at least one client device 112 switches from
the first conditional access system to the second conditional
access system, as shown in block 1012.
[0170] FIGS. 11-12 illustrate the operations presented in FIGS.
9-10 in greater detail.
Assigning a Client Device to a Group
[0171] FIG. 11 illustrates operations that may be performed to
assign a client device 112 to a group. This illustrates additional
detail regarding the operations illustrated in blocks 902 and 904
of FIG. 9 and blocks 1002-1006 of FIG. 10.
[0172] Client devices 112 are assigned to a particular group upon
activation via a group identifier stored in non volatile memory
(NVM). The group identifier allows a subset of the client device
112 population to switch to another CAS system stored in the client
device, but dormant (e.g. not installed and operating). This group
assignment by provision of the group identifier is in addition to
the other actions that may be required by the CAS currently active
in the client device. Then an application executing on the client
device 112 updates the group identifier by storing it in NVM upon
reception of a message having an Assign Group Action.
[0173] As shown in 1152, an operator 1102 issues an assign group
command to the private generator or PDG 1104. The operator 1102 may
comprise a human or a computer executing instructions to generate
the command based on input from humans or another computer. As
shown in 1154, the PDG 1104 generates private data comprising a
group identifier, and provides this identifier to a multiplexer
1106 which multiplexes the private data having the group identifier
into the data stream transmitted to the client device. The private
data is then transmitted in a data stream to the client device 112
where it is accepted by the client device 112 (set top box or STB)
application 1108, as shown in 1156. The client device 112 then
updates the group identifier of the client device 112 by storing
the received group identifier in non-volatile memory (NVM) as shown
in 1158.
[0174] FIG. 12 illustrates operations that may be performed to
initiate a CAS switch. This illustrates additional detail regarding
the operations illustrated in blocks 906 of FIG. 9 and blocks
1008-1012 of FIG. 10.
[0175] A CAS switch is initiated by a Switch CAS message generated
by the PDG. The Switch CAS messages can be addressed to one or more
individual client devices 112, a group of client devices 112 or all
client devices 112. This paradigm permits a single message to be
sent to all client device 112 members in the group as opposed to
sending many single, independent messages to individual client
devices 112. The Switch CAS message may include an activation date
to allow pushing of the message before the CAS switch is to
actually take place. In such cases where the activation date/time
is in the future, the STB application 1108 executing in the client
device 112 sets an event and writes the CAS ID to a NVM memory
location for future use by the CAS Switch activation event. When
the activation event occurs (in the future or immediately), the STB
application 1108 writes the CAS ID to a well-known location memory
location in NVM (that is designated to be executed on reboot) and
reboots. On reboot, the STB application 1108 reads the CAS ID and
activate the corresponding CAS kernel to install and execute the
new CAS.
[0176] Referring to FIG. 11, the operator 1102 selects which group
of the client devices 112 are desired for a CAS switch, an
identifier of the CAS to be switched to (CAS ID) and issues a CAS
switch command identifying these devices and providing the CAS ID,
as shown in 1202. In 1204, the PDG generates private data
comprising the group number of the group of client devices 112 for
which the CAS switch was desired, and provides that PDG to the
multiplexer 1106, which multiplexes the private data having the
group identifier and information indicating that a switch is
desired into the data stream as a CAS switch command. The private
data is then transmitted in a data stream to the client device 112
where it is accepted by the client device application 1108, as
shown in 1208. As described further below the CAS switch may be
performed immediately upon receipt by the client device, or may be
performed as a future event. In cases that the update is to occur
immediate, the CAS ID is updated in NVM, and the client device 112
is rebooted as shown in 1210 and 1212. In cases where the update is
to occur at a later time or date, the CAS ID is updated in NVM, and
a future event is set, at which time the CAS switch will take place
by rebooting 1212 the client device.
Client Device Operations to Perform CAS Switch
[0177] As a part of the booting process, middleware executing on
the client device 112 checks the known flash location (designated
to be executed on reboot) to determine which CAS to initialize.
This information was included in the form of the CAS ID (for
example, CAS-A, CAS-B or CAS-C) transmitted with the CAS Switch
message described above. Next, the middleware executing on the
client device 112 provides CAS specific data to a secure processor
of the client device 112 (e.g. a SoC 114 or system on a chip) so
that the SoC 114 can derive keys associated with the selected CAS
and pertaining to the appropriate CAS vendor 108B. Such keys may
include, for example keys or intermediate results required to
derive keys for decrypting media programs encrypted by the headend
102.
[0178] Next, the middleware executing on the client device 112
initializes the appropriate CAS, which then operates as a CAS
client. The middleware monitors the appropriate channel to receive
the CAT from the headend 102, and once the CAT is received, the
middleware passes the CAT to the CAS client.
[0179] Using the CAT, the CAS client instructs the middleware to
monitor the appropriate channel to receive EMMs. The appropriate
channel can be defined according to a particular DVB PID, which may
be placed in the CAT with a "dummy" CAS identifier. For example, in
a DVB system, the PID used for EMM reception may be monitored.
[0180] When the client device 112 is tuned to the appropriate
channel, the middleware receives the PMT and parses the PMT to
determine the PID of the ECMs that correspond to the CAS currently
in operation (e.g. the CAS recently switched to). The middleware
then filters the incoming data stream for ECMs having the
determined PID, and passes those ECMs to the CAS client. The CAS
client (cooperating with the middleware if necessary) then process
the ECM to load decrypting information such as keys and/or
software, and uses that information to generate keys or other
information that is needed to decrypt media program(s).
Message Definitions
[0181] This section provides an exemplary format and syntax of the
messages communicated with the client device. It is noted that
message of differing format and/or syntax may be used. In a
preferred embodiment, the messages themselves are cryptographically
protected, either through encryption, hashing or other means.
[0182] Messages communicated with the middle ware include (1) an
address (intended target of message, such as global, group,
specific), (2) a sequence number (to prevent duplicate processing),
(3) a message type, and (4) payload. Message types include but are
not limited to (1) Assign group, (2) Assign CAS Vendor 108B, and
(3) Reboot. Payloads are specific to a particular message type, as
further described below. Based on message type, middleware will
take appropriate action (i.e. store group info in flash, store
selected CAS vendor 108B in flash, reboot at the appropriate
time).
[0183] Message include an action code, describing a particular
action that the message is to command. In the example below,
actions are embedded in the message in a tag-length-value (TLV)
format.
Action Table
[0184] Table V defines one embodiment of a minimal list of Actions
to implement for CAS Switching messages.
TABLE-US-00005 TABLE V Action (Hex) Description Comments 01
Sequence number Sequence number of the message 02 Timestamp
Timestamp of the message in system time 10 Unique Addressing Unique
address of STB 11 Group Addressing Group address of STB 12 Global
Addressing All STB's 20 Assign Group Assign a STB to an addressing
Group 21 CAS Switch Switch from current CAS to CAS identified in
the message
[0185] Each message minimally requires the following Actions (1)
Addressing (unique, group, or global) (2) Timestamp (3) Sequence
number (4) Primary action (Assign Group or CAS Switch).
[0186] The Sequence Number action (01) is used communicate the
sequence number of the message to the STB Application 1108. This
information prevents the STB application 1108 from reprocessing
messages. Data associated with this action is presented in Table
VI.
TABLE-US-00006 TABLE VI Field Size Description Action Code 1 01 -
Sequence Number Length 1 Length (does not include action or length
fields) Sequence Number 2 Sequence number
[0187] The Timestamp action (02) is used to indicate system time.
Messages with Timestamps in the past should not be processed. Data
associated with this action is presented in Table VII.
TABLE-US-00007 TABLE VII Field Size Description Action Code 1 02 -
Timestamp Length 1 Length (does not include action or length
fields) Time Var User defined time
[0188] The Unique Addressing action (10) is used to address a
single client device. Data associated with this action is presented
in Table VIII.
TABLE-US-00008 TABLE VIII Field Size Description Action Code 1 10 -
Addressing Unique Length 1 Length (not including action and length
fields) Address var The unique address of the STB (Transport Chip
ID)
[0189] The Group Addressing (11) action is used to address a group
of client devices 112 assigned to a Group Identifier. Data
associated with this action is presented in Table IX.
TABLE-US-00009 TABLE IX Field Size Description Action Code 1 11 -
Addressing Group Length 1 Length (not including action and length
fields) Group ID 2 The Group Identifier
[0190] The Global Addressing (12) action is used to address all
client devices 112. Data associated with this action is presented
in Table X.
TABLE-US-00010 TABLE X Field Size Description Action Code 1 12 -
Addressing Global Length 1 Length (not including action and length
fields) Shall be 0
[0191] The Assign Group (20) action is used to assign a STB to a
Group Identifier. Data associated with this action is presented in
Table XI.
TABLE-US-00011 TABLE XI Field Size Description Action Code 1 20 -
Assign Group Length 1 Length (not including action and length
fields) Group ID 2 The Group Identifier
[0192] The CAS Switch (21) action is used to signal a CAS Switch.
Data associated with this action is presented in Table XII.
TABLE-US-00012 TABLE XII Field Size Description Action Code 1 21 -
CAS Switch Length 1 Length (not including action and length fields)
CAS ID 4 CAS ID to switch to Activation 1 The length of the
Activation Time to follow Time Length Activation var The time at
which the CAS Switch should occur. Time There may be an encoding of
`Now,` meaning perform CAS Switch immediately on reception.
Derived Key Mechanism in SoCs
[0193] The system and method described above permits programming of
unique secrets into the SoC 114 at the SoC 114 manufacturing site
104 and permits later allocation of these SoCs 114 to any one of a
number of potential CE device manufacturers 108A and many
independent CAS/DRM vendors 108B. SoC 114 programming can also
occur at the packaging or product manufacturing facility by
execution of an in-field programming sequence on the SoC 114.
[0194] In traditional broadcast and cable system, content is
offered to subscribers within the content distribution ecosystem
directly from the service provider, i.e. satellite or cable
provider. In some embodiments, a Hardware Root of Trust Security is
offered for high value content with easy integration with a CAS and
DRM technology to enable many content providers to provide their
media programs directly to consumers using their CE devices. In
both models (i.e. traditional broadcast model versus the content
provider direct model) of content distribution, a security provider
independent architecture can support multiple concurrent or serial
CAS and DRM implementations using a single black box programming
security platform with limited One Time Programming (OTP) resources
to store secrets representing the hardware root of trust. This
security architecture implementation provides a means for
instantaneous switching between security profiles offered by
different and independent CAS and DRM security providers.
[0195] In a derived key SoC architecture providing security
providers with different security key debases is accomplished by
allowing SoCs 114 to use black box OTP resources as the basis to
derive security keys to enable different security schemes by
altering the key generation inputs based on