ETSI GS ECI 001-5-1 V1.1.1 (2017-07)

Embedded Common Interface (ECI) for exchangeable CA/DRM solutions; Part 5: The Advanced Security System; Sub-part 1: ECI specific functionalities

DGS/ECI-001-5-1

General Information

• Status: Published
• Publication Date: 26-Jul-2017
• Technical Committee: ECI - Embedded Common Interface for exchangeable CA/DRM solutions
• Current Stage: 12 - Completion
• Due Date: 20-Jun-2017
• Completion Date: 27-Jul-2017

Standards Content (Sample)

GROUP SPECIFICATION
Embedded Common Interface (ECI)
for exchangeable CA/DRM solutions;
Part 5: The Advanced Security System;
Sub-part 1: ECI specific functionalities
Disclaimer
The present document has been produced and approved by the Embedded Common Interface (ECI) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

2 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)

Reference
DGS/ECI-001-5-1
Keywords
authentication, CA, DRM, encryption, swapping

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3 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
Contents
Intellectual Property Rights . 7
Foreword . 7
Modal verbs terminology . 7
Introduction . 8
1 Scope . 9
2 References . 9
2.1 Normative references . 9
2.2 Informative references . 10
3 Definitions and abbreviations . 10
3.1 Definitions . 10
3.2 Abbreviations . 12
4 Principles . 12
4.1 Overview . 12
4.2 System Robustness Model . 14
4.3 Specification Principles . 14
4.3.1 Implementation Freedom . 14
4.3.2 Specification Style and relation to AS-API . 15
5 Key Ladder Application and Associated Functions . 15
5.1 General . 15
5.2 AS System and client data authentication . 15
5.3 Asymmetrical Micro Server mode . 15
5.4 Interface to Content Processing System . 16
5.5 AS Key Ladder Block input output definition . 17
5.6 ACF definition . 19
6 Advanced Security Slot . 20
6.1 Advanced Security Slot introduction . 20
6.2 AS Slot Definition . 20
6.2.1 General . 20
6.2.2 AS Slot state definition . 21
6.2.2.1 Slot and session state . 21
6.2.2.2 Decryption configuration . 22
6.2.2.3 Encryption Configuration . 23
6.2.2.4 Random session Key control . 24
6.2.2.5 Total session configuration . 24
6.2.2.6 Random Session Key state . 25
6.2.2.7 Import Export state . 25
6.2.3 Content Property Authentication . 26
6.2.4 AS Slot functions . 29
6.2.4.1 Overview . 29
6.2.4.2 AS Slot initialization . 30
6.2.4.3 AS Slot session and random key control. 30
6.2.4.4 AS Slot Export control . 34
6.2.4.5 LK1 Key Ladder initialization . 35
6.2.4.6 Encryption Control Word calculation . 35
6.2.4.7 Decryption Control Word calculation . 37
6.2.4.8 Computing akClient and its application . 38
6.2.4.9 AS Slot Session Configuration Authentication . 39
6.2.4.10 Loading a Micro Server secret key . 41
6.2.4.11 Generating MinitLk1 for Micro Clients . 42
6.2.4.12 Computing ECI Client image decryption key . 42
6.2.4.13 Reading Advanced Security Information . 43
6.2.4.14 Generating Client Random Numbers . 44
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4 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
6.2.4.15 Error codes . 44
7 Scrambling/descrambling and Content Export . 45
7.1 Basic Functionality . 45
7.2 Scrambler and Descrambler specifications . 45
7.3 Export Control . 46
7.4 Output Control . 46
7.5 Content Property Comparison on Coupled Sessions . 46
7.6 Content Property Propagation on Export . 46
7.7 Basic URI Enforcement on Export . 47
7.8 Content Property Application on Industry Standard Outputs . 47
7.9 Control Word Synchronization. 47
8 Certificate Processing Subsystem . 49
8.1 Basic processing rules for Certificate Chains . 49
8.2 Specific rules for Host Image Chains . 50
8.3 Specific rules for Client Image Chains . 50
8.4 Specific rules for Platform Operation Certificates . 50
8.5 Specific rules for Export/Import chains. 50
8.5.1 Export Authorization chain processing . 50
8.5.2 Export Chain verification . 51
8.5.3 Third Party Export Chain verification . 51
8.5.4 Export System Certificate processing . 51
8.5.5 Target Client Chain Processing Rules . 52
8.6 CPS ECI Root Key initialization . 52
9 Loader Core . 52
9.1 Introduction . 52
9.2 Host Loader Rules . 52
9.3 Client Loader Rules . 53
9.4 Revocation enforcement . 53
9.5 Client Image decryption . 54
10 Timing requirements . 54
10.1 Introduction . 54
10.2 Administrative Functions . 54
10.3 Symmetrical Cryptography Functions . 54
10.4 Asymmetrical Cryptography Functions . 54
Annex A (normative): Cryptography Function Definitions . 55
A.1 Hash Function . 55
A.2 Asymmetrical Cryptography . 55
A.3 Random Number Generation . 55
Annex B (informative): Sample Micro DRM system application . 56
B.1 Introduction . 56
B.2 Application scenario . 56
B.3 Assumptions and notation . 57
B.4 Micro Server pseudo code . 58
B.5 Micro Client pseudo code . 61
B.6 Micro DRM system cascading effect on ECM pre-delay . 62
B.7 Content property change timing interface convention . 62
Annex C (informative): Authors & contributors . 64
Annex D (informative): Change History . 65
History . 66
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5 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
List of Figures
Figure 4.1-1: Block diagram of Advanced Security System .13
Figure 4.2-1: System robustness premise for ECI .14
Figure 5.3-1: Computation of the Asymmetrical Micro Server mode .16
Figure B.2-1: Example of control word computation key hierarchy evolution .56
Figure B.6-1: Temporal relations for pre-delay and optional delay compensation .62

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6 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
List of Tables
Table 5.5-1: C-variable naming convention for Key Ladder interface .18
Table 5.6-1: ACF[0] for Key Ladder application .19
Table 5.6-2: AkModeField definition for AcfAk1Mode .19
Table 6.2-1: AS Slot state structure definition .21
Table 6.2-2: DecryptConfig structure definition .22
Table 6.2-3: EncryptConfig structure definition .23
Table 6.2-4: CpCtrl definition .23
Table 6.2-5: BasicUriTrfr values and description .24
Table 6.2-6: Random Key structure for decryption and encryption session .24
Table 6.2-7: EciRootState structure field description.25
Table 6.2-8: The RkState Random Key State field description .25
Table 6.2-9: ImportExportState structure definition .26
Table 6.2-10: field1 structure definition .27
Table 6.2-11: FieldControl structure definition .27
Table 6.2-12: largeProperty tag field values and meaning .28
Table 6.2-13: Overview of Advanced Security Functions .29
Table 6.2-14: Error return code definition .45

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7 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
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Foreword
This Group Specification (GS) has been produced by ETSI Industry Specification Group (ISG) Embedded Common
Interface (ECI) for exchangeable CA/DRM solutions.
The present document is part 5, sub-part 1 of a multi-part deliverable covering the ECI specific functionalities of an
advanced security system, as identified below:
Part 1: "Architecture, Definitions and Overview";
Part 2: "Use cases and requirements";
Part 3: "CA/DRM Container, Loader, Interfaces, Revocation";
Part 4: "The Virtual Machine";
Part 5: "The Advanced Security System:
Sub-part 1: "ECI specific functionalities";
Sub-part 2: "Key Ladder Block".
Part 6: "Trust Environment".
The use of terms in bold and starting with capital characters in the present document shows that those terms are defined
with an ECI specific meaning which may deviate from the common use of those terms.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
8 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
Introduction
Service and content protection realized by Conditional Access (CA) and Digital Rights Management (DRM) are
essential in the rapidly developing area of digital Broadcast and Broadband, including content, services, networks and
customer premises equipment (CPE), to protect business models of content owners, network operators and
PayTVoperators. It is also essential for consumers that they are able to continue using the CPEs they bought e.g. after a
move or a change of network provider or even utilize devices for services of different commercial video portals. This
can be achieved by the implementation of interoperable CA and DRM mechanisms inside CPEs, based on an
appropriate security architecture.
As part of a security architecture the present document defines a security processing system for the authentication and
verification of protected media content and of software images to be processed inside an ECI-compliant CPE. The core
of the security architecture is built by a Key Ladder Block that supports secure processing with secret keys, targeting
of keys to specific chips and authentication of the origin of key material.
Clause 4 gives an overview about the system architecture, defines robustness rules to fight attacks and describes the
relation between the elements of the security architecture, ECI Host and ECI Clients.
Clause 5 describes the applications the Key Ladder Block can be used for, together with the associated functions.
For proper operations, the security processing system needs information about the state of each loaded ECI Client. This
state information, as some of it needs to be secret, is handled with the help of an advanced security slot. The ECI Host
assigns to each ECI Client such a slot that needs to be protected against malicious modifications. The definition of a
slot and its configuration for several operations like decrypting or exporting content is described in clause 6.
In an ECI-compliant CPE content can be decrypted, it can be forwarded to standard outputs if permitted and it can be
re-encrypted for export. The usage of an advanced security slot for these operations is specified in clause 7.
A Certificate Processing Subsystem that is realized as a special function of an advanced security slot is responsible for
the authentication of items. Clause 8 specifies the rules that are applied for authentication.
The ECI system uses a loader mechanism that permits ECI Clients to securely verify the version of the ECI Host and
ECI Client credentials that are loaded so as to detect any known security issue. The loader mechanism relies on
robustness principles that are described in clause 9.
Clause 10 contains timing constraints for the operations described in the present document.

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9 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
1 Scope
The present document defines a robust security processing subsystem for ECI called the Advanced Security System.
The Advanced Security System provides a secure basis for software elements to be authenticated and loaded, performs
security computations and verifications, manages the encryption and decryption of content and the exchange of content
with associated rights and obligations. As such the Advanced Security System is part of a "secure video path" as it is
referred to in contemporary specifications. The Advanced Security System applies the ECI Key Ladder Block [5] to
perform secure calculations.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or non-
specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] ETSI GS ECI 001-1: "Embedded Common Interface (ECI) for exchangeable CA/DRM solutions;
Part 1: Architecture, Definitions and Overview".
[2] ETSI GS ECI 001-2: "Embedded Common Interface (ECI) for exchangeable CA/DRM solutions;
Part 2: Use cases and requirements".
[3] ETSI GS ECI 001-3: "Embedded Common Interface (ECI) for exchangeable CA/DRM solutions;
Part 3: CA/DRM Container, Loader, Interfaces, Revocation".
[4] ETSI GS ECI 001-4: "Embedded Common Interface (ECI) for exchangeable CA/DRM solutions;
Part 4: The Virtual Machine".
[5] ETSI GS ECI 001-5-2: "Embedded Common Interface (ECI) for exchangeable CA/DRM
solutions; Part 5: The Advanced Security System; Sub-part 2: Key Ladder Block".
[6] ISO/IEC 9899:2011: "Information technology - Programming languages - C".
[7] NIST FIPS PUB 180-4: "Secure Hash Standard (SHS)".
[8] NIST Special Publication 800-90A revision 1: "Recommendation for Random Number Generation
Using Deterministic Random Bit Generators", June 2015.
NOTE: Available at http://dx.doi.org/10.6028/NIST.SP.800-90Ar1.
[9] ETSI ETR 289 (CSA1/2): "Digital Video Broadcasting (DVB); Support for use of scrambling and
Conditional Access (CA) within digital broadcasting systems".
[10] ETSI TS 100 289 (V1.2.1) (CSA3): "Digital Video Broadcasting (DVB); Support for use of the
DVB Scrambling Algorithm version 3 within digital broadcasting systems".
[11] ETSI TS 103 127 (V1.1.1) (CISSA): "Digital Video Broadcasting (DVB); Content Scrambling
Algorithms for DVB-IPTV Services using MPEG2 Transport Streams".
[12] ISO/IEC 23001-7 (2016) (CENC): "Information technology - MPEG systems technologies -
Part 7: Common encryption in ISO base media file format files".
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10 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
[13] ISO/IEC 23009-4 (2013): "Information technology - Dynamic adaptive streaming over HTTP
(DASH) - Part 4: Segment encryption and authentication".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or non-
specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI: "Using the DVB CSA algorithm" (licencing arrangement).
NOTE: Available at http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/csa-licences.
[i.2] ETSI: "Using the DVB CSA3 algorithm" (licensing conditions).
NOTE: Available at http://www.etsi.org/about/what-we-do/security-algorithms-and-codes/csa3-licences.
[i.3] ETSI GR ECI 004: "Embedded Common Interface (ECI) for exchangeable CA/DRM solutions;
Guidelines for the implementation of ECI".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Advanced Security System (AS System): robust secure processing system providing basic and highly secure
processing functions for ECI Clients
AS Slot: resources of the Advanced Security block provided exclusively to an ECI Client by the ECI Host
AS-API: application programming interface between the ECI Client and its ECI Host permitting the ECI Client to
exchange information with and perform operations on its AS Slot
Authentication Mechanism: Key Ladder Block function as defined in [5] that permits an AS Slot to provide secure
key applications for purposes other than content decryption and encryption, like authentication
certificate: data with a complementary secure digital signature that identifies an Entity
NOTE: The holder of the secret key of the signature attests to the correctness of the data - authenticates it - by
signing it with its secret key. Its public key can be used to verify the data.
certificate chain: sequence of Certificates where the next Certificate can be authenticated by the public key of the
preceding one
NOTE: Typically, in ECI Certificates are accompanied by a Revocation List that excludes Certificates that
cannot be validated.
Certificate Processing Subsystem (CPS): subsystem of the ECI Host that provides Certificate verification processing
and providing additional robustness against tampering
Content Properties (CP): properties of the content that provide information on rights and obligations associated with
subsequent applications or transformations of the content, like usage rights information, selective output control and
parental control information
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11 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
ECI (Embedded CI): architecture and the system specified in the ETSI ISG "Embedded CI", which allows the
development and implementation of software-based swappable ECI Clients in customer premises equipment and thus
provides interoperability of CPE devices with respect to this system
ECI Client (Embedded CI Client): implementation of a CA/DRM client which is compliant with the ECI
specifications
ECI Client Loader: functionality of the ECI Host that uses the AS system to exclusively provide the function , verify
and install a new ECI Client software image in an ECI container of the ECI Host
ECI Host: hardware and software system of a CPE, which covers ECI related functionalities and has interfaces to an
ECI Client
ECI Host Loader: CPE bootloading functionality that uses the AS system to exclusively provide the function to verify
and install ECI Host software into a CPE
ECI Root Key: public key providing the origin of authentication for ECI certified entities and Certificates
entity: organization (e.g. manufacturer, Operator or Security Vendor) or real world item (e.g. ECI Host, Platform
Operation or ECI Client) identified by an ID in a Certificate
export connection: relation between an AS Slot decrypting content and an AS Slot subsequently re-encrypting the
decrypted content indicating such re-encryption is permitted
Key Ladder: function of the Key Ladder Block as defined in ETSI GS ECI 001-5-2 [5] for computing control words
and associated control word usage information for application in the content decryption or re-encryption function of a
CPE
Key Ladder Block: robust secure mechanism to compute decryption, encryption and authentication keys as defined in
ETSI GS ECI 001-5-2 [5], both Key Ladder and Authentication Mechanism
micro client: ECI Client or non-ECI client that can decrypt content which was re-encrypted by a Micro Server
micro DRM system: content protection system that re-encrypts content on a CPE with a Micro Server and that
permits decoding of that re-encrypted content by authenticated Micro Clients
micro server: ECI Client that encrypts such that it can only be decoded by the targeted Micro Client or group of
Micro Clients
operator: organization providing Platform Operations that is enlisted with the ECI TA for signing the ECI eco
system
NOTE: An Operator may operate multiple Platform Operations.
Platform Operation (PO): specific instance of a technical service delivery operation having a single ECI identity with
respect to security
Provisioning Server: server, typically located in a secure back office location, that provisions keys and other secure
information to facilitate an encryption or decryption function through an AS Slot
revocation: status of exclusion of an entity in accordance with its enumeration in a Revocation List
Revocation List (RL): list of Certificates that have been revoked and therefore should no longer be used
robustness: property of the implementation of a specified secure function representing the effort and/or cost involved
to compromise the security of the implemented secure function
root certificate: trusted certificate that is the origin of authentication for a chain of certificates
security vendor: company providing ECI security systems including ECI Clients for Operators of ECI Platform
Operations
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12 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACF Advanced Security Control Field
AD Input of the Key Ladder Block
AES Advanced Encryption Standard
AK Authentication Key
API Application Programming Interface
ARK Advanced Security Random Key
AS Advanced Security
CA Conditional Access
CBC Cypher Block Chaining
CENC Common Encryption
CISSA Common IPTV Software-oriented Scrambling Algorithm
CP Content Properties
CPE Customer Premises Equipment
CPS Certificate Processing Subsystem
CSA Common Scrambling Algorithm
CTR Counter Mode
CW Control Word
DRM Digital Rights Management
EAC Export Authorization Certificate
EAOC Export Authorization Operator Certificate
ECI Embedded Common Interface
ECM Entitlement Control Message
EGC Export Group Certificate
ERC Export Revocation Certificate
ESC Export System Certificate
LK Link Key
MPEG Moving Picture Experts Group
MSCSK Micro Server Chipset Secret Key
PES Packetized Elementary Stream
PO Platform Operator
POC Platform Operation Certificate
POPK Platform Operation Public Key
REAOC Revocation Export Authentication Operator Certificate
RFU Reserved for Future Use
RK Random Key
RL Revocation List
SPK Sender Public Key
TA Trust Authority
TPEGC Third Party Export Group Certificate
TS MPEG 2 Transport Stream
URI Usage Rights Information
XT eXTension field
4 Principles
4.1 Overview
The present document is part of the Multipart ISG Group Specifications ECI 001, based on the ECI architecture ETSI
GS ECI 001-1 [1] and ECI basic requirements ETSI GS ECI 001-2 [2].
Figure 4.1-1 presents the main principles of the Advanced Security System. The core of the Advanced Security
System is formed by the Key Ladder Block as defined in [5], allowing secure processing with secret keys, targeting of
keys to specific chips and authentication of the origin of key material.
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13 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
The basis for loading images is embodied in the loader core. It uses the Certificate Processing Subsystem to verify
the ECI status of ECI Host images, ECI Client images and Platform Operator (PO) credentials using a recent ECI
Root Key and ECI root Revocation List. The version numbers of the ECI Root Key and ECI root Revocation List
used by the ECI Host and other ECI Clients can be checked by ECI Clients that are loaded. These can refuse to
descramble content on detecting unacceptable versions in accordance with the ECI revocation enforcement principle.
Encrypted ECI Client images are decrypted upon loading.
Each ECI Client uses an Advanced Security slot. The AS Slot is identified by the Platform Operation Public Key of
the ECI Client. The ECI Host ensures that ECI Client interactions through the AS-API are directed to the AS Slot
allocated to that ECI Client. Each AS Slot is described by a slot state and a session state per encryption/decryption
operation. The AS Slot can be used either for decryption purposes or for encryption purposes. The AS Slot session state
also includes a configuration (config) defining the details of the operation and how the session state should be
authenticated. The ECI Client provides the configuration information and input for other state information. The Key
Ladder Block is used to authenticate SPK, POPK and the configuration information. The AS Slot can supply random
numbers to selected Key Ladder Block inputs so as to generate random keys or to use as a nonce to ensure freshly
computed Key Ladder Block inputs. This mechanism can be used to prevent replay of encrypted content and to ensure
always online provisioning of an AS Slot by a Provisioning Server.
When decrypting content the Content Properties can be authenticated along with computing the control words, thus
creating a strong link with the decrypted content. Content Properties are forwarded with the content to any standard
output to ensure the proper setting of protection mechanisms for such an output. These properties are compared to those
with which the content is re-encrypted on an Export Connection. An Export Connection is permitted only through the
appropriate export/import Certificate Chains. These are verified by the Certificate Processing Subsystem on behalf
of the AS Slot. Standard outputs can be disabled through the output control mechanism.
Computed control words can be synchronized to MPEG Transport Stream formatted content using the alternating bit
protocol. For this purpose the content processing system uses a double buffering mechanism with a current/next control
word for stream processing.
Figure 4.1-1: Block diagram of Advanced Security System
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14 ETSI GS ECI 001-5-1 V1.1.1 (2017-07)
4.2 System Robustness Model
The AS System requires a robust implementation. Robustness is typically measured in terms of the effort and/or cost
required to circumvent any security measures: i.e. observe secret values or manipulate state or values in a secure
system.
The present document does not define a specific Robustness regime for various ECI functions. Nevertheless, the ECI
Robustness architecture is based on the premise that some functions are more robust than others. This is illustrated in
Figure 4.2-1.
Outside world
CPE
Rich OS, browser based App
M
o
r
e
r
o
b
ECI Client
ECI Client
u
s
t
container container
ECI Host
AS  RootKeys
(incl. content property enforcement)
Key ladder  CSSK
Figure 4.2-1: System robustness premise for ECI
The least robust environment is the outside world where any threat may exist. Data passing through that environment
should be protected against manipulation and unauthorized inspection using authentication and encryption techniques.
The rich operating system (typically including a browser) can be somewhat robust against manipulation and invasion,
but is typically not able to withstand user-assisted or aggressive external hacking attacks. The ECI Clients and ECI
Host security sensitive functions operate in an environment that is well protected from such attacks. In case the ECI
Host is compromised also ECI Clients are compromised. In addition to resilience towards outside attacks the ECI
Clients are sandboxed using the ECI virtual machine [4]: i.e. they neither can access information in the ECI Host nor
can access any other ECI Client, apart from through defined ECI API interfaces. The ECI Host also ensures the ECI
Clients have access to the Advanced Security System and the Key Ladder Block. At the core of the Key Ladder
Block is the Chip Set Secret Key with allows each ECI CPE to be addressed uniquely. Typically the Key Ladder
Block and major parts of the Advanced Security System are implemented in hardware and/or highly robust firmware.
4.3 Specification Principles
4.3.1 Implementation Freedom
The present document defines states and functions that operate on the AS System which results in a new state. The
specific representation of the state of an implementation is not defined by the present document and
...