ETSI TS 103 799 V1.1.1 (2021-04)

Publicly Available Specification (PAS); DASH-IF Content Protection Information Exchange Format

DTS/JTC-060

General Information

• Status: Not Published
• Technical Committee: BROADCAS - EBU/CENELEC/ETSI on Broadcasting
• Current Stage: 12 - Completion
• Due Date: 08-Apr-2021
• Completion Date: 13-Apr-2021

Standards Content (Sample)

ETSI TS 103 799 V1.1.1 (2021-04)






TECHNICAL SPECIFICATION
Publicly Available Specification (PAS);
DASH-IF Content Protection Information Exchange Format





CAUTION
The present document has been submitted to ETSI as a PAS produced by DASH-IF and
approved by the Joint Technical Committee (JTC) Broadcast of the European Broadcasting Union (EBU), Comité Européen de
Normalisation ELECtrotechnique (CENELEC) and the European Telecommunications Standards Institute (ETSI).
DASH-IF is owner of the copyright of the document DASH-IF CPIX and/or had all relevant rights and had assigned said rights to ETSI
on an "as is basis". Consequently, to the fullest extent permitted by law, ETSI disclaims all warranties whether express, implied,
statutory or otherwise including but not limited to merchantability, non-infringement of any intellectual property rights of third parties.
No warranty is given about the accuracy and the completeness of the content of the present document.

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2 ETSI TS 103 799 V1.1.1 (2021-04)



Reference
DTS/JTC-060
Keywords
DASH, encryption, internet, PAS, video

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®
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ETSI

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3 ETSI TS 103 799 V1.1.1 (2021-04)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 8
4 Use Cases and Requirements . 9
4.1 Introduction . 9
4.2 Overview of the End-to-End Architecture . 9
4.3 Use Cases for the Preparation of Content . 11
4.3.1 Introduction. 11
4.3.2 On-Demand Content . 11
4.3.3 Live Content . 12
4.3.4 Catch-up . 12
4.3.5 Electronic Sell Through . 12
4.4 Exchange over an Interface . 13
4.4.1 Introduction. 13
4.4.2 Content Key Delivery to One Entity . 13
4.4.3 Secure Content Key Delivery to Several Entities . 13
4.4.4 Content Key Delivery with Usage Rules . 13
4.4.4.1 Introduction . 13
4.4.4.2 Label Filter . 14
4.4.4.3 Key Period Filter . 14
4.4.4.4 Policy-based Filters . 14
4.4.5 Content Key Delivery with DRM Signaling . 14
4.4.6 Incremental Update and Extension of the document . 15
4.4.7 Content Key Hierarchy Delivery for Content Packaging. 15
4.4.8 Root Key Delivery for License Server Operation . 16
4.5 Workflow Examples . 16
4.5.1 Encryptor Producer and Encryptor Consumer . 16
4.5.1.1 Introduction . 16
4.5.1.2 Encryptor Producer . 17
4.5.1.3 Encryptor Consumer . 17
4.5.1.4 Multiple Producers . 18
5 XSD Schema Definition . 19
5.1 Introduction . 19
5.2 Requirements . 19
5.3 Structure Overview. 20
5.4 Hierarchical Data Model . 22
5.4.1 Introduction. 22
5.4.2 CPIX Element . 22
5.4.3 DeliveryDataList Element . 23
5.4.4 DeliveryData Element . 24
5.4.5 ContentKeyList Element . 26
5.4.6 ContentKey Element . 26
5.4.7 DRMSystemList Element . 29
5.4.8 DRMSystem Element . 29
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4 ETSI TS 103 799 V1.1.1 (2021-04)
5.4.9 HLSSignalingData Element . 31
5.4.10 ContentKeyPeriodList Element . 32
5.4.11 ContentKeyPeriod Element . 33
5.4.12 ContentKeyUsageRuleList Element . 33
5.4.13 ContentKeyUsageRule Element . 34
5.4.14 Usage Rules Filters . 35
5.4.14.1 Introduction . 35
5.4.14.2 KeyPeriodFilter Element . 36
5.4.14.3 LabelFilter Element . 36
5.4.14.4 VideoFilter Element . 37
5.4.14.5 AudioFilter Element . 38
5.4.14.6 BitrateFilter Element . 39
5.4.15 UpdateHistoryItemList Element . 39
5.4.16 UpdateHistoryItem Element . 40
6 Key Management . 41
6.1 Key Encryption in the CPIX Document . 41
6.1.1 Introduction. 41
6.1.2 Keys Used to Secure the CPIX Document . 41
6.1.3 Authenticated Encryption . 42
6.1.4 Digital Signature . 42
6.1.5 Mandatory Algorithms . 42
6.2 Key Rotation Support . 43
6.3 Hierarchical Keys . 43
Annex A (normative): CPIX XSD Schema . 44
History . 48


ETSI

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5 ETSI TS 103 799 V1.1.1 (2021-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European
Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique (CENELEC) and the European
Telecommunications Standards Institute (ETSI).
NOTE: The EBU/ETSI JTC Broadcast was established in 1990 to co-ordinate the drafting of standards in the
specific field of broadcasting and related fields. Since 1995 the JTC Broadcast became a tripartite body
by including in the Memorandum of Understanding also CENELEC, which is responsible for the
standardization of radio and television receivers. The EBU is a professional association of broadcasting
organizations whose work includes the co-ordination of its members' activities in the technical, legal,
programme-making and programme-exchange domains. The EBU has active members in about
60 countries in the European broadcasting area; its headquarters is in Geneva.
European Broadcasting Union
CH-1218 GRAND SACONNEX (Geneva)
Switzerland
Tel: [phone]
Fax: [phone]
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

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6 ETSI TS 103 799 V1.1.1 (2021-04)
Introduction
The present document defines a container allowing the exchange between entities of content protection information
typically made of keys used for encrypting content and any associated DRM specific information. There may be one or
several keys and these keys may be protected by one or several DRMs, hence there may be one or several DRM specific
information. There is no assumption on the entities exchanging this information, but it is not expected that a client
device will use this exchange format. The goal is to allow entities involved in the content preparation workflow to get
the content protection information so that, for example a DASH MPD can be generated with all content protection
information.
Because the defined container is not made for a specifically defined content preparation workflow but is generic,
conformance is not considered to be a critical part of CPIX. As a consequence, no conformance is defined for the
present document.

ETSI

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7 ETSI TS 103 799 V1.1.1 (2021-04)
1 Scope
The scope of the present document is to define a Content Protection Information Exchange (CPIX) Format. A CPIX
document contains keys and DRM information used for encrypting and protecting content and can be used for
exchanging this information among entities needing it in many possibly different workflows for preparing, for example,
DASH or HLS content. The CPIX document itself can be encrypted, signed and authenticated so that its receivers can
be sure that its confidentiality, source and integrity are also protected.
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] Guidelines for Implementation: "DASH-IF Interoperability Points", version 4.3, November 2018.
NOTE: Available at https://dashif.org/guidelines/.
[2] DASH-IF registry of DRM System IDs.
NOTE: Available at https://dashif.org/identifiers/content_protection/.
[3] IETF RFC 6030: "Portable Symmetric Key Container (PSKC)", October 2010.
®
[4] W3C Recommendation 5 April 2012: "W3C XML Schema Definition Language (XSD) 1.1
Part 2: Datatypes", David Peterson et al.
NOTE: Available at https://www.w3.org/TR/xmlschema11-2/.
®
[5] W3C Recommendation 11 April 2013: "XML Encryption Syntax and Processing Version 1.1",
Donald Eastlake, Joseph Reagle, 10 December 2002.
NOTE: Available at https://www.w3.org/TR/xmlenc-core/.
®
[6] W3C Recommendation 11 April 2013: " XML Signature Syntax and Processing Version 1.1",
Donald Eastlake, Joseph Reagle, David Solo, et al. (Second Edition). 10 June 2008.
NOTE: Available at https://www.w3.org/TR/xmldsig-core/.
[7] ISO/IEC 23001-7:2016: "Information technology -- MPEG systems technologies --
Part 7: Common encryption in ISO base media file format files", February 2016.
NOTE: Available at https://www.iso.org/standard/68042.html.
ETSI

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8 ETSI TS 103 799 V1.1.1 (2021-04)
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.
Not applicable.
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
content: one or more audio-visual elementary streams and the associated MPD if in DASH format
content key: cryptographic key used for encrypting part of the content
content key context: portion of a media stream which is encrypted with a specific content key
content protection: mechanism ensuring that only authorized devices get access to content
document key: cryptographic key used for encrypting the content key(s) in the CPIX document
DRM signaling: DRM specific information to be added in content for proper operation of the DRM system when
authorizing a device for this content
NOTE: It is made of proprietary information for licensing and key retrieval.
Protection System Specific Header (PSSH): part of an ISO BMFF file
NOTE: This box contains DRM Signaling.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AES Advanced Encryption Standard
BMFF Base Media File Format
CBC Cypher Block Chaining
CDN Content Delivery Network
CMS Content Management System
CPIX Content Protection Information eXchange
DASH Dynamic Adaptive Streaming over HTTP
DRM Digital Right Management
EPG Electronic Program Guide
FPS Frames Per Second
HD High Definition
HDR High Dynamic Range
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9 ETSI TS 103 799 V1.1.1 (2021-04)
HDS HTTP Dynamic Streaming
HLS HTTP Live Streaming
ISO International Organization for Standardization
IV Initialization Vector
KID Key IDentifier
MAC Message Authentication Code
MPD Media Presentation Description
OD Optional with Default value
PKCS Public Key Cryptography Standards
PSSH Protection System Specific Header
RSA Rivest, Shamir, & Adleman
SD Standard Definition
SHA Secure Hash Algorithm
UHD Ultra High Definition
URI Uniform Ressource Identifier
UUID Universally Unique IDentifier
VOD Video On Demand
WCG Wide Color Gamut
XML eXtensible Markup Language
XSD XML Schema Definition
4 Use Cases and Requirements
4.1 Introduction
Content Keys and DRM Signaling, a.k.a. content protection information, need to be created and exchanged between
some system entities when preparing Content. The flows of information are of very different nature depending on where
Content Keys are created and also depending on the type of Content that can be either On-Demand or Live.
This clause presents different use cases where such exchanges are required. Clause 4.2 is an overview of the general
context in which exchange of content protection information is happening, clause 4.3 describes some workflows for
content creation and clause 4.4 goes in the details of how content protection information can be exchanged over an
interface between two entities.
4.2 Overview of the End-to-End Architecture
This clause gives a general overview of the context in which content protection information needs to be exchanged
between entities in the backend. It completes clause 7.5 of [1] by putting more emphasis on the backend aspects.
This clause takes DASH content as an example for providing more specific and clear understanding, but this can be
generalized to other streaming formats, such as HLS.
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10 ETSI TS 103 799 V1.1.1 (2021-04)
Content
Provider
DRM Service Encoder
DRM Information
Player & Packager
DRM Client Encryptor
Manifest
Creator

Figure 1: Logical roles that exchange DRM information and media
Figure 1 shows logical entities that may send or receive DRM information such as media keys, asset identifiers,
licenses, and license acquisition information. A physical entity may combine multiple logical roles, and the point of
origin for information, such as media keys and asset identifiers, can differ; so various information flows are possible.
This is an example of how the roles are distributed to facilitate the description of workflow and use cases. Alternative
roles and functions can be applied to create conformant content. The different roles are:
• Content Provider: A publisher who provides the rights and rules for delivering protected media, also possibly
source media (mezzanine format, for transcoding), asset identifiers, key identifiers (KID), key values,
encoding instructions, and content description metadata.
• Encoder: A service provider who encodes media in a specified set of formats with different bitrates,
resolutions, etc., possibly determined by the publisher.
• Packager/Encryptor: A service provider who encrypts and packages media, inserting DRM Signaling and
metadata into the media files. In the case of DASH packaging, this consists of adding the default_KID in the
file header tenc box, initialization vectors and subsample byte ranges in track fragments indexed by saio and
saiz boxes, and possibly one or more PSSH boxes containing license acquisition information (from the DRM
Service). Tracks that are partially encrypted or encrypted with multiple keys require sample to group boxes
and sample group description boxes in each track fragment to associate different KIDs to groups of samples.
The Packager could originate values for KIDs, Content Keys, encryption layout, etc., then send that
information to other entities that need it, including the DRM Service and Streamer, and probably the Content
Provider. However, the Packager could receive that information from a different point of origin, such as the
Content Provider or DRM Service.
• Manifest Creator: A service provider which generates the media manifests which group the various media
files into a coherent presentation. These manifest files may contain DRM Signaling information. For DASH,
the MPD Creator is assumed to create one or more types of DASH MPD files and provide indexing of
Segments and/or sidx indexes for download so that players can byte range index Subsegments. The MPD
shall include descriptors for Common Encryption and DRM key management systems and should include
identification of the @default_KID for each AdaptationSet element, and sufficient information in UUID
ContentProtection elements to acquire a DRM license. The @default_KID is available from the
Packager and any other role that created it, and the DRM specific information is available from the DRM
Service.
• DRM Client: It gets information from different sources: media manifest files, media files, and DRM licenses.
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11 ETSI TS 103 799 V1.1.1 (2021-04)
• DRM Service: The DRM Service creates licenses containing a protected Content Key that can only be
decrypted by a trusted DRM Client.
The DRM Service needs to know the @
...