"keyids" Initialization Data Format

W3C Group Note

More details about this document
This version:
https://www.w3.org/TR/2024/NOTE-eme-initdata-keyids-20240718/
Latest published version:
https://www.w3.org/TR/eme-initdata-keyids/
Latest editor's draft:
https://w3c.github.io/encrypted-media/format-registry/initdata/keyids.html
History:
https://www.w3.org/standards/history/eme-initdata-keyids/
Commit history
Editors:
Joey Parrish (Google Inc.)
Greg Freedman (Netflix Inc.)
Former editors:
Mark Watson (Netflix Inc.) (Until September 2019)
David Dorwin (Google Inc.) (Until September 2017)
Jerry Smith (Microsoft Corporation) (Until September 2017)
Adrian Bateman (Microsoft Corporation) (Until May 2014)
Feedback:
GitHub w3c/encrypted-media (pull requests, new issue, open issues)
public-media-wg@w3.org with subject line [eme-initdata-keyids] … message topic … (archives)

Copyright © 2024 World Wide Web Consortium. W3C® liability, trademark and permissive document license rules apply.

Abstract

This specification defines the "keyids" initialization data format for use with the Encrypted Media Extensions [ENCRYPTED-MEDIA].

Note

It defines a stream format-independent format for specifying a list of key ID(s). This type can be used by applications to directly provide information necessary to generate a license request without using media data or constructing container-specific formats.

Status of This Document

This section describes the status of this document at the time of its publication. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

This document was published by the Media Working Group as a Group Note using the Note track.

This Group Note is endorsed by the Media Working Group, but is not endorsed by W3C itself nor its Members.

This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

The W3C Patent Policy does not carry any licensing requirements or commitments on this document.

This document is governed by the 03 November 2023 W3C Process Document.

1. Format

The format is a JSON object, encoded in UTF-8 as specified in the Encoding specification [encoding], containing the following member:

"kids"
An array of key ID(s). Each element of the array is the base64url encoding of the octet sequence containing the key ID value.
Note

See Using base64url.

Note

Applications may encode the JSON string using the TextEncoder interface [encoding].

2. Example

This section is non-normative.

The following example will generate a license request for two key ID(s). (Line breaks are for readability only.)

Example 1 
{
  "kids":
    [
     "LwVHf8JLtPrv2GUXFW2v_A",
     "0DdtU9od-Bh5L3xbv0Xf_A"
    ]
}

3. Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

A. References

A.1 Normative references

[encoding]
Encoding Standard. Anne van Kesteren. WHATWG. Living Standard. URL: https://encoding.spec.whatwg.org/
[ENCRYPTED-MEDIA]
Encrypted Media Extensions. David Dorwin; Jerry Smith; Mark Watson; Adrian Bateman. W3C. 18 September 2017. W3C Recommendation. URL: https://www.w3.org/TR/encrypted-media/

A.2 Informative references

[eme-initdata-cenc]
"cenc" Initialization Data Format. David Dorwin; Adrian Bateman; Mark Watson; Jerry Smith. W3C. 15 September 2016. W3C Working Group Note. URL: https://www.w3.org/TR/eme-initdata-cenc/