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Key System Registry


This registry is intended to enhance interoperability among implementations and users of Key Systems as employed by the Encrypted Media Extension (EME). In particular, this registry provides the means (1) to identify and avoid name collisions among Key Systems, (2) to categorize Key Systems according to their openness, and (3) to disclose specifications or information about further details of Key Systems in order to promote interoperability.


The overall Key System Registry defined here is divided into two sub-registries:

  • Open Key System Registry
  • Non-Open Key System Registry

An "Open" Key System is one believed to be implementable according to some standard of openness. A "Non-Open" Key System is one believed to not satisfy such a standard. Since there is no single, universally accepted definition of openness, no specific definition is adopted here.

The determination of whether a Key System is listed as an Open Key System Registry or a Non-Open Key System is made by the registrant themselves when they create (or request creation of) a registry entry. More specifically, neither the W3C nor its members are asked to endorse or withhold endorsement of a given registry entry as being Open or Non-Open.

If an entry is placed in the Open Key System Registry, then the registrant must be prepared to justify it being labeled as such.

N.B. This registry is not intended to include any information on whether a Key System is encumbered by intellectual property claims. Implementers and users are advised to seek appropriate legal counsel in this matter if they intend to implement or use a specific Key System.

Registration Entry Requirements

  1. Each registry entry must include a unique identification which must take the form of a reversed DNS domain name that is (at the time of registration) held by the registrant or their agent.
  2. Each entry listed as an Open Key System must include a link that references a public available specification (PAS) which the registrant believes satisfies some standard of openness. It is recommended that such a specification be made available without cost (other than reasonable shipping and handling if not available by online means).
  3. Each entry listed as a Non-Open Key System is encouraged to include a link that references some form of publicly available information about the Key System.
  4. Registrations for keysystems that may be implemented using publicly specified and available APIs to an Operating System or platform-provided CDM capability MUST provide a reference to a publicly available specification(s) detailing the mapping between EME APIs and the relevant platform APIs, sufficient for independent interoperable implementation of the keysystem using those platform APIs.

If a registration fails to satisfy a mandatory requirement specified above, then it may be removed from the registry (without prejudice).

Open Key System Registry

Identifier Name Public Specification(s)
org.w3.clearkey Clear Key EME ED

Non-Open Key System Registry

Identifier Name Public Reference(s)
org.example.private Private System
Last modified on 27 August 2013, at 15:07