Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The MediaKeySession interface of the Encrypted Media Extensions API represents a context for message exchange with a content decryption module (CDM).

EventTarget MediaKeySession

Instance properties

MediaKeySession.closed Read only

Returns a Promise signaling when a MediaKeySession closes. This promise can only be fulfilled and is never rejected. Closing a session means that licenses and keys associated with it are no longer valid for decrypting media data.

MediaKeySession.expiration Read only

The time after which the keys in the current session can no longer be used to decrypt media data, or NaN if no such time exists. This value is determined by the CDM and measured in milliseconds since January 1, 1970, UTC. This value may change during a session lifetime, such as when an action triggers the start of a window.

MediaKeySession.keyStatuses Read only

Contains a reference to a read-only MediaKeyStatusMap of the current session's keys and their statuses.

MediaKeySession.sessionId Read only

Contains a unique string generated by the CDM for the current media object and its associated keys or licenses.



Fires when there has been a change in the keys in a session or their statuses.


Fires when the content decryption module has generated a message for the session.

Instance methods


Returns a Promise after notifying the current media session is no longer needed and that the CDM should release any resources associated with this object and close it.


Returns a Promise after generating a media request based on initialization data.


Returns a Promise that resolves to a boolean value after loading data for a specified session object.


Returns a Promise after removing any session data associated with the current object.


Returns a Promise after loading messages and licenses to the CDM.


// TBD


Encrypted Media Extensions
# mediakeysession-interface

Browser compatibility

BCD tables only load in the browser