public
final
class
MediaDrm
extends Object
java.lang.Object | |
↳ | android.media.MediaDrm |
MediaDrm can be used to obtain keys for decrypting protected media streams, in
conjunction with MediaCrypto
. The MediaDrm APIs
are designed to support the ISO/IEC 23001-7: Common Encryption standard, but
may also be used to implement other encryption schemes.
Encrypted content is prepared using an encryption server and stored in a content library. The encrypted content is streamed or downloaded from the content library to client devices via content servers. Licenses to view the content are obtained from a License Server.
Keys are requested from the license server using a key request. The key response is delivered to the client app, which provides the response to the MediaDrm API.
A Provisioning server may be required to distribute device-unique credentials to the devices.
Enforcing requirements related to the number of devices that may play content simultaneously can be performed either through key renewal or using the secure stop methods.
The following sequence diagram shows the interactions between the objects involved while playing back encrypted content:
The app first constructs MediaExtractor
and
MediaCodec
objects. It accesses the DRM-scheme-identifying UUID,
typically from metadata in the content, and uses this UUID to construct an instance
of a MediaDrm object that is able to support the DRM scheme required by the content.
Crypto schemes are assigned 16 byte UUIDs. The method isCryptoSchemeSupported(UUID)
can be used to query if a given scheme is supported on the device.
The app calls openSession()
to generate a sessionId that will uniquely identify
the session in subsequent interactions. The app next uses the MediaDrm object to
obtain a key request message and send it to the license server, then provide
the server's response to the MediaDrm object.
Once the app has a sessionId, it can construct a MediaCrypto object from the UUID and
sessionId. The MediaCrypto object is registered with the MediaCodec in the
configure(MediaFormat, Surface, MediaCrypto, int)
method to enable the codec to decrypt content.
When the app has constructed MediaExtractor
,
MediaCodec
and MediaCrypto
objects,
it proceeds to pull samples from the extractor and queue them into the decoder. For
encrypted content, the samples returned from the extractor remain encrypted, they
are only decrypted when the samples are delivered to the decoder.
MediaDrm methods throw MediaDrm.MediaDrmStateException
when a method is called on a MediaDrm object that has had an unrecoverable failure
in the DRM plugin or security hardware.
MediaDrm.MediaDrmStateException
extends
IllegalStateException
with the addition of a developer-readable
diagnostic information string associated with the exception.
In the event of a mediaserver process crash or restart while a MediaDrm object
is active, MediaDrm methods may throw MediaDrmResetException
.
To recover, the app must release the MediaDrm object, then create and initialize
a new one.
As MediaDrmResetException
and
MediaDrm.MediaDrmStateException
both extend
IllegalStateException
, they should be in an earlier catch()
block than IllegalStateException
if handled separately.
Applications should register for informational events in order
to be informed of key state updates during playback or streaming.
Registration for these events is done via a call to
setOnEventListener(MediaDrm.OnEventListener)
. In order to receive the respective
callback associated with this listener, applications are required to create
MediaDrm objects on a thread with its own Looper running (main UI
thread by default has a Looper running).
Nested classes | |
---|---|
class |
MediaDrm.CryptoSession
In addition to supporting decryption of DASH Common Encrypted Media, the MediaDrm APIs provide the ability to securely deliver session keys from an operator's session key server to a client device, based on the factory-installed root of trust, and then perform encrypt, decrypt, sign and verify operations with the session key on arbitrary user data. |
class |
MediaDrm.KeyRequest
Contains the opaque data an app uses to request keys from a license server |
class |
MediaDrm.KeyStatus
Defines the status of a key. |
class |
MediaDrm.MediaDrmStateException
Thrown when an unrecoverable failure occurs during a MediaDrm operation. |
interface |
MediaDrm.OnEventListener
Interface definition for a callback to be invoked when a drm event occurs |
interface |
MediaDrm.OnExpirationUpdateListener
Interface definition for a callback to be invoked when a drm session expiration update occurs |
interface |
MediaDrm.OnKeyStatusChangeListener
Interface definition for a callback to be invoked when the keys in a drm session change states. |
class |
MediaDrm.ProvisionRequest
Contains the opaque data an app uses to request a certificate from a provisioning server |
Constants | |
---|---|
int |
EVENT_KEY_EXPIRED
This event type indicates that the licensed usage duration for keys in a session has expired. |
int |
EVENT_KEY_REQUIRED
This event type indicates that the app needs to request keys from a license server. |
int |
EVENT_PROVISION_REQUIRED
This constant was deprecated
in API level 23.
Handle provisioning via |
int |
EVENT_SESSION_RECLAIMED
This event indicates that a session opened by the app has been reclaimed by the resource manager. |
int |
EVENT_VENDOR_DEFINED
This event may indicate some specific vendor-defined condition, see your DRM provider documentation for details |
int |
KEY_TYPE_OFFLINE
This key request type specifies that the keys will be for offline use, they will be saved to the device for use when the device is not connected to a network. |
int |
KEY_TYPE_RELEASE
This key request type specifies that previously saved offline keys should be released. |
int |
KEY_TYPE_STREAMING
This key request type species that the keys will be for online use, they will not be saved to the device for subsequent use when the device is not connected to a network. |
String |
PROPERTY_ALGORITHMS
String property name: a comma-separated list of cipher and mac algorithms supported by CryptoSession. |
String |
PROPERTY_DESCRIPTION
String property name: describes the DRM engine plugin |
String |
PROPERTY_DEVICE_UNIQUE_ID
Byte array property name: the device unique identifier is established during device provisioning and provides a means of uniquely identifying each device. |
String |
PROPERTY_VENDOR
String property name: identifies the maker of the DRM engine plugin |
String |
PROPERTY_VERSION
String property name: identifies the version of the DRM engine plugin |
Public constructors | |
---|---|
MediaDrm(UUID uuid)
Instantiate a MediaDrm object |
Public methods | |
---|---|
void
|
closeSession(byte[] sessionId)
Close a session on the MediaDrm object that was previously opened
with |
MediaDrm.CryptoSession
|
getCryptoSession(byte[] sessionId, String cipherAlgorithm, String macAlgorithm)
Obtain a CryptoSession object which can be used to encrypt, decrypt,
sign and verify messages or data using the session keys established
for the session using methods |
MediaDrm.KeyRequest
|
getKeyRequest(byte[] scope, byte[] init, String mimeType, int keyType, HashMap<String, String> optionalParameters)
A key request/response exchange occurs between the app and a license server to obtain or release keys used to decrypt encrypted content. |
byte[]
|
getPropertyByteArray(String propertyName)
Read a DRM engine plugin byte array property value, given the property name string. |
String
|
getPropertyString(String propertyName)
Read a DRM engine plugin String property value, given the property name string. |
MediaDrm.ProvisionRequest
|
getProvisionRequest()
A provision request/response exchange occurs between the app and a provisioning server to retrieve a device certificate. |
byte[]
|
getSecureStop(byte[] ssid)
Access secure stop by secure stop ID. |
List<byte[]>
|
getSecureStops()
A means of enforcing limits on the number of concurrent streams per subscriber across devices is provided via SecureStop. |
static
final
boolean
|
isCryptoSchemeSupported(UUID uuid, String mimeType)
Query if the given scheme identified by its UUID is supported on this device, and whether the drm plugin is able to handle the media container format specified by mimeType. |
static
final
boolean
|
isCryptoSchemeSupported(UUID uuid)
Query if the given scheme identified by its UUID is supported on this device. |
byte[]
|
openSession()
Open a new session with the MediaDrm object. |
byte[]
|
provideKeyResponse(byte[] scope, byte[] response)
A key response is received from the license server by the app, then it is provided to the DRM engine plugin using provideKeyResponse. |
void
|
provideProvisionResponse(byte[] response)
After a provision response is received by the app, it is provided to the DRM engine plugin using this method. |
HashMap<String, String>
|
queryKeyStatus(byte[] sessionId)
Request an informative description of the key status for the session. |
final
void
|
release()
|
void
|
releaseAllSecureStops()
Remove all secure stops without requiring interaction with the server. |
void
|
releaseSecureStops(byte[] ssRelease)
Process the SecureStop server response message ssRelease. |
void
|
removeKeys(byte[] sessionId)
Remove the current keys from a session. |
void
|
restoreKeys(byte[] sessionId, byte[] keySetId)
Restore persisted offline keys into a new session. |
void
|
setOnEventListener(MediaDrm.OnEventListener listener)
Register a callback to be invoked when an event occurs |
void
|
setOnExpirationUpdateListener(MediaDrm.OnExpirationUpdateListener listener, Handler handler)
Register a callback to be invoked when a session expiration update occurs. |
void
|
setOnKeyStatusChangeListener(MediaDrm.OnKeyStatusChangeListener listener, Handler handler)
Register a callback to be invoked when the state of keys in a session change, e.g. |
void
|
setPropertyByteArray(String propertyName, byte[] value)
Set a DRM engine plugin byte array property value. |
void
|
setPropertyString(String propertyName, String value)
Set a DRM engine plugin String property value. |
Protected methods | |
---|---|
void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
int EVENT_KEY_EXPIRED
This event type indicates that the licensed usage duration for keys in a session has expired. The keys are no longer valid.
Constant Value: 3 (0x00000003)
int EVENT_KEY_REQUIRED
This event type indicates that the app needs to request keys from a license
server. The request message data is obtained using getKeyRequest(byte[], byte[], String, int, HashMap
.
Constant Value: 2 (0x00000002)
int EVENT_PROVISION_REQUIRED
This constant was deprecated
in API level 23.
Handle provisioning via NotProvisionedException
instead.
This event type indicates that the app needs to request a certificate from
the provisioning server. The request message data is obtained using
getProvisionRequest()
Constant Value: 1 (0x00000001)
int EVENT_SESSION_RECLAIMED
This event indicates that a session opened by the app has been reclaimed by the resource manager.
Constant Value: 5 (0x00000005)
int EVENT_VENDOR_DEFINED
This event may indicate some specific vendor-defined condition, see your DRM provider documentation for details
Constant Value: 4 (0x00000004)
int KEY_TYPE_OFFLINE
This key request type specifies that the keys will be for offline use, they will be saved to the device for use when the device is not connected to a network.
Constant Value: 2 (0x00000002)
int KEY_TYPE_RELEASE
This key request type specifies that previously saved offline keys should be released.
Constant Value: 3 (0x00000003)
int KEY_TYPE_STREAMING
This key request type species that the keys will be for online use, they will not be saved to the device for subsequent use when the device is not connected to a network.
Constant Value: 1 (0x00000001)
String PROPERTY_ALGORITHMS
String property name: a comma-separated list of cipher and mac algorithms supported by CryptoSession. The list may be empty if the DRM engine plugin does not support CryptoSession operations.
Constant Value: "algorithms"
String PROPERTY_DESCRIPTION
String property name: describes the DRM engine plugin
Constant Value: "description"
String PROPERTY_DEVICE_UNIQUE_ID
Byte array property name: the device unique identifier is established during device provisioning and provides a means of uniquely identifying each device.
Constant Value: "deviceUniqueId"
String PROPERTY_VENDOR
String property name: identifies the maker of the DRM engine plugin
Constant Value: "vendor"
String PROPERTY_VERSION
String property name: identifies the version of the DRM engine plugin
Constant Value: "version"
MediaDrm (UUID uuid)
Instantiate a MediaDrm object
Parameters | |
---|---|
uuid |
UUID :
The UUID of the crypto scheme. |
Throws | |
---|---|
UnsupportedSchemeException |
if the device does not support the specified scheme UUID |
void closeSession (byte[] sessionId)
Close a session on the MediaDrm object that was previously opened
with openSession()
.
Parameters | |
---|---|
sessionId |
byte
|
MediaDrm.CryptoSession getCryptoSession (byte[] sessionId, String cipherAlgorithm, String macAlgorithm)
Obtain a CryptoSession object which can be used to encrypt, decrypt,
sign and verify messages or data using the session keys established
for the session using methods getKeyRequest(byte[], byte[], String, int, HashMap
and
provideKeyResponse(byte[], byte[])
using a session key server.
Parameters | |
---|---|
sessionId |
byte :
the session ID for the session containing keys
to be used for encrypt, decrypt, sign and/or verify |
cipherAlgorithm |
String :
the algorithm to use for encryption and
decryption ciphers. The algorithm string conforms to JCA Standard
Names for Cipher Transforms and is case insensitive. For example
"AES/CBC/NoPadding". |
macAlgorithm |
String :
the algorithm to use for sign and verify
The algorithm string conforms to JCA Standard Names for Mac
Algorithms and is case insensitive. For example "HmacSHA256".
The list of supported algorithms for a DRM engine plugin can be obtained
using the method |
Returns | |
---|---|
MediaDrm.CryptoSession |
MediaDrm.KeyRequest getKeyRequest (byte[] scope, byte[] init, String mimeType, int keyType, HashMap<String, String> optionalParameters)
A key request/response exchange occurs between the app and a license server to obtain or release keys used to decrypt encrypted content.
getKeyRequest() is used to obtain an opaque key request byte array that is delivered to the license server. The opaque key request byte array is returned in KeyRequest.data. The recommended URL to deliver the key request to is returned in KeyRequest.defaultUrl.
After the app has received the key request response from the server,
it should deliver to the response to the DRM engine plugin using the method
provideKeyResponse(byte[], byte[])
.
Parameters | |
---|---|
scope |
byte :
may be a sessionId or a keySetId, depending on the specified keyType.
When the keyType is KEY_TYPE_STREAMING or KEY_TYPE_OFFLINE,
scope should be set to the sessionId the keys will be provided to. When the keyType
is KEY_TYPE_RELEASE, scope should be set to the keySetId of the keys
being released. Releasing keys from a device invalidates them for all sessions. |
init |
byte :
container-specific data, its meaning is interpreted based on the
mime type provided in the mimeType parameter. It could contain, for example,
the content ID, key ID or other data obtained from the content metadata that is
required in generating the key request. init may be null when keyType is
KEY_TYPE_RELEASE. |
mimeType |
String :
identifies the mime type of the content |
keyType |
int :
specifes the type of the request. The request may be to acquire
keys for streaming or offline content, or to release previously acquired
keys, which are identified by a keySetId. |
optionalParameters |
HashMap :
are included in the key request message to
allow a client application to provide additional message parameters to the server.
This may be null if no additional parameters are to be sent. |
Returns | |
---|---|
MediaDrm.KeyRequest |
Throws | |
---|---|
NotProvisionedException |
if reprovisioning is needed, due to a problem with the certifcate |
byte[] getPropertyByteArray (String propertyName)
Read a DRM engine plugin byte array property value, given the property name string.
Standard fields names are PROPERTY_DEVICE_UNIQUE_ID
Parameters | |
---|---|
propertyName |
String
|
Returns | |
---|---|
byte[] |
String getPropertyString (String propertyName)
Read a DRM engine plugin String property value, given the property name string.
Standard fields names are:
PROPERTY_VENDOR
, PROPERTY_VERSION
,
PROPERTY_DESCRIPTION
, PROPERTY_ALGORITHMS
Parameters | |
---|---|
propertyName |
String
|
Returns | |
---|---|
String |
MediaDrm.ProvisionRequest getProvisionRequest ()
A provision request/response exchange occurs between the app and a provisioning server to retrieve a device certificate. If provisionining is required, the EVENT_PROVISION_REQUIRED event will be sent to the event handler. getProvisionRequest is used to obtain the opaque provision request byte array that should be delivered to the provisioning server. The provision request byte array is returned in ProvisionRequest.data. The recommended URL to deliver the provision request to is returned in ProvisionRequest.defaultUrl.
Returns | |
---|---|
MediaDrm.ProvisionRequest |
byte[] getSecureStop (byte[] ssid)
Access secure stop by secure stop ID.
Parameters | |
---|---|
ssid |
byte :
- The secure stop ID provided by the license server.
|
Returns | |
---|---|
byte[] |
List<byte[]> getSecureStops ()
A means of enforcing limits on the number of concurrent streams per subscriber across devices is provided via SecureStop. This is achieved by securely monitoring the lifetime of sessions.
Information from the server related to the current playback session is written to persistent storage on the device when each MediaCrypto object is created.
In the normal case, playback will be completed, the session destroyed and the Secure Stops will be queried. The app queries secure stops and forwards the secure stop message to the server which verifies the signature and notifies the server side database that the session destruction has been confirmed. The persisted record on the client is only removed after positive confirmation that the server received the message using releaseSecureStops().
Returns | |
---|---|
List<byte[]> |
boolean isCryptoSchemeSupported (UUID uuid, String mimeType)
Query if the given scheme identified by its UUID is supported on this device, and whether the drm plugin is able to handle the media container format specified by mimeType.
Parameters | |
---|---|
uuid |
UUID :
The UUID of the crypto scheme. |
mimeType |
String :
The MIME type of the media container, e.g. "video/mp4"
or "video/webm"
|
Returns | |
---|---|
boolean |
boolean isCryptoSchemeSupported (UUID uuid)
Query if the given scheme identified by its UUID is supported on this device.
Parameters | |
---|---|
uuid |
UUID :
The UUID of the crypto scheme.
|
Returns | |
---|---|
boolean |
byte[] openSession ()
Open a new session with the MediaDrm object. A session ID is returned.
Returns | |
---|---|
byte[] |
Throws | |
---|---|
NotProvisionedException |
if provisioning is needed |
ResourceBusyException |
if required resources are in use |
byte[] provideKeyResponse (byte[] scope, byte[] response)
A key response is received from the license server by the app, then it is
provided to the DRM engine plugin using provideKeyResponse. When the
response is for an offline key request, a keySetId is returned that can be
used to later restore the keys to a new session with the method
restoreKeys(byte[], byte[])
.
When the response is for a streaming or release request, null is returned.
Parameters | |
---|---|
scope |
byte :
may be a sessionId or keySetId depending on the type of the
response. Scope should be set to the sessionId when the response is for either
streaming or offline key requests. Scope should be set to the keySetId when
the response is for a release request. |
response |
byte :
the byte array response from the server |
Returns | |
---|---|
byte[] |
Throws | |
---|---|
NotProvisionedException |
if the response indicates that reprovisioning is required |
DeniedByServerException |
if the response indicates that the server rejected the request |
void provideProvisionResponse (byte[] response)
After a provision response is received by the app, it is provided to the DRM engine plugin using this method.
Parameters | |
---|---|
response |
byte :
the opaque provisioning response byte array to provide to the
DRM engine plugin. |
Throws | |
---|---|
DeniedByServerException |
if the response indicates that the server rejected the request |
HashMap<String, String> queryKeyStatus (byte[] sessionId)
Request an informative description of the key status for the session. The status is in the form of {name, value} pairs. Since DRM license policies vary by vendor, the specific status field names are determined by each DRM vendor. Refer to your DRM provider documentation for definitions of the field names for a particular DRM engine plugin.
Parameters | |
---|---|
sessionId |
byte :
the session ID for the DRM session
|
Returns | |
---|---|
HashMap<String, String> |
void releaseAllSecureStops ()
Remove all secure stops without requiring interaction with the server.
void releaseSecureStops (byte[] ssRelease)
Process the SecureStop server response message ssRelease. After authenticating the message, remove the SecureStops identified in the response.
Parameters | |
---|---|
ssRelease |
byte :
the server response indicating which secure stops to release
|
void removeKeys (byte[] sessionId)
Remove the current keys from a session.
Parameters | |
---|---|
sessionId |
byte :
the session ID for the DRM session
|
void restoreKeys (byte[] sessionId, byte[] keySetId)
Restore persisted offline keys into a new session. keySetId identifies the
keys to load, obtained from a prior call to provideKeyResponse(byte[], byte[])
.
Parameters | |
---|---|
sessionId |
byte :
the session ID for the DRM session |
keySetId |
byte :
identifies the saved key set to restore
|
void setOnEventListener (MediaDrm.OnEventListener listener)
Register a callback to be invoked when an event occurs
Parameters | |
---|---|
listener |
MediaDrm.OnEventListener :
the callback that will be run. Use null to
stop receiving event callbacks.
|
void setOnExpirationUpdateListener (MediaDrm.OnExpirationUpdateListener listener, Handler handler)
Register a callback to be invoked when a session expiration update occurs. The app's OnExpirationUpdateListener will be notified when the expiration time of the keys in the session have changed.
Parameters | |
---|---|
listener |
MediaDrm.OnExpirationUpdateListener :
the callback that will be run, or null to unregister the
previously registered callback. |
handler |
Handler :
the handler on which the listener should be invoked, or
null if the listener should be invoked on the calling thread's looper.
|
void setOnKeyStatusChangeListener (MediaDrm.OnKeyStatusChangeListener listener, Handler handler)
Register a callback to be invoked when the state of keys in a session change, e.g. when a license update occurs or when a license expires.
Parameters | |
---|---|
listener |
MediaDrm.OnKeyStatusChangeListener :
the callback that will be run when key status changes, or
null to unregister the previously registered callback. |
handler |
Handler :
the handler on which the listener should be invoked, or
null if the listener should be invoked on the calling thread's looper.
|
void setPropertyByteArray (String propertyName, byte[] value)
Set a DRM engine plugin byte array property value.
Parameters | |
---|---|
propertyName |
String
|
value |
byte
|
void setPropertyString (String propertyName, String value)
Set a DRM engine plugin String property value.
Parameters | |
---|---|
propertyName |
String
|
value |
String
|
void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize
method to dispose of
system resources or to perform other cleanup.
The general contract of finalize
is that it is invoked
if and when the JavaTM virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize
method may take any action, including
making this object available again to other threads; the usual purpose
of finalize
, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize
method of class Object
performs no
special action; it simply returns normally. Subclasses of
Object
may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize
method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize
method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize
method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize
method causes
the finalization of this object to be halted, but is otherwise
ignored.