MediaDrm.java revision 3ed38266c1647c6219ae5ad89cb3f867cf66caaa
1/* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.media; 18 19import android.media.MediaDrmException; 20import java.lang.ref.WeakReference; 21import java.util.UUID; 22import java.util.HashMap; 23import java.util.List; 24import android.os.Handler; 25import android.os.Looper; 26import android.os.Message; 27import android.os.Bundle; 28import android.os.Parcel; 29import android.util.Log; 30 31/** 32 * MediaDrm can be used to obtain keys for decrypting protected media streams, in 33 * conjunction with {@link android.media.MediaCrypto}. The MediaDrm APIs 34 * are designed to support the ISO/IEC 23001-7: Common Encryption standard, but 35 * may also be used to implement other encryption schemes. 36 * <p> 37 * Encrypted content is prepared using an encryption server and stored in a content 38 * library. The encrypted content is streamed or downloaded from the content library to 39 * client devices via content servers. Licenses to view the content are obtained from 40 * a License Server. 41 * <p> 42 * <p><img src="../../../images/mediadrm_overview.png" 43 * alt="MediaDrm Overview diagram" 44 * border="0" /></p> 45 * <p> 46 * Keys are requested from the license server using a key request. The key 47 * response is delivered to the client app, which provides the response to the 48 * MediaDrm API. 49 * <p> 50 * A Provisioning server may be required to distribute device-unique credentials to 51 * the devices. 52 * <p> 53 * Enforcing requirements related to the number of devices that may play content 54 * simultaneously can be performed either through key renewal or using the secure 55 * stop methods. 56 * <p> 57 * The following sequence diagram shows the interactions between the objects 58 * involved while playing back encrypted content: 59 * <p> 60 * <p><img src="../../../images/mediadrm_decryption_sequence.png" 61 * alt="MediaDrm Overview diagram" 62 * border="0" /></p> 63 * <p> 64 * The app first constructs {@link android.media.MediaExtractor} and 65 * {@link android.media.MediaCodec} objects. It accesses the DRM-scheme-identifying UUID, 66 * typically from metadata in the content, and uses this UUID to construct an instance 67 * of a MediaDrm object that is able to support the DRM scheme required by the content. 68 * Crypto schemes are assigned 16 byte UUIDs. The method {@link #isCryptoSchemeSupported} 69 * can be used to query if a given scheme is supported on the device. 70 * <p> 71 * The app calls {@link #openSession} to generate a sessionId that will uniquely identify 72 * the session in subsequent interactions. The app next uses the MediaDrm object to 73 * obtain a key request message and send it to the license server, then provide 74 * the server's response to the MediaDrm object. 75 * <p> 76 * Once the app has a sessionId, it can construct a MediaCrypto object from the UUID and 77 * sessionId. The MediaCrypto object is registered with the MediaCodec in the 78 * {@link MediaCodec.#configure} method to enable the codec to decrypt content. 79 * <p> 80 * When the app has constructed {@link android.media.MediaExtractor}, 81 * {@link android.media.MediaCodec} and {@link android.media.MediaCrypto} objects, 82 * it proceeds to pull samples from the extractor and queue them into the decoder. For 83 * encrypted content, the samples returned from the extractor remain encrypted, they 84 * are only decrypted when the samples are delivered to the decoder. 85 * <p> 86 * <a name="Callbacks"></a> 87 * <h3>Callbacks</h3> 88 * <p>Applications should register for informational events in order 89 * to be informed of key state updates during playback or streaming. 90 * Registration for these events is done via a call to 91 * {@link #setOnEventListener}. In order to receive the respective 92 * callback associated with this listener, applications are required to create 93 * MediaDrm objects on a thread with its own Looper running (main UI 94 * thread by default has a Looper running). 95 */ 96public final class MediaDrm { 97 98 private final static String TAG = "MediaDrm"; 99 100 private EventHandler mEventHandler; 101 private OnEventListener mOnEventListener; 102 103 private int mNativeContext; 104 105 /** 106 * Query if the given scheme identified by its UUID is supported on 107 * this device. 108 * @param uuid The UUID of the crypto scheme. 109 */ 110 public static final boolean isCryptoSchemeSupported(UUID uuid) { 111 return isCryptoSchemeSupportedNative(getByteArrayFromUUID(uuid)); 112 } 113 114 private static final byte[] getByteArrayFromUUID(UUID uuid) { 115 long msb = uuid.getMostSignificantBits(); 116 long lsb = uuid.getLeastSignificantBits(); 117 118 byte[] uuidBytes = new byte[16]; 119 for (int i = 0; i < 8; ++i) { 120 uuidBytes[i] = (byte)(msb >>> (8 * (7 - i))); 121 uuidBytes[8 + i] = (byte)(lsb >>> (8 * (7 - i))); 122 } 123 124 return uuidBytes; 125 } 126 127 private static final native boolean isCryptoSchemeSupportedNative(byte[] uuid); 128 129 /** 130 * Instantiate a MediaDrm object 131 * 132 * @param uuid The UUID of the crypto scheme. 133 * 134 * @throws UnsupportedSchemeException if the device does not support the 135 * specified scheme UUID 136 */ 137 public MediaDrm(UUID uuid) throws UnsupportedSchemeException { 138 Looper looper; 139 if ((looper = Looper.myLooper()) != null) { 140 mEventHandler = new EventHandler(this, looper); 141 } else if ((looper = Looper.getMainLooper()) != null) { 142 mEventHandler = new EventHandler(this, looper); 143 } else { 144 mEventHandler = null; 145 } 146 147 /* Native setup requires a weak reference to our object. 148 * It's easier to create it here than in C++. 149 */ 150 native_setup(new WeakReference<MediaDrm>(this), 151 getByteArrayFromUUID(uuid)); 152 } 153 154 /** 155 * Register a callback to be invoked when an event occurs 156 * 157 * @param listener the callback that will be run 158 */ 159 public void setOnEventListener(OnEventListener listener) 160 { 161 mOnEventListener = listener; 162 } 163 164 /** 165 * Interface definition for a callback to be invoked when a drm event 166 * occurs 167 */ 168 public interface OnEventListener 169 { 170 /** 171 * Called when an event occurs that requires the app to be notified 172 * 173 * @param md the MediaDrm object on which the event occurred 174 * @param sessionId the DRM session ID on which the event occurred 175 * @param event indicates the event type 176 * @param extra an secondary error code 177 * @param data optional byte array of data that may be associated with the event 178 */ 179 void onEvent(MediaDrm md, byte[] sessionId, int event, int extra, byte[] data); 180 } 181 182 /** 183 * This event type indicates that the app needs to request a certificate from 184 * the provisioning server. The request message data is obtained using 185 * {@link #getProvisionRequest} 186 */ 187 public static final int EVENT_PROVISION_REQUIRED = 1; 188 189 /** 190 * This event type indicates that the app needs to request keys from a license 191 * server. The request message data is obtained using {@link #getKeyRequest}. 192 */ 193 public static final int EVENT_KEY_REQUIRED = 2; 194 195 /** 196 * This event type indicates that the licensed usage duration for keys in a session 197 * has expired. The keys are no longer valid. 198 */ 199 public static final int EVENT_KEY_EXPIRED = 3; 200 201 /** 202 * This event may indicate some specific vendor-defined condition, see your 203 * DRM provider documentation for details 204 */ 205 public static final int EVENT_VENDOR_DEFINED = 4; 206 207 private static final int DRM_EVENT = 200; 208 209 private class EventHandler extends Handler 210 { 211 private MediaDrm mMediaDrm; 212 213 public EventHandler(MediaDrm md, Looper looper) { 214 super(looper); 215 mMediaDrm = md; 216 } 217 218 @Override 219 public void handleMessage(Message msg) { 220 if (mMediaDrm.mNativeContext == 0) { 221 Log.w(TAG, "MediaDrm went away with unhandled events"); 222 return; 223 } 224 switch(msg.what) { 225 226 case DRM_EVENT: 227 Log.i(TAG, "Drm event (" + msg.arg1 + "," + msg.arg2 + ")"); 228 229 if (mOnEventListener != null) { 230 if (msg.obj != null && msg.obj instanceof Parcel) { 231 Parcel parcel = (Parcel)msg.obj; 232 byte[] sessionId = parcel.createByteArray(); 233 if (sessionId.length == 0) { 234 sessionId = null; 235 } 236 byte[] data = parcel.createByteArray(); 237 if (data.length == 0) { 238 data = null; 239 } 240 mOnEventListener.onEvent(mMediaDrm, sessionId, msg.arg1, msg.arg2, data); 241 } 242 } 243 return; 244 245 default: 246 Log.e(TAG, "Unknown message type " + msg.what); 247 return; 248 } 249 } 250 } 251 252 /* 253 * This method is called from native code when an event occurs. This method 254 * just uses the EventHandler system to post the event back to the main app thread. 255 * We use a weak reference to the original MediaPlayer object so that the native 256 * code is safe from the object disappearing from underneath it. (This is 257 * the cookie passed to native_setup().) 258 */ 259 private static void postEventFromNative(Object mediadrm_ref, 260 int eventType, int extra, Object obj) 261 { 262 MediaDrm md = (MediaDrm)((WeakReference)mediadrm_ref).get(); 263 if (md == null) { 264 return; 265 } 266 if (md.mEventHandler != null) { 267 Message m = md.mEventHandler.obtainMessage(DRM_EVENT, eventType, extra, obj); 268 md.mEventHandler.sendMessage(m); 269 } 270 } 271 272 /** 273 * Open a new session with the MediaDrm object. A session ID is returned. 274 * 275 * @throws NotProvisionedException if provisioning is needed 276 * @throws ResourceBusyException if required resources are in use 277 */ 278 public native byte[] openSession() throws NotProvisionedException; 279 280 /** 281 * Close a session on the MediaDrm object that was previously opened 282 * with {@link #openSession}. 283 */ 284 public native void closeSession(byte[] sessionId); 285 286 /** 287 * This key request type species that the keys will be for online use, they will 288 * not be saved to the device for subsequent use when the device is not connected 289 * to a network. 290 */ 291 public static final int KEY_TYPE_STREAMING = 1; 292 293 /** 294 * This key request type specifies that the keys will be for offline use, they 295 * will be saved to the device for use when the device is not connected to a network. 296 */ 297 public static final int KEY_TYPE_OFFLINE = 2; 298 299 /** 300 * This key request type specifies that previously saved offline keys should be released. 301 */ 302 public static final int KEY_TYPE_RELEASE = 3; 303 304 /** 305 * Contains the opaque data an app uses to request keys from a license server 306 */ 307 public final static class KeyRequest { 308 KeyRequest() {} 309 310 /** 311 * Get the opaque message data 312 */ 313 public byte[] getData() { return mData; } 314 315 /** 316 * Get the default URL to use when sending the key request message to a 317 * server, if known. The app may prefer to use a different license 318 * server URL from other sources. 319 */ 320 public String getDefaultUrl() { return mDefaultUrl; } 321 322 private byte[] mData; 323 private String mDefaultUrl; 324 }; 325 326 /** 327 * A key request/response exchange occurs between the app and a license server 328 * to obtain or release keys used to decrypt encrypted content. 329 * <p> 330 * getKeyRequest() is used to obtain an opaque key request byte array that is 331 * delivered to the license server. The opaque key request byte array is returned 332 * in KeyRequest.data. The recommended URL to deliver the key request to is 333 * returned in KeyRequest.defaultUrl. 334 * <p> 335 * After the app has received the key request response from the server, 336 * it should deliver to the response to the DRM engine plugin using the method 337 * {@link #provideKeyResponse}. 338 * 339 * @param scope may be a sessionId or a keySetId, depending on the specified keyType. 340 * When the keyType is KEY_TYPE_STREAMING or KEY_TYPE_OFFLINE, 341 * scope should be set to the sessionId the keys will be provided to. When the keyType 342 * is KEY_TYPE_RELEASE, scope should be set to the keySetId of the keys 343 * being released. Releasing keys from a device invalidates them for all sessions. 344 * @param init container-specific data, its meaning is interpreted based on the 345 * mime type provided in the mimeType parameter. It could contain, for example, 346 * the content ID, key ID or other data obtained from the content metadata that is 347 * required in generating the key request. init may be null when keyType is 348 * KEY_TYPE_RELEASE. 349 * @param mimeType identifies the mime type of the content 350 * @param keyType specifes the type of the request. The request may be to acquire 351 * keys for streaming or offline content, or to release previously acquired 352 * keys, which are identified by a keySetId. 353 * @param optionalParameters are included in the key request message to 354 * allow a client application to provide additional message parameters to the server. 355 * 356 * @throws NotProvisionedException if reprovisioning is needed, due to a 357 * problem with the certifcate 358 */ 359 public native KeyRequest getKeyRequest(byte[] scope, byte[] init, 360 String mimeType, int keyType, 361 HashMap<String, String> optionalParameters) 362 throws NotProvisionedException; 363 364 365 /** 366 * A key response is received from the license server by the app, then it is 367 * provided to the DRM engine plugin using provideKeyResponse. When the 368 * response is for an offline key request, a keySetId is returned that can be 369 * used to later restore the keys to a new session with the method 370 * {@link #restoreKeys}. 371 * When the response is for a streaming or release request, null is returned. 372 * 373 * @param scope may be a sessionId or keySetId depending on the type of the 374 * response. Scope should be set to the sessionId when the response is for either 375 * streaming or offline key requests. Scope should be set to the keySetId when 376 * the response is for a release request. 377 * @param response the byte array response from the server 378 * 379 * @throws NotProvisionedException if the response indicates that 380 * reprovisioning is required 381 * @throws DeniedByServerException if the response indicates that the 382 * server rejected the request 383 * @throws ResourceBusyException if required resources are in use 384 */ 385 public native byte[] provideKeyResponse(byte[] scope, byte[] response) 386 throws NotProvisionedException, DeniedByServerException; 387 388 389 /** 390 * Restore persisted offline keys into a new session. keySetId identifies the 391 * keys to load, obtained from a prior call to {@link #provideKeyResponse}. 392 * 393 * @param sessionId the session ID for the DRM session 394 * @param keySetId identifies the saved key set to restore 395 */ 396 public native void restoreKeys(byte[] sessionId, byte[] keySetId); 397 398 /** 399 * Remove the current keys from a session. 400 * 401 * @param sessionId the session ID for the DRM session 402 */ 403 public native void removeKeys(byte[] sessionId); 404 405 /** 406 * Request an informative description of the key status for the session. The status is 407 * in the form of {name, value} pairs. Since DRM license policies vary by vendor, 408 * the specific status field names are determined by each DRM vendor. Refer to your 409 * DRM provider documentation for definitions of the field names for a particular 410 * DRM engine plugin. 411 * 412 * @param sessionId the session ID for the DRM session 413 */ 414 public native HashMap<String, String> queryKeyStatus(byte[] sessionId); 415 416 /** 417 * Contains the opaque data an app uses to request a certificate from a provisioning 418 * server 419 */ 420 public final static class ProvisionRequest { 421 ProvisionRequest() {} 422 423 /** 424 * Get the opaque message data 425 */ 426 public byte[] getData() { return mData; } 427 428 /** 429 * Get the default URL to use when sending the provision request 430 * message to a server, if known. The app may prefer to use a different 431 * provisioning server URL obtained from other sources. 432 */ 433 public String getDefaultUrl() { return mDefaultUrl; } 434 435 private byte[] mData; 436 private String mDefaultUrl; 437 } 438 439 /** 440 * A provision request/response exchange occurs between the app and a provisioning 441 * server to retrieve a device certificate. If provisionining is required, the 442 * EVENT_PROVISION_REQUIRED event will be sent to the event handler. 443 * getProvisionRequest is used to obtain the opaque provision request byte array that 444 * should be delivered to the provisioning server. The provision request byte array 445 * is returned in ProvisionRequest.data. The recommended URL to deliver the provision 446 * request to is returned in ProvisionRequest.defaultUrl. 447 */ 448 public native ProvisionRequest getProvisionRequest(); 449 450 /** 451 * After a provision response is received by the app, it is provided to the DRM 452 * engine plugin using this method. 453 * 454 * @param response the opaque provisioning response byte array to provide to the 455 * DRM engine plugin. 456 * 457 * @throws DeniedByServerException if the response indicates that the 458 * server rejected the request 459 */ 460 public native void provideProvisionResponse(byte[] response) 461 throws DeniedByServerException; 462 463 /** 464 * A means of enforcing limits on the number of concurrent streams per subscriber 465 * across devices is provided via SecureStop. This is achieved by securely 466 * monitoring the lifetime of sessions. 467 * <p> 468 * Information from the server related to the current playback session is written 469 * to persistent storage on the device when each MediaCrypto object is created. 470 * <p> 471 * In the normal case, playback will be completed, the session destroyed and the 472 * Secure Stops will be queried. The app queries secure stops and forwards the 473 * secure stop message to the server which verifies the signature and notifies the 474 * server side database that the session destruction has been confirmed. The persisted 475 * record on the client is only removed after positive confirmation that the server 476 * received the message using releaseSecureStops(). 477 */ 478 public native List<byte[]> getSecureStops(); 479 480 481 /** 482 * Process the SecureStop server response message ssRelease. After authenticating 483 * the message, remove the SecureStops identified in the response. 484 * 485 * @param ssRelease the server response indicating which secure stops to release 486 */ 487 public native void releaseSecureStops(byte[] ssRelease); 488 489 490 /** 491 * String property name: identifies the maker of the DRM engine plugin 492 */ 493 public static final String PROPERTY_VENDOR = "vendor"; 494 495 /** 496 * String property name: identifies the version of the DRM engine plugin 497 */ 498 public static final String PROPERTY_VERSION = "version"; 499 500 /** 501 * String property name: describes the DRM engine plugin 502 */ 503 public static final String PROPERTY_DESCRIPTION = "description"; 504 505 /** 506 * String property name: a comma-separated list of cipher and mac algorithms 507 * supported by CryptoSession. The list may be empty if the DRM engine 508 * plugin does not support CryptoSession operations. 509 */ 510 public static final String PROPERTY_ALGORITHMS = "algorithms"; 511 512 /** 513 * Read a DRM engine plugin String property value, given the property name string. 514 * <p> 515 * Standard fields names are: 516 * {@link #PROPERTY_VENDOR}, {@link #PROPERTY_VERSION}, 517 * {@link #PROPERTY_DESCRIPTION}, {@link #PROPERTY_ALGORITHMS} 518 */ 519 public native String getPropertyString(String propertyName); 520 521 522 /** 523 * Byte array property name: the device unique identifier is established during 524 * device provisioning and provides a means of uniquely identifying each device. 525 */ 526 public static final String PROPERTY_DEVICE_UNIQUE_ID = "deviceUniqueId"; 527 528 /** 529 * Read a DRM engine plugin byte array property value, given the property name string. 530 * <p> 531 * Standard fields names are {@link #PROPERTY_DEVICE_UNIQUE_ID} 532 */ 533 public native byte[] getPropertyByteArray(String propertyName); 534 535 536 /** 537 * Set a DRM engine plugin String property value. 538 */ 539 public native void setPropertyString(String propertyName, String value); 540 541 /** 542 * Set a DRM engine plugin byte array property value. 543 */ 544 public native void setPropertyByteArray(String propertyName, byte[] value); 545 546 547 private static final native void setCipherAlgorithmNative(MediaDrm drm, byte[] sessionId, 548 String algorithm); 549 550 private static final native void setMacAlgorithmNative(MediaDrm drm, byte[] sessionId, 551 String algorithm); 552 553 private static final native byte[] encryptNative(MediaDrm drm, byte[] sessionId, 554 byte[] keyId, byte[] input, byte[] iv); 555 556 private static final native byte[] decryptNative(MediaDrm drm, byte[] sessionId, 557 byte[] keyId, byte[] input, byte[] iv); 558 559 private static final native byte[] signNative(MediaDrm drm, byte[] sessionId, 560 byte[] keyId, byte[] message); 561 562 private static final native boolean verifyNative(MediaDrm drm, byte[] sessionId, 563 byte[] keyId, byte[] message, 564 byte[] signature); 565 566 /** 567 * In addition to supporting decryption of DASH Common Encrypted Media, the 568 * MediaDrm APIs provide the ability to securely deliver session keys from 569 * an operator's session key server to a client device, based on the factory-installed 570 * root of trust, and then perform encrypt, decrypt, sign and verify operations 571 * with the session key on arbitrary user data. 572 * <p> 573 * The CryptoSession class implements generic encrypt/decrypt/sign/verify methods 574 * based on the established session keys. These keys are exchanged using the 575 * getKeyRequest/provideKeyResponse methods. 576 * <p> 577 * Applications of this capability could include securing various types of 578 * purchased or private content, such as applications, books and other media, 579 * photos or media delivery protocols. 580 * <p> 581 * Operators can create session key servers that are functionally similar to a 582 * license key server, except that instead of receiving license key requests and 583 * providing encrypted content keys which are used specifically to decrypt A/V media 584 * content, the session key server receives session key requests and provides 585 * encrypted session keys which can be used for general purpose crypto operations. 586 * <p> 587 * A CryptoSession is obtained using {@link #getCryptoSession} 588 */ 589 public final class CryptoSession { 590 private MediaDrm mDrm; 591 private byte[] mSessionId; 592 593 CryptoSession(MediaDrm drm, byte[] sessionId, 594 String cipherAlgorithm, String macAlgorithm) 595 { 596 mSessionId = sessionId; 597 mDrm = drm; 598 setCipherAlgorithmNative(drm, sessionId, cipherAlgorithm); 599 setMacAlgorithmNative(drm, sessionId, macAlgorithm); 600 } 601 602 /** 603 * Encrypt data using the CryptoSession's cipher algorithm 604 * 605 * @param keyid specifies which key to use 606 * @param input the data to encrypt 607 * @param iv the initialization vector to use for the cipher 608 */ 609 public byte[] encrypt(byte[] keyid, byte[] input, byte[] iv) { 610 return encryptNative(mDrm, mSessionId, keyid, input, iv); 611 } 612 613 /** 614 * Decrypt data using the CryptoSessions's cipher algorithm 615 * 616 * @param keyid specifies which key to use 617 * @param input the data to encrypt 618 * @param iv the initialization vector to use for the cipher 619 */ 620 public byte[] decrypt(byte[] keyid, byte[] input, byte[] iv) { 621 return decryptNative(mDrm, mSessionId, keyid, input, iv); 622 } 623 624 /** 625 * Sign data using the CryptoSessions's mac algorithm. 626 * 627 * @param keyid specifies which key to use 628 * @param message the data for which a signature is to be computed 629 */ 630 public byte[] sign(byte[] keyid, byte[] message) { 631 return signNative(mDrm, mSessionId, keyid, message); 632 } 633 634 /** 635 * Verify a signature using the CryptoSessions's mac algorithm. Return true 636 * if the signatures match, false if they do no. 637 * 638 * @param keyid specifies which key to use 639 * @param message the data to verify 640 * @param signature the reference signature which will be compared with the 641 * computed signature 642 */ 643 public boolean verify(byte[] keyid, byte[] message, byte[] signature) { 644 return verifyNative(mDrm, mSessionId, keyid, message, signature); 645 } 646 }; 647 648 /** 649 * Obtain a CryptoSession object which can be used to encrypt, decrypt, 650 * sign and verify messages or data using the session keys established 651 * for the session using methods {@link #getKeyRequest} and 652 * {@link #provideKeyResponse} using a session key server. 653 * 654 * @param sessionId the session ID for the session containing keys 655 * to be used for encrypt, decrypt, sign and/or verify 656 * @param cipherAlgorithm the algorithm to use for encryption and 657 * decryption ciphers. The algorithm string conforms to JCA Standard 658 * Names for Cipher Transforms and is case insensitive. For example 659 * "AES/CBC/NoPadding". 660 * @param macAlgorithm the algorithm to use for sign and verify 661 * The algorithm string conforms to JCA Standard Names for Mac 662 * Algorithms and is case insensitive. For example "HmacSHA256". 663 * <p> 664 * The list of supported algorithms for a DRM engine plugin can be obtained 665 * using the method {@link #getPropertyString} with the property name 666 * "algorithms". 667 */ 668 public CryptoSession getCryptoSession(byte[] sessionId, 669 String cipherAlgorithm, 670 String macAlgorithm) 671 { 672 return new CryptoSession(this, sessionId, cipherAlgorithm, macAlgorithm); 673 } 674 675 @Override 676 protected void finalize() { 677 native_finalize(); 678 } 679 680 public native final void release(); 681 private static native final void native_init(); 682 683 private native final void native_setup(Object mediadrm_this, byte[] uuid); 684 685 private native final void native_finalize(); 686 687 static { 688 System.loadLibrary("media_jni"); 689 native_init(); 690 } 691} 692