Added in API level 18

MediaDrm.CryptoSession


public final class MediaDrm.CryptoSession
extends Object

java.lang.Object
   ↳ android.media.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.

The CryptoSession class implements generic encrypt/decrypt/sign/verify methods based on the established session keys. These keys are exchanged using the getKeyRequest/provideKeyResponse methods.

Applications of this capability could include securing various types of purchased or private content, such as applications, books and other media, photos or media delivery protocols.

Operators can create session key servers that are functionally similar to a license key server, except that instead of receiving license key requests and providing encrypted content keys which are used specifically to decrypt A/V media content, the session key server receives session key requests and provides encrypted session keys which can be used for general purpose crypto operations.

A CryptoSession is obtained using MediaDrm.getCryptoSession(byte, String, String)

Summary

Public methods

byte[] decrypt(byte[] keyid, byte[] input, byte[] iv)

Decrypt data using the CryptoSessions's cipher algorithm

byte[] encrypt(byte[] keyid, byte[] input, byte[] iv)

Encrypt data using the CryptoSession's cipher algorithm

byte[] sign(byte[] keyid, byte[] message)

Sign data using the CryptoSessions's mac algorithm.

boolean verify(byte[] keyid, byte[] message, byte[] signature)

Verify a signature using the CryptoSessions's mac algorithm.

Inherited methods

Public methods

decrypt

Added in API level 18
public byte[] decrypt (byte[] keyid, 
                byte[] input, 
                byte[] iv)

Decrypt data using the CryptoSessions's cipher algorithm

Parameters
keyid byte: specifies which key to use This value cannot be null.

input byte: the data to encrypt This value cannot be null.

iv byte: the initialization vector to use for the cipher This value cannot be null.

Returns
byte[] This value cannot be null.

encrypt

Added in API level 18
public byte[] encrypt (byte[] keyid, 
                byte[] input, 
                byte[] iv)

Encrypt data using the CryptoSession's cipher algorithm

Parameters
keyid byte: specifies which key to use This value cannot be null.

input byte: the data to encrypt This value cannot be null.

iv byte: the initialization vector to use for the cipher This value cannot be null.

Returns
byte[] This value cannot be null.

sign

Added in API level 18
public byte[] sign (byte[] keyid, 
                byte[] message)

Sign data using the CryptoSessions's mac algorithm.

Parameters
keyid byte: specifies which key to use This value cannot be null.

message byte: the data for which a signature is to be computed This value cannot be null.

Returns
byte[] This value cannot be null.

verify

Added in API level 18
public boolean verify (byte[] keyid, 
                byte[] message, 
                byte[] signature)

Verify a signature using the CryptoSessions's mac algorithm. Return true if the signatures match, false if they do no.

Parameters
keyid byte: specifies which key to use This value cannot be null.

message byte: the data to verify This value cannot be null.

signature byte: the reference signature which will be compared with the computed signature This value cannot be null.

Returns
boolean