背景
在我使用的一个应用程序中，我将重要的东西（令牌）存储到 EncryptedSharedPreferences 中（取自此处和此处）：
/** a hardware-encrypted based shared preference (for the values).
* Note that it is a bit slow, so it's better to always use it in a background thread.
* Also, avoid having it being backed-up in the manifest, as it's hardware based and will become useless: https://stackoverflow.com/a/63795282/878126*/
object SecuredSharedPreferences {
private var cachedDefaultSharedPreferences: SharedPreferences? = null
/**warning: using this function can take some time (249 ms on Pixel 4, for example). Very recommended to avoid calling it on UI thread */
@WorkerThread
fun getDefaultSecuredSharedPreferences(context: Context): SharedPreferences {
if (cachedDefaultSharedPreferences != null)
return cachedDefaultSharedPreferences!!
synchronized(this) {
if (cachedDefaultSharedPreferences != null)
return cachedDefaultSharedPreferences!!
cachedDefaultSharedPreferences = getSecuredSharedPreferences(context, context.packageName + "_secured_preferences")
}
return cachedDefaultSharedPreferences!!
}
@WorkerThread
private fun getSecuredSharedPreferences(context: Context, fileName: String): SharedPreferences {
val masterKey = MasterKey.Builder(context, MasterKey.DEFAULT_MASTER_KEY_ALIAS).setKeyScheme(MasterKey.KeyScheme.AES256_GCM).build()
return EncryptedSharedPreferences.create(context, fileName, masterKey,
EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
)
}
}
毕业典礼：
implementation 'androidx.security:security-crypto:1.1.0-alpha03'
问题
我注意到使用此代码时通过 Crashlytics 报告了 2 个错误（在此处报告）：
- 第一个是
MasterKey.Builder：GeneralSecurityException
Fatal Exception: java.security.GeneralSecurityException: Keystore operation failed
at androidx.security.crypto.MasterKeys.generateKey(MasterKeys.java:146)
at androidx.security.crypto.MasterKeys.getOrCreate(MasterKeys.java:97)
at androidx.security.crypto.MasterKey$Builder.buildOnM(MasterKey.java:357)
at androidx.security.crypto.MasterKey$Builder.build(MasterKey.java:314)
...
Caused by java.security.ProviderException: Keystore operation failed
at android.security.keystore.AndroidKeyStoreKeyGeneratorSpi.engineGenerateKey(AndroidKeyStoreKeyGeneratorSpi.java:372)
at javax.crypto.KeyGenerator.generateKey(KeyGenerator.java:612)
at androidx.security.crypto.MasterKeys.generateKey(MasterKeys.java:142)
at androidx.security.crypto.MasterKeys.getOrCreate(MasterKeys.java:97)
at androidx.security.crypto.MasterKey$Builder.buildOnM(MasterKey.java:357)
at androidx.security.crypto.MasterKey$Builder.build(MasterKey.java:314)
- 第二个是
EncryptedSharedPreferences.create在线的KeyStoreException，并且发生的频率更高，用户也更多：
Fatal Exception: java.security.KeyStoreException: the master key android-keystore://_androidx_security_master_key_ exists but is unusable
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.readOrGenerateNewMasterKey(AndroidKeysetManager.java:275)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.build(AndroidKeysetManager.java:236)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:155)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:120)
...
Caused by java.security.UnrecoverableKeyException: Failed to obtain information about key
at android.security.keystore.AndroidKeyStoreProvider.loadAndroidKeyStoreSecretKeyFromKeystore(AndroidKeyStoreProvider.java:282)
at android.security.keystore.AndroidKeyStoreSpi.engineGetKey(AndroidKeyStoreSpi.java:98)
at java.security.KeyStore.getKey(KeyStore.java:825)
at com.google.crypto.tink.integration.android.AndroidKeystoreAesGcm.<init>(AndroidKeystoreAesGcm.java:58)
at com.google.crypto.tink.integration.android.AndroidKeystoreKmsClient.getAead(AndroidKeystoreKmsClient.java:164)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.readOrGenerateNewMasterKey(AndroidKeysetManager.java:267)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.build(AndroidKeysetManager.java:236)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:155)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:120)
编辑：似乎还有更多类型的例外：
- 无效协议缓冲区异常：
Fatal Exception: com.google.crypto.tink.shaded.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
at com.google.crypto.tink.shaded.protobuf.GeneratedMessageLite.parsePartialFrom(GeneratedMessageLite.java:1566)
at com.google.crypto.tink.shaded.protobuf.GeneratedMessageLite.parseFrom(GeneratedMessageLite.java:1663)
at com.google.crypto.tink.proto.Keyset.parseFrom(Keyset.java:957)
at com.google.crypto.tink.integration.android.SharedPrefKeysetReader.read(SharedPrefKeysetReader.java:84)
at com.google.crypto.tink.CleartextKeysetHandle.read(CleartextKeysetHandle.java:58)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.read(AndroidKeysetManager.java:328)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.readOrGenerateNewKeyset(AndroidKeysetManager.java:287)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.build(AndroidKeysetManager.java:238)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:160)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:120)
- 空指针异常：
Fatal Exception: java.lang.NullPointerException: Attempt to invoke interface method 'android.security.keymaster.OperationResult android.security.IKeystoreService.begin(android.os.IBinder, java.lang.String, int, boolean, android.security.keymaster.KeymasterArguments, byte[], int)' on a null object reference
at android.security.KeyStore.begin(KeyStore.java:501)
at android.security.keystore.AndroidKeyStoreCipherSpiBase.ensureKeystoreOperationInitialized(AndroidKeyStoreCipherSpiBase.java:248)
at android.security.keystore.AndroidKeyStoreCipherSpiBase.engineInit(AndroidKeyStoreCipherSpiBase.java:109)
at javax.crypto.Cipher.tryTransformWithProvider(Cipher.java:2977)
at javax.crypto.Cipher.tryCombinations(Cipher.java:2884)
at javax.crypto.Cipher$SpiAndProviderUpdater.updateAndGetSpiAndProvider(Cipher.java:2789)
at javax.crypto.Cipher.chooseProvider(Cipher.java:956)
at javax.crypto.Cipher.init(Cipher.java:1199)
at javax.crypto.Cipher.init(Cipher.java:1143)
at com.google.crypto.tink.integration.android.AndroidKeystoreAesGcm.encryptInternal(AndroidKeystoreAesGcm.java:84)
at com.google.crypto.tink.integration.android.AndroidKeystoreAesGcm.encrypt(AndroidKeystoreAesGcm.java:72)
at com.google.crypto.tink.integration.android.AndroidKeystoreKmsClient.validateAead(AndroidKeystoreKmsClient.java:248)
at com.google.crypto.tink.integration.android.AndroidKeystoreKmsClient.getAead(AndroidKeystoreKmsClient.java:165)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.readOrGenerateNewMasterKey(AndroidKeysetManager.java:267)
at com.google.crypto.tink.integration.android.AndroidKeysetManager$Builder.build(AndroidKeysetManager.java:236)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:155)
at androidx.security.crypto.EncryptedSharedPreferences.create(EncryptedSharedPreferences.java:120)
我试过的
在 Internet 上搜索，我只发现了第一个异常 (GeneralSecurityException) 的线索，这可能是自定义 ROM 发生的，因为它们可能无法很好地实现用于加密的硬件密钥。
事实上，查看 Crashlytics 上的设备，查看每个设备的 Android 版本，我发现它们领先于我所看到的支持它们的最新版本。
对于第二个例外，可悲的是，我找不到任何解释，也没有解决方案。我认为这可能与应用程序的恢复有关，但这很奇怪，因为它经常发生。在 reddit（此处）上，有人写道，如果出现这种异常，他选择了wrap the initialization of EncryptedSharedPreferences with "clear all data if fails" and bite the bullet. 还建议它可能与android:allowBackup被禁用有关（确实如此）。
不知道其余的。
问题
为什么会出现这些异常？我能对他们做什么？
清除数据是唯一可以做的事情吗？我什至不确定它是否真的有帮助，因为如果我选择拥有它，这意味着每次它即将发生时崩溃报告都会消失......
和android:allowBackup残疾有关系吗？