应用程序在使用Android L以下的KeyGuardManager时崩溃

Question

KeyGuardManager在安卓L以上运行良好，但在安卓及以下版本中抛出异常。

我正在使用以下功能：

@RequiresApi(api = Build.VERSION_CODES.M)
private void createKey() {
try {
KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
keyStore.load(null);
KeyGenerator keyGenerator = KeyGenerator.getInstance(
KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
keyGenerator.init(new KeyGenParameterSpec.Builder(KEY_NAME,
KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
.setBlockModes(KeyProperties.BLOCK_MODE_CBC)
.setUserAuthenticationRequired(true)
// Require that the user has unlocked in the last 30 seconds
.setUserAuthenticationValidityDurationSeconds(AUTHENTICATION_DURATION_SECONDS)
.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
.build());
keyGenerator.generateKey();
} catch (NoSuchAlgorithmException | NoSuchProviderException
| InvalidAlgorithmParameterException | KeyStoreException
| CertificateException | IOException e) {
throw new RuntimeException("Failed to create a symmetric key", e);
}
}

但它在Android L&下图：

dalvikvm: Could not find class 'android.security.keystore.KeyGenParameterSpec$Builder', referenced from method com.example.myapp.MainActivity.createKey
java.lang.VerifyError: com/example/myapp/MainActivity
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)

我还添加了一个条件，这个功能只能在Android L以上调用。尽管如此，我还是超越了例外。

如有任何帮助，我们将不胜感激。

Answer 1

问题出在加密方法中，您试图从KeyStore初始化密码。Catch块正试图捕获在Android 23+中实现的UserNotAuthenticatedException，因此它会给您Class not found Exception。与其用这种方式实现catch块，不如试试下面的代码，它在我的代码中就像一个魅力。

private boolean tryEncrypt() {
try {
KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
keyStore.load(null);
SecretKey secretKey = (SecretKey) keyStore.getKey(KEY_NAME, null);
Cipher cipher = Cipher.getInstance(
KeyProperties.KEY_ALGORITHM_AES + "/" + KeyProperties.BLOCK_MODE_CBC + "/"
+ KeyProperties.ENCRYPTION_PADDING_PKCS7);
cipher.init(Cipher.ENCRYPT_MODE, secretKey);
cipher.doFinal(SECRET_BYTE_ARRAY);
return true;
} catch (Exception e) {
if (e instanceof UserNotAuthenticatedException) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
showAuthenticationScreen();
}
return false;
}
if (e instanceof KeyPermanentlyInvalidatedException) {
return false;
}
return false;
}
}