@RequiresApi(Build.VERSION_CODES.M)
  public static Aead getOrGenerateNewAeadKey(String keyUri)
      throws GeneralSecurityException, IOException {
    AndroidKeystoreKmsClient client = new AndroidKeystoreKmsClient();
    synchronized (keystoreLock) {
      if (!client.hasKey(keyUri)) {
        generateNewAesGcmKeyWithoutExistenceCheck(keyUri);
      }
      return client.getAead(keyUri);
    }
  }
Generates a new key in Android Keystore, if it doesn't exist.

<p>Generates AES256-GCM keys.
java_src/src/main/java/com/google/crypto/tink/integration/android/AndroidKeystoreKmsClient.java