@ChecksSdkIntAtLeast(api = Build.VERSION_CODES.M)
  private static boolean isAtLeastM() {
    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M;
  }
Returns whether Android Keystore is being used to wrap Tink keysets.
java_src/src/main/java/com/google/crypto/tink/integration/android/AndroidKeysetManager.java