public static byte[] getAsciiBytes(String value) {
    try {
      return value.getBytes("US-ASCII");
    } catch (UnsupportedEncodingException e) {
      throw new RuntimeException("US-ASCII character encoding not supported", e);
    }
  }
Encodes the provided string as a byte array using the {@code US-ASCII} character encoding.
java/com/google/android/apps/authenticator/util/Utilities.java