public boolean verify(String sign , String appKey , String orderId) throws UnsupportedEncodingException{

		if(sign.length()<14){

			return false;

		}

		String verityStr = sign.substring(0,8);

		sign = sign.substring(8);

		String temp = MD5Util.toMD5(sign);

		if(!verityStr.equals(temp.substring(0,8))){

			return false;

		}

		String keyB =  sign.substring(0,6);

		String randKey = keyB+appKey;

		randKey = MD5Util.toMD5(randKey);

		byte[] signB = Base64.decodeFast(sign.substring(6));

		int signLength = signB.length;

		String verfic="";

		for(int i =0 ; i< signLength ; i++){

			char b = (char)(signB[i]^randKey.getBytes()[i%32]);

			verfic +=String.valueOf(b);

		}

		return verfic.equals(orderId);

	}

def verifyPayment(appkey, %{"tradeSign" => tradeSign} = params) do

    sign_length = String.length(tradeSign)

    if sign_length < 14 do

      false

    else

      verityStr = String.slice(tradeSign, 0, 8)

      sign = String.slice(tradeSign, 8, sign_length + 1)

      temp = Utils.md5_sign(sign)

      temp = String.slice(temp, 0, 8)

      if verityStr == temp do

        keyB = String.slice(sign, 0, 6)

        randKey = keyB <> appkey

        randKey = Utils.md5_sign(randKey)

        signB =  String.slice(sign, 6, sign_length + 1) |> Base.decode64! |> String.to_char_list

        randKey = randKey |> String.to_char_list

        signedOrderId =  signB |> Enum.with_index |> Enum.map fn({c, i}) -> Bitwise.bxor c,  Enum.at(randKey, rem(i, 32)) end

        params["orderID"] == signedOrderId

      else

        false

      end

    end

  end