Php demo:
$key = 'test';
$arrParam = array(
'timestamp' => 1488854485,
'tp_code' => 'test',
'data' => '{"merchant_code":"test","order_id":123}',
);
ksort($arrParam);
$strParam = http_build_query($arrParam);
$strParam = $strParam . '&key=' . $key;
$sign = sha1($strParam, false);
心有余而力不足.....或者你可以写出你的md5的实现方式来看看能不能写
http://www.cnblogs.com/computer-lzy/archive/2011/04/28/2031649.html