PFinal\Wechat\SDK\Redpack\MD5SignUtil::verifySignature PHP Method

    function verifySignature($content, $sign, $md5Key)
    {
        $signStr = $content . "&key=" . $md5Key;
        $calculateSign = strtolower(md5($signStr));
        $tenpaySign = strtolower($sign);
        return $calculateSign == $tenpaySign;
    }