下面是腾讯云短信API 签名字符串生成的文档说明：
     sig字段：根据公式 sha256（appkey=$appkey&random=$random&time=$time&mobile=$mobile）生成，其伪代码如下：

                string strMobile = "13788888888"; //tel 的 mobile 字段的内容
                string strAppKey = "5f03a35d00ee52a21327ab048186a2c4"; //sdkappid 对应的 appkey，需要业务方高度保密
                string strRand = "7226249334"; //URL 中的 random 字段的值
                string strTime = "1457336869"; //UNIX 时间戳
 string sig = sha256(appkey=5f03a35d00ee52a21327ab048186a2c4&random=7226249334&time=1457336869&mobile=13788888888)
           = ecab4881ee80ad3d76bb1da68387428ca752eb885e52621a3129dcf4d9bc4fd4;

下面是我用foxtable生成的短信API 签名字符串：
                                   Dim appkey As String="5f03a35d00ee52a21327ab048186a2c4"
                                   Dim random As Long= 7226249334
                                   Dim time As Integer=1457336869
                                   Dim moblile As String ="13788888888"
                                            Dim aryTmp() As String = {appkey,random,time,moblile}
                                               Array.Sort(aryTmp)
                                            Dim sig As String = String.Join("", aryTmp)
              sig = Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sig, "SHA256").ToLower()
                   =f893b1887560bbbca3384b0396c7b348db5c5af219b7ba8406e5f85d2aab6e6a
带入的参数值一样，但sig 的生成的只不一样。
      请求老师给指点一下。我是刚入foxtable的小白。