问ORC签名错误？

下面是我生成签名的代码，有什么问题吗

仔细研究过文档了，文档连接就不用发了。

/// <summary>

/// 生成鉴权字符串

/// </summary>

/// <returns></returns>

public static string OrtData()

{

string appid = "APPID";

string bucket = "xkr";

string secret_id = "ECRETID";

long expired = timestamp() + 2592000;

long current = timestamp();

int rdm = 12341233;

string strOrgData = "a=["+appid+"]&b=["+bucket+"]&k=["+secret_id+"]&e=["+expired+"]&t=["+ current + "]&r=["+rdm+"]&u=[0]&f=";

return strOrgData;

}

/// <summary>

/// ORC身份识别API鉴权编码生成

/// </summary>

/// <returns></returns>

public static string SHA1key()

{

string strOrgData = OrtData();

string secret = "加密KEY";

String res1 = (String)ApiHelper.hash_hmac(strOrgData, secret);

return Convert.ToBase64String(Encoding.UTF8.GetBytes(res1+strOrgData));

}

/// <summary>

/// 生成时间戳

/// </summary>

/// <returns></returns>

public static long timestamp()

{

DateTime dt = DateTime.Now;

var start = new DateTime(1970, 1, 1, 0, 0, 0, dt.Kind);

return Convert.ToInt64((dt - start).TotalSeconds);

}