//加密算法HmacSHA256
private static string HmacSHA256(string secret, string signKey)
{
string signRet = string.Empty;
using (HMACSHA256 mac = new HMACSHA256(Encoding.UTF8.GetBytes(signKey)))
{
byte[] hash = mac.ComputeHash(Encoding.UTF8.GetBytes(secret));
signRet = Convert.ToBase64String(hash);
//signRet = ToHexString(hash); ;
}
return signRet;
}