string secretkey = "CD45FF96D6752A4D";
string token = Convert.ToBase64String(Guid.NewGuid().ToByteArray());
string sectoken = Convert.ToBase64String(Guid.NewGuid().ToByteArray());
var enc = Encoding.ASCII;
HMACSHA256 hmac = new HMACSHA256(enc.GetBytes(secretkey));
hmac.Initialize();
byte[] buffer = enc.GetBytes(sectoken);
string signature = BitConverter.ToString(hmac.ComputeHash(buffer)).Replace("-", "").ToLower();
change token and sectoken