This is my code:
var signature_parameters = new SortedDictionary<string, string>()
{
{ "client_id", client_id },
{ "timestamp", timestamp },
};
var signature_base_string = string.Join("&", signature_parameters.Select(p => string.Format("{0}={1}", p.Key, p.Value)));
Response.Write(signature_base_string);
which prints client_id=2446782×tamp=1291723521
What is ×?