// Convert an existing Updatedescription to xml and sign it
public string ToXml(string rsakey)
{
if (String.IsNullOrWhiteSpace(rsakey))
{
throw new ArgumentException("Empty rsakey provided");
}
RSACryptoServiceProvider rsa;
try
{
rsa = new RSACryptoServiceProvider();
rsa.FromXmlString(rsakey);
}
catch
{
throw new ArgumentException("Invalid rsakey provided");
}
if (rsa.PublicOnly)
{
throw new ArgumentException("rsakey has only public part");
}
try
{
XmlDocument xdoc = new XmlDocument();
xdoc.LoadXml(this.ToXml());
xdoc.AddSignature(rsa);
return(xdoc.OuterXml);
}
catch
{ return(""); }
}
