protected ProtocolTreeNode addAuthResponse()
{
if (!this.challengeArray.ContainsKey("nonce"))
this.challengeArray.Add("nonce", "");
string resp = this.authenticate(this.challengeArray["nonce"]);
var node = new ProtocolTreeNode("response",
new KeyValue[] { new KeyValue("xmlns", "urn:ietf:params:xml:ns:xmpp-sasl") },
Func.EncodeTo64(resp, this.sysEncoding));
return node;
}