New Post: uploading encrypt data

hi friend

i using this code for connecting to sftp server :

 var connectionInfo = new PasswordConnectionInfo(txtHost.Text, 22, txtUsername.Text, txtPassword.Text, ProxyTypes.Http, "209.xxx.xxx.xx", 3128,"proxyUser","proxyPass");
                sftp = new SftpClient(connectionInfo);
                try
                {
                    sftp.Connect();
                    addItemToListBox("Connect", "Connect to server Success.");
                   
                }

now , when sniffing my connection with wireshark , i can see my http request !!!

how to encrypt my requests and packets ???
thanks