linux下的rdesktop连接win的3389是否是加密的？

oar

rdeskop 回车后看到
Usage: rdesktop [options] server[:port]
   -u: user name
   -d: domain
   -s: shell
   -c: working directory
   -p: password (- to prompt)
   -n: client hostname
   -k: keyboard layout on terminal server (us,sv,gr,etc.)
   -g: desktop geometry (WxH)
   -f: full-screen mode
   -b: force bitmap updates
   -e: disable encryption (French TS)
   -m: do not send motion events
   -C: use private colour map
   -K: keep window manager key bindings
   -T: window title
   -D: hide window manager decorations

中间这个参数   -e: disable encryption (French TS) 用上了表示不加密对吧
那么不用这个是否表示是加密的？