title: Can I turn off SRTP when use webrtc
body: <p>Now I test webrtc communicate with SIP Client(sx20)</p>
  
  <p>I send invite message with webrtc sdp.  but sip client answer has not finger print, and </p>
  
  <p>sip client answer is not SRTP just RTP.</p>
  
  <p>So I need to turn off SRTP in WEBRTC.  Can I do it?</p>
  
  <p>and one more question...   I think, finger print is encrypt key,<br>
  so, sender and receiver need to each key?  we need two key?  sender's key, receive's key?
  or we need just sender' key?</p>