title: Eavesdropping in SIP Communication
body: <p>For a school project, I need to make an eavesdropping experiment between a SIP user agent and a SIP server. The experiment has to include the following steps:</p>
  
  <pre><code>  i)Establish a voice/data communication between two SIP agent.
  
    ii) Capture the signal (i.e. SIP packets) in wireshark.
  
    iii) Change the content of the signal via wireshark or some 
    other tool that fits better to this purpose.
  
    iv) Encrypting/securing the communication between the agents somehow 
    to avoid third parties (e.g. wireshark to eavesdrop the communication) 
     from eavesdropping.
  </code></pre>
  
  <p>Could you please tell me if there are tools for simulating the above scenario? I prefer to do this programmatically actually and I know there is an open source SIP stack named resip (resiprocate.org) which provides an example user agent and server already in C++. Can I simulate this scenario programmatically or it's better to use some tools that can do this?</p>