title: Restrict access to audio device under Windows XP-8 to specific application/user
body: <p>I have written an c# 4.0 application that analyses the microphone input and records DTMF tones that represent credit card numbers entered by our clients. This all works well, but since we are working under <em>PCI Compliance</em> (see <a href="https://www.pcisecuritystandards.org" rel="nofollow">www.pcisecuritystandards.org</a>), we don't want to allow the logged in user (call centre staff) to listen or even record the microphone input so that they then can parse the credit card numbers on their own with a 3rd party app or their phones. So the question I have is:</p>
  
  <ul>
  <li>How can I <strong>restrict</strong> the <strong>microphone input</strong> to a <strong>specific application</strong> so
  that it can't be heard or recorded somewhere else?</li>
  </ul>
  
  <p>If there is no solution to this, the 2nd question arises:</p>
  
  <ul>
  <li>How can I <strong>restrict</strong> the <strong>microphone input</strong> to a <strong>specific user</strong> so that it
  can't be heard or recorded somewhere else (I could run the software
  as a Windows service under specific user credentials)?</li>
  </ul>
  
  <p>Kind regards,
  JB</p>