title: OPDA Certificate
body: <p>What is OPDA Certificate? </p>
  
  <p>Because during installation of unsigned symbian apps, it gives an error.</p>
  
  <p>"unable to install a protected app from an unknown supplier" </p>
  
  <p>So what does this certificate contains actually????? </p>
  
  <p>And after signing the application with this OPDA certificate and the key, the application works....</p>