title: Firefox 33.0 won't open a specific local application: Error code: sec_error_invalid_key
body: <p>Firefox upgraded to version 33.0 this morning. Since then, I cannot load a specific local application over HTTPS -- note that it uses a self-signed certificate. It displays the following error message:</p>
  
  <p><code>The key does not support the requested operation. (Error code: sec_error_invalid_key)</code></p>
  
  <p>I cannot see anything in Firebug. I restarted Firefox in safe mode, to make sure no add-on was the problem. I also cleaned my cache and cookies. The same application opens fine with Chrome, and Firefox can open other applications that use HTTPS with a self-signed certificate.</p>
  
  <p>Any idea how I could troubleshoot this issue?</p>
  
  <p><strong>Edit:</strong> Mozilla has made several important changes to security in Firefox 33.0. Details can be found <a href="https://developer.mozilla.org/en-US/Firefox/Releases/33/Site_Compatibility#Security">here</a>.</p>
  
  <p>In my particular situation, the self-signed certificate was blocked because it was deemed too weak:</p>
  
  <blockquote>
    <p>RSA 512, 1000 and 1023-bit certificates are now blocked by Firefox since they are not sufficient for security. Most certificates currently being issued should have a 2048-bit key length.</p>
  </blockquote>