title: How to automatically install a client certificate in a web browser?
body: <p>I want to authenticate users with X.509 certificates to my web site.</p>
  
  <p>I can generate an RSA key pair with <code>keygen</code> element of HTML, and then send the <code>SignedPublicKeyAndChallenge</code> structure to the server. The server can then check and sign the public key and generate a X.509 certificate for that key, for the client.</p>
  
  <p>Now, when I signed up at StartSSL, the HTML pages there installed the certificate into my browser’s store without me doing more than clicking a button and I want to do the same. How do I go about that? Send the certificate with a certain Content-Type? Do it with client-side scripting? How do the browser know it’s supposed to install a client certificate?</p>
  
  <p>I know I can tell the user to install it manually, but if it <em>can</em> be automated, then I want to make it so.</p>