title: Issuing SSL certificates myself for subdomains of a domain I have an SSL cert for
body: <p>I guess it can't be done, but if so, I'd like to know why.</p>
  
  <p>Let's say I get an SSL certificate for example.com from one of the official certificate authorities around. Let's also say I'm running a.example.com and b.c.d.example.com and would like to have SSL certificates for those as well.</p>
  
  <p>Can I use the example.com certificate to issue certificates for a.example.com and b.c.d.example.com myself? And will they be recognized by users' browsers? If not, why not?</p>
  
  <p>(My guess that it can't be done is because it would break the very lucrative wildcard cert business model, wouldn't it?)</p>
  
  <p><strong>Clarification:</strong> can't I act as a "self-signed" certificate authority using the keypair for which I obtained the official cert, and simply add my official cert in the validation chain? </p>