title: X.509 Are all parts of a DN optional?
body: <p>Are all the parts of the DN in a X.509 optional?<br>
  From RFC3280:  </p>
  
  <blockquote>
    <p>Implementations of this specification MUST    be prepared to receive
    the following standard attribute types in    issuer and subject
    (section 4.1.2.6) names:</p>
  
  <pre><code>  * country,
    * organization,
    * organizational-unit,
    * distinguished name qualifier,
    * state or province name,
    * common name (e.g., "Susan Housley"), and
    * serial number.
  </code></pre>
  </blockquote>
  
  <p>I could not find if any of these is mandatory.<br>
  I am asking because I am seeing a certificate that is signed by a trusted CA but in the issuer's field the <code>CN</code> is missing (and the <code>C</code> but I don't think that's important).<br>
  I was expecting that <code>CN</code> is mandatory. Is it?<br>
  Is there any security implications of the omission of the<code>CN</code> from the issuer's field?</p>