title: Openssl: create CSR string_mask illegal characters
body: <p>While creating a CSR with characters such as &quot;ƒŸ&quot;, causes the error displayed below however other characters with accents are allowed like &quot;éó&quot;</p>
  <blockquote>
  <p>openssl_csr_new(): dn: add_entry_by_NID 15 -&gt; test�� (failed; check
  error queue and value of string_mask OpenSSL option if illegal
  characters are reported) in CSR.class.php on line 95</p>
  </blockquote>
  <p>Within the openssl.cnf the string_mask nombstr however I cannot find any documentation on what this filter includes? So I can detect and filter before calling openssl function.</p>
  <pre><code># nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
  string_mask = nombstr
  </code></pre>