public Set getCriticalExtensionOIDs()
{
if (this.getVersion() == 3)
{
HashSet set = new HashSet();
X509Extensions extensions = c.getTBSCertificate().getExtensions();
if (extensions != null)
{
Enumeration e = extensions.oids();
while (e.hasMoreElements())
{
DERObjectIdentifier oid = (DERObjectIdentifier)e.nextElement();
X509Extension ext = extensions.getExtension(oid);
if (ext.isCritical())
{
set.add(oid.getId());
}