notBefore = (Date) val.getValue();
notBefore = (Date) val.getValueAs (DER.GENERALIZED_TIME);
  public PrivateKeyUsagePeriod(final byte[] encoded) throws IOException  {    super(encoded);    DERReader der = new DERReader(encoded);    DERValue val = der.read();    if (!val.isConstructed())      throw new IOException("malformed PrivateKeyUsagePeriod");    if (val.getLength() > 0)      val = der.read();    if (val.getTagClass() == DER.APPLICATION || val.getTag() == 0)      {        notBefore = (Date) val.getValue();        val = der.read();      }    else      notBefore = null;    if (val.getTagClass() == DER.APPLICATION || val.getTag() == 1)      {        notAfter = (Date) val.getValue();      }    else      notAfter = null;  }