code: public static void
  verifyMessage(Message message, byte [] b, KEYRecord key, SIGRecord previous)
  	throws DNSSEC.DNSSECException
  {
  	SIGRecord sig = null;
  	Record [] additional = message.getSectionArray(Section.ADDITIONAL);
  	for (int i = 0; i < additional.length; i++) {
  		if (additional[i].getType() != Type.SIG)
  			continue;
  		if (((SIGRecord) additional[i]).getTypeCovered() != 0)
  			continue;
  		sig = (SIGRecord) additional[i];
  		break;
  	}
  	DNSSEC.verifyMessage(message, b, sig, previous, key);
  }
docs: Verify a message using SIG(0).
  @param message The message to be signed
  @param b An array containing the message in unparsed form.  This is
  necessary since SIG(0) signs the message in wire format, and we can't
  recreate the exact wire format (with the same name compression).
  @param key The KEY record to verify the signature with.
  @param previous If this message is a response, the SIG(0) from the query