code: public PublicKey
  getPublicKey() throws DNSSEC.DNSSECException {
  	if (publicKey != null)
  		return publicKey;
  
  	publicKey = DNSSEC.toPublicKey(this);
  	return publicKey;
  }
docs: Returns a PublicKey corresponding to the data in this key.
  @throws DNSSEC.DNSSECException The key could not be converted.