this.encData = new KerberosEncData(decrypted, keysByAlgo);
                }
                catch ( GeneralSecurityException e ) {
                    throw new PACDecodingException("Decryption failed " + serverKey.getKeyType(), e);
                }
                break;
            default:
                throw new PACDecodingException("Unrecognized field " + tagged.getTagNo());
            }

    }


    /**
     * 
     * @param dialect
     * @param sessionKey
     * @param preauthIntegrity
     * @return derived decryption key
     */
    public static byte[] deriveDecryptionKey ( int dialect, byte[] sessionKey, byte[] preauthIntegrity ) {
        return derive(
            sessionKey,