/**
     * {@inheritDoc}
     *
     * @see jcifs.smb.NtlmPasswordAuthenticator#getUserSessionKey(jcifs.CIFSContext, byte[])
     */
    @Override
    public byte[] getUserSessionKey(final CIFSContext tc, final byte[] chlng) {
        if (this.hashesExternal) {
            return null;
        }
        return super.getUserSessionKey(tc, chlng);
    }

    /**
     * {@inheritDoc}
     *

                auth.getUserSessionKey(transport.server.encryptionKey, macSigningKey, 0);
                System.arraycopy(auth.getUnicodeHash(transport.server.encryptionKey), 0, macSigningKey, 16, 24);
                break;
            case 3:
            case 4:
            case 5:
                macSigningKey = new byte[16];
                auth.getUserSessionKey(transport.server.encryptionKey, macSigningKey, 0);