class InvalidInputs {
        @Test
        @DisplayName("getSigningKey throws when unavailable")
        void testGetSigningKeyThrows() {
            DummySSPContext ctx = new DummySSPContext(null, false, null, null, 0, false);
            CIFSException ex = assertThrows(CIFSException.class, ctx::getSigningKey);
            assertTrue(ex.getMessage().contains("signing key"));
        }

        @Test

    }

    @Test
    @DisplayName("getSigningKey delegates to underlying mechanism context")
    void testGetSigningKeyDelegates() throws Exception {
        SpnegoContext ctx = newContext();
        byte[] key = new byte[] { 1, 2, 3 };
        when(this.mechContext.getSigningKey()).thenReturn(key);
        assertSame(key, ctx.getSigningKey());
        verify(this.mechContext, times(1)).getSigningKey();
    }

    @Test

        NtlmContext context = new NtlmContext(mockAuth, true);
        assertNotNull(context);
        assertFalse(context.isEstablished());
        assertNull(context.getServerChallenge());
        assertNull(context.getSigningKey());
        assertNull(context.getNetbiosName());

        int expectedFlags = NtlmFlags.NTLMSSP_REQUEST_TARGET | NtlmFlags.NTLMSSP_NEGOTIATE_NTLM2 | NtlmFlags.NTLMSSP_NEGOTIATE_128

	canonicalRequestBytes := sha256.Sum256([]byte(canonicalRequest))
	stringToSign += hex.EncodeToString(canonicalRequestBytes[:])
	return stringToSign
}

// getSigningKey hmac seed to calculate final signature.
func getSigningKey(secretKey string, t time.Time, region string, stype serviceType) []byte {
	date := sumHMAC([]byte("AWS4"+secretKey), []byte(t.Format(yyyymmdd)))
	regionBytes := sumHMAC(date, []byte(region))

    public String getNetbiosName() {
        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SSPContext#getSigningKey()
     */
    @Override
    public byte[] getSigningKey() throws CIFSException {
        return this.mechContext.getSigningKey();
    }

    /**
     * Initialize the GSSContext to provide SPNEGO feature.
     *
     * @param inputBuf
     * @param offset

     */
    byte[] getSessionKey();

    /**
     * Gets the signing key for SMB2/3
     *
     * @return the signing key or null if not available
     */
    byte[] getSigningKey();

    /**
     * Validates authentication credentials
     *
     * @return true if credentials are valid
     */
    boolean validateCredentials();

    /**

    /**
     * Gets the signing key for the session.
     * @return the signing key for the session
     * @throws CIFSException if an error occurs retrieving the signing key
     */
    byte[] getSigningKey() throws CIFSException;

    /**
     * Checks whether the security context is established.
     * @return whether the context is established
     */
    boolean isEstablished();

    /**

     */
    @Override
    public String getNetbiosName() {
        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SSPContext#getSigningKey()
     */
    @Override
    public byte[] getSigningKey() throws SmbException {
        /*
         * The kerberos session key is not accessible via the JGSS API. IBM and
         * Oracle both implement a similar API to make an ExtendedGSSContext

                    this.sessionKey = ctx.getSigningKey();
                    if (request != null && request.getDigest() != null) {
                        /* success - install the signing digest */
                        setDigest(request.getDigest());
                    } else if (!anonymous && isSignatureSetupRequired()) {
                        byte[] signingKey = ctx.getSigningKey();

		cr.seedDate.Format(iso8601Format) + "\n" +
		getScope(cr.seedDate, cr.region) + "\n" +
		cr.seedSignature + "\n" +
		emptySHA256 + "\n" +
		hashedChunk

	// Get hmac signing key.
	signingKey := getSigningKey(cr.cred.SecretKey, cr.seedDate, cr.region, serviceS3)

	// Calculate signature.
	newSignature := getSignature(signingKey, stringToSign)

	return newSignature
}