// Test HMAC-MD5
        byte[] mac1 = PacMac.calculateMac(PacSignature.KERB_CHECKSUM_HMAC_MD5, keys, TEST_DATA);
        assertNotNull(mac1);
        assertEquals(16, mac1.length);

        // Test AES128
        byte[] mac2 = PacMac.calculateMac(PacSignature.HMAC_SHA1_96_AES128, keys, TEST_DATA);
        assertNotNull(mac2);
        assertEquals(12, mac2.length);

        try (MockedStatic<PacMac> pacMacMock = mockStatic(PacMac.class)) {
            // Mock the calculateMac method to return a valid checksum
            byte[] mockChecksum = new byte[16];
            pacMacMock.when(() -> PacMac.calculateMac(anyInt(), any(), any())).thenReturn(mockChecksum);

            // Create a minimal valid PAC structure

                    this.serverSignature.getType(), Hexdump.toHexString(this.serverSignature.getChecksum())));
        }

        byte checksum[] = PacMac.calculateMac(this.serverSignature.getType(), keys, checksumData);
        if (!MessageDigest.isEqual(this.serverSignature.getChecksum(), checksum)) {
            if (log.isDebugEnabled()) {

     * @param data the data to calculate the MAC for
     * @return the calculated mac bytes
     * @throws PACDecodingException if the MAC calculation fails or required keys are missing
     */
    public static byte[] calculateMac(int type, Map<Integer, KerberosKey> keys, byte[] data) throws PACDecodingException {
        try {
            int usage = 17;
            if (type == PacSignature.KERB_CHECKSUM_HMAC_MD5) {

        verify(this.mechContext, times(1)).dispose();
    }

    @Test
    @DisplayName("calculateMIC throws when context not established")
    void testCalculateMICRequiresEstablished() throws Exception {
        SpnegoContext ctx = newContext();
        CIFSException ex = assertThrows(CIFSException.class, () -> ctx.calculateMIC(new byte[] { 1 }));
        assertEquals("Context is not established", ex.getMessage());

     * @param data the data to calculate MIC for
     * @return MIC
     * @throws CIFSException if an error occurs calculating the MIC
     */
    byte[] calculateMIC(byte[] data) throws CIFSException;

    /**
     * Verifies a Message Integrity Code (MIC) for the given data.
     * @param data the data to verify
     * @param mic the MIC to verify against