private static final byte[] ZERO_IV = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

    /**
     * Calculates a MAC using the ARCFOUR-HMAC-MD5 algorithm.
     * This method implements the Microsoft variant of the Kerberos ARCFOUR-HMAC-MD5 checksum.
     *
     * @param keyusage the Kerberos key usage number for this operation
     * @param key the encryption key to use for MAC calculation

 * supporting various checksum algorithms including HMAC-MD5 and HMAC-SHA1 with AES.
 */
public class PacSignature {

    /**
     * Kerberos checksum type for HMAC-MD5 (ARCFOUR-HMAC).
     */
    public static final int KERB_CHECKSUM_HMAC_MD5 = 0xFFFFFF76;
    /**
     * Kerberos checksum type for HMAC-SHA1-96 with AES-128.
     */
    public static final int HMAC_SHA1_96_AES128 = 0x0000000F;

    /** DES encryption type identifier */
    int DES_ENC_TYPE = 3;
    /** RC4 encryption type identifier */
    int RC4_ENC_TYPE = 23;
    /** RC4 algorithm name */
    String RC4_ALGORITHM = "ARCFOUR";
    /** HMAC algorithm name */
    String HMAC_ALGORITHM = "HmacMD5";
    /** Size of confounder in bytes */
    int CONFOUNDER_SIZE = 8;
    /** Size of checksum in bytes */
    int CHECKSUM_SIZE = 16;

import org.mockito.MockedStatic;

class PacTest {

    private Map<Integer, KerberosKey> keys;

    @BeforeEach
    void setUp() {
        keys = new HashMap<>();
        // Use ARCFOUR-HMAC encryption type (23) which matches KERB_CHECKSUM_HMAC_MD5
        KerberosKey serverKey = new KerberosKey(new KerberosPrincipal("******@****.***"), "serverKey1234567".getBytes(),
                PacSignature.ETYPE_ARCFOUR_HMAC, 1);

 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.smb1.util;

/**
 * Implementation of the RC4 (ARCFOUR) stream cipher algorithm.
 * This class provides RC4 encryption/decryption functionality used in SMB1 protocol operations.
 */
public class RC4 {

    byte[] s;
    int i, j;

    /**

     */
    @Test
    void testCalculateMacArcfourHMACMD5() throws GeneralSecurityException {
        // Using a key with a known value for reproducibility
        SecretKeySpec key = new SecretKeySpec(new byte[16], "ARCFOUR");
        byte[] mac = PacMac.calculateMacArcfourHMACMD5(3, key, TEST_DATA);
        assertNotNull(mac);
        assertEquals(16, mac.length);

        // Test with a different key usage

                    tc.getConfig().getRandom().nextBytes(this.masterKey);

                    final byte[] exchangedKey = new byte[16];
                    final Cipher arcfour = Crypto.getArcfour(ntlm2SessionKey);
                    arcfour.update(this.masterKey, 0, 16, exchangedKey, 0);
                    setEncryptedSessionKey(exchangedKey);
                } else {
                    this.masterKey = ntlm2SessionKey;