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

    /** 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;

 * 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;

    /**

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);

Valid values: 
```
aes128-ctr
aes192-ctr
aes256-ctr
******@****.***
******@****.***
******@****.***
arcfour256
arcfour128
arcfour
aes128-cbc
3des-cbc
```

`--sftp=mac-algos=...` specifies a default set of MAC algorithms in preference order.
This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed because they have 

var supportedCiphers = []string{
	"aes128-ctr", "aes192-ctr", "aes256-ctr",
	"******@****.***", gcm256CipherID,
	chacha20Poly1305ID,
	"arcfour256", "arcfour128", "arcfour",
	aes128cbcID,
	tripledescbcID,
}

// preferredCiphers specifies the default preference for ciphers.
// https://cs.opensource.google/go/x/crypto/+/refs/tags/v0.22.0:ssh/common.go;l=37