Arrays.fill(decrypted, '\0');
    }

    @Test
    public void testEncryptDecryptEmpty() throws Exception {
        char[] plaintext = new char[0];

        byte[] encrypted = storage.encryptCredentials(plaintext);
        assertNotNull(encrypted, "Encrypted empty data should not be null");

        char[] decrypted = storage.decryptCredentials(encrypted);
        assertNotNull(decrypted, "Decrypted empty data should not be null");

    /** WAVE DASH */
    public static final char WAVE_DASH = '\u301C';

    /** FULLWIDTH TILDE */
    public static final char FULLWIDTH_TILDE = '\uFF5E';

    /** DOUBLE VERTICAL LINE */
    public static final char DOUBLE_VERTICAL_LINE = '\u2016';

    /** PARALLEL TO */
    public static final char PARALLEL_TO = '\u2225';

    /** MINUS SIGN */
    public static final char MINUS_SIGN = '\u2212';

            return null;
        }
        final char[] chars = new char[text.length()];
        for (int i = 0; i < chars.length; i++) {
            final char c = text.charAt(i);
            if (c >= 'ａ' && c <= 'ｚ') {
                chars[i] = (char) (c - 'ａ' + 'a');
            } else if (c >= 'Ａ' && c <= 'Ｚ') {
                chars[i] = (char) (c - 'Ａ' + 'A');
            } else if (c >= '０' && c <= '９') {

    }

    /**
     * Generates the NT password hash for the given password.
     * This version accepts char[] for better security.
     *
     * @param password the password to hash as char array
     * @return nt password hash
     */
    public static byte[] getNTHash(final char[] password) {
        if (password == null) {
            throw new NullPointerException("Password parameter is required");

        if (length == 0) {
            return;
        }

        final int s = length % 16;
        final int r = s == 0 ? length / 16 : length / 16 + 1;
        final char[] c = new char[r * (74 + NL_LENGTH)];
        final char[] d = new char[16];
        int i;
        int si = 0;
        int ci = 0;

        do {
            toHexChars(si, c, ci, 5);
            ci += 5;
            c[ci] = ':';

        // Test integer conversion
        char[] dst1 = new char[8];
        Hexdump.toHexChars(0x1234ABCD, dst1, 0, 8);
        assertEquals("1234ABCD", new String(dst1));

        // Test with smaller size
        char[] dst2 = new char[4];
        Hexdump.toHexChars(0xABCD, dst2, 0, 4);
        assertEquals("ABCD", new String(dst2));

        // Test with offset
        char[] dst3 = new char[10];

            int i = 0;
            do {
                if (i >= buf.length) {
                    final char[] nb = new char[buf.length * 2];
                    System.arraycopy(buf, 0, nb, 0, buf.length);
                    buf = nb;
                }
                buf[i++] = (char) peekc;
                peekc = read();
                peekct = peekc < 0 ? CT_WHITESPACE : peekc < 256 ? ctype[peekc] : CT_ALPHA;

        Field passwordField = NtlmPasswordAuthenticator.class.getDeclaredField("password");
        passwordField.setAccessible(true);

        char[] originalPassword = (char[]) passwordField.get(authenticator);
        char[] clonedPassword = (char[]) passwordField.get(cloned);

        assertNotSame(originalPassword, clonedPassword, "Cloned password should be a different array instance");

            final char originalChar1 = sb.charAt(i);
            final char originalChar2 = sb.charAt(i + 1);
            final char margedChar = mergeChar(originalChar1, originalChar2);
            if (margedChar != originalChar1) {
                sb.setCharAt(i, margedChar);
                sb.deleteCharAt(i + 1);
            } else {

    }

    /**
     * Test password in equals method
     */
    @Test
    public void testEqualsWithSecurePassword() {
        char[] password1 = "TestPass123!".toCharArray();
        char[] password2 = "TestPass123!".toCharArray();
        char[] password3 = "DifferentPass!".toCharArray();

        NtlmPasswordAuthenticator auth1 = new NtlmPasswordAuthenticator("DOMAIN", "user", password1);