final DerivationParameters param = new KDFCounterParameters(sessionKey, null /* prefix */, suffix /* suffix */, r /* r */);
        gen.init(param);

        final byte[] derived = new byte[16];
        gen.generateBytes(derived, 0, 16);
        return derived;
    }

    /**
     * @param string
     * @return null terminated ASCII bytes
     */
    private static byte[] toCBytes(final String string) {

            }
          };
      ClosingFuture<V> derived = new ClosingFuture<>(futureCombiner().call(callable, executor));
      derived.closeables.add(closeables, directExecutor());
      return derived;
    }

    /**
     * Returns a new {@code ClosingFuture} pipeline step derived from the inputs by applying a

            }
          };
      ClosingFuture<V> derived = new ClosingFuture<>(futureCombiner().call(callable, executor));
      derived.closeables.add(closeables, directExecutor());
      return derived;
    }

    /**
     * Returns a new {@code ClosingFuture} pipeline step derived from the inputs by applying a

        // Arrange - use a real cause so message is derived from cause.toString()
        Throwable cause = new IllegalStateException("proto mismatch");
        String expectedMessage = cause.toString();

        // Act
        SMBProtocolDowngradeException ex = new SMBProtocolDowngradeException(cause);

        // Assert - cause preserved, message derived from cause
        assertSame(cause, ex.getCause());

        byte[] derived1 = keyManager.deriveKey(baseKey, "label1", null, 32);
        byte[] derived2 = keyManager.deriveKey(baseKey, "label2", null, 32);
        byte[] derived3 = keyManager.deriveKey(baseKey, "label1", new byte[] { 1, 2, 3 }, 32);

        assertEquals(32, derived1.length, "Derived key should have correct length");
        assertEquals(32, derived2.length, "Derived key should have correct length");

        assertEquals(10, ndrBuffer.getLength());

        ndrBuffer.setLength(20);
        assertEquals(20, ndrBuffer.getLength());

        // Test with derived buffer
        NdrBuffer derived = ndrBuffer.derive(0);
        derived.setLength(5);
        assertEquals(5, derived.getLength());
        assertEquals(5, ndrBuffer.getLength()); // Should affect original's deferred length
    }

    @Test
    void testAdvance() {

        labelType1.setName("Test Label 1");
        labelType1.setValue("test1");
        labelType1.setPermissions(new String[0]);
        labelType1.setVirtualHost("");
        // Locale is derived from value, not set directly
        labelType1.setIncludedPaths("/test.*");
        labelType1.setExcludedPaths("/exclude.*");
        labelTypeList.add(labelType1);

        LabelType labelType2 = new LabelType();

        // Then
        assertFalse(Arrays.equals(signingKey1, signingKey2), "Different session keys should produce different derived keys");
    }

    @Test
    @DisplayName("Should derive unique keys for different preauth values")
    void testDeriveKeys_UniquePreauthValues() {
        // Given
        byte[] preauth1 = new byte[64];

    }

    /**
     * Derive a new key from an existing key
     *
     * @param baseKey the base key
     * @param label key derivation label
     * @param context key derivation context
     * @param length desired key length in bytes
     * @return derived key
     * @throws GeneralSecurityException if key derivation fails
     */

        this.start = index = start;
        length = 0;
        deferred = this;
    }

    /**
     * Creates a derived NdrBuffer at the specified index position.
     *
     * @param idx the index position for the derived buffer
     * @return the derived NdrBuffer
     */
    public NdrBuffer derive(final int idx) {
        final NdrBuffer nb = new NdrBuffer(buf, start);
        nb.index = idx;
        nb.deferred = deferred;