*/
    static Stream<Arguments> messages() {
        return Stream.of(Arguments.of((String) null), Arguments.of(""), Arguments.of("unexpected downgrade"));
    }

    @Test
    @DisplayName("Default ctor: null message/cause; toString is class name; type hierarchy")
    void defaultConstructor_hasNullMessageAndCause_andTypeHierarchy() {
        // Arrange & Act

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.smb;

import jcifs.CIFSException;

/**
 * Exception thrown when an SMB protocol downgrade attack is detected.
 * Indicates that the negotiated protocol version is lower than expected or required.
 *
 * @author mbechler
 *
 */
public class SMBProtocolDowngradeException extends CIFSException {

    /**

    }
  }

  companion object {
    /**
     * The cipher suite used during TLS connection fallback to indicate a fallback. See
     * https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00
     */
    const val TLS_FALLBACK_SCSV = "TLS_FALLBACK_SCSV"
  }

- **Encryption Context**: Per-session encryption state management
- **Key Derivation**: SMB3 KDF implementation with dialect-specific parameters
- **Pre-Authentication Integrity**: SMB 3.1.1 PAI for preventing downgrade attacks
- **Automatic Detection**: Encryption automatically enabled when servers require it
- **Secure Key Management**: Proper key derivation and nonce generation

### Core Features

import jcifs.internal.util.SMBUtil;

/**
 * SMB2 Pre-authentication Integrity Negotiate Context.
 *
 * This negotiate context is used in SMB 3.1.1 to establish
 * pre-authentication integrity protection against downgrade attacks.
 *
 * @author mbechler
 */
public class PreauthIntegrityNegotiateContext implements NegotiateContextRequest, NegotiateContextResponse {

    /**
     * Context type
     */

	// Current version being written.
	xlVersionCurrent [4]byte
)

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.
	xlVersionMajor = 1

	// Non breaking changes.
	// Bumping this is informational, but should be done
	// if any change is made to the data stored, bumping this