# Return some error
    ...
```

But by using the `secrets.compare_digest()` it will be secure against a type of attacks called "timing attacks".

### Timing Attacks { #timing-attacks }

But what's a "timing attack"?

Let's imagine some attackers are trying to guess the username and password.

And they send a request with a username `johndoe` and a password `love123`.

- **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

 */
package jcifs.ntlmssp.av;

import jcifs.internal.util.SMBUtil;

/**
 * NTLMSSP AV pair representing timestamp information in NTLM authentication.
 * Contains time-based data used to prevent replay attacks and ensure message freshness.
 *
 * @author mbechler
 */
public class AvTimestamp extends AvPair {

    /**
     * Constructs an AvTimestamp from raw byte data
     *

 */
package jcifs.util;

import java.util.regex.Pattern;

/**
 * Comprehensive input validation utility for SMB protocol implementation.
 * Provides validation methods to prevent buffer overflows, injection attacks,
 * and other security vulnerabilities.
 */
public final class InputValidator {

    private InputValidator() {
        // Utility class
    }

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
     */

## `TrustedHostMiddleware` { #trustedhostmiddleware }

Enforces that all incoming requests have a correctly set `Host` header, in order to guard against HTTP Host Header attacks.

{* ../../docs_src/advanced_middleware/tutorial002.py hl[2,6:8] *}

The following arguments are supported:

import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.smb.SmbException;

/**
 * Rate limiter for authentication attempts to prevent brute force attacks.
 *
 * Features:
 * - Per-account rate limiting
 * - Per-IP rate limiting
 * - Global rate limiting
 * - Exponential backoff for repeated failures
 * - Account lockout after threshold

        constantTimeCopy(output, message.length, authTag, 0, tagLength);

        return new EncryptionResult(ciphertext, authTag);
    }

    /**
     * Perform constant-time encryption to prevent timing attacks
     */
    private byte[] performConstantTimeEncryption(Cipher cipher, byte[] message) throws Exception {
        // Pad to fixed block size to prevent timing leaks
        int blockSize = cipher.getBlockSize();

import jcifs.internal.smb2.nego.PreauthIntegrityNegotiateContext;

/**
 * Enhanced Pre-Authentication Integrity Service for SMB 3.1.1.
 *
 * Provides comprehensive pre-authentication integrity protection against
 * downgrade attacks by maintaining cryptographic hash chains of all
 * negotiation and session setup messages.
 */
public class PreauthIntegrityService {

		header.Set("X-XSS-Protection", "1; mode=block")                                // Prevents against XSS attacks
		header.Set("X-Content-Type-Options", "nosniff")                                // Prevent mime-sniff
		header.Set("Strict-Transport-Security", "max-age=31536000; includeSubDomains") // HSTS mitigates variants of MITM attacks

		// Previously, this value was set right before a response was sent to