### Hardware attacks

Physical GPUs or TPUs can also be the target of attacks. [Published
research](https://scholar.google.com/scholar?q=gpu+side+channel) shows that it
might be possible to use side channel attacks on the GPU to leak data from other
running models or processes in the same system. GPUs can also have
implementation bugs that might allow attackers to leave malicious code running

    # 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`.

    # Return some error
    ...
```

Pero al usar `secrets.compare_digest()` será seguro contra un tipo de ataques llamados "timing attacks".

### Timing Attacks

¿Pero qué es un "timing attack"?

Imaginemos que algunos atacantes están tratando de adivinar el nombre de usuario y la contraseña.

Y envían un request con un nombre de usuario `johndoe` y una contraseña `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
     *

import java.util.Collection;
import java.util.Map;
import org.jspecify.annotations.Nullable;

/**
 * An implementation of ImmutableMultiset backed by a JDK Map and a list of entries. Used to protect
 * against hash flooding attacks.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class JdkBackedImmutableMultiset<E> extends ImmutableMultiset<E> {
  private final Map<E, Integer> delegateMap;
  private final ImmutableList<Entry<E>> entries;

 */
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:

    # Return some error
    ...
```

Porém, ao utilizar o `secrets.compare_digest()`, isso estará seguro contra um tipo de ataque chamado "timing attacks" (ataques de temporização).

### Ataques de Temporização

Mas o que é um "timing attack" (ataque de temporização)?

Vamos imaginar que alguns invasores estão tentando adivinhar o usuário e a senha.