* specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash
   * functions together: {@code Hashing.concatenating(Hashing.sha512(), Hashing.sha512())}.
   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {

    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(MD5_KEY).toString());
    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(keyData).toString());

    assertEquals(
        "Hashing.hmacSha1(Key[algorithm=HmacSHA1, format=RAW])",
        Hashing.hmacSha1(SHA1_KEY).toString());
    assertEquals(

    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(MD5_KEY).toString());
    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(keyData).toString());

    assertEquals(
        "Hashing.hmacSha1(Key[algorithm=HmacSHA1, format=RAW])",
        Hashing.hmacSha1(SHA1_KEY).toString());
    assertEquals(

# OAuth2 com Senha (e hashing), Bearer com tokens JWT { #oauth2-with-password-and-hashing-bearer-with-jwt-tokens }

Agora que temos todo o fluxo de segurança, vamos tornar a aplicação realmente segura, usando tokens <abbr title="JSON Web Tokens">JWT</abbr> e hashing de senhas seguras.

Este código é algo que você pode realmente usar na sua aplicação, salvar os hashes das senhas no seu banco de dados, etc.

Vamos começar de onde paramos no capítulo anterior e incrementá-lo.

    }

    if (hashTableKToV.length < minCapacity) {
      int newTableSize = Hashing.closedTableSize(minCapacity, 1.0);
      hashTableKToV = createFilledWithAbsent(newTableSize);
      hashTableVToK = createFilledWithAbsent(newTableSize);

      for (int entryToRehash = 0; entryToRehash < size; entryToRehash++) {
        int keyHash = Hashing.smearedHash(keys[entryToRehash]);
        int keyBucket = bucket(keyHash);

# OAuth2 mit Passwort (und Hashing), Bearer mit JWT-Tokens { #oauth2-with-password-and-hashing-bearer-with-jwt-tokens }

Da wir nun über den gesamten Sicherheitsablauf verfügen, machen wir die Anwendung tatsächlich sicher, indem wir <abbr title="JSON Web Tokens">JWT</abbr>-Tokens und sicheres Passwort-Hashing verwenden.

Diesen Code können Sie tatsächlich in Ihrer Anwendung verwenden, die Passwort-Hashes in Ihrer Datenbank speichern, usw.

# OAuth2 con Password (y hashing), Bearer con tokens JWT { #oauth2-with-password-and-hashing-bearer-with-jwt-tokens }

Ahora que tenemos todo el flujo de seguridad, hagamos que la aplicación sea realmente segura, usando tokens <abbr title="JSON Web Tokens">JWT</abbr> y hashing de contraseñas seguras.

Este código es algo que puedes usar realmente en tu aplicación, guardar los hashes de las contraseñas en tu base de datos, etc.

Sie sollten niemals Klartext-Passwörter speichern, daher verwenden wir ein (gefaktes) Passwort-Hashing-System.

Wenn die Passwörter nicht übereinstimmen, geben wir denselben Fehler zurück.

#### Passwort-Hashing { #password-hashing }

„Hashing“ bedeutet: Konvertieren eines Inhalts (in diesem Fall eines Passworts) in eine Folge von Bytes (ein schlichter String), die wie Kauderwelsch aussieht.

///

## Password hashing { #password-hashing }

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

### Why use password hashing { #why-use-password-hashing }

 *       array. This hashing API accepts an arbitrary sequence of byte and multibyte values (via
 *       {@link Hasher}), but this is merely a convenience; these are always translated into raw
 *       byte sequences under the covers.
 *   <li><b>hash code:</b> each hash function always yields hash codes of the same fixed bit length
 *       (given by {@link #bits}). For example, {@link Hashing#sha1} produces a 160-bit number,