# OAuth2 实现密码哈希与 Bearer  JWT 令牌验证

至此，我们已经编写了所有安全流，本章学习如何使用 <abbr title="JSON Web Tokens">JWT</abbr> 令牌（Token）和安全密码哈希（Hash）实现真正的安全机制。

本章的示例代码真正实现了在应用的数据库中保存哈希密码等功能。

接下来，我们紧接上一章，继续完善安全机制。

## JWT 简介

JWT 即**JSON 网络令牌**（JSON Web Tokens）。

JWT 是一种将 JSON 对象编码为没有空格，且难以理解的长字符串的标准。JWT 的内容如下所示：

```

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"encoding/binary"
	"errors"
	"fmt"
	"hash/crc32"
	"math/rand"
	"net/http"
	"reflect"
	"strings"
	"sync"
	"time"

	"github.com/dchest/siphash"
	"github.com/google/uuid"
	"github.com/minio/madmin-go/v3"
	"github.com/minio/minio-go/v7/pkg/set"

 * client.connectionPool().evictAll();
 * ```
 *
 * If your client has a cache, call [close()][Cache.close]. Note that it is an error to create calls
 * against a cache that is closed, and doing so will cause the call to crash.
 *
 * ```java
 * client.cache().close();
 * ```
 *
 * OkHttp also uses daemon threads for HTTP/2 connections. These will exit automatically if they
 * remain idle.
 */

Para o OAuth2, eles são apenas strings.

///

## Visão global { #global-view }

Primeiro, vamos olhar rapidamente as partes que mudam dos exemplos do **Tutorial - Guia de Usuário** para [OAuth2 com Senha (e hash), Bearer com tokens JWT](../../tutorial/security/oauth2-jwt.md){.internal-link target=_blank}. Agora utilizando escopos OAuth2:

{* ../../docs_src/security/tutorial005_an_py310.py hl[5,9,13,47,65,106,108:116,122:126,130:136,141,157] *}

pkg hash/crc64, const ISO ideal-int
pkg hash/crc64, const Size ideal-int
pkg hash/crc64, func Checksum([]uint8, *Table) uint64
pkg hash/crc64, func MakeTable(uint64) *Table
pkg hash/crc64, func New(*Table) hash.Hash64
pkg hash/crc64, func Update(uint64, *Table, []uint8) uint64
pkg hash/crc64, type Table [256]uint64
pkg hash/fnv, func New32() hash.Hash32
pkg hash/fnv, func New32a() hash.Hash32
pkg hash/fnv, func New64() hash.Hash64

  public void testCapacityForNegativeSizeFails() {
    assertThrows(IllegalArgumentException.class, () -> Maps.capacity(-1));
  }

  /**
   * Tests that nHMWES makes hash maps large enough that adding the expected number of elements
   * won't cause a rehash.
   *
   * <p>As of jdk7u40, HashMap has an empty-map optimization. The argument to new HashMap(int) is
   * noted, but the initial table is a zero-length array.
   *

### Reiniciar Después del Colapso { #restart-after-crash }

Pero en esos casos con errores realmente malos que colapsan el **proceso en ejecución**, querrías un componente externo encargado de **reiniciar** el proceso, al menos un par de veces...

/// tip | Consejo

labels.crawler=Crawler
labels.crudMode=Modalità
labels.errorCountMax=Numero massimo di errori
labels.errorCountMin=Numero minimo di errori
labels.facet=Faccetta
labels.geo=Geo
labels.groups=Gruppi
labels.hash=Hash
labels.maxSize=Dimensione massima
labels.order=Ordine
labels.purgeSuggestSearchLogDay=Elimina informazioni suggerite precedenti
labels.q=Query
labels.roles=Ruoli
labels.suggestSearchLog=Log di ricerca suggeriti

fancied she heard the Rabbit just under the window, she suddenly
spread out her hand, and made a snatch in the air.  She did not
get hold of anything, but she heard a little shriek and a fall,
and a crash of broken glass, from which she concluded that it was
just possible it had fallen into a cucumber-frame, or something
of the sort.

  Next came an angry voice--the Rabbit's--`Pat! Pat!  Where are

channel

// charity : Public Interest Registry
// https://www.iana.org/domains/root/db/charity.html
charity

// chase : JPMorgan Chase Bank, National Association
// https://www.iana.org/domains/root/db/chase.html
chase

// chat : Binky Moon, LLC
// https://www.iana.org/domains/root/db/chat.html
chat

// cheap : Binky Moon, LLC