参考地址：https://laravel-china.org/articles/5963/toggle-laravel-login-default-bcrypt-encryption-validation

自己做一个备份记录
1.编写自己的hasher

<?php

namespace App\Helpers\Hasher;

use Illuminate\Contracts\Hashing\Hasher;

class MD5Hasher implements Hasher
{
    public function check($value, $hashedValue, array $options = [])
    {

        return $this->make($value) === $hashedValue;
    }

    public function needsRehash($hashedValue, array $options = [])
    {
        return false;
    }

    public function make($value, array $options = [])
    {
        $value = env('SALT', '').$value;

        return md5($value);
    }

}

2.用自己的Hasher替换默认的Hasher
创建MD5HashServiceProvider

php artisan make:provider MD5HashServiceProvider

<?php

namespace App\Providers;

use App\Helpers\Hasher\MD5Hasher;
use Illuminate\Support\ServiceProvider;

class MD5HashServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap the application services.
     *
     * @return void
     */
    public function boot()
    {
        $this->app->singleton('hash', function () {
            return new MD5Hasher;
        });
    }

    /**
     * Register the application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    public function provides()
    {
        return ['hash'];
    }
}

3.然后在config/app.php的providers中，将加密服务替换

Illuminate\Hashing\HashServiceProvider::class,

替换为

\App\Providers\MD5HashServiceProvider::class,