vuefilemanager/app/Http/Requests/Share/AuthenticateShareRequest.php

<?php
namespace App\Http\Requests\Share;

use Illuminate\Foundation\Http\FormRequest;

class AuthenticateShareRequest extends FormRequest
{
    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            'password' => 'required|string',
        ];
    }
}