安装 HTMLPurifier for Laravel 5？

Installation failed, reverting ./composer.json to its original content.

[Composer\Repository\RepositorySecurityException]
The contents of https://packagist.laravel-china.org/p/prov...
4608817794edd62fe23415175b561e13bb9c2e5fa5415a92d8f468131ac.json do not mat
ch its signature. This should indicate a man-in-the-middle attack. Try runn
ing composer again and report this if you think it is a mistake.