In late 2012, companies providing VPN services claimed the Great Firewall of China became able to "learn, discover and block" the encrypted communications methods used by a number of different VPN systems.
2012年底，提供VPN服务的公司声称，中国的防火长城已经可以“学习、发现并屏蔽”许多不同VPN系统的加密通讯手段。