How does China conduct one of world's toughest exams to prevent any leaks?

China’s Gaokao is considered one of world's toughest and most secure exams. Papers are treated as "state secrets" and printed in heavily guarded facilities monitored 24/7. They are transported with armed police escorts, GPS tracking, CCTV monitoring, and multi-level authorisation systems to prevent leaks. China also imposes harsh penalties for exam fraud, including jail terms of up to seven years.