From laser shields to iPhone detectors: inside China’s booming secrecy industry

A group of Chinese officials are in the middle of a highly sensitive meeting involving critical decisions yet to be made behind closed doors, with documents stamped “classified” spread across the table.Suddenly, an invisible laser beams into the room, sweeping across a glass window and allowing the contents of the meeting to be transmitted elsewhere.China’s Ministry of State Security laid out this seemingly futuristic scenario six months ago, warning government departments and other entities against a new form of laser-based eavesdropping potentially conducted by foreign spies.Sophisticated contactless surveillance technology like this relies on detecting vibrations in glass windows caused by sound waves inside a room. By directing an invisible laser beam at a window, receiving the reflected signal and analysing it, an operator can reconstruct speech from within the room, according to the ministry.