The Beijing institute developed the technique to crack an iPhone’s encrypted device log to identify the numbers and emails of senders who share AirDrop content, the city’s judicial bureau said in an online post. Police have identified multiple suspects via that method, the agency said, without disclosing if anyone was arrested. “It improves the efficiency and accuracy of case-solving and prevents the spread of inappropriate remarks as well as potential bad influences,” the bureau said.
Further read: https://sfj.beijing.gov.cn/sfj/sfdt/ywdt82/flfw93/436331732/index.html
You can still have more certainty or less. If it’s open-source - it doesn’t guarantee safety by any means, sure, but if it’s proprietary like this one - you don’t even get a chance to check what’s going on.