Chinese security agencies have reportedly developed a technique to trace the sender of AirDrop transmissions. This attack was actually discovered in 2019 by researchers from TU Darmstadt, who reverse-engineered the Apple AirDrop protocol and disclosed several privacy flaws to Apple. The vulnerability allows police to identify the sender of unauthorized AirDrop materials using rainbow tables. While this capability may not yet be in widespread deployment, it represents a new tool that could suppress the use of AirDrop in China and Hong Kong, which has been used to disseminate unauthorized protest materials. The challenge for Apple is whether they should fix this vulnerability as it may be viewed negatively by the Chinese government, which could impact their business in China.
https://blog.cryptographyengineering.com/2024/01/11/attack-of-the-week-airdrop-tracing/