A Chinese state-backed institute has found a way to identify who sent any material to another person via Apple’s AirDrop, according to Beijing’s government. The institution is said to have cracked the feature to find the email addresses and phone numbers of those who send AirDrop messages as part of an effort to stamp out “undesirable content,” as Bloomberg reports.

Police have used the AirDrop crack to identify several suspects. However, Beijing’s judicial bureau has not said whether there were any arrests as a result. The approach “improves the efficiency and accuracy of case-solving and prevents the spread of inappropriate remarks as well as potential bad influences,” according to the bureau.

Those with a Mac, iPhone or iPad can use AirDrop to easily send the likes of photos, videos, documents, contacts and passwords to another nearby Apple device. Protesters used AirDrop to share pro-democracy slogans during the demonstrations in Hong Kong in 2019. As MacRumors notes, Apple touts AirDrop as being secure since it employs Transport Layer Security encryption. But the Beijing Municipal Bureau of Justice claims an institute has found a way around the encryption.

In 2022, Apple rolled out a new limit for AirDrop in China after protesters used the feature to share anti-government messages. The company restricted the length of time users can receive a file or message via AirDrop from non-contacts to 10-minute spells. Previously, users were able to let anyone AirDrop them material over an indefinite period of time. Apple later expanded this limitation to all iPhone users, purportedly in an effort to cut down on spam in busy locations.