Painting a portrait

Li said he can understand some complaints about the technology, "as it can seem excessive after people have provided ID card and mobile phone numbers, along with fingerprint details".

Feng, from Zhengzhou, said: "There's too much to be disclosed. It's like being naked in public."

He said the use of facial recognition technology by public security bureaus for investigation purposes is acceptable, "because I know why they collect the information and they also promise not to release it and use it illegally under their investigation rules".

"But elsewhere, such as hotels and colleges ... ID card numbers and fingerprint details should be sufficient to verify identities."

Zhao said: "The use of facial information by institutions including internet platforms and public service providers is akin to painting a person's portrait or figuring out who the person is more accurately. But I think the need for such a portrait should be the main factor in applying the technology."

Many netizens were attracted when ZOA, the app, made its debut at the end of August, as it promised "amazing face exchanges". But later, public enthusiasm waned on suspicion that the app was collecting an excessive amount of personal information.

An agreement for using the app, which sparked widespread controversy online, stated, "Before you upload or post any content, you agree to grant ZAO, its affiliates and ZAO users worldwide the right to irrevocably use your original photos, synthesized photo and videos for free and for good ... and to make changes to the portraits of the original holders."

Zhao said: "At least people can refuse the app if they don't want their facial information disclosed, but sometimes such recognition is inevitable. For example, some businesses, banks and government departments have adopted the technology to check employees' work attendance."

He said there is no clear line governing who or which institution can collect people's facial information. "Some collect it for security purposes, others for enhanced efficiency, or even for fun."