A popular hand gesture adopted by China's online community in uploaded pictures could be used by criminals to steal people's fingerprints, Chinese cybersecurity experts have warned.
The "scissor hand" pose - similar to the peace sign or "V" for victory- could reveal a perfect fingerprint if held close enough to the camera, according to Zhang Wei, vice-director of the Shanghai Information Security Trade Association.
Speaking at an event promoting a national cybersecurity awareness campaign in Shanghai on Sunday, Zhang said photo magnifying and artificial intelligence-enhancing technologies meant it was possible to extract enough detail to make a perfect copy of the sensitive information.
According to a report by online news portal, Zhang's advice was that scissor-hand pictures taken closer than three metres (10 feet) could be vulnerable and should not be published on the internet.
"A scissor-hand picture taken within 1.5 metres (four feet 11 inches) can be used to restore 100 per cent of people's fingerprints, while pictures taken about 1.5-3 metres away can turn out 50 per cent of the fingerprints," he said.
Based on the information extracted from the pictures, criminals could make models of the prints which could then be used to register at fingerprint-based identity recognition checks, such as door access and payment systems, Zhang said.
Feng Jianjiang, a professor on fingerprint identification from the Department of Automation at Tsinghua University, told the South China Morning Post that, theoretically, pictures could show fingerprints clearly enough to be copied, but said he was unsure of what distance would be safe.
"Some people's fingerprints could not be captured [at any distance] because of skin problems [for example]," Feng said. "But the fingerprint images would be fairly clear if the distance, angle, focus and lighting were all ideal."
Feng suggested people check the clarity of detail by zooming in on their fingerprints in pictures before uploading them to social media.
Zang Yali, a researcher from the Institute of Automation at the Chinese Academy of Sciences, agreed that the conditions required to be able to harvest sufficiently detailed fingerprint information were "very demanding", according to a report in China Science and Technology Daily.
The warning had been viewed on China's Twitter-like platform Weibo 390 million times within 24 hours of Zhang's address on Sunday, with 49,000 comments left on the website by Monday afternoon.
"It's horrifying. I always present a scissor hand in photos," one Weibo user wrote.
"Advanced technology has brought us convenience but meanwhile has also brought us risk and danger. What can we do now?" another commenter wrote.
One social media user had the perfect solution, writing: "No worries. just show the back of your hand to the camera if you are concerned."
This article was first published in South China Morning Post.