How Chinese police used phones and faces to track protesters

On Sunday, when Mr Zhang went to protest China’s strict Covid policies in Beijing, he thought he was ready to go undetected.

He wore a balaclava and goggles to cover his face. When it appeared that plainclothes police were following him, he hid in the bushes and put on a new jacket. He lost his tail. That night, when Mr. Zhang, who is in his twenties, returned home without being arrested, he thought he was safe.

But the police called the next day. They knew he was out because they could detect his phone was in the protest area, they told him. Twenty minutes later, even though he hadn’t told them where he lived, three officers knocked on his door.

Similar stories are being told by protesters across China this week, according to interviews with these targeted groups and human rights groups following cases. As authorities seek to track, intimidate and detain those who marched in defiance of the government’s strict Covid policies last weekend, they are turning to powerful surveillance tools the state has spent the past decade to build for times like this, when parts of the population come forward and question the authority of the ruling Chinese Communist Party.

Police used faces, phones and informants to identify those who attended the protests. Usually, they force those they track down to pledge not to protest anymore. Often inexperienced in tracking, protesters expressed bewilderment at how they were discovered. For fear of further repercussions, many have taken down foreign apps like Telegram that have been used to coordinate and broadcast footage of the protests overseas.

Chinese police have set up one of the most sophisticated surveillance systems in the world. They hung cameras by the millions on street corners and building entrances. They purchased powerful facial recognition software and programmed it to identify local citizens. Special software analyzes the recovered data and images.

Although the construction of the surveillance system was no secret, to many in China it seemed remote. Police use it more commonly to hunt down dissidents, ethnic minorities and migrant workers. Many express their support under the idea that if you have done nothing wrong, you have nothing to hide.

The interrogations of the past week could shake this perspective. It is the first time that the surveillance state has directly targeted large numbers of middle-class people in China’s wealthier cities. While many have experience with censorship – and this week proved they can sometimes circumvent it – a police home visit is less common and more intimidating.

“We hear stories of police showing up at people’s doorsteps asking where they were during protests, and that seems to be based on evidence gathered through mass surveillance,” said China researcher Alkan Akad. to Amnesty International. “China’s ‘Big Brother’ technology is never extinguished, and the government hopes it will now show its effectiveness in quelling unrest,” he added.

The marches and protests were among the most widespread and overtly political since those in 1989, which Beijing suppressed with deadly military force in Tiananmen Square. Now Chinese authorities can quell the unrest by using the high-tech net to target and detain organizers and the most outspoken malcontents. Followers and spectators often get away with a severe threat.

Mr. Zhang’s experience is common. Although he knows about the facial recognition cameras that clutter Chinese public spaces, he underestimated the phone trackers. Small boxes with antennas, devices are much easier to miss. Mimicking a cell tower, they connect to the phones of everyone who passes by and log the data for the police to verify. Still, Mr. Zhang, who like other protesters interviewed for this article declined to give his full name for fear of police reprisals, was lucky. After harsh questioning and a warning not to attend any more demonstrations, the police left his apartment.

He said the ordeal left him “terrified” and he believed it would be effective in dampening the momentum the rallies had generated. “It’s going to be very difficult to mobilize people again,” he said. “At this point, people will come off the streets.”

For others, their faces betrayed them. One man, Mr Wang, who joined protests in Beijing, said he received a warning call from police two days after Sunday’s rally. He was told he had been identified using facial recognition technology.

Unlike other protesters in Beijing, Mr. Wang did not cover his face with a hat or sunglasses, and he removed his medical mask at one point during the event. He said he was not surprised that the police were able to identify him, but the use of such technology made him feel uneasy.

“I knew the risks of going to such a gathering,” he said. “If they want to find us, they can certainly succeed.”

The phone call from the police only lasted 10 minutes, but the policeman did his best to intimidate him: “He made it clear that there were no second chances.

After being stopped or approached by police, many protesters were hesitant to use VPNs (virtual private networks) or other foreign apps like Telegram and Signal. The fear, they said, is that now that they are on authorities’ radar, the software they use on their phones could come under closer scrutiny, leading to greater police attention and possible detention.

A man, who was arrested during a protest in central China’s Chengdu on Monday, said his phone was checked while he was detained by police, who saw he had Telegram and other foreign applications. It deleted the apps when it came out.

Some protesters have tried to fight back against the surveillance, using tactics similar to those used in Hong Kong in 2019, when protesters tried to reveal the identities of officers, just as police tried to unmask them. This week, a list of the identities of about 60,000 Shanghai police officers was distributed in some Telegram groups. The name spreadsheet is from a leak of Chinese Communist Party members in 2020, according to cybersecurity group Internet 2.0, which researched the original leak. The New York Times confirmed the accuracy of some of the data, which included national ID numbers, addresses, marital status, ethnicity and height of the agents.

For many protesters, the shock of being identified worked as an intimidation tactic in its own right.

Ms Wang, a filmmaker in her twenties, said she joined a group of friends in Beijing on Sunday evening. Together they took precautions: they covered their faces with medical masks, took a taxi several miles away and walked to the site of a vigil. Even though they had been warned to turn off their phones, they simply disabled GPS and Face ID functions.

“We thought at the time that there were so many people. Think about it, how could they be able to find everyone? How could they have the energy to catch everyone? ” she says.

She and her friends were surprised when a number of them received phone calls or visits from the police. Some were forced to help the police in their investigation by going to the police station.

“I think my friends, if there’s a next time, they won’t dare to go,” she said.

However, Ms. Wang slipped through the cracks. That night she used a phone with a number that was not linked to systems that could identify her, such as the country’s health code software used to track Covid cases and ensure that people get tested regularly in outbreak areas.

She was not intimidated by her experience.

“I’ll go anyway; if the police find me, we will see,” she said. When asked if she would attend a public gathering again, she added, “I just feel like you have to go.”

John Liu contributed report.