Until last week, few Americans would have been familiar with the enigmatic chief executive of TikTok, Shou Zi Chew.
But concern over the amount of information the Chinese-owned video-sharing app collects on its 150 million users in the United States has prompted calls from US politicians to ban it, citing national security risks.
Mr Chew, a Singaporean businessman, was thrust into the spotlight when he testified before a congressional committee in Washington, DC.
For nearly five hours, he was grilled by Republicans and Democrats alike over TikTok's data privacy policies, content-recommendation algorithm and potential ties to the Chinese government.
"Mr Chew, you are here because the American people need the truth about the threat TikTok poses to our national and personal security," Cathy McMorris Rodgers, the Republican chair of the House Energy and Commerce Committee, said in her opening statement.
She labelled the app "a gateway to spy" for the Chinese government and argued it could be used to spread propaganda or "manipulate America as a whole".
TikTok has tried to distance itself from its Chinese parent company, ByteDance, and Mr Chew vigorously denied the claims.
"Let me state this unequivocally: ByteDance is not an agent of China or any other country," Mr Chew said.
Such assurances have all but failed to assuage some American fears about TikTok, which was banned on federal government devices in February.
In March, the Biden administration ramped up its efforts to curb the influence of the wildly popular social media platform by demanding it be sold to US-based owners or face a nationwide ban.
Experts say neither option is straightforward, and ByteDance and Beijing are unlikely to be the only ones to oppose such drastic moves.
Following the hearing, Mr Chew received a wave of support from TikTok users, who shared clips of Congress members appearing out of their depth asking bizarre questions such as: "Does TikTok access home Wi-Fi?"
Other critics of the proposed ban include TikTok activists and creators, whose livelihoods depend on the app, and free-speech advocates.
So, how real are the risks? And is a ban even possible?
Here's what we know.
Why the US government is targeting TikTok
TikTok has long been dogged by claims ByteDance could be forced to share sensitive user data, including browsing histories and location information, with the Chinese government.
Those have been fuelled in part by China's sweeping internet laws, which require tech companies to help Beijing with "intelligence work" if asked to.
"Currently, TikTok is allowed to share its data with its parent company or subsidiaries or partners," said Aynne Kokas, an associate professor of media studies at the University of Virginia.
"And so even if TikTok is protecting user data, it's very difficult to assess or know how well that parent company, those subsidiaries or those partners are protecting user data.
"This is particularly true in the case of ByteDance, where the Chinese government has taken something called 'golden shares', which allow for the ... government to have oversight and control of the firm."
Ms Kokas added that the "national security audits" Chinese companies can be subject to also involve sharing data with the government for oversight.
"And that process is also not very transparent," she said.
US intelligence officials and politicians — including former president Donald Trump, who tried to ban the app by executive order in 2020 — have long warned TikTok could be dangerous for Americans.
The FBI's director Christopher Wray recently told senators the app "screams" of national security risks, including that its algorithm could be tweaked to feed Americans favourable narratives about China.
"[We're] not sure that we would see many of the outward signs of it happening, if it was happening," he said.
While misinformation and disinformation may be hard to quantify, some of the surveillance fears seemed vindicated last year when Forbes reported plans by ByteDance employees to use TikTok location data to track American citizens, including journalists.
A subsequent internal investigation by ByteDance confirmed some employees accessed information about two reporters, and a small group of people connected to them, through their TikTok accounts.
The company characterised the incident as an isolated plan by four rogue employees, who were all fired, but the US Department of Justice and the FBI have launched their own investigation.
"If this happened in that case, and that's what we found out about, what else might be happening?" said Sarah Kreps, a professor of law and public policy at Cornell University, who studies the intersection of technology and national security.
She said the sheer quantity of information the app collects about its users is also troubling.
"If you can access that data, then you understand this segment of two-thirds of young Americans [and] what they like and dislike," Mr Kreps said.
In theory, a tweak to TikTok's algorithm could be used to manipulate those beliefs with "psychological operations" and misinformation, for example around elections, she said.
In one particularly tense exchange during the recent congressional hearing, Mr Chew vowed TikTok would "protect the US user data from all foreign access".
But critics, including Ms Kreps, argue that TikTok's promised solution — a $US1.5 billion (roughly $AUD2.2 billion) plan to store US user data in the US dubbed Project Texas — won't solve all its problems.
"I really think that the testimony raised a lot more questions than it answered," she said.
What is Project Texas?
The hearing made at least one thing apparent: There is broad bipartisan for banning TikTok in the US.
The company's plan to avoid that ban is Project Texas, which would see the country's user data stored and overseen by a US company, Oracle, based in Austin, Texas.
"Our approach has never been to dismiss or trivialise any of your concerns," Mr Chew said during the hearing.
"We have addressed them with real action now."
Mr Chew explained the goal of the project was to build "a firewall" to block "unauthorised foreign access" to data.
"The bottom line is this is American data stored on American soil by an American company overseen by American personnel," he said.
Ms McMorris Rogers dismissed the plan as a "marketing scheme".
Project Texas, which began rolling out in July 2022, involves restructuring the US arm of the company, allowing it to be siloed and monitored by an in-house committee approved by the US government.
It's unclear if the ban could come before the project is complete, rendering it useless.
Even if it does move forward, Ms Kokas said, how TikTok would respond to complaints or concerns, such as a data breach, remains to be seen.
"So, in some ways the scrutiny that TikTok has been under has forced it to adapt and to develop new mechanisms that might actually provide more transparency and oversight of user data," she said.
"The challenge here, though, is because of weak US data security, it's not clear what the next steps would be if there was a kind of violation of Project Texas."
Is TikTok any worse than its US competitors?
Ms Kokas described the US government's mechanisms for oversight as "very limited", even if Project Texas was "valuable conceptually".
"The Committee on Foreign Investment in the United States and other digital regulatory agencies … do not have the capacity to oversee the data of 150 million users each month, and that number is growing," she said.
"So, it's also a situation where it still requires reliance on … statements by the tech company that are very much in its interest and not in the interest of the American people and their national and data security concerns.
"But … this is the nature of the US system where there is very little oversight and very little protection for user data."
In 2018, another polished tech chief executive fronted a government panel dressed in a dark suit and blue tie.
The founder of Facebook, Mark Zuckerberg, was called before the Senate's Commerce and Judiciary committees to answer questions on data privacy, foreign disinformation, and addictive algorithms harming users' mental health.
The similarities between the two hearings underscore what many critics of the ban have also said: The dangers of social media are well-established and not TikTok's alone.
"I don't think ownership is the issue here," Mr Chew said during the hearing.
"With a lot of respect: American social [media] companies don't have a great record with privacy and data security. I mean, look at Facebook and Cambridge Analytica."
Even so, despite TikTok's stated mission to "inspire creativity and bring joy", its powerful algorithm, which serves up an endless stream of targeted videos, has been shown to promote harmful content, often to young people.
But this, as well, is arguably in part due to a lack of US laws governing content for young people.
The Chinese version of the app, Douyin, has far stronger protections for younger users including in-app parental control.
A "teenager mode" that only shows whitelisted content limits access to the app to 40 minutes between 6am and 10pm each day.
"I think it's important to recognise there are advantages to having a system with more consumer protections," said Ms Kokas.
"Then we see less of these efforts at driving self-harm content, of driving pro-anorexia content or any number of other things that are part of our current online environment in the US.
"And so, I think, in some ways, that particular critique should be focused back at lawmakers to question why they haven't done a better job protecting kids."
Could a ban really happen?
While support for forcing a sale of TikTok or banning it outright may be gaining traction in Washington, there are several obstacles likely to stymy either move.
Trump's previous ban was struck down in the US federal courts, for one, and Beijing has since set up guardrails to prevent the sale of the company.
China's Ministry of Commerce updated its list of "forbidden or restricted technology exports" to include "personalised information recommendation services based on data analysis", effectively giving the government veto power over a sale.
Free speech advocates argue banning TikTok would have serious consequences for free expression in an era of increased online censorship.
While acknowledging the genuine national security red flags the app raises, more than a dozen organisations, including Pen America and the ACLU, co-signed a letter to Congress objecting to the ban.
"Whether [Americans] use the app to live-stream, promote a small business, share their creative work, connect with family, or find information on how to vote, their speech is protected by the First Amendment," the letter said.
While some of the TikTok influencers and activists who recently descended on Washington to protest the ban were paid by the company to do so, there is also a real and significant grassroots push to protect the platform many rely on for income and to organise.
Some progressive Democrats are also worried a ban would risk causing a backlash from Gen Z voters, who skew overwhelmingly to the left.
"I think if there were going to be an issue that would drive angry Gen Z voters to the polls … this would be it," said Ms Kokas.
In her first and only TikTok, millennial congresswoman Alexandria Ocasio-Cortez said Congress has yet to receive an intelligence briefing justifying the ban.
But, the Democrat added, her colleagues on both sides of the aisle should have more pressing concerns.
"Our first priority should be in protecting your ability to exist without social media companies harvesting and commodifying every single piece of data about you without you and without your consent," she said.
