Having TikTok on a device issued by the federal government has become illegal under a sprawling spending bill for the upcoming fiscal year signed by President Biden on Thursday. The government has up to 60 days to set up guidelines to impose the ban.

While the Chinese-owned app is already not allowed on many federal government devices — including on U.S. House mobile devices — the measure in the newly enacted spending bill expands the prohibition. The ban will likely result in a hit to TikTok's reputation at a time when the Biden administration is still attempting to complete a national security review of the popular app.

TikTok is used by more than 100 million monthly active users in the U.S. alone, and its ability to create instant viral hits has put it at the forefront of internet culture, though concerns about data security have long dogged the app.

If you count yourself among its users and you're wondering how this crackdown might affect you, here is what you need to know:

Is this going to affect my use of TikTok?

Probably not — unless you're a federal government employee who uses a work phone to browse TikTok. The White House, the Pentagon, the Department of Homeland Security and the State Department already prohibit staff from having TikTok on government-issued devices, so this ban just extends the rule for all U.S. government employees. More than a dozen states have passed similar TikTok bans for devices issued by state governments.

Why did the ban happen?

Republicans and Democrats alike have long taken aim at TikTok, since it is owned by Beijing-based tech behemoth ByteDance. Lawmakers worry about the Chinese Communist Party using the app to spy on Americans, or using the app's algorithm to amplify pro-China narratives.

While the company denies it would ever be used for nefarious purposes, national security experts say China-based businesses usually have to give unfettered access to the authoritarian regime if information is ever sought.

Former President Donald Trump tried — and failed — to outright ban TikTok. And federal lawmakers have proposed more punitive anti-TikTok bills that have not gained traction.

So the ban on federal government devices is an incremental restriction: Most drastic measures have not advanced, since the efforts lacked the political will, or courts intervened to stop them.

"I think some concern about TikTok is warranted," said Julian McAuley, a professor of computer science at the University of California San Diego, who noted that the main difference between TikTok and other social media apps is that TikTok is much more driven by user-specific recommendations.

"Arguably this would mean that TikTok could be more open to that feed being manipulated to achieve some sinister goal," McAuley said.

What evidence is there that TikTok is a national security threat?

Not much solid evidence. The case against TikTok largely falls into the "it is theoretically possible that this can happen" category. But because TikTok is owned by a Chinese company, the hypothetical risk of millions of Americans being potentially the target of espionage at the hands of a adversarial government has Washington alarmed. FBI Director Chris Wray has said TikTok is a national security threat, saying the app could "manipulate content, and if they want to, to use it for influence operations."

Getting to the bottom of just how safe TikTok is for U.S. users is something that is not quickly understood even by privacy scholars.

"While ByteDance claims that it maintains its operations in the United States separately, there is no easy way to determine the extent to which that claim is true," said Sameer Patil, a professor at the University of Utah who studies user privacy online.

A report in BuzzFeed found the TikTok owner ByteDance once used another app the company owned to push content sympathetic to the Chinese government. That app, which was separate from TikTok, no longer exists. Still, some observers wondered: If ByteDance was willing to do that for one of its previous services, why wouldn't it try to do the same on TikTok?

It's a question the company dismisses. Earlier this year, TikTok announced an initiative that will route "100% of U.S. user traffic" to servers controlled by American tech company Oracle. TikTok said it is working on deleting U.S. users' private data from its own servers and transferring it all to servers hosted in the U.S., with backup storage in Singapore.

McAuley said that TikTok, like all major social media companies, is vacuuming up vast amounts of personal data of the people using the app, though he questions what exactly TikTok might be able to do with what it knows: a user's age, contact information, viewing habits, search history, location.

"While social media companies are certainly harvesting all kinds of data about users, I think it's usually overblown to what extent they 'know' about users on an individual level," he said.

Patil said if TikTok users are worried about their privacy, he suggests restricting posts to friends only and to remove location data from videos, which can be done in the app's settings.

What are the chances that TikTok becomes more widely banned in the U.S.?

It is still possible, but it does not appear imminent.

The Committee on Foreign Investment in the United States (CFIUS), a powerful interagency federal panel that reviewing foreign investment in the U.S., began examining TikTok during the Trump administration and the probe is still underway.

The committee could set a wider TikTok ban in motion, or it can force the app to be sold to an American company, something the Chinese government will likely forcefully oppose, as it did when such a sale was floated during the Trump years.

Another possible resolution is that the committee is satisfied with the steps TikTok has taken to ensure there is a firewall between U.S. user data and ByteDance employees in Beijing and the Chinese government.

CFIUS deliberations are famously secretive and happen behind closed doors. It is not clear when the committee might finish its investigation, nor is it known which way it is leaning.

How has TikTok responded to the latest action?

Brooke Oberwetter, a TikTok spokesperson, said the company is disappointed that Congress moved to ban TikTok on government devices, calling the action "a political gesture that will do nothing to advance national security interests."

TikTok, Oberwetter said, has faith in the CFIUS process, which is centered on making sure the video app does not become manipulated by the influence of the Chinese government.

"The agreement under review by CFIUS will meaningfully address any security concerns that have been raised at both the federal and state level," Oberwetter said. "These plans have been developed under the oversight of our country's top national security agencies — plans that we are well underway in implementing—to further secure our platform in the United States, and we will continue to brief lawmakers on them."