The Great Firewall of China has always been porous, allowing an easy flow of information from the outside world and into the hands of those who possessed the simple technological tools to digitally tunnel through it.
Now Beijing is preparing to create a much harder barrier against unapproved information, calling on state-owned telecommunications providers to stamp out the virtual private networks, or VPNs, that everyone from scientists to dissidents and amateur musicians use to access foreign content.
It's a move that would give China's Communist Party leadership an even greater chokehold on information.
China has mandated that personal access to VPNs be stamped out nationwide by next February, according to a Bloomberg report.
VPN software masks an Internet connection in a way that allows a user to browse websites as if their computer or smartphone is situated overseas.
Few of the details on the coming ban are clear; it appears it will apply to individuals rather than businesses.
Even that would mark a major change.
"If the authorities really move to neuter all VPNs, it will also mean that they have to cut off China from the global Internet," said Charlie Smith, the pseudonym used by the co-founder of GreatFire.org, which monitors and works to defeat Chinese Internet censorship.
"The long-term effects will be devastating," he added.
"A climate of fear exists inside China and even Chinese outside of China are increasingly wary of speaking their minds. By denying access to VPNs, the authorities are also effectively preventing Chinese from discovering that there are other dissenting voices out there like theirs."
A person who answered the phone at China's Ministry of Industry and Information Technology said he did not know about the new mandate. The Foreign Ministry also said it had no information. The country's telecommunications giants did not answer requests for comment.
But signs have already emerged that China is preparing for a crackdown. In January, the Ministry of Industry and Information Technology demanded all VPN providers be registered as part of a 14-month "cleanup" of the Internet that prohibited the use of VPNs without permission. In recent weeks, several VPNs have already been removed from smartphone digital-download stores.
The megacity of Chongqing last year banned individuals and corporations from getting past the Great Firewall.
Expanding that to a nationwide ban would constitute a harsh new step in a campaign under President Xi Jinping to bring Chinese civil society, religion, entertainment and the news media to heel under the authority of the Communist Party.
China censors large portions of the foreign-language Internet, blocking access to Google services, many foreign news organizations and international social media companies such as Twitter and Facebook. Without a VPN, foreign content that isn't directly censored can also be frustratingly slow to load, and international websites that do work in China – notably Microsoft's Bing search engine and LinkedIn – accommodate Chinese censorship demands.
The majority of Chinese citizens take no steps to penetrate the Great Firewall, spending their online lives in the walled garden planted and pruned for them by the Chinese government.
But access to world knowledge is important for reasons that go well beyond seeking critical commentary on the Chinese government: vital economic data and scientific research exist outside China.
If that becomes much harder to access, it stands to hurt China's competitiveness and even more unmistakably mark the country as one dedicated to erecting barriers rather than pursuing openness, as its leadership has sought to proclaim in the months since Donald Trump became U.S. President.
"The Chinese concept of globalization is very, very different," said Arthur Kroeber, managing director of consultancy Gavekal Dragonomics.
"It's much more restrictive and involves a lot more controls."
At the same time, China wants its companies, including its Internet giants, to be multinational champions. A hard block on information flow would make that tough and could also interfere with recruiting talented people, including Chinese students who have studied abroad.
In part for those reasons, China has until now left wiggle room in its Internet restrictions.
"Many Internet companies, including China's lucrative gaming industry, are using VPNs to better their user experience. It is hard to imagine China will cut off all VPNs," said Lotus Ruan, a research fellow at the Munk School of Global Affairs' Citizen Lab, which researches Internet security and human rights.
A spokesperson for one VPN provider, ExpressVPN, also expressed little worry. "The number of individuals and businesses in China relying on VPNs like ours has continued to grow. In the absence of any official statements on the matter, we see no reason to believe that there is now a fundamental shift from this status quo," said the spokesperson, who declined to provide their name.
If China does choose to make the Great Firewall impenetrable, it's unlikely to encounter much difficulty.
"Shutting down widely used VPN traffic of any scale is technically possible," said Matthew Prince, chief executive of Internet security firm Cloudflare.
In China, suspicions have emerged that Beijing's worry about VPNs has been elevated by Guo Wengui, a Chinese tycoon who has in recent months waged a YouTube and Twitter campaign to disseminate embarrassing information about China's elite political leaders.
"The Guo Effect, I'd think, has definitely given them pause," said Yaxue Cao, founder of chinachange.org, which translates Chinese democracy voices into English.
But, she added, "China is living a dangerous conceit that the world needs it no matter what and will adjust to whatever it does, with or without complaints."
The danger, Ms. Cao said, lies in China going so far that it provokes international reprisal.
It also risks internal pushback.
A ban on VPNs, in "key areas like tech in Shenzhen, it's absolutely going have an impact. Because if you are a tech company, you simply can't have the unreliability of Internet," said Christopher Balding, a business and economics scholar with the HSBC Business School in Shenzhen.
Such a move would be a transparent attempt to "slow collaboration with any foreigners at all."
Chinese propaganda and information control have already sculpted a young generation whose mentality separates them from the rest of the world, said Jasmine Bernstein Yin, a Chinese-born Columbia University student.
"My middle-school classmates who remained in China think very different from the study abroad groups," she said.
"It's nearly impossible to escape and become an independent thinker."
For someone like her, she said, it's a major obstacle to ever returning home.
The idea of "living in a 1984-like society scares me," she said.