But earlier this week, after a number of V.P.N. companies, including StrongVPN and Golden Frog, complained that the Chinese government had disrupted their services with unprecedented sophistication, a senior official for the first time acknowledged its hand in the attacks and implicitly promised more of the same.
The move to disable some of the most widely used V.P.N.s has provoked a torrent of outrage among video artists, tech entrepreneurs and university professors who complain that in its quest for so-called "Internet sovereignty" — Beijing's euphemism for online filtering — the Communist Party is stifling the innovation and productivity needed to revive the Chinese economy at a time of slowing growth.
"I need to stay tuned into the rest of the world," said Henry Yang, 25, the international news editor of a state-owned media company who uses Facebook to follow broadcasters like Diane Sawyer, Ann Curry and Anderson Cooper. "I feel like we're like frogs being slowly boiled in a pot."
Read MoreMicrosoft Outlook 'hacked' by Chinese authorities
Multinational companies are also alarmed by the growing online constraints. Especially worrisome, they say, are new regulations that would force foreign tech and telecom companies to give the government "back doors" to their hardware and software and require them to store data within China's borders.
Like their Chinese counterparts, Western business owners have been complaining about their inability to gain access to many Google services since the summer. A few weeks ago, the government cut off the ability to receive Gmail on smartphones through third-party email services like Apple Mail or Microsoft Outlook.
The recent disabling of several widely used V.P.N.'s has made it difficult for company employees to use collaborative programs like Google Docs, although some people have found workarounds — for the time being.
"One unfortunate result of excessive control over email and Internet traffic is the slowing down of legitimate commerce, and that is not something in China's best interest," said James Zimmerman, chairman of the American Chamber of Commerce in China. "In order to attract and promote world-class commercial enterprises, the government needs to encourage the use of the Internet as a crucial medium for the sharing of information and ideas to promote economic growth and development."
Chinese authorities have long had the ability to interfere with V.P.N.s, but their interest in disrupting such programs has mounted alongside the government's drive for so-called cyber-sovereignty, especially since President Xi Jinping came to power two years ago. Lu Wei, the propaganda official Mr. Xi appointed as Internet czar, has been unapologetic in promoting the notion that China has the right to block a wide array of online content.
A co-founder of Greatfire.org, which tracks online censorship in China, suggested the government had decided that soaring V.P.N. use among ordinary Chinese warranted a more aggressive attack on such tunneling software.
"This is just a further, logical step," said the co-founder, who requested anonymity to avoid government scrutiny. "The authorities are hellbent on establishing cyber-sovereignty in China. If you look at what has taken place since last summer it is quite astounding."
Government officials have denied any role in blocking Google and they have dismissed accusations that Chinese authorities were behind a "man-in-the-middle" attack on Outlook two weeks ago as well as earlier hacking incidents here involving Yahoo and Apple.
But such claims have by and large fallen on deaf ears, especially given Beijing's strident campaign against the "hostile foreign forces" it says are seeking to undermine the country though the Internet.
On Tuesday, however, a senior official at the Ministry of Industry and Information Technology acknowledged that the government was targeting V.P.N.'s to foster the "healthy development" of the nation's Internet and he announced that such software was essentially illegal in China. "The country needs new methods to tackle new problems," Wen Ku, a director at the ministry, told a news conference, according to People's Daily.