When the reports started trickling out in September, they were met with disbelief and then outrage among technophiles. The Chinese government had blocked its citizens from using the popular search engine Google by exercising its control of the nation's Net service providers.

The move surprised Nart Villeneuve, a 28-year-old computer student at the University of Toronto who has been interested in Chinese technology issues. Blocking one of the most popular Web sites was a far cry from Beijing's practice of restricting access to the sites of dissident groups or Western news organizations.

From his research, Villeneuve knew that the Chinese firewall was less a wall than a net, and the holes could be exploited. So he sat down at his home computer and within three hours had created the basics of a program that would enable Chinese Net users to get access to Google through an unblocked look-alike site.

Villeneuve considers himself a "hacktivist" -- an activist who uses technology for political ends.

"I think of hacktivism as a philosophy: taking the hacker ethic of understanding things by reverse engineering and applying that concept to traditional activism," he said.

He takes part in Hacktivismo, a two-year-old group of about 40 programmers and computer security professionals scattered across five continents. It is just one of a handful of grass-roots organizations and small companies that are uniting politically minded programmers and technologically astute dissidents to combat Internet surveillance and censorship by governments worldwide.

Some protect the identities of computer users in countries where Net use is monitored closely. Others are creating peer-to-peer networks that allow for anonymous file sharing. Some have taken established techniques for encrypting data and made them easier to use. Others are adopting techniques used by commercial e-mail spammers to send political e-mail messages past restrictive filters.

"They are computer scientists who have principled causes," said Ronald Deibert, an associate professor of political science at the University of Toronto who has studied the activities of such groups and runs the Citizen Lab, a political science technology laboratory that supported Villeneuve's work.

One group, the Freenet Project, has built an anonymous file-sharing network from which Internet users can download antigovernment documents without fear of reprisal. Dynamic Internet Technology, a small company in Asheville, N.C., provides technical services to efforts by the Voice of America to get e-mail newsletters into China, using spammers' techniques such as altering subject lines or inserting odd characters in key terms (like "June~4," the date of the crackdown on protests in Tiananmen Square in 1989). Chinese Internet service providers use filters that scan e-mail for such politically sensitive terms.

SafeWeb, a maker of networking hardware in Emeryville, Calif., that has drawn some financing from the CIA, recently provided free software called Triangle Boy that protected Internet users' identities by routing their browsing through SafeWeb's server. The service was popular in Saudi Arabia, the United Arab Emirates and China but has been suspended for lack of money.

Villeneuve's project, which he calls a "pseudoproxy," is fairly simple. A computer user in China who knows the right Web address -- usually learned through word of mouth -- can visit the Google look-alike site on unblocked computers that run Villeneuve's software. Those computers call upon Google's servers and return the search results to the user. (Google's main site is no longer blocked by China, although search requests are being filtered.)

Most groups are ad-hoc operations made up almost entirely of volunteers with shoestring budgets. The impact of their David-vs.-Goliath struggles can be difficult to gauge. But lately these groups and companies have been receiving more attention from U.S. officials. In August the House Policy Committee, the forum in which the Republican leadership develops priorities and policies, issued a statement that included a call for the United States to "aggressively defend global Internet freedom" by supporting nonprofit and commercial efforts.

Some members of Congress are trying to make more money available for efforts to circumvent Internet censorship. Rep. Christopher Cox, R-Calif., chairman of the House Policy Committee, has introduced legislation that would create a sister agency to the Voice of America called the Office of Global Internet Freedom. It would receive $50 million a year over the next two years.

"We want to organize and support our government-directed effort to defeat state-sponsored jamming of the Internet," Cox said.

Some remain wary of any alliance with the U.S. government. "The most effective strategies are always done on a grass-roots level," said Deibert of the University of Toronto. "Anything that emanates from large bureaucratic organizations tends to be heavy-handed, misconceived and ill-planned."

But many politically minded technology specialists welcome the institutional support and money. "The government has lots of manpower and resources to put in," said the 29-year-old Chinese immigrant who runs Dynamic Internet Technology and goes by the name Bill Dong. "If you have two companies, it's nothing compared to resources the government has."