The curt knock on the door of his hotel room woke Alan Huang with a start. He looked at the clock: 5:30 am. Huang had been in Shenzhen, China, for only a few days; who could be looking for him at this hour? He groggily undid the lock—and found a half-dozen police officers in the corridor. The cops were there, they said, because the 37-year-old software engineer was a follower of the Falun Gong spiritual movement. It was December 1999, and the Beijing government had outlawed the sect just months earlier.

In fact, that’s why Huang had left his home in Sunnyvale, California, to come to Shenzhen. A Chinese computer programmer who had long ago emigrated to the US, Huang was back in China to protest the government’s jailing of thousands of his fellow practitioners. He hadn’t expected to join them.

Huang ended up packed into a cold cell with 20 other men, sleeping on the floor in shifts and forced to clean pigpens every day. Huang’s wife, back in California with their 3-year-old daughter, was terrified. After a very long two weeks and the help of a few American politicians, Huang and two other US-based Falun Gong practitioners who had accompanied him were released. “I got lucky because I was a US resident,” he says. “Others were not so lucky.”

It was Huang’s first experience with prison, but not with Communist Party repression. When he was an electrical engineering student at Shanghai’s Fudan University in the 1980s, Huang marched in the pro-democracy protests that roiled China. But the heady days in the streets came to a bloody end when the government sent tanks into Tiananmen Square. Huang wasn’t arrested, but some of his acquaintances disappeared. And he was shocked by the way the government’s ensuing propaganda barrage convinced many Chinese that the protesting students were themselves to blame for the bloodshed. Disillusioned, Huang left China, got his graduate degree at the University of Toronto, and moved to Silicon Valley in 1992. He spent most of the 1990s quietly living the immigrant-American dream, starting a family and building a career. Along the way, he also became one of the Bay Area’s hundreds of Falun Gong practitioners, leading study sessions and group exercises. So when Beijing launched its crackdown on the sect, it felt to Huang like 1989 all over again: The government was brutalizing a peaceful movement while painting its adherents as dangerous criminals. This time, he was determined to fight back. His aborted trip to China and frightening weeks in jail only left him more resolute. “My experience told me that the persecution was more severe than what we can imagine,” Huang says in accented English. “I felt I needed to do something.”

Huang has hunched shoulders and a round face thatched with bushy black hair; his bashful mien occasionally retreats into a nervous giggle. He’s no charismatic revolutionary. But by 2002, he had assembled a dozen like-minded Falun Gong-practicing colleagues. In the small garage attached to his four-bedroom bungalow, they developed a digital weapon for their compatriots back in China: a program designed to foil government censorship and surveillance. Dubbed UltraSurf, it has since become one of the most important free-speech tools on the Internet, used by millions from China to Saudi Arabia.

A separate group of Falun Gong practitioners, it turned out, was working on something similar, and in 2006 the two groups joined forces as the Global Internet Freedom Consortium. Most GIFC members spend their days as cubicle-bound programmers and engineers at places ranging from Microsoft to NASA. But off the clock, at night and on weekends, they wage digital guerrilla warfare on the Chinese government’s cyberpolice, matching their technical savvy, donated computers, and home-office resources against the world’s second-largest superpower. Again and again, Beijing has attacked the firewall-beating programs; again and again, the scrappy band of volunteers has defeated those attacks.

The victories don’t come easily. Huang quit a lucrative job to devote all his time to the cause. He has drained almost all of his savings. He had to sell his home and move his family into a rental, where he now works out of a spare room, making ends meet with freelance consulting gigs. Most days he sits in an armless swivel chair, bent over computers set up on a folding table. But there is one major consolation. “More and more people are using our technology,” he says. “And that’s the force that will tear down the Great Firewall.”

China maintains what is probably the world’s most advanced system for controlling digital communication. Authorities and opponents call it the Great Firewall, and the Chinese take it extremely seriously. At least 72 Chinese citizens—more than in any other country—are currently locked up for things they said online. Firewalls typically block access to certain sites, but the centerpiece of the Chinese system, called Golden Shield, does much more. It’s essentially a national digital surveillance network that monitors China’s estimated 420 million online citizens. This titanic task is facilitated by the fact that all international Internet traffic passes through just a handful of state-run pipelines.

A censor—be it a government, school, or corporation—has several options for preventing people from visiting places on the web. The simplest is to block a site’s Internet protocol address, the numbers that identify the computer hosting the site. A similar trick is to block DNS names, the text versions of IP addresses. Both tactics place an entire website off-limits. More technically difficult is keyword filtering, which blocks any traffic—search request, URL, or email—containing specific words or phrases. The Golden Shield does all those things so well that China reportedly exports the technology to other authoritarian countries, including Cuba and Belarus. And it’s supplemented by thousands of human censors who scour blogs, chat rooms, and everything else for offending content. China even jams seditious text messages.

Programs designed to defeat those measures are called circumvention tools. That’s what UltraSurf is: Operating through a web browser, it drops search queries or emails into an encrypted tunnel that scrambles the data to make it unreadable. Then the data gets routed to a network of computers—proxy servers—located in the US or some other unrestricted country. Though the circuitous path slows the connection a bit, it also provides access to sites like CNN, YouTube, and Twitter and leaves no record on the user’s computer.

But building robust circumvention tools is tough—as David Tian, a researcher at NASA’s Goddard Space Flight Center, knows well. Like Huang, Tian left China after narrowly avoiding arrest as a pro-democracy protester. He emigrated to the US and started practicing Falun Gong. Following the Beijing crackdown, at about the same time Huang started working on UltraSurf, Tian teamed up with a North Carolina programmer named Bill Xia and others via Falun Gong chat rooms. They planned to create a newsletter to counter Beijing’s propaganda, but they had to work carefully; six students and professors at Tsinghua University had been imprisoned in 2001 for posting Falun Gong materials. (Like all other GIFC members I met, Tian politely refused to let me see where he actually does his work. They’re a secretive bunch, afraid that the Chinese government might find out too much about them. Most don’t even want their names known. So despite the thumping midsummer humidity, we spoke at an outdoor lunch spot in the Maryland suburbs.)

The Great Escape The computer scientists behind the Global Internet Freedom Consortium supply circumvention tools to people all over the world. Here’s how those users scale the Great Firewall of China. —Rachel Swaby 1. Acquire The sites that host these programs tend to get blocked, but lots of users obtain a copy via email, in a zip file over IM, or passed hand to hand on a thumb drive. 2. Launch With every use, the software opens a new, encrypted connection to a computer somewhere abroad—a “proxy server” that connects to the net free of surveillance. 3. Browse YouTube searches, BBC comments, and other proscribed online actions join all the rest of the encrypted traffic coming out of China—too much for censors to block en masse. 4. Misdirect Chinese censors instead try to quash the proxy servers—if they can find them. The GIFC cycles its IP addresses 10,000 times an hour (constantly updating users). 5. Engage All that hoop-jumping slows the connection, but it does free users to watch a dancing dog on YouTube or leave a comment on Voice of America.

Initially, Tian and company just gathered email addresses in China from relatives and friends and started sending out news items and commentary. The list grew quickly, and soon they were generating millions of emails a week. “That triggered the alarm,” Tian says. Subscribers said the messages weren’t getting through; China’s Internet-censoring apparatus was blocking them. So Tian’s group started coming up with tricks to sneak their emails in. They converted the text into images, for example, or scrolled it vertically rather than horizontally to make it unreadable to the censoring software. And they broke the address list into chunks that they parceled out to dozens of volunteers, rather than sending everything in one massive, readily spotted blast from a central server.

But simply helping Chinese citizens passively receive emails wasn’t enough. “We wanted to let people read Western media, Falun Gong sites, whatever they wanted, and to respond,” Tian says. His group ended up developing software very similar to UltraSurf—they called theirs Freegate—and released it around the same time Huang’s group released its version.

At first, the proxy servers that both groups used were just the private computers of volunteers who offered up spare bandwidth from their businesses, schools, and homes. Huang would set up a connection node on, say, a laptop in someone’s living room in San Jose and some UltraSurf user in Shanghai would be routed through it, traffic running invisibly in the background. Several thousand volunteered computers still carry such traffic, Huang says, but now he also rents bandwidth in server farms.

While UltraSurf and Freegate aren’t the only circumvention tools out there, they caught on quickly and continue to spread. There’s no way to know exactly how many people have acquired the programs, since most of the sites they’re downloaded from get blocked and copies are often emailed from friend to friend. And naturally, people using these programs don’t want to advertise the fact. But GIFC members say their logs record around a million unique users daily and several times that many every month. A 2007 study by Harvard Law School’s Berkman Center for Internet and Society that field-tested circumvention software declared UltraSurf “the best of any tool tested in filtering countries.”

Of course, most UltraSurfers are not distributing samizdat or organizing hunger strikes. They just want to do the same stuff the rest of us do on the net. This becomes clear when Huang, sitting in a generic chain cafè9 in Cupertino, opens up his laptop to show me a random hour’s worth of UltraSurf’s user logs.

Lines of text zoom by, showing thousands of IP addresses and web pages visited. A search reveals that only a tiny handful of users went to Falun Gong-related sites. Pulling out a few others at random, we see that somebody in Beijing visited Dolce & Gabbana’s site, somebody in Turkey hit Facebook, and somebody in the United Arab Emirates spent quality time at ShemaleTubeVideos .com. We check out that site, and Huang grimaces at some biologically baffling photos. “We don’t want to spend our money supporting that,” he says. In a hard-to-miss irony, the GIFC tools block access to many video sites, especially pornographic ones. That’s partly because their network lacks the bandwidth to accommodate so much data-heavy traffic, but also because Falun Gong frowns on erotica.

Still, it’s clear that many people—perhaps even transgender-porn aficionados—also use the tools as an antidote to propaganda. “Whenever something happens, like the SARS outbreak or the Tibet unrest, our user base grows, because people don’t trust the official information,” Tian says. And the programs let important news flow out as well as in: Burmese dissidents used them to post videos of police beating protesters during the 2007 “Saffron Revolution.”

The fact that administrators like Huang can see data about where users are coming from and going to, however, makes privacy fundamentalists leery of the GIFC tools. They favor similar software like Hotspot Shield and Tor, which can’t gather user data. Logs could be hacked into or turned over to US law enforcement—something Xia and Huang say they’d do if ordered by a court. “I know plenty of people in China who don’t like what their government does to the Falun Gong, but they don’t want to entrust their data to the Falun Gong either,” says Rebecca MacKinnon, a New America Foundation fellow specializing in global Internet policy and human rights. Xia and Huang insist their logs are secure and, in any case, are deleted after a couple of weeks at most. They keep them for that long, they say, to analyze the traffic for signs of interference or surveillance.

Which happens all the time. “UltraSurf and Freegate are blocked very aggressively in China,” says Hal Roberts of the Berkman Center for Internet and Society. “In response, they’ve gotten into a very sophisticated arms race.”

The battle rages in a strange silence. There has been only one alleged violent incident, when a handful of Asian men burst into a GIFC member’s home outside Atlanta in 2006, roughed him up, and stole two laptops. Huang and his colleagues are convinced that this was a warning from Beijing. Other than that, the programmers know they are under attack only when the traffic through their servers drops suddenly.

Sometimes the censors manage to recognize patterns in an encryption header—a notice indicating which algorithms they’re employing. The government agents can’t read the encrypted information but will block anything carrying that header. Sometimes they find distinctive patterns in how the tools split up data into packets, and then they block anything with those signatures. And they’re constantly gathering the IP addresses of the proxy servers by pirating their own copies of UltraSurf and Freegate.

The GIFC programmers struggle constantly to stay one step ahead—fast-moving mice to Beijing’s powerful cat. They revamp their encryption header protocols. They disguise their transmission patterns by inserting fake data with their packets. They mask their users’ traffic as some other form of data—say, a Skype phone call. Most important, they have come up with ways to change the IP addresses of their proxy servers up to 10,000 times an hour. The programs automatically retrieve a handful of those fresh IP addresses for users when they start up; by the time the censors find and block a server’s IP address, that server has already been given 10 new, unblocked ones.

“There have been many, many rounds of blocking and upgrading,” says Xia, who is so uptight about security that he refused to meet me in person. “It’s a constant back-and-forth war.” When access is blocked, the users themselves alert the programmers and help to diagnose the problem. “Some of them are very good programmers,” Xia says. “We’re not vendors and customers—we’re a big team.”

One of the biggest strains on that team, however, has been money. Huang almost went broke getting UltraSurf off the ground. He quit his job, hoping he could make a living fighting firewalls through his one-man company, UltraReach. But apart from a few small contracts helping Voice of America and a human rights organization get information into China, no money has come in. That’s why he had to move and start taking part-time contract jobs in database management and network administration. He still spends about half his week on UltraSurf, unpaid.

Huang says his wife is supportive, but she’s interested in neither technology nor Falun Gong. It’s not an easy life. On a tour of Sunnyvale and nearby Cupertino to see his old home and the park where his Falun Gong group exercises, Huang gets a bit morose as we pass Apple’s sprawling headquarters. One of his friends who works there, he says, recently built a million-dollar house—with cash. “A lot of my college mates have done very well. Some are successful entrepreneurs. Some are already retired,” he says. “I don’t expect to be rich. But I sometimes feel like my wife and daughter deserve better.”

Those money woes are among the reasons Tian and Huang, along with a couple of smaller Falun Gong-affiliated outfits, established the nonprofit GIFC. Together, they figured, they had a better shot at getting some real money from the world’s biggest free-speech funder: the US government. As computer geeks who speak English as a second language, GIFC members aren’t exactly skilled Beltway operators. They have, however, attracted some key allies—most important, a pair of well-connected conservative true believers for whom battling the world’s last great Communist autocracy is the highest calling. The first is Mark Palmer, a onetime speechwriter for Henry Kissinger and the Soviet-relations point person in President Reagan’s State Department. Today he’s a pro-democracy advocate in DC. “I was amazed at what they’d done with chewing gum and baling wire,” he says.

Palmer knows that simply routing around firewalls won’t end Internet censorship. But he believes circumvention tools can play a critical role. “If you ask dissidents from the Soviet days what were the best things the West did to help them, they all say Radio Free Europe and the BBC made an enormous difference. They were ways for them to get information and communicate with one another,” he says. “The Internet is the modern version of those programs, but of course it goes much further.”

Palmer brought in Michael Horowitz, a Reagan administration official who has since become a freelance paladin on a head-spinning range of issues, from the persecution of Christians in Muslim countries to prison rape and sex trafficking. The pair set about putting the group on the capital’s radar. It was a tough sell at first; Falun Gong has a bit of a nutty, Scientology-like reputation, especially in Washington, DC, where it’s a visible presence. They’re the guys in yellow T-shirts outside the Chinese embassy, waving gruesome pictures of torture victims and yowling crazy-sounding allegations about Communist officials harvesting the organs of imprisoned Falun Gong members.

“Their eagerness to persuade you about how bad their situation is makes them their own worst PR enemy,” Horowitz says. “Sometimes they overstate things because they’re so anxious to get coverage.” But the religious-freedom angle got traction with pols who supported Horowitz’s crusade for Christian-minority rights. Among other things, he secured a Senate subcommittee hearing for GIFC member Shiyu Zhou, a Rutgers computer science professor. With $50 million, Zhou testified, the GIFC could attract and serve 23 million users in China. “Imagine the possibilities,” he continued, “of the Pope being able to conduct an interactive worship service with millions of Chinese Catholics, or members of this committee being able to conduct seminars in democracy with tens of thousands of Iranian students.”

A handful of Communist-hating members of Congress were persuaded. In 2008, they passed a bill appropriating $15 million to efforts to defeat firewalls in “dictatorships and autocracies.” But the State Department gave almost all of the money to a group that mainly trains journalists abroad. “The goddamn State Department just pissed that money away,” the normally diplomatic Palmer fumes. “I’m virtually certain the reason was fear of Beijing.” He and Horowitz maintain that the State Department doesn’t want to anger China by funding a Falun Gong-related organization.

Michael Posner, head of the State Department’s human rights branch, declined to respond to that charge, saying he didn’t “want to get into the details of any of the grants.” Still, it’s a fact that the mere mention of the sect makes Communist Party officials practically foam at the mouth. “This organization preaches heretical fallacies that are anti-humanity and antiscience,” says Wang Baodong, spokesperson for the Chinese Embassy. “It is a cult that seriously violates human rights and is a cancer in the body of the modern, civilized society.”

Falun Gong isn’t a religion per se. It’s a modern variant of the ancient Chinese practice of qigong, similar to the exercises and meditation of tai chi, which had a massive resurgence in the 1980s. A decade later, a former grain clerk named Li Hongzhi mixed it with Buddhism and Daoism and called it Falun Gong. By 1998, the movement had 40 million followers by the government’s count, including thousands of Communist Party members and military officers. But China has a long history of quasi-religious movements arising to threaten the country’s rulers. So on April 25, 1999, when 10,000 Falun Gong practitioners surrounded the Communist Party’s compound in the heart of Beijing, the government freaked out. China declared Falun Gong an “illegal, evil cult.” Since then, say human rights advocates, many Falun Gong members have been tortured, and hundreds—perhaps thousands—have died in custody.

Though that cause has always been the GIFC’s main motivation, its biggest public relations coup came last year in Iran. The group wasn’t doing a thing to promote its tools there, but somehow they started spreading rapidly in 2008. The Voice of America helped develop a Farsi interface for the programs, and by year’s end they had as many users in Iran as in China—between half a million and a million daily. Then came the chaotic green movement protests surrounding the June 2009 election. “People were using circumvention tools to find out where the demonstration routes were, download posters, and repost news on their own sites,” says Iranian-American cyber activist Cameran Ashraf. Freegate and UltraSurf were especially popular, and the tsunami of Iranian traffic overwhelmed the GIFC servers. “A lot of us worked through the night to get the servers back online,” Zhou says. “We understood the Iranians’ pain.” They were up the next day, but since then the GIFC has had to impose limits on traffic from Iran to keep its cobbled-together network from being overwhelmed. Unfortunately, that forces some users to wait hours for a connection.

Nonetheless, the performance of the group’s tools that summer won them plaudits from members of Congress and columnists at The New York Times and The Washington Post . The hype about the “Twitter revolution” helped firewall-busting pick up momentum as a cause in Washington. “Nations that censor the Internet should understand that our government is committed to helping promote Internet freedom,” secretary of state Hillary Clinton said last January. The US is “supporting the development of new tools,” she added, “that enable citizens to exercise their rights of free expression by circumventing politically motivated censorship.”

A few months later, the State Department promised $1.5 million in funding for the GIFC. That’s peanuts by Washington standards, of course. The budget for Voice of America alone is more than $200 million. Nonetheless, Palmer says, the fact that the US government is now funding the GIFC gives the group a certain legitimacy and an acknowledgment that its tools work. That will be important in the months ahead, when the Feds decide who will get a portion of the $30 million in Internet freedom funding that Congress has approved for this fiscal year.

More money could let the GIFC expand its server network enough to lift the cap on Iranian traffic and accommodate millions more users. It could also let it hire programmers to develop Mac, Linux, and iPad versions of UltraSurf and Freegate. And it could allow Alan Huang to quit his consulting gigs and do battle full-time with the censors. “Sometimes,” he says, “I joke that Falun Gong may not be a religion, but Internet freedom has become a religion for me.”

In a way, it has indeed become the faith that defines his life. After an hours-long interview, Huang gets in his road-worn Camry and heads home for dinner with his family. Later, after they’re in bed, he’ll sit down at the folding table in the spare room, open his laptop, and throw himself once again at the Great Firewall.

Vince Beiser (vincelb@sbcglobal.net) wrote about laser guns in issue 18.08.