The Obama administration may not be lending arms to dissidents in the Middle East, but it is offering aid in another critical way: helping them surf the Web anonymously as they seek to overthrow their governments.

Federal agencies - such as the State Department, the Defense Department and the Broadcasting Board of Governors - have been funding a handful of technology firms that allow people to get online without being tracked or to visit news or social media sites that governments have blocked. Many of these little-known organizations - such as the Tor Project and UltraReach- are unabashedly supportive of the activists in the Middle East.

But the United States' backing of these firms has the potential to put the government in an awkward diplomatic position, not only with the countries where uprisings are active, but also with economic partners such as Saudi Arabia and China, which are known to block Web sites they deem dangerous.

The technology comes with its own perils: Some of the tools may not always conceal the users' identities. Autocratic foreign governments are constantly updating their censorship and monitoring technology. And, of course, the software can be handy for terrorists seeking to communicate in clandestine ways.

In Egypt, Mohammad Hamama, a 24-year-old computer programmer, said he learned about the Tor Project's software in January through chatter on Twitter. He downloaded the software and checked on friends protesting in Cairo's Tahrir Square.

Still, he worries about the technology's safety.

"I wanted to make sure my Twitter friends were okay during the protests," he said in a phone interview. "But I didn't feel safe at all. I don't know what the government was using to track us down. I was just hoping the Tor browser would be good for me to tweet some things, but I managed to get away without being tracked."

The technology that is now taking off in Egypt, Tunisia and Libya through word of mouth began as tools of digital disobedience elsewhere. In general, these programs work by redirecting users' Web traffic to servers outside their country. That makes it more difficult to identify the users while giving them access to blocked sites.

"What began as an effort to tear down firewalls in China has become something with extraordinary potential throughout the world," said Michael Horowitz, a Reagan administration official who serves as an adviser to UltraReach. "When UltraReach started getting hits in Egypt, the company had no idea how the people there found out about it. But they feel like they can't cut them off now - the company feels like it has a responsibility. But for every dollar that gets spent by companies like UltraReach, there's $10,000 spent by the governments to protect the firewalls."

Federal agencies have funded these companies through grants and contracts. By late spring, the State Department is expected to begin doling out even more money - about $30 million - to technology firms and human rights groups to help and train people to shatter firewalls and surf the Web without being tracked.

Daniel B. Baer, deputy assistant secretary in the State Department, said his bureau is moving as quickly as possible to appropriate the money. More than 60 nonprofit groups and other organizations have applied for awards, which range from $500,000 to $8 million.

The department, he said, is unequivocal in its support of a free Internet and the rights of protesters in the Middle East as well as other regions where governments restrict Web use or monitor dissident movements. The department supports about a dozen Web circumvention technologies; the top three attract nearly 2 million unique users a month.