The open Internet's role in popular uprising is now undisputed. Look no further than Egypt, where the Mubarak regime today reportedly shut down Internet and cell phone communications -- a troubling predictor of the fierce crackdown that has followed.

What's even more troubling is news that one American company is aiding Egypt's harsh response through sales of technology that makes this repression possible.

The Internet's favorite offspring -- Twitter, Facebook and YouTube -- are now heralded on CNN, BBC and Fox News as flag-bearers for a new era of citizen journalism and activism. (More and more these same news organizations have abandoned their own, more traditional means of newsgathering to troll social media for breaking information.)

But the open Internet's power cuts both ways: The tools that connect, organize and empower protesters can also be used to hunt them down.

Telecom Egypt, the nation's dominant phone and Internet service provider, is a state-run enterprise, which made it easy on Friday morning for authorities to pull the plug and plunge much of the nation into digital darkness.

Moreover, Egypt also has the ability to spy on Internet and cell phone users, by opening their communication packets and reading their contents. Iran used similar methods during the 2009 unrest to track, imprison and in some cases, "disappear" truckloads of cyber-dissidents.

The companies that profit from sales of this technology need to be held to a higher standard. One in particular is an American firm, Narus of Sunnyvale, Calif., which has sold Telecom Egypt "real-time traffic intelligence" equipment.

Narus, now owned by Boeing, was founded in 1997 by Israeli security experts to create and sell mass surveillance systems for governments and large corporate clients.

The company is best known for creating NarusInsight, a supercomputer system which is allegedly used by the National Security Agency and other entities to perform mass, real-time surveillance and monitoring of public and corporate Internet communications in real time.

Narus provides Egypt Telecom with Deep Packet Inspection equipment (DPI), a content-filtering technology that allows network managers to inspect, track and target content from users of the Internet and mobile phones, as it passes through routers on the information superhighway.

Other Narus global customers include the national telecommunications authorities in Pakistan and Saudi Arabia -- two countries that regularly register alongside Egypt near the bottom of Human Rights Watch's world report.

"Anything that comes through (an Internet protocol network), we can record," Steve Bannerman, Narus' marketing vice president, once boasted to Wired about the service. "We can reconstruct all of their e-mails along with attachments, see what web pages they clicked on; we can reconstruct their (Voice Over Internet Protocol) calls."

Other North American and European companies are selling DPI to enable their business customers "to see, manage and monetize individual flows to individual subscribers." But this "Internet-enhancing" technology has been sought out by regimes in Iran, China and Burma for more brutal purposes.

In addition to Narus, there are a number of companies, including many others in the United States, that produce and traffic in similar spying and control technology. This list of DPI providers includes Procera Networks (USA), Allot (Israel), Ixia (USA), AdvancedIO (Canada) and Sandvine (Canada), among others.

These companies typically partner with Internet Service Providers to insert DPI along the main arteries of the Web. All Net traffic in and out of Iran, for example, travels through one portal -- the Telecommunications Company of Iran -- which facilitates the use of DPI.

When commercial network operators use DPI, the privacy of Internet users is compromised. But in government hands, the use of DPI can crush dissent and lead to human rights violations.

Setting the Bar High for DPI Sales

Even Republicans and Democrats seem to agree on this problem.

"Internet censorship is a real challenge, and not one any particular industry -- much less any single company -- can tackle on its own, " Rep. Mary Bono Mack wrote in a 2009 letter to Rep. Henry Waxman, then chair of the House Commerce Committee. "Efforts to promote freedom of expression and to limit the impact of censorship require both private and public sector engagement."

Earlier this week, Secretary of State Hillary Clinton urged Egypt's government "not to prevent peaceful protests or block communications, including on social media."

Bono Mack's letter and Clinton's statement echo Free Press' call for a congressional inquiry into the issue. But this is just a start.

Before DPI becomes more widely deployed around the world and at home, the Congress ought to establish clear criteria for authorizing the use of such surveillance and control technologies.

The power to control the Internet and the resulting harm to democracy are so disturbing that the threshold for using DPI must be very high.

Today we're seeing the grave dangers of this technology unfold in real time on the streets of Cairo.

Correction: An earlier version of this post erroneously included Camiant and Zeguma Systems on a list of DPI providers. Both have been removed from this list. Camiant has partnered with Deep Packet Inspection (DPI) companies to provide "policy control solutions" that enable network operators "to better control and manage network usage," according to 2009 press reports. Zeguma Systems went out of business in 2010.