(Photo - NASA)

Security specialists say the United States and many other countries are now exposed to a host of terrorist threats from cyberspace, as the world's most developed nations increasingly rely on millions of computer networks and the Internet to run critical infrastructure.

A study released earlier this year by the White House says the primary concern is the danger of organized cyber attacks that could have devastating consequences for a wide variety of human and economic targets.

Wayne Crews is the director of technology policy at the CATO Institute, a non-profit public-policy research foundation based in Washington.

Mr. Crews says the U.S. government and the private sector have become so dependent on computers and the Internet that they are very vulnerable to cyber-terrorism.

"Well I think we do have a problem," he said. "The nature of the beast now is that we have a public Internet that the private sector, for both good and bad, has opted to opt into. We are relying on it for our banking, commerce and everything. We do have vulnerabilities there. There are key networks, electrical grids and others that have openings to the Internet and vise-versa, so we do have these potential vulnerabilities where the Net can be attacked and we can face some kinds of threats."

Dan Verton is the author of a recently published book called Black Ice, the Invisible Threat of Cyber-Terrorism.

A retired intelligence officer in the U.S. Marine Corps, Mr. Verton says many people have what he calls a "perception problem" when thinking about who belongs to terrorist organizations.

Mr. Verton says the new, young terrorists are, as a puts it, not a "mindless horde of thugs living a hand-to-mouth existence in caves in Afghanistan."

" The problem is that we have failed to acknowledge that tomorrow's threat may not look like today's threat," said Dan Verton. "There is a real concern about the radicalization of young people around the world by the likes of Osama bin Laden and his supporters where these young people are getting a healthy dose of hatred for America on one hand, and, oh by the way, they are also being taught computer science, mathematics, and engineering."

It is those highly trained young terrorists, Mr. Verton says, that pose the biggest threat to America's infrastructure.

"The forms of terrorism that I am talking about, both the use of modern technology to complement traditional forms of terrorism and also the deliberate targeting in a physical sense of key cyber infrastructures that power the economy and national security, fit in perfectly with the strategic goals of groups like al-Qaida and others," he said.

A senior analyst with the Internet company Global Security.org, George Smith, is less critical of the government's efforts to make information technology more secure.

Mr. Smith says reports of cyber-threats are frequently accepted without serious evaluation. w

"I have to be a realist that we have not seen any direct physical attacks that rise to the level that fit the long-term prognostications of the doomsayers," said George Smith.

The U.S. Department of Homeland Security is taking the threat seriously. Officials in the department have created a National Cyber Security Division that operates 24-hours a day, seven days a week.