Fourteen small white boxes with green glowing screens were installed this week at customs booths around John F. Kennedy International Airport here.

Now, in addition to handing over a passport to Customs and Border Protection agents, every noncitizen visitor has to place all four fingers and thumb from each hand on the glowing screen. Within seconds, CBP has their 10 digital fingerprints on file.

This expanded effort to collect fingerprints of noncitizen visitors is part of a national test of improved biometrics technology that the Department of Homeland Security hopes will make it harder for people with forged documents or criminal pasts to enter the United States. Eventually, they hope to use this technology to ensure that foreign visitors who come leave when their visas have expired.

Estimates are that between one-quarter and one-half of immigrants in the United States arrived with a valid visa, but remained here illegally when it expired and they didn't leave. The US does little if anything to track them.

The rolling out of this more extensive 10-finger digital print entry technology has raised privacy concerns about how the data will be stored and protected. DHS officials contend there are plenty of privacy protections in place. And they insist the new system will shore up current security efforts because 10-print matches are the most accurate way to identify individuals.

"We're testing it at multiple locations throughout the US just to get some metrics and practice before we roll it out domestically at all of the ports of entry," says Robert Mocny, director of the DHS US-VISIT program. "By the end of December 2008 all air, land, and sea ports of entry will have the devices."

Four years ago, with the memory of 9/11 still fresh, the US started collecting two digital fingerprints and a picture from each noncitizen visitor. As a result, it already has a database of 90 million fingerprints. With this 10-finger digital print technology, it believes it will add 20 million to 23 million fingerprints each year. DHS will keep them in a database for 75 years.

Other countries are also joining the biometric bandwagon. Japan last year began collecting some fingerprints when foreign visitors enter the country and the European Union is considering it. These countries are also talking about sharing these databases That has raised alarms among privacy advocates who worry the data can be accessed or misused.

"Everyone's data is being stored and disseminated and there are definitely questions about the ability to keep this information secure, as well as whether it will be properly used," says Melissa Ngo, of the Electronic Privacy Information Center. "We also wonder why exactly there is a need to increasingly grow this database."