The full-body scanners being installed at US airports are capable of recording, storing and transmitting the nude images they make of passengers, says the Electronic Privacy Information Center.

EPIC, a watchdog group that monitors privacy in the digital age, has obtained documents showing that the Transportation Security Administration requires its body scanners to be able to record and transmit images.

"I don't think the TSA has been forthcoming with the American public about the true capability of these devices," EPIC Executive Director Marc Rotenberg told CNN. "If you look at the actual technical specifications and you read the vendor contracts, you come to understand that these machines are capable of doing far more than the TSA has let on."

That body scanners can capture and send images will raise fears about the possibility of naked images of passengers being exploited for non-security purposes.

The British government recently deemed that the full-body scanners being installed at UK airports illegally create images of child pornography when they are used on underage individuals. Authorities in the UK ordered that the scanners not be used on passengers under 18, leading some observers to wonder about their usefulness if they are not applied to persons as old as 17.

EPIC says the documents "contradict assurances made by the TSA" that the scanners would not record or transmit images.

On its Web site, the TSA explains that "this state-of-the-art technology cannot store, print, transmit or save the image. In fact, all machines are delivered to airports with these functions disabled."

The last part of the quote here is key -- the machines will be delivered with those functions disabled, not without those functions at all. The TSA's procurement guidelines (PDF) for the body scanners state that the machines will have two modes, a "test mode" and a "screening mode." The machines will not be able to store and transmit images when in "screening mode," but will be able to do so in "test mode."

"When not being used for normal screening operations, the capability to capture images of non-passengers for training and evaluation purposes is needed," the TSA document states.

It was not immediately clear from those documents how easy it is to switch a machine from "screening mode" to "test mode," or who would have the authority or ability to do so.

The TSA's claims about safeguarding privacy have been at the core of many media defenses of the technology, such as this Washington Post editorial that declares "There's nothing to fear from the use of full-body scanners at airports."

EPIC obtained the documents through a freedom-of-information request. The group sued (PDF) the Department of Homeland Security in November to force it to release details of its body-scanning technology.