Following complaints from privacy groups, California lawmakers on Friday suspended legislation to embed radio-frequency identification chips, or RFIDs, in its driver's licenses and state identification cards.

The legislation, S.B. 397, was put on hold by the state Assembly Appropriations Committee, despite it having been approved by the California Senate, where it likely will be re-introduced in the coming months. Had the measure passed, it would have transformed the Golden State's standard form of ID into one of the most sophisticated identification documents in the country, mirroring the four other states that have embraced the spy-friendly technology.

Radio-frequency identification devices already are a daily part of the electronic age — found in passports, library and payment cards, school identification cards and eventually are expected to replace bar-code labels on consumer goods.

Michigan, New York, Vermont and Washington have already begun embedding drivers licenses with the tiny transceivers, and linking them to a national database – complete with head shots – controlled by the Department of Homeland Security. The enhanced cards can be used to re-enter the U.S. at a land border without a passport.

Privacy advocates worry that, if more states begin embracing RFID, the licenses could become mandatory nationwide and evolve into a government-run surveillance tool to track the public's movements.

The IDs are the offspring of the 2009 Western Hemisphere Travel Initiative requiring travelers to show passports when they cross the U.S. border of Canada and Mexico. Those carrying the EDL "Enhanced Drivers License" or an "enhanced" state ID, do not have to display a passport when traveling across the country's government-run land borders.

The RFID-enabled card would have been optional under the California measure. It was aimed in particular at Californians who make frequent visits to Mexico, and want to ease their return back into the U.S.

"It's not difficult to imagine a time when the EDL programs cease to be optional—and when EDLs contain information well beyond a picture, a signature, and citizenship status. The government also tends to expand programs far beyond their original purpose," writes Jim Harper, the Cato Institute's director of information policy studies. "Californians should not walk – they should run away from 'enhanced' drivers licenses."

According to DHS, about 95 percent of land-border crossings are equipped with RFID-reading technology, making it easy for Customs Border Patrol officials to know who you are. The RFID chip "will signal a secure system to pull up your biographic and biometrics data for the CBP officer as you approach the border inspection booth," the DHS says.

"An individual that does not understand the privacy and security risks of an Enhanced Driver's License (EDL) might think, 'Why not get an one so that I can use it to drive and also cross the border?' It seems like common sense," said Nicole Ozer, an American Civil Liberties Union lawyer. "But the cost to privacy and security far outweighs any benefits. If you carry one of these licenses in your wallet or purse, you can be tracked and stalked without your knowledge or consent."

Sen. Ben Hueso, a Democrat whose district touches the Mexican border, maintains the legislation he sponsored makes both financial and security sense.

"Enhanced Driver’s Licenses can provide a significant economic benefit to the state of California, while strengthening border security," he wrote in a press release last May. "They will greatly reduce wait times at the border thereby incentivizing economic development in our border region."

The California measure's shortcomings, among other things, was that it did not prevent state law enforcement officials from eventually tapping into the chips.

Law enforcement already monitors drivers' whereabouts via the mass deployment of license-plate readers. But the ability to scan for identification cards in public areas could evolve into another surveillance tool.

As the "Identity Project" sees it:

Logs of citizens' border crossings and movements through non-border checkpoints are obviously of interest to the Feds and their state and local law enforcement partners, especially in conjunction with logs of vehicle movements obtained from automated license-plate readers. Cops don’t need to ask, 'Can I see some ID?' when, from outside your vehicle, they can obtain the EDL chip number and corresponding lifetime DHS travel history of every occupant of the vehicle. And as more people carry EDLs, how soon will not broadcasting your ID number be deemed sufficiently suspicious to justify detention, search, or interrogation?

To be sure, the Orwellian nature of these new IDs is – to an extent – speculation.

For the moment, the DHS says that "No personally identifiable information is stored on the card's RFID chip." The DHS said "The card uses a unique identification number that links to information contained in a secure Department of Homeland Security database."

But things could easily change. Government-issued cards routinely evolve away from their original purpose.

Consider the Social Security card. It was created to track your government retirement benefits. Now you need it to purchase health insurance and even obtain employment.