for National Geographic News
Office supplies have fingerprints, too, it seems.
A laser-based technology can read and record the unique "fingerprint" found in every piece of paper, cardboard, and plastic.
Scientists say the new tech offers an array of applications, from thwarting forged IDs and prescription drug packages to preventing identity theft and combating terrorism.
"For any strong security system what we need to know is, is the person really who they say they are and is the document real?" said Russell Cowburn, a nanotechnology professor at Imperial College London.
New biometric security systems, such as iris scanners or hand scanners (which read signature vein patterns), can help suss out a person's true identity. But there are fewer ways to determine a document's authenticity.
"We are providing the missing link in the security chain," Cowburn said.
Document fingerprints arise from imperfections in the seemingly flat surfaces of paper, plastic, and similar materials. The flaws are evident at the microscopic level and are measured in microns and nanometersscales approaching the size of molecules and atoms.
To read fingerprints at such small scales, the technology takes advantage of the optical phenomenon known as laser speckle.
"You shine a laser light onto any surface that is anything except perfectly flat. With even the smallest irregularities there is an imprint in the light that reflects off, an imprint of the irregularities," Cowburn explained.
The irregularities are different for every item. A digital recording of the irregularities serves as the fingerprint.
Cowburn and colleagues describe the application in tomorrow's issue of the science journal Nature.
Joshua Smith, now a principal investigator at Intel Research Seattle and an affiliate professor of electrical engineering at the University of Washington in Seattle, had previously developed a similar technology.
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