Looks like someone has figured out a way to scan and record the uniqueness of materials at a nano-level. The Guardian has the story:

After tuning the laser system, he also discovered that the probability of two pieces of paper producing an identical reading was unimaginably remote.

Credit cards, metals and coated paper boards were swiftly tried with the same startling results. Putting the now defunct microchips aside, Cowburn realised that all he needed was to scan an item’s surface, convert the reflected laser speckle pattern into numbers, and store a security signature in a database.

Several applications are discussed, but I think this one is particularly interesting:

laser surface authentication might provide rapid checking of ordinary paper passports without the need for costly microchipped identity cards

One problem I see is the susceptibility of a material, especially paper, to being altered by liquid, pressure, heat, etc.. Wonder how they’ll account for that.