DVD plus nano-rods equals security, density: researchers
A little light encryption
Swinburne and Taiwanese researchers have demonstrated technology that can use a single laser beam to create 3D polarization in nanomaterials.
What’s cool about this is that they demonstrate that the polarization can be used to encrypt information – as well as expanding the storage capacity of optical media like DVDs.
As is shown in the illustration at the bottom of this story, the polarization technique – in its infancy at the moment – allows different images to be encoded in one place, showing up depending on the polarization the “read” beam uses.
Using polarization to encode information like this isn’t new: however, achieving 3D polarization using a single beam is, according to the researchers.
As the abstract in Nature states, “arbitrary three-dimensional polarization orientation of a beam hasn’t been achieved yet”.
Gold nano-rods tuned to specific wavelengths are added to the surface of the DVD, according to Swinburne’s Professor Min Gu. The rods are sensitive to the polarization of the “write-laser” – so while one polarization will align some particles in the rods, a different polarization will affect a different set of particles.
Professor Gu says the laser can be polarized “in any direction” – yielding the “arbitrary” polarization referred to in the Nature paper. This characteristic of the laser is what provides both the lift in storage density and the technique’s encryption possibilities. ®
Depending on write polarization, the same area can store different images. Source: Nature
I may be wrong but here goes ......
Thinking about it briefly (very briefly), this will give you the ability to encode successive bits of data with different polarisation, the discrete sequence of the polarisation direction (in 3D) which is known to the creator but not to any unauthorised person who tries to read it. However, there will be a finite and limited set of possible polarisations otherwise an authorised recipient would not have the equipment to read it. It's like being presented with a box containing a bit of data then being told that there are in fact, say, 100 sub-boxes (determined by the polarisation direction) so which sub-box do you want?
Isn't this actually high density steganography? Or am I splitting hairs?
This is science at its sexiest, no doubt about it.
Just one question though : is my GS-DVD (Gold-Sprinkled) going to take six times longer to "burn" due to all those polarization changes ?
In addition to costing me an arm and a leg for a stack of ten, of course.
Re: I may be wrong but here goes ......
I'm failing to see that this is nothing but expanding the key-depth though. In the case of 100 sub-boxes (say 128 to make it easer), you could get away with having a 6-bit key instead.
It's good, I'll grant you, but I don't think the killer app is crypto. They've just created a very expensive 1-time pad.