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Carbon nanotubes – is there anything they can’t do? They’re strong, hard, loaded with unique electrical, thermal, and optical properties, and have been heralded as the secret ingredient in everything from hydrogen storage to space elevators. Now, new research reveals they show promise in improving hardware cryptography.
Due to the semiconductor-like properties of carbon nanotubes, proposals of their application for microchips have been floating around for years. But the difficulty of working with the material, of positioning it in the precise way required for a working processor, and the unpredictable blend of semiconducting and non-conducting tubes made these proposals essentially unworkable.
A team of researchers from academia and IBM have come up with a way to harness precisely these properties of the tiny structure to create truly random hardware cryptography. Hardware cryptography involves setting a pre-existing key into the hardware. This, of course, can make the pre-determined key vulnerable to being discovered.
The method the team came up with makes the wiring of the chip itself random. To do so, they coated some nanotubes in a negatively charged solution, which in turn had them attracted to positively charged segments of the chip. Neighbouring areas of the chip were given a negative charge, increasing the randomness through a tug-of-war-like mechanism.
Due to the spacing between the areas, the team was able to relatively accurately determine the number of the areas with carbon nanotubes, but the areas themselves are much harder to discover. The only way to find out which areas of the chip are conductive is to get down to the wiring level, greatly deterring snooping.
This random arrangement of conductive and nonconductive areas of the chip makes for a perfect starting point for random cryptographic keys.
The manufacturing process is relatively simple, so while more research is still needed, in the not-so-distant future carbon nanotubes could be incorporated into regular computer chips, greatly increasing cryptographic strength and overall security.