Silk could become a means of authentication and unbreakable encryption, according to South Korean boffins.

Silk can take on this role, as explained in Nature Communications, because security boffins are increasingly interested in “physical unclonable functions” (PUFs) – physical objects whose properties are impossible to replicate. As we explained in 2018, the electrical variation present in individual semiconductors has seen them used to generate keys unique to each device, making each chip a PUF.

The authors of the Nature paper, from South Korea’s Gwangju Institute of Science and Technology, think we need more PUFs to help with tasks ranging from better encryption keys to providing unique identifiers for physical objects.

Silk weaves its way into this tale thanks to the complex structure of its interwoven fibres.

“When a beam of light hits the disordered silk fibres of an optimal density, it causes light diffraction,” stated Gwangju Institute’s professor Young Min Song, a senior author of the paper. As each piece of silk has its own unique pattern of fibres, the resulting light is also unique.

The paper’s authors captured, analysed, and digitised that light and found a lot of entropy. So much entropy, in fact, that they reckon it would take 5×1041 years to replicate the unique light signature a swatch of silk possesses.

The boffins also devised a simple reader for silk, tested a silken ID card, and suggested a PUF module could be used to identify objects.

Plenty of experimentation and engineering is always required to turn this sort of research into a product, and the paper doesn’t touch on whether a silk ID card could survive time in your wallet, nor if a trip through a washing machine or time spent scrunched up in a bottom drawer could wipe your ID from a scarf.

The authors point out that silk is a renewable resource, but without considering whether it is ethical to add silkworms to the infosec workforce. ®