Scientists Say Silk’s Randomness Makes Great Encryption Keys

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

Silk can play this role, as explained in Nature Communication, as security specialists are increasingly interested in “physically 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 Institute of Science and Technology in Gwangju, thinks we need more PUFs to help us 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 intertwined fibres.

“When a beam of light strikes the disordered silk fibers of optimum density, it causes light diffraction,” said Gwangju Institute professor Young Min Song, lead author of the paper. As each piece of silk has its own unique pattern of fibers, the resulting light is also unique.

The authors of the paper captured, analyzed and digitized this light and found a lot of entropy. So much entropy, in fact, that they estimate it would take 5×10⁴¹ years to reproduce the unique luminous signature possessed by a sample of silk.

Boffins also designed a simple reader for silk, tested a silk ID card, and suggested that a PUF module could be used to identify objects.

A lot of experimentation and engineering is still required to turn this kind of research into a product, and the document doesn’t say whether a silk ID card could survive in your wallet, or a trip to a washing machine. or time spent crumpled up in a bottom drawer could wipe out your ID from a scarf.

The authors point out that silk is a renewable resource, but do not question whether it is ethical to add silkworms to the infosec workforce. ®