Smartcards more secure with invisibly printed optical encryption keys

November 19, 2015 // By Julien Happich
At this year's Cartes & Secure Connexions exhibition, Swiss startup NISS Group won the SÉSAME award for its NANO-ID technology, featured in the best identification application category.

‎At the company booth, International Key Account Manager for the ‎NISS Group, Thomas Diamantidis demonstrated the virtually undetectable encoding technology for EETimes Europe. Taking two seemingly identical smart cards, he shone an IR laser across a small area of the cards, just a few millimetre square, to unveil a photo-luminescent dot pattern only on the genuine card.

Until then invisible, the bright dot pattern was printed out of a proprietary ink formulation featuring 25nm sized nanoparticles, whose IR-induced visible luminescence (in the green region) reveals the dot pattern to the appropriate card reader.

The patented technology (including encoding algorithms during dot printing and the management of non-repeatable codes in a printer's database) is implemented as several product offerings that turn these stealth optical patterns into unique identification keys (up to 1024 combinations for the hexagonally-shaped Nano-ID code Diamantidis showcased.)

Equipped with an optical detection unit pointing at the hidden area of interest and running vision processing algorithms, the smart card reader can then decode the dot pattern and use the matching encryption key to decipher data encrypted on the secure chip (this reading step may be additionally secured with a PIN entry or fingerprint authentication from the reader's operator).

These measures mean that even a cloned card (without the hard to detect dot pattern), would remain unreadable.

"We usually place the pattern centrally, but it could be printed just anywhere as it doesn’t affect the look and feel of the card", commented Diamantidis, "and the coding pattern could take any other shape or size depending on the specific requirements of our customers", he added, as the reader could also be customized for any given implementation.