The bio-sig pen I signed with (here, and here, and here) had microscopic barbs in the shaft that scraped skin cells from the pad of my thumb to mix with the ink. Signed in blood. Or DNA, which is close enough.
Moxyland by Lauren Beukes
The bio-sig pen I signed with (here, and here, and here) had microscopic barbs in the shaft that scraped skin cells from the pad of my thumb to mix with the ink. Signed in blood. Or DNA, which is close enough.
Moxyland by Lauren Beukes