For centuries, personal signatures have carried a lot of weight. Your own John Hancock binds you to the most official of obligations. It verifies that you are who you say you are. If you’re famous, it’s even worth something.

Yet for something so attached to one’s public identity, we tend not to think twice when scribbling it on a check or receipt. And after our 10-year-old selves are finished practicing it on pages and pages of notebook paper, we certainly don’t change it. Nor do we question its pen-and-paper (now sometimes pen-and-pad) medium.

But the way people think about the metho…