Well, a piece of paper is easier to lose than a key on a keychain. I would suggest a metal key-chainable object that has the code written on it with relief bump

Well, a piece of paper is easier to lose than a key on a keychain. I would suggest a metal key-chainable object that has the code written on it with relief bump-outs. On the flip side the same thing with brail. Even then, it's not equivalent: a hidden wireless camera installed by a thief can easily see the code on the paper or key thing, or even typed into the pad.