The goal is great, yeah! But the solution is very, very wrong. You don't want to authenticate with a key that you can't change. E.g. someone copies your face w

The goal is great, yeah! But the solution is very, very wrong. You don't want to authenticate with a key that you can't change. E.g. someone copies your face with a 3D printer and you find out. You want to be able to stop him from accessing your secrets. But you don't want to apply plastic surgery for that. Second e.g. someone captures you and wants to open something you can only access with a part of your body (like a finger, or a face or an eye). In that case you want to be able to give it to him without him cutting off parts of your body. The security is broken, but at least your body doesn't have to be. So yeah, this solution is very very wrong. (It's weird that the physical key has the attribute that someone can steal it is in some cases a feature not a bug, but if you think about it it's true.)