Today, we let any input device (such as a keyboard, or any USB device actually) take full control of our computer. If it's a hacked device (even something just

Today, we let any input device (such as a keyboard, or any USB device actually) take full control of our computer. If it's a hacked device (even something just inserted into the USB) it can type anything to our computer, issue commands, make it download stuff, sniff passwords, etc. It takes a lot of work to make a computer secure enough that you can plug a non-trusted keyboard into it. It may not even be truly doable if you consider the habits of computer users.