In this imaginary future, everyone carries an implant like an RFID chip that identifies them to scanners that then authorize access or orders. Today, such chips are usually implanted subdermally, often in the hand. But in a future where such chips are not experiments or gadgets for rare individuals and useless to anyone else, but ubiquitious and powerful, I think implanting them under the skin of the hand would allow criminals and hackers to tamper with them much too easily.
So I wonder if they would rather be implanted in a place were they would be difficult and dangerous to remove, e.g. in the brain. Or am I overthinking the issue, as passports are not implanted safely either and still difficult enough to "hack"?
Where would the president carry the implant that would authorize his order to launch a war? What would make it secure from hacking it remotely?
I think it needs to be difficult to remove and the ID must be hardwired. On the other hand it must be possible to insert and remove such an implant when a person is elected or resigns from an office, without any danger to his life, so an operation on the brain every now and then seems to be out of the question.
Please don't take the example of the president farther than is meaningful. The president today carries a passport as his ID. This is easy to steal, easy to fake. Still, the nuclear launch procedure is secure enough, as it doesn't depend on the president's passport alone. So of course in a future with RFID chips, the security of the nuclear launch procedure wouldn't depend on the president's chip alone.
Also, RFID was an example only. If you can come up with a better technology to wirelessly transmit (or read) a person's identity, then that is even better. But it has to work with sunglasses, so reading the retina is out of the question.
Finally, don't go over board. Nothing is unfakeable today, and we still get by. So nothing has to be totally unfakeable or unbreachable in the future. The requirement for security is that the chip has to be reasonably secure. Which, to return to the president, is why no sane person would rely on the chip alone in matters of national security.
Keep the question in context.