I can't imagine that anything less than subdermal implants will be reliable, for some people.
If the implant fails, you can just go back to the government office / mega corp, show your DNA, and get a new one.
On further reflection, person a) has an evil twin who steals their identity, and person b) doesn't trust the government / mega corp. Back to the drawing board.
If the implant fails, you can just go back to the government office / mega corp, show your DNA, and get a new one.
On further reflection, person a) has an evil twin who steals their identity, and person b) doesn't trust the government / mega corp. Back to the drawing board.