"Ames: The President's own vital signs -- heartbeat, brainwave pattern, blood pressure and so on -- are constantly monitored and relayed by his internal nanomachines. This information along with the DNA pattern serve as a biometric password, unbreakable even by the latest parallel processor supercomputers. The password entry itself cannot be performed unless brainwave patterns and heartbeats fall within normal parameters, rendering chemical and other forms of coercion impractical."