They aren’t taking any chances at Barclays Bank in Britain. Stating an account number and other bona fides isn’t enough to get to your money at the bank’s wealth and investment management service. As an additional safeguard, a program analyzes customers’ voices when they call in, to make sure they match a voice print on file.

At some A.T.M.’s in Japan, getting cash isn’t simply a matter of entering a bank card and a password. The machine scans the vein pattern in a person’s palm before issuing money.

And, since September, people have been using fingerprint sensors on their iPhone 5s to unlock their devices, or to shop at the iTunes store.

These are three examples of biometrics systems, which have long been the province of border control, military surveillance and national intelligence. Now they are rapidly moving into the consumer mainstream to unlock laptops and smartphones, or as a supplement to passwords at banks, hospitals and libraries.