Biometrics are essential to the long-term success of mobile computing. The obvious place is in security: Swipe your finger instead of typing a password. This is convenient—but worrisome.

Apple’s new iPhone 5s incorporates a fingerprint scanner. The phone’s Touch ID features have been receiving lots of news coverage because it’s from Apple, but it’s not the first fingerprint unlock, not by a long shot. My Motorola Atrix, released in early 2011, had a very effective fingerprint scanner. Laptops and other devices have had those as well for several years.

There are other ways of incorporating biometrics into mobile computing. Wearable bio sensors, like the Fitbit and the FuelBand, are hot holiday gift items: they can keep track of your pulse, sleep pattern, steps and more.

Right now, those devices are used primarily for fitness. But biometrics clearly are part of a multiphase security plan. Imagine having your unique heartbeat electrical pattern unlock your phone!

The best security schemes incorporate “something you have” with “something you know.”

My family has a safe deposit box at a local bank. Instead of asking a bank teller for access to the vault, we now walk over to the vault, place our palms on a reader, and tap out an access code number on a keypad. Click. We’re in. Biometrics.

Beyond fingerprints and handprints, iris scanners are real and growing in popularity, though I don’t believe there’s a mobile version yet. Movies like “Minority Report” and the upcoming “The Lost Symbol” demonstrate, albeit in grisly fashion, the scary downside of security biometrics without requiring an access code. Similarly, “The Dark Knight Rises” shows off an expensive loophole in fingerprint scanning.

There are a lot of privacy concerns regarding biometric data. Forget the gory details: Imagine a man-in-the-middle attack, or a straightforward hack or theft. What could someone use your biometric signature data for? As Gandalf would say, is it secret? Is it safe?