Imagine you're standing in line to buy a snack at a store. You step up to the counter and the cashier scans your food. Next , you have to pay, but instead of scanning a QR Code(二维码) with your smart phone, you just hold out your hand so the cashier can scan your fingerprint. Or, a camera scans your face, your eyes or even your car.

Now, this type of technology might not be fa r away. As technology companies move away from the traditional password, biometric(生物特征识别的) security, which includes fingerprint, face and voice ID, is becoming increasingly popular.

In 2013, Apple introduced the iPhone 5s, one of the first smart phones with a fingerprint scanner. Since then,using one's fingerprint to unlock a phone and make mobile payments has become commonplace, bringing convenience to our lives . And since 2016, Samsung has featured eye-scanning technology in its top smart phones.while Apple's new iphone X can even scan a user's face. But despite its popularity, experts warn that biometries might not be as secure as we imagine."Biometries is ideally good in practice, not so much, "said John Michener,a biometries expert.

When introducing the new iPhone's face ID feature, Phil Schiller, Apple's senior vice-president, said."The chance that a random person in the population could look at your iPhones X and unlock it with their face is about one in a million' But it's already been done. In a video posted on a community website Read fit, two brothers showed how they were each able to unlock the same iPhone X gunning their own face. And they aren't even twins.

"We may expect too much from biometries," Anil Jain, a computer science profess or at Michigan State University , told CBS News."No security systems are perfect."

Earlier last year, Jain found a way to trick biometric security. Using a printed copy of a thumbprint, she was able to unlock a dead person's smart phone for the police, according to a tech website Splister."It's good to see biometrica being used more," Jain told CBS News,"because it adds another factor for security. But using multiple security measures is the best defense."