They covered it in the article. > Full human fingerprints are difficult to falsify, but the finger scanners on phones are so small that they read only partial

They covered it in the article. > Full human fingerprints are difficult to falsify, but the finger scanners on phones are so small that they read only partial fingerprints. When a user sets up fingerprint security on an Apple iPhone or a phone that runs Google’s Android software, the phone typically takes eight to 10 images of a finger to make it easier to make a match. And many users record more than one finger — say, the thumb and forefinger of each hand. > Since a finger swipe has to match only one stored image to unlock the phone, the system is vulnerable to false matches. > “It’s as if you have 30 passwords and the attacker only has to match one,” said Nasir Memon