Fingerprint locks not very safe

No two people are supposed to have the same fingerprint. That would lead you to think that using your fingerprint to unlock your smartphone is the best way to keep it safe. Not so, say researchers at Michigan State and New York universities. It seems that our smartphones take only partial scans of our finger because the sensors used are too small to capture the full fingerprint. The sensors actually take multiple partial scans of our finger so that it can be recognised immediately. The more partial prints a phone stores, the more chances there are of a "masterprint" unlocking it.

Nasir Memon, a professor of Computer Science and Engineering at NYU Tandon and his colleagues, NYU Tandon Postdoctoral Fellow Aditi Roy and Michigan State University professor of Computer Science and Engineering Arun Ross, used commercial fingerprint verification software to find out if 8,200 partial fingerprints could be falsely matched in a computer simulation. They found an average of 92 potential masterprints for every randomly sampled batch of 800 partial prints. (A masterprint matched at least 4 per cent of prints in a batch.) They found, however, just one full-fingerprint masterprint in a sample of 800 full prints. "There's a much greater chance of falsely matching a partial print than a full one, and most devices rely only on partials for identification," said Memon. These masterprints would theoretically be able to unlock 25 per cent to 65 per cent phones, based on how many partial prints it stores.