An inkjet printer can fool your smartphone with fake fingerprints

Android easily tricked, but iOS seems more secure

A fingerprint reader is the best way to keep your phone secure, right? Not so fast - it only takes a printer to crack it wide open.

It used to take a top-end printer, some expensive hardware scanning and almost an hour of waiting for ink to dry to make a detailed enough print to bypass a smartphone’s sensor, but Michigan State University researchers Kai Cao and Anil Jain have figured out how to do it with a regular home inkjet.

It’s not quite as easy as scanning your fingers and printing out some fake prints though; the two researchers had to buy ink that conducts electricity once it gets printed onto special paper.

You’d normally use this type of ink for printing simple circuits, but when you use it to make a high resolution fingerprint, it can fool a phone.

Samsung’s Galaxy S6 and the Huawei Honor 7 both unlocked using the fake print, but apparently an iPhone had mixed results.

The whole thing only took 15 minutes to snap, scan, edit and print a fake print, which is at least twice as fast as older methods. It's not cheap, though; a set of ink and paper costs around US$350.

With some of the biggest phones out there falling to this new hack, companies that make fingerprint sensors are making a lot of noise about new, foolproof designs.

At least one is working on a sensor that detects the blood flowing through your finger, which would stop any kind of printout or mould from unlocking your phone.

In the meantime, crims would still need to get hold of your phone, and take a clear, hi-res photo of your fingers before they could get beyond your lock screen.