An anonymous reader writes: Two researchers have come up with a new method of hacking smartphones that use fingerprint biometrics to protect and lock the user's data. Their method only needs a regular inkjet printer, three AgIC silver conductive ink cartridges, a normal black ink cartridge, and special AgIC paper. The entire attack takes no more than 15 minutes. Current tests only included a Samsung Galaxy S6 and a Huawei Hornor 7. The researchers said that while the Samsung was easy to crack, the Huawei phone needed more tries.