A Wall Street Journal reported that iPhone 5s which is equipped with a fingerprint scanner will not store actual images of users’ fingerprints on the device according to an Apple spokesman.
They said that the new Touch ID system will only store “fingerprint data,” which remains encrypted within the iPhone’s processor. It uses the digital signature to unlock itself or make purchases in Apple’s iTunes, iBooks or App stores.
In practice, this means that even if someone cracked an iPhone’s encrypted chip, they likely wouldn’t be able to reverse engineer someone’s fingerprint.
However, in my last post "NSA able to hack your smartphone" are you really sure that the NSA can't access your fingerprints? and you'll never know what will they do with it.