iPhone 5's Fingerprint Lock
If you have the iPhone 5s, you should at least try Touch ID, the clever new fingerprint authentication scheme that not only lets you bypass the Lock screen by pressing your thumb or another finger against the Home button, but also lets you purchase stuff in the iTunes and App Stores.
You can store up to five fingerprints in your iPhone 5(yours and people you trust with whom you share the phone). To do so, tap Add a Fingerprint and go through the training session that you likely encountered back when you set up your phone. If the iPhone doesn’t recognize your finger, you see Try Again at the top of the screen. You get three wrong tries before you're forced to use a traditional passcode instead, at least for this session.
As an added security measure, a regular passcode is required the first time you try to get past a Lock screen after restarting the phone.
If you want to delete an authorized fingerprint, tap Edit, and then tap the red circle with a horizontal white line through it next to whichever finger is about to, in effect, get the finger (if you get the drift).