With the introduction of Android Marshmallow, you could now use a built-in fingerprint scanner to unlock your device. In order to set this functionality up, you need to follow some fairly simple steps to get the best experience: 1. Go to the Fingerprint Settings Menu 2. Add a Backup Unlock Method 3. Register Your Fingerprint As for making sure that your fingerprint will always be recognized, it's recommended to set up multiple fingerprints. This will cut down on the number of times the scanner may not recognize your fingerprint.