Android devices offer a number of authentication methods in order to access the device that have varying levels of security associated with them. Not all authentication methods are available on all devices and may be depend upon the operation system.
Swipe: This method only requires the user to do a swiping motion to unlock the screen to access the phone. It is not meant to secure the phone but to prevent accidentally pressing buttons on the phone.
Face Unlock: This method takes a picture of the user using the device camera then compares it against the stored image on the device of that user. It allows the user to unlock their phone by just using a facial picture and not having to remember a PIN or password. This authentication method is vulnerable to attack by simply holding a picture of the user in front of the phone. [10] In Android 4.1 and there is a liveness check added which requires you to blink at the phone when unlocking it. This is a very low security method of device authentication and it should not be considered secure.
Pattern: This method allows the user to trace a pattern on a series of dots to unlock the phone. It must be at least 4 dots long. The smudge left on the screen by a user tracing their unlock pattern could be used by a malicious person to gain access to the device. [9] This method is a low to medium security method of device authentication.
PIN: This method allows the user to choose a PIN between 4-16 digits long. The longer the PIN the more secure the device will be. Choosing simple PINs of 1234 or similar should be avoided as the device will not be very secure. This is a medium to high security method of device authentication.
Password: This method allows the user to choose a password that has at least 4 letters or numbers. The longer the password the more secure the device will be. Choosing a simple password should be avoided as the device will not be very secure. This is a medium to high security method of device authentication.
In order to enable encryption the Android device it usually requires a PIN or password to be in place. The device will not encrypt without one of those authentication methods turned on. While the device is encrypted the PIN or password may not be disabled.