Lollipop: Familiarity Induces Confidence to Waive Security

I recall an evening walk with my grandson, Arnav.  We turned into an alley that was new for him.  He immediately tightened his grip on my hand and said, "I don't like going too far away from home."  I picked him up and held him close to my chest.  He looked intently at my face and relaxed.  Sometimes I drive him to unknown places in the old car retained by my son.  He never becomes apprehensive as long as he is in the car.  He has known this car since his birth.  The familiarity breeds confidence in him.

Security in Lollipop, Android's latest version, seems to be modeled after Arnav. It implements security through password / patterns and at the same time tells the system to have confidence when it finds itself in a familiar place or when it sees a familiar face or when it is close to a familiar device.  In these cases it unlocks itself.  If none of the reassuring factors are present, it asks for the password or the pattern.

This confidence based security is implemented through Smart Lock.  It is called smart because it unlocks the system when having confidence in the owner, place or connected devices.  If the confidence is lacking the system can only be unlocked through password / pattern.  Smart Lock is called a Trust Agent that tells the system about what to trust.  The design suggests that other trust agents may also be added later on.

I have experimented with all the three Smart Locks (connected device, place and face.). Face based unlocking doesn't work every time.  This is only as expected.  Place based unlocking is working well.  Documentation says the device remains unlocked within 80 meters of the defined place.

Smart unlocking in the presence of a recognized Bluetooth device may prove a weakness if both the devices get stolen together!

Needless to add that Smart Lock can be activated only if a password or pattern is active.  Unless there is a lock there is nothing to smartly lock or unlock.  It is also a fallback if smart unlock doesn't work as happens many times in case of trusted faces.

The settings for Smart Lock are found here: Settings->Security->Smart Lock.