For more about this, there's an excellent paper about hacking lightbulbs: http://www.dhanjani.com/docs/Hacking%20Lighbulbs%20Hue%20Dhanjani%202013.pdf http://ww

For more about this, there's an excellent paper about hacking lightbulbs: http://www.dhanjani.com/docs/Hacking%20Lighbulbs%20Hue%20Dhanjani%202013.pdf http://www.dhanjani.com/docs/Hacking%20Lighbulbs%20Hue%20Dha... "In order to change the state of the lightbulbs (such as turning all the associated bulbs off) the bridge uses the ZigBee Light Link (ZLL) wireless technology and protocol.... "ZLL requires the use of a manufacturer issued master key. This master key is stored on the bridge as well as the light bulbs. Upon initiation (when the user presses the button on the bridge), the bridge generates a random network key and encrypts it using the master key. The lightbulbs unwrap the network key since they also have the master key and use it to subsequently communicate with the bridge."