Security for group addressed data packets in wireless networks

A non-transitory machine readable medium storing one or more sequences of instructions for operating a wireless node of a wireless network, wherein execution of said one or more instructions by one or more processors contained in said wireless node enables said wireless node to perform the actions of:

• receiving a group key from a parent node of said wireless node, wherein said parent node is comprised in said wireless network;
• and
• forwarding said group key to a child node of said wireless node, wherein said child node is comprised in said wireless network.

A wireless network based system comprising:

• a border router, a plurality of router nodes and a plurality of end devices, all communicating via wireless medium according a hierarchy in which said border router is a root at the highest level and said plurality of end devices are at the lowest level in said hierarchy, said router nodes operating at intermediate levels in said hierarchy to receive and forward packets to said plurality of end devices on said wireless medium,
• wherein all of said border router, said plurality of router nodes and said plurality of end devices operate based on a same group key in encrypting and decrypting payloads of a first plurality of layer-2 multicast packets.