[Florian] and [Xavier Carcelle] started the day at 25C3 by covering power line communication. PLC technology is not widespread in the US, but has gained popularity in countries like France where it’s included in set-top boxes. PLC lets you create a local network using the AC wires in your wall. The team started exploring PLC because despite being newer technology, it had a few principles that made it similar to old networks. There’s no segmentation in the wiring, which means it behaves like a layer 2 hub. You get to see all of the traffic unlike a switched network. Most power meters don’t filter out the signal, so it’s possible that you might see your next-door neighbor’s traffic on your line. [Florian] reports having seen all the traffic in a six-story building just by plugging in. The wiring also acts as a large antenna so you could employ tempest attacks.