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> In addition, the signalling information for switching Economy 7 electricity meters is carried on Radio 4 LW. https://en.wikipedia.org/wiki/Radio_teleswitch h

by darkr 11y ago

> In addition, the signalling information for switching Economy 7 electricity meters is carried on Radio 4 LW. https://en.wikipedia.org/wiki/Radio_teleswitch https://en.wikipedia.org/wiki/Radio_teleswitch Fascinating stuff.

comboy 11y ago
Indeed to allow electricity suppliers to switch large numbers of electricity meters between different tariffs by broadcasting an embedded signal in broadcast radio signals I kind of heavily doubt these are signed broadcasts that cannot be replayed..
- Piskvorrr 11y ago
  Something akin to this? http://gpsworld.com/wirelessinfrastructuregoing-against-time-13278/ http://gpsworld.com/wirelessinfrastructuregoing-against-time... I believe that operating a rogue transmitter in a licensed band would get you located rather quickly - even though the tech itself may not necessarily be secure, there are other enforcement mechanisms.
  - pbhjpbhj 11y ago
    Surely you only need the rogue transmitter to be stronger at the receiver (your electric meter?) than the signal from the transmitter. That doesn't seem like a strong enough signal to easily locate you? Seems a complicated way to do something - doesn't Economy7 operate between fixed times overnight? I wonder if they can cut power using the transmissions - seems like something that could be used for emergency control of demand in times when the National Grid has problems.
    - Piskvorrr 11y ago
      Hm, that's probably the point: there is no threat (to the utility provider) in that model. Worst thing you could do is make someone's appliances run with a more expensive rate; hardly a likely event or one worth preventing. (As for power cutting, that seems unlikely - the system is in place to provide larger power consumption when base production exceeds the load. Around here, the basic low/high rate info is provided by https://en.wikipedia.org/wiki/Load_management#Ripple_control https://en.wikipedia.org/wiki/Load_management#Ripple_control , which needs a not-really-smart power meter, but runs on top of the power line, obviating the need for a side channel)
      - jon-wood 11y ago
        The smart metres that are being rolled out at the moment have a remote kill switch, although it couldn't really be used to implement rolling blackouts as you have to physically hit a button to reactivate it.
        Piskvorrr 11y ago
        That's a DoS waiting to happen, IMNSHO. If it's easy to transmit on the frequency locally at low power and there's no auth, a drive around the neighborhood could create a blackout at anyone's demand.
        flapjackdan 11y ago
        At least in the UK, smart meters don't use radio-based time switching as they have their own clocks which are synchronized with their remote system. All commands to these smart meters (including the ability to remotely disconnect them) are cryptographically protected to ensure integrity and authenticity, and also have anti-replay protections. Disclaimer: I've worked for a smart metering manufacturer.
        Piskvorrr 11y ago
        Well, that's excellent news then. Thank you for the clarification.
  - leoedin 11y ago
    It depends how strong it is. The obvious benefit for a malicious person would be to set their meter to the cheaper tariff by replaying the signal. It wouldn't need to be a powerful signal - if you were broadcasting right next to the meter even a few milliwatts would be enough. Build a faraday cage around the meter to be sure! Just remember to dismantle it before the meter reader comes round.
    - Piskvorrr 11y ago
      That would also disable the legit switching, no?
oxplot 11y ago
I was under the impression that most if not all meters of any kind (electricity, gas, etc.) have GSM modems that not only allow for this kind of signalling but also report their reading to the energy company.

by darkr 11y ago

comboy 11y ago

Indeed to allow electricity suppliers to switch large numbers of electricity meters between different tariffs by broadcasting an embedded signal in broadcast radio signals I kind of heavily doubt these are signed broadcasts that cannot be replayed..

Piskvorrr 11y ago
Something akin to this? http://gpsworld.com/wirelessinfrastructuregoing-against-time-13278/ http://gpsworld.com/wirelessinfrastructuregoing-against-time... I believe that operating a rogue transmitter in a licensed band would get you located rather quickly - even though the tech itself may not necessarily be secure, there are other enforcement mechanisms.
- pbhjpbhj 11y ago
  Surely you only need the rogue transmitter to be stronger at the receiver (your electric meter?) than the signal from the transmitter. That doesn't seem like a strong enough signal to easily locate you? Seems a complicated way to do something - doesn't Economy7 operate between fixed times overnight? I wonder if they can cut power using the transmissions - seems like something that could be used for emergency control of demand in times when the National Grid has problems.
  - Piskvorrr 11y ago
    Hm, that's probably the point: there is no threat (to the utility provider) in that model. Worst thing you could do is make someone's appliances run with a more expensive rate; hardly a likely event or one worth preventing. (As for power cutting, that seems unlikely - the system is in place to provide larger power consumption when base production exceeds the load. Around here, the basic low/high rate info is provided by https://en.wikipedia.org/wiki/Load_management#Ripple_control https://en.wikipedia.org/wiki/Load_management#Ripple_control , which needs a not-really-smart power meter, but runs on top of the power line, obviating the need for a side channel)
    - jon-wood 11y ago
      The smart metres that are being rolled out at the moment have a remote kill switch, although it couldn't really be used to implement rolling blackouts as you have to physically hit a button to reactivate it.
      - Piskvorrr 11y ago
        That's a DoS waiting to happen, IMNSHO. If it's easy to transmit on the frequency locally at low power and there's no auth, a drive around the neighborhood could create a blackout at anyone's demand.
        flapjackdan 11y ago
        At least in the UK, smart meters don't use radio-based time switching as they have their own clocks which are synchronized with their remote system. All commands to these smart meters (including the ability to remotely disconnect them) are cryptographically protected to ensure integrity and authenticity, and also have anti-replay protections. Disclaimer: I've worked for a smart metering manufacturer.
        Piskvorrr 11y ago
        Well, that's excellent news then. Thank you for the clarification.
- leoedin 11y ago
  It depends how strong it is. The obvious benefit for a malicious person would be to set their meter to the cheaper tariff by replaying the signal. It wouldn't need to be a powerful signal - if you were broadcasting right next to the meter even a few milliwatts would be enough. Build a faraday cage around the meter to be sure! Just remember to dismantle it before the meter reader comes round.
  - Piskvorrr 11y ago
    That would also disable the legit switching, no?

oxplot 11y ago

I was under the impression that most if not all meters of any kind (electricity, gas, etc.) have GSM modems that not only allow for this kind of signalling but also report their reading to the energy company.