5 ms·

It is extremely strange they don't use even primitive encryption. I work for Russian company "Strizh Telematics", we are making smart resource meters. We take s

It is extremely strange they don't use even primitive encryption. I work for Russian company "Strizh Telematics", we are making smart resource meters. We take security very seriously here: all transmits are encrypted with 64 bit keys and data protocols are specifically protected from statistical and repeat-packet attacks.

wcoenen 9y ago
Why 64 bit? The minimum key strength supported by AES is 128 bits, so 64 bits seems very low.
- arrayjumper 9y ago
  Probably to keep hardware costs low.
- SergeAx 9y ago
  To reduce power consumption by using simple hardware. See my answer to @mrb above.
mrb 9y ago
That's great, but using a 64-bit key in 2017 isn't "taking security seriously". Especially if you are designing meters that will have a lifespan of 10+ years, therefore must be secure until 2027 and beyond.
- SergeAx 9y ago
  Our most talkative meters are currently broadcasting 4 packets of data per hour. Water meters with autonomous power are limited to one or two (for central hot water supply) packets per day. With all the randomness added collecting data for successful key bruteforcing will take months or even years. On the other hand, using 64 bits allows us to use 16- or even 8-bit microcontrollers, which is beneficial to power consumption. Of four recources commonly metered in Russia - electricity, water, gas and heat - three should use autonomous power. We also making an autonomous plug-in modules for popular "dumb" electricity meters - to simplify installation. They broadcast once a day too so the battery could last for 6 years.
  - orf 9y ago
    Still, the comment above still stands. Not sure about the key bruteforcing estimates, surely a couple of days of readings would be enough. Are the keys stored on the devices? Is it a shared key?
    - SergeAx 9y ago
      Every device has it's own unique keys - one for transmitting data and another for receiving commands. They are burned with firmware in production. If you are interested in bruteforcing - I can send you two weeks worth of my home water meters' data packets to play with :) See, the CRC is calculated for encrypted data, so there is no way to know if the guessed key is correct.
      - glogla 9y ago
        No MACs?
        SergeAx 9y ago
        There are unique device Ids, they kinda like MACs.
        darklajid 9y ago
        Old thread, but GP probably talked about a different thing. Not MAC as in Ethernet.. https://en.m.wikipedia.org/wiki/Message_authentication_code https://en.m.wikipedia.org/wiki/Message_authentication_code
        SergeAx 9y ago
        Oh, those MACs) No, we've spend that bandwidth for iterators to mitigate replay attack. But the idea of one-time MAC is interesting, thank you.
  - ris 9y ago
zzzcpan 9y ago
I'm curious, if someone finds a vulnerability in your algorithms somewhere, will you be able to quickly deploy updates to all the installed smart meters? Because, honestly, "taking security very seriously" doesn't mean anything anymore.
- SergeAx 9y ago
  Everyone knows that in "IoT" letter "S" means "security" :) We do have an ability to burn updated firmware for most of the devices on premises using special hardware pieces, similar to ones used by factory staff. For less complicated devices we can just replace microcontroller modules, and reuse old ones later. That would be quite expensive, but we'll live. I heard there's some sort of insurance contract for that matter.

wcoenen 9y ago

Why 64 bit? The minimum key strength supported by AES is 128 bits, so 64 bits seems very low.

arrayjumper 9y ago
Probably to keep hardware costs low.
SergeAx 9y ago
To reduce power consumption by using simple hardware. See my answer to @mrb above.

mrb 9y ago

That's great, but using a 64-bit key in 2017 isn't "taking security seriously". Especially if you are designing meters that will have a lifespan of 10+ years, therefore must be secure until 2027 and beyond.

SergeAx 9y ago
Our most talkative meters are currently broadcasting 4 packets of data per hour. Water meters with autonomous power are limited to one or two (for central hot water supply) packets per day. With all the randomness added collecting data for successful key bruteforcing will take months or even years. On the other hand, using 64 bits allows us to use 16- or even 8-bit microcontrollers, which is beneficial to power consumption. Of four recources commonly metered in Russia - electricity, water, gas and heat - three should use autonomous power. We also making an autonomous plug-in modules for popular "dumb" electricity meters - to simplify installation. They broadcast once a day too so the battery could last for 6 years.
- orf 9y ago
  Still, the comment above still stands. Not sure about the key bruteforcing estimates, surely a couple of days of readings would be enough. Are the keys stored on the devices? Is it a shared key?
  - SergeAx 9y ago
    Every device has it's own unique keys - one for transmitting data and another for receiving commands. They are burned with firmware in production. If you are interested in bruteforcing - I can send you two weeks worth of my home water meters' data packets to play with :) See, the CRC is calculated for encrypted data, so there is no way to know if the guessed key is correct.
    - glogla 9y ago
      No MACs?
      - SergeAx 9y ago
        There are unique device Ids, they kinda like MACs.
        darklajid 9y ago
        Old thread, but GP probably talked about a different thing. Not MAC as in Ethernet.. https://en.m.wikipedia.org/wiki/Message_authentication_code https://en.m.wikipedia.org/wiki/Message_authentication_code
        SergeAx 9y ago
        Oh, those MACs) No, we've spend that bandwidth for iterators to mitigate replay attack. But the idea of one-time MAC is interesting, thank you.
- ris 9y ago

zzzcpan 9y ago

I'm curious, if someone finds a vulnerability in your algorithms somewhere, will you be able to quickly deploy updates to all the installed smart meters? Because, honestly, "taking security very seriously" doesn't mean anything anymore.

SergeAx 9y ago
Everyone knows that in "IoT" letter "S" means "security" :) We do have an ability to burn updated firmware for most of the devices on premises using special hardware pieces, similar to ones used by factory staff. For less complicated devices we can just replace microcontroller modules, and reuse old ones later. That would be quite expensive, but we'll live. I heard there's some sort of insurance contract for that matter.