4 ms·

> with redundant power, cooling, etc The doors the system controls don't have any of this. Hell, the whole building doesn't have any of this. And it definitely

> with redundant power, cooling, etc The doors the system controls don't have any of this. Hell, the whole building doesn't have any of this. And it definitely doesn't have redundant internet connections to the cloud-based control plane. This is fear-mongering when a passive PC running a container image on boot will suffice plenty. For updates a script that runs on boot and at regular intervals that pulls down the latest image with a 30s timeout if it can't reach the server.

lazide 9mo ago
Those devices can be trivially power cycled, and won’t have as many issues with dodgy power. Some PC somewhere with storage is a bigger problem.
- Nextgrid 9mo ago
  > Some PC somewhere with storage is a bigger problem Both an embedded microcontroller and a PC have storage. The reason you can power-cycle a microcontroller at will is because that storage is read-only and only a specific portion dedicated to state is writable (and the device can be reset if that ever gets corrupted). Use a buildroot/yocto image on the PC with read-only partitions and a separate state partition that the system can rebuild on boot if it gets corrupted and you'll have something that can be power-cycled with no issues. Network hardware is internally often Linux-based and manages to do fine for exactly this reason.
  - lazide 9mo ago
    PCs are orders of magnitude more complex, with a lot more to break. Sounds like a whole lot of work for… what? Assuming the internet connection and AWS work of course. Which they won’t always, then oops.
    - Nextgrid 9mo ago
      If you're relying on AWS you either way have a "PC" to relay communication between AWS and the keycard readers & door latches.
      - lazide 9mo ago
        There are IoT libraries that don’t require that.
    - bluGill 9mo ago
      A large number of embedded micro controllers are just PCs running Yocto linux configured as GP said. You can save money with a $.05 micro controller, but in most cases the development costs to make that entire system work are more than just buying an off the shelf raspberry pi.
onli 9mo ago
What updates? That would be on a local network and have no internet connection, if done right.
- sofixa 9mo ago
  And? That doesn't mean, especially for a system with security impact (like door access), that it should never be updated.
- csomar 9mo ago
  I am guessing the main attraction of such a system is that owners can set the cards remotely and get data about it (ie: who accessed and when)
Telemakhos 9mo ago
You know what else would suffice plenty? Physical keys and mechanical locks. They worked (and still work) without electricity. The tech is mature and well-understood.
- Nextgrid 9mo ago
  The reason for moving away from physical keys is that key management becomes a nightmare; you can't "revoke" a key without changing all the locks which is an expensive operation and requires distributing new keys to everyone else. Electronic access control solves that.
- hoistbypetard 9mo ago
  You might find Matt Blaze's paper on vulnerabilities in master-keyed physical locks interesting: https://eprint.iacr.org/2002/160.pdf https://eprint.iacr.org/2002/160.pdf

lazide 9mo ago

Those devices can be trivially power cycled, and won’t have as many issues with dodgy power. Some PC somewhere with storage is a bigger problem.

Nextgrid 9mo ago
> Some PC somewhere with storage is a bigger problem Both an embedded microcontroller and a PC have storage. The reason you can power-cycle a microcontroller at will is because that storage is read-only and only a specific portion dedicated to state is writable (and the device can be reset if that ever gets corrupted). Use a buildroot/yocto image on the PC with read-only partitions and a separate state partition that the system can rebuild on boot if it gets corrupted and you'll have something that can be power-cycled with no issues. Network hardware is internally often Linux-based and manages to do fine for exactly this reason.
- lazide 9mo ago
  PCs are orders of magnitude more complex, with a lot more to break. Sounds like a whole lot of work for… what? Assuming the internet connection and AWS work of course. Which they won’t always, then oops.
  - Nextgrid 9mo ago
    If you're relying on AWS you either way have a "PC" to relay communication between AWS and the keycard readers & door latches.
    - lazide 9mo ago
      There are IoT libraries that don’t require that.
  - bluGill 9mo ago
    A large number of embedded micro controllers are just PCs running Yocto linux configured as GP said. You can save money with a $.05 micro controller, but in most cases the development costs to make that entire system work are more than just buying an off the shelf raspberry pi.

onli 9mo ago

What updates? That would be on a local network and have no internet connection, if done right.

sofixa 9mo ago
And? That doesn't mean, especially for a system with security impact (like door access), that it should never be updated.
csomar 9mo ago
I am guessing the main attraction of such a system is that owners can set the cards remotely and get data about it (ie: who accessed and when)

Telemakhos 9mo ago

You know what else would suffice plenty? Physical keys and mechanical locks. They worked (and still work) without electricity. The tech is mature and well-understood.

Nextgrid 9mo ago
The reason for moving away from physical keys is that key management becomes a nightmare; you can't "revoke" a key without changing all the locks which is an expensive operation and requires distributing new keys to everyone else. Electronic access control solves that.
hoistbypetard 9mo ago
You might find Matt Blaze's paper on vulnerabilities in master-keyed physical locks interesting: https://eprint.iacr.org/2002/160.pdf https://eprint.iacr.org/2002/160.pdf