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Google posted another blog on how they built the new Find My Device network: https://security.googleblog.com/2024/04/find-my-device-network-security-privacy-pro

Google posted another blog on how they built the new Find My Device network: https://security.googleblog.com/2024/04/find-my-device-network-security-privacy-protections.html https://security.googleblog.com/2024/04/find-my-device-netwo...

ryukoposting 3y ago
As a chronic loser of keys and wallets, I recognize the user need here. However, this is a prime example of a piece of software that can only be trusted when an open-source implementation is provided. Google and their customers don't have much to gain through a proprietary implementation. If anything, open-sourcing Find My Device Network would allow third party devices to join the network, enhancing its value to Google's customers. Google emphasizes ad nauseum that this system is extremely private and secure, so third party implementations shouldn't be cause for worry. Governments and various potentially dangerous organizations stand to benefit greatly from a closed implementation for reasons that hardly need explaining. Google makes a lot of lofty claims about E2EE and privacy considerations in that blog post, I'd just like to see them prove it.
- phkahler 3y ago
  Would an open source version allow anyone to track anyone? The ultimate stalker app...
  - cookiengineer 3y ago
    > Would an open source version allow anyone to track anyone? The ultimate stalker app... An open source version would make absolute no difference on what is trackable. That's the point: transparency is necessary with critical data like this.
    - ssl-3 3y ago
      Open-source software would allow us to see how that published software handles our data, but it would not allow us to see how the cumulative sum of that data is handled after it is passed over to a central body. Unless, of course: That centralized data store were also open -- perhaps even by using something like DNS -- but then, anyone of sufficient skill would be able to craft an application to see where others' things are. (Unless... E2E encryption for location data, so it can only be understood by those who generate it? Hmm.)
      - cookiengineer 3y ago
        An open source backend that requires end to end encryption on a per-user-storage basis, while not sharing those keys in the open source client (reference implementation) could effectively prevent third parties from seeing the data. Something like shamir's secret sharing with split up keys effectively making the encrypted data useless, or based on time frames so you can only track the last "epoche" (like the last 24 hours, maybe?) similar to how HOTP/TOTP works could work nicely I'd imagine. At Tholian (my company) we're using team based keys where at least 2 of x keys (the elected lead and co lead) in the team must co-sign a data changing action. It's peer to peer, meaning those peers can find each other and co-sign this without our servers having to store any transaction queue that could be compromised. This way we prevent abuse, and if the feds come knocking on our doors, our users stay protected because without those keys we cannot see what's going on in any of the registered teams. That's how I think it should be like, for any web service that supposedly keeps their privacy promises. If they don't do this, their promises were likely lies and once the root keys or the databases are compromised there's no turning back. Looking at you, cross-tenant keys at Azure. Everyone knows you were and are still lying about the security aspects.
- mikae1 3y ago
  > this is a prime example of a piece of software that can only be trusted when an open-source implementation is provided. Try FMD. https://f-droid.org/packages/de.nulide.findmydevice/ https://f-droid.org/packages/de.nulide.findmydevice/
  - md_ 3y ago
    But that doesn't use the "find my device" netowrk. I think the parent wasn't saying, "I want an app that continually reports its location to my server so I can monitor my phone's location." Indeed, that's fairly trivial to build, but is useless if, say, your phone doesn't have internet access (like, someone turns it off or it runs out of battery). The thing Google is announcing here is like the Apple "find my" network--it seems to allow you to use other people's devices to find your lost device simply based on a BLE ping. That is something that is hard to build by yourself, and would benefit greatly from an industry-wide standard (more peer devices reporting locations!).
    - ranguna 3y ago
      > your phone doesn't have internet access > simply based on a BLE ping What if they disable Bluetooth? The linked open source find my device app uses cell network to both receive commands and for location.
      - md_ 3y ago
        On Apple's devices, you cannot disable that BLE broadcast. The same is true on the Pixel 8: https://www.theverge.com/2024/4/8/24123909/google-pixel-8-pro-offline-dead-battery-location-finding https://www.theverge.com/2024/4/8/24123909/google-pixel-8-pr.... That's the whole point of this design, and fundamentally different than just having some app ping a server once in a while so long as it has network access.
        extraduder_ire 3y ago
        Even if you turn on airplane mode on the device?
- KennyBlanken 3y ago
  Apple extensively describes how "Find My" works: https://support.apple.com/guide/security/find-my-security-sec6cbc80fd0/web https://support.apple.com/guide/security/find-my-security-se...
- deleted 3y ago
  [deleted]
- rickdeckard 3y ago
  Beside of open-source, this whole use-case should be built as an industry standard, not as a ammunition for an adjacent platform war. With these few huge tech-companies, the industry has lost its natural "feature" that required competing players to work together and form an Alliance/SIG to make really big things happen. Instead, the really big companies are happy to take the fruits from that time (Wi-Fi, Bluetooth, NFC,...) and build something proprietary on top instead of contributing back to it...
  - ryukoposting 3y ago
    Open standards are still a very common thing. Google and Apple themselves cooperated in development of Matter... then failed to address the key-sharing issue that facilitates vendor lock-in on Matter... so yeah, uhh... never mind.
    - rickdeckard 3y ago
      Yeah, a bad example on many levels. It also took them almost a DECADE to acknowledge that they should work together on this topic, and STILL they don't fully acknowledge that. I wonder how long it will take for them to complete the journey on NOT cooperating on messaging, by butchering the RCS-specification in secrecy...
- sirsinsalot 3y ago
  Governments already have the means to position your phone, all the time, whenever they wish. They don't need google for that. It's built right into the phone network.

ryukoposting 3y ago

As a chronic loser of keys and wallets, I recognize the user need here. However, this is a prime example of a piece of software that can only be trusted when an open-source implementation is provided. Google and their customers don't have much to gain through a proprietary implementation. If anything, open-sourcing Find My Device Network would allow third party devices to join the network, enhancing its value to Google's customers. Google emphasizes ad nauseum that this system is extremely private and secure, so third party implementations shouldn't be cause for worry. Governments and various potentially dangerous organizations stand to benefit greatly from a closed implementation for reasons that hardly need explaining. Google makes a lot of lofty claims about E2EE and privacy considerations in that blog post, I'd just like to see them prove it.

phkahler 3y ago
Would an open source version allow anyone to track anyone? The ultimate stalker app...
- cookiengineer 3y ago
  > Would an open source version allow anyone to track anyone? The ultimate stalker app... An open source version would make absolute no difference on what is trackable. That's the point: transparency is necessary with critical data like this.
  - ssl-3 3y ago
    Open-source software would allow us to see how that published software handles our data, but it would not allow us to see how the cumulative sum of that data is handled after it is passed over to a central body. Unless, of course: That centralized data store were also open -- perhaps even by using something like DNS -- but then, anyone of sufficient skill would be able to craft an application to see where others' things are. (Unless... E2E encryption for location data, so it can only be understood by those who generate it? Hmm.)
    - cookiengineer 3y ago
      An open source backend that requires end to end encryption on a per-user-storage basis, while not sharing those keys in the open source client (reference implementation) could effectively prevent third parties from seeing the data. Something like shamir's secret sharing with split up keys effectively making the encrypted data useless, or based on time frames so you can only track the last "epoche" (like the last 24 hours, maybe?) similar to how HOTP/TOTP works could work nicely I'd imagine. At Tholian (my company) we're using team based keys where at least 2 of x keys (the elected lead and co lead) in the team must co-sign a data changing action. It's peer to peer, meaning those peers can find each other and co-sign this without our servers having to store any transaction queue that could be compromised. This way we prevent abuse, and if the feds come knocking on our doors, our users stay protected because without those keys we cannot see what's going on in any of the registered teams. That's how I think it should be like, for any web service that supposedly keeps their privacy promises. If they don't do this, their promises were likely lies and once the root keys or the databases are compromised there's no turning back. Looking at you, cross-tenant keys at Azure. Everyone knows you were and are still lying about the security aspects.
mikae1 3y ago
> this is a prime example of a piece of software that can only be trusted when an open-source implementation is provided. Try FMD. https://f-droid.org/packages/de.nulide.findmydevice/ https://f-droid.org/packages/de.nulide.findmydevice/
- md_ 3y ago
  But that doesn't use the "find my device" netowrk. I think the parent wasn't saying, "I want an app that continually reports its location to my server so I can monitor my phone's location." Indeed, that's fairly trivial to build, but is useless if, say, your phone doesn't have internet access (like, someone turns it off or it runs out of battery). The thing Google is announcing here is like the Apple "find my" network--it seems to allow you to use other people's devices to find your lost device simply based on a BLE ping. That is something that is hard to build by yourself, and would benefit greatly from an industry-wide standard (more peer devices reporting locations!).
  - ranguna 3y ago
    > your phone doesn't have internet access > simply based on a BLE ping What if they disable Bluetooth? The linked open source find my device app uses cell network to both receive commands and for location.
    - md_ 3y ago
      On Apple's devices, you cannot disable that BLE broadcast. The same is true on the Pixel 8: https://www.theverge.com/2024/4/8/24123909/google-pixel-8-pro-offline-dead-battery-location-finding https://www.theverge.com/2024/4/8/24123909/google-pixel-8-pr.... That's the whole point of this design, and fundamentally different than just having some app ping a server once in a while so long as it has network access.
      - extraduder_ire 3y ago
        Even if you turn on airplane mode on the device?
KennyBlanken 3y ago
Apple extensively describes how "Find My" works: https://support.apple.com/guide/security/find-my-security-sec6cbc80fd0/web https://support.apple.com/guide/security/find-my-security-se...
deleted 3y ago
[deleted]
rickdeckard 3y ago
Beside of open-source, this whole use-case should be built as an industry standard, not as a ammunition for an adjacent platform war. With these few huge tech-companies, the industry has lost its natural "feature" that required competing players to work together and form an Alliance/SIG to make really big things happen. Instead, the really big companies are happy to take the fruits from that time (Wi-Fi, Bluetooth, NFC,...) and build something proprietary on top instead of contributing back to it...
- ryukoposting 3y ago
  Open standards are still a very common thing. Google and Apple themselves cooperated in development of Matter... then failed to address the key-sharing issue that facilitates vendor lock-in on Matter... so yeah, uhh... never mind.
  - rickdeckard 3y ago
    Yeah, a bad example on many levels. It also took them almost a DECADE to acknowledge that they should work together on this topic, and STILL they don't fully acknowledge that. I wonder how long it will take for them to complete the journey on NOT cooperating on messaging, by butchering the RCS-specification in secrecy...
sirsinsalot 3y ago
Governments already have the means to position your phone, all the time, whenever they wish. They don't need google for that. It's built right into the phone network.