7 ms·

The whole point of Signal is not having to trust them because the protocol is open source and peer-reviewed.

by lima 3y ago

thx-2718 3y ago
Yeah but have you viewed it? I haven't. Also what about iPhone blobs or similar? I'm actually curious here as to what we can & can't prove as to being 'secure'.
- lima 3y ago
  There have been a number of third party audits and lots of academic research: https://community.signalusers.org/t/overview-of-third-party-security-audits/13243 https://community.signalusers.org/t/overview-of-third-party-...
bboygravity 3y ago
Yeah, but the client and/or server are closed source aren't they? AFAIK Signal server source code nor servers themselves are audited. So that means all bets are off: it's entirely possible to implement a perfect peer reviewed protocol in a client and/or server full of backdoors that entirely bypasses the protocol deliberately?
- lima 3y ago
  Clients and server are open source: https://github.com/signalapp https://github.com/signalapp The protocol does not trust the server. Android has reproducible builds, iOS doesn't.
  - c00lio 3y ago
    For certain things in signal you need to trust the server hardware and suspicious technologies like SGX. SGX is a prime target for a NSA backdoor. That some upper-layer software there is open source (with lots of caveats, e.g. you cannot verify which server version is really running and signal has a history of lagging behind on publishing their "open source" version of the server code) is a distraction at best.
    - jruohonen 3y ago
      Don't forget side-channels in SGX.
    - _kbh_ 3y ago
      > For certain things in signal you need to trust the server hardware and suspicious technologies like SGX. SGX is a prime target for a NSA backdoor. That some upper-layer software there is open source (with lots of caveats, e.g. you cannot verify which server version is really running and signal has a history of lagging behind on publishing their "open source" version of the server code) is a distraction at best. Before you worry about super expensive hard to remove hardware bugs, you should worry far more about the software running on that hardware. It is much more likely that theres bugs in the software than the hardware.
      - c00lio 3y ago
        Yes, of course you are right. My comment was meant more along the lines of "even if the software were ultimately trustworthy because of open source, thousand eyes, careful development and fairy dust, those hardware problems would still be a way in".
    - upofadown 3y ago
      Those "certain things" have nothing to do with message security. The SGX thing was an idea intended to provide a bit better protection against metadata leakage about who was talking to who. It turned out that there were other ways to get that sort of metadata. Does Signal even use the SGX stuff anymore?
      - c4mpute 3y ago
        Signal backup encryption works by trusting SGX. If you cannot trust SGX, you have to assume the attacker can decrypt your signal backups, of course including all media and messages.
    - deleted 3y ago
      [deleted]
- msm_ 3y ago
  >So that means all bets are off: it's entirely possible to implement a perfect peer reviewed protocol in a client and/or server full of backdoors that entirely bypasses the protocol deliberately? No, that's not how cryptography works. Signal clients don't trust the servers, and it's entirely possible to review the client protocol and make sure that malicious server can't learn anything about the communication (except the dreaded metadata - who talks to whom). That's the point of E2E encryption.
c00lio 3y ago
Doesn't matter at all. If your adversary is the CIA, you cannot trust your mobile phone OS, firmware and drivers not to read and report your memory contents.
- matheusmoreira 3y ago
  I used to think that as well but IOMMU is a thing now. Read strcat's posts, they're really informative. He's the developer of GrapheneOS. https://news.ycombinator.com/threads?id=strcat https://news.ycombinator.com/threads?id=strcat
  - c00lio 3y ago
    Your IOMMU needs to be programmed, just like your MMU. Programming is provided by the OS and driver. Early IOMMU configuration is provided by the firmware. Check mate.
    - matheusmoreira 3y ago
      https://news.ycombinator.com/item?id=20151431 https://news.ycombinator.com/item?id=20151431 > It can't improve the security of firmware directly, but it can certainly improve the isolation of it by auditing and improving IOMMU configuration
  - pgeorgi 3y ago
    The IOMMU that is subservient to the cell modem, where the latter runs code of unknown provenance with the ability for ad-hoc, targeted updates over the network?
    - matheusmoreira 3y ago
      Isn't the modem one of the things isolated by the IOMMU? How is it subservient to it?
- fsflover 3y ago
  What if they all are FLOSS or isolated from the OS like on Linux phones?

The whole point of Signal is not having to trust them because the protocol is open source and peer-reviewed.

by lima 3y ago

The whole point of Signal is not having to trust them because the protocol is open source and peer-reviewed.

Yeah but have you viewed it? I haven't. Also what about iPhone blobs or similar? I'm actually curious here as to what we can & can't prove as to being 'secure'.

lima 3y ago
There have been a number of third party audits and lots of academic research: https://community.signalusers.org/t/overview-of-third-party-security-audits/13243 https://community.signalusers.org/t/overview-of-third-party-...

bboygravity 3y ago

Yeah, but the client and/or server are closed source aren't they? AFAIK Signal server source code nor servers themselves are audited. So that means all bets are off: it's entirely possible to implement a perfect peer reviewed protocol in a client and/or server full of backdoors that entirely bypasses the protocol deliberately?

lima 3y ago
Clients and server are open source: https://github.com/signalapp https://github.com/signalapp The protocol does not trust the server. Android has reproducible builds, iOS doesn't.
- c00lio 3y ago
  For certain things in signal you need to trust the server hardware and suspicious technologies like SGX. SGX is a prime target for a NSA backdoor. That some upper-layer software there is open source (with lots of caveats, e.g. you cannot verify which server version is really running and signal has a history of lagging behind on publishing their "open source" version of the server code) is a distraction at best.
  - jruohonen 3y ago
    Don't forget side-channels in SGX.
  - _kbh_ 3y ago
    > For certain things in signal you need to trust the server hardware and suspicious technologies like SGX. SGX is a prime target for a NSA backdoor. That some upper-layer software there is open source (with lots of caveats, e.g. you cannot verify which server version is really running and signal has a history of lagging behind on publishing their "open source" version of the server code) is a distraction at best. Before you worry about super expensive hard to remove hardware bugs, you should worry far more about the software running on that hardware. It is much more likely that theres bugs in the software than the hardware.
    - c00lio 3y ago
      Yes, of course you are right. My comment was meant more along the lines of "even if the software were ultimately trustworthy because of open source, thousand eyes, careful development and fairy dust, those hardware problems would still be a way in".
  - upofadown 3y ago
    Those "certain things" have nothing to do with message security. The SGX thing was an idea intended to provide a bit better protection against metadata leakage about who was talking to who. It turned out that there were other ways to get that sort of metadata. Does Signal even use the SGX stuff anymore?
    - c4mpute 3y ago
      Signal backup encryption works by trusting SGX. If you cannot trust SGX, you have to assume the attacker can decrypt your signal backups, of course including all media and messages.
  - deleted 3y ago
    [deleted]
msm_ 3y ago
>So that means all bets are off: it's entirely possible to implement a perfect peer reviewed protocol in a client and/or server full of backdoors that entirely bypasses the protocol deliberately? No, that's not how cryptography works. Signal clients don't trust the servers, and it's entirely possible to review the client protocol and make sure that malicious server can't learn anything about the communication (except the dreaded metadata - who talks to whom). That's the point of E2E encryption.

c00lio 3y ago

Doesn't matter at all. If your adversary is the CIA, you cannot trust your mobile phone OS, firmware and drivers not to read and report your memory contents.

matheusmoreira 3y ago
I used to think that as well but IOMMU is a thing now. Read strcat's posts, they're really informative. He's the developer of GrapheneOS. https://news.ycombinator.com/threads?id=strcat https://news.ycombinator.com/threads?id=strcat
- c00lio 3y ago
  Your IOMMU needs to be programmed, just like your MMU. Programming is provided by the OS and driver. Early IOMMU configuration is provided by the firmware. Check mate.
  - matheusmoreira 3y ago
    https://news.ycombinator.com/item?id=20151431 https://news.ycombinator.com/item?id=20151431 > It can't improve the security of firmware directly, but it can certainly improve the isolation of it by auditing and improving IOMMU configuration
- pgeorgi 3y ago
  The IOMMU that is subservient to the cell modem, where the latter runs code of unknown provenance with the ability for ad-hoc, targeted updates over the network?
  - matheusmoreira 3y ago
    Isn't the modem one of the things isolated by the IOMMU? How is it subservient to it?
fsflover 3y ago
What if they all are FLOSS or isolated from the OS like on Linux phones?