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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 ar

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.

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.